Big Trouble for Cancun and the Gulf

In math and science, Delta is used to reference change. Using that definition, Hurricane Delta has been aptly named, as it has been changing by the minute.

Hurricane Delta has rapidly intensified into a Category 4 Hurricane. Loop provided by NOAA.

Tropical Depression 26 developed late Sunday night south of Jamaica. Just 36 hours later, the system has become Hurricane Delta, a Category 4 storm with maximum sustained winds near 140 mph. While rapid intensification was always a possibility since the storm was sitting in the northwestern Caribbean over some of the warmest waters of the entire Atlantic Basin, nobody expected it to become this powerful this quickly, and it may not be done yet.

As of 2pm EDT Tuesday, Delta was centered about 260 miles east-southeast of Cozumel, Mexico, moving toward the west-northwest at 16 mph. Hurricane Warnings are in effect for parts of the Yucatan, including the resort locations of Cancun and Cozumel. Tropical Storm Warnings are also in effect for parts of the Yucatan and western Cuba.

Forecast track for Hurricane Delta.

Delta is expected to move across the northeastern Yucatan on Wednesday as a Category 4 storm, passing close to or over Cozumel and Cancun. Likely impacts include a storm surge of 6-12 feet, wind gusts in excess of 100mph, and rainfall totals of 3-6 inches and locally heavier will produce flooding and mudslides. The only saving grace is that Delta should be moving along fairly quickly, so that will limit the amount of time that hurricane conditions are expected.

Delta will produce heavy rain across the Yucatan and western Cuba. Image provided by WeatherBell.

Once Delta emerges in the southern Gulf of Mexico, it should eventually start to turn more toward the northwest and then north. When that turn occurs will be important for determining where landfall will happen. Most of the models are currently clustered in central or western Louisiana, with a timeframe of late Friday night or early Saturday. This is the same area that was battered by Hurricane Laura several weeks ago. However, this can, and probably will change a little over the next few days.

While the models are clustered together, there is still uncertainty as to where land will occur. Image provided by Tomer Burg.

As far as intensity, Delta should weaken a little as it moves over the Yucatan on Wednesday, but then strengthen again as it moves back over the Gulf of Mexico. The recent trend has been for storms to continue to intensify up until landfall in the Gulf, but that does not look like it will be the case with Delta. For one, some wind shear will start to impact the system as it moves across the central and northern Gulf, but water temperatures closer to the Gulf Coast has dropped recently thanks to a series of cold front moving into the region. Delta should still be a formidable storm, but it likely won’t be a Category 4 at landfall along the Gulf Coast.

Water temperatures in the northern Gulf of Mexico have dropped a few degrees recently. Image provided by Tropical Tidbits.

Meanwhile, in the Pacific Ocean, Tropical Storm Marie continues to wind down and should dissipate over open water in the next 12-24 hours. However, Tropical Storm Norbert has formed off the southwestern coast of Mexico. Norbert is centered about 365 miles south-southwest of Manzanillo, Mexico, and has maximum sustained winds near 45 mph. Norbert is expected to meander around over open water, with some strengthening possible in the next few days.

Tropical Storm Norbert is not a threat to land. Image provided by the National Hurricane Center.

Much farther to the west, Tropical Storm Chan-Hom could become a threat to parts of southwestern and southern Japan late this week. Chan-Hom currently has maximum sustained winds near 65 mph, but strengthening is likely, and it could become a typhoon in the next day or two. A northwestward track towards the Ryukyu Islands will continue for the next day or two, before the system starts to recurve towards the north and eventually northeast. When that recurve takes place will determine what, if any, impacts, the system has on southern Japan. Right now, it looks like heavy rain will be the biggest threat, but obviously, wind could become a factor, depending on the actual track.

Forecast track for Tropical Storm Chan-Hom. Image provided by the Japan Meteorological Agency.

Tropical Update: Naming Thunderstorms Again

A quick look at a map of the tropics shows that they remain active with four “named” storms out there. A deeper look shows that some of the storms aren’t as bad as they sound.

There are still several areas to watch in the Atlantic. Image provided by the Canadian Hurricane Center.

With the formation of Tropical Storm Beta in the western Gulf of Mexico, three “Tropical Storms” have formed on the same day in the Atlantic for the only the second time ever. Of course, the problem is, at least one of those storms should not have been named. In fact, it doesn’t even show up on the map above which shows the entire “tropical” Atlantic basin.

We’ll start with the most egregious system – Subtropical Storm Alpha. It formed just off the coast of Portugal this afternoon. It’s a cold-core storm, which means that it isn’t tropical. However, the National Hurricane Center claimed that it had acquired enough characteristics to become classified as “subtropical.” We claim that they’re padding the stats to break records, and we know that numerous other meteorologists think the same thing. As you can see on the satellite loop below, the center of the storm is already inland over Portugal. Monte Real Air Base along the coast of Portugal reported sustained winds of 36 mph with a gusts to 55 mph as the storm moved through. Winds only gusted to 20 mph or higher for 3 hours in that location. The storm will move into Spain and then dissipate in the next 12-24 hours.

This is a named storm? Loop provided by Tropical Tidbits.

Next up is Tropical Storm Wilfred. Wilfred formed this morning over the central Atlantic. As of late Friday afternoon, it was centered about 735 miles west-southwest of the Cabo Verde Islands, moving toward the west-northwest at 18 mph. Maximum sustained winds were estimated to be near 40 mph. Most of the models aren’t bullish on the future of Wilfred, though the Hurricane Center thinks it may strengthen a little over the next 24 hours, but after that, conditions will be even less favorable for the system, and it will likely weaken. It will probably dissipate over open water late this weekend or early next week. It is not a threat to land.

Forecast track for Tropical Storm Wilfred. Image provided by the National Hurricane Center.

In the western Gulf of Mexico, Tropical Depression 22 has become Tropical Storm Beta. As of late Friday afternoon, it was centered about 180 miles east-southeast of the Rio Grande, moving toward the north-northeast at 9 mph. Maximum sustained winds have increased to near 40 mph. There are no watches or warnings in effect for the coast of Mexico or Texas yet, but some will likely be issued tonight or early Saturday.

Model forecasts for the track of Tropical Storm Beta. Image provided by WeatherBell.

Beta is forecast to continue to strengthen over the weekend as wind shear decreases, and it could become a hurricane before the end of the weekend. As a ridge of high pressure builds in to the north, the storm should turn more towards the west, heading towards the Texas Coast. By late in the weekend, things get tricky. Another trough of low pressure will start to move into the nation’s midsection, turning Beta back towards the north and eventually northeast. The question is, when does that turn occur? Most of the models show it happening before the storm can get to the Texas coast, then it would likely parallel the coast, and possibly make landfall near the Texas/Louisiana border towards mid-week. This is the same area that was just devastated by Hurricane Laura a few weeks ago. Of course, a later turn would allow it to make landfall along the southern or south-central Texas coast, then head across inland portions of coastal Texas in a weakened state. Either way, very heavy rain is likely across parts of the southeastern Texas and into western Louisiana over the next 5-7 days.

Flooding is likely along the Texas coast and into southwestern Louisiana over the next week or so due to very heavy rainfall. Image provided by Weathermodels.com

Finally, we get to the strongest storm of the bunch – Hurricane Teddy. As of late Friday afternoon, Teddy was centered about 800 miles southeast of Bermuda, moving toward the northwest at 14 mph. Maximum sustained winds have decreased to near 125 mph. Teddy will remain a formidable storm through the weekend, but some gradual weakening is expected. A turn more toward the north is likely, which should keep Teddy about 100-150 miles east of Bermuda late this weekend. A Tropical Storm Watch has been issued for Bermuda as a precaution, but the most significant weather with the storm will stay well to the east.

Forecast track for Hurricane Teddy. Image provided by the National Hurricane Center.

Once it is past Bermuda, Teddy will continue northward while weakening, but it also will start to transition into an extratropical storm. Although it will likely no longer be tropical, it will still bring strong winds and heavy rain to parts of Nova Scotia and Prince Edward Island when it moves across these areas Tuesday into Wednesday. Wind gusts of up to 80 mph are possible along the Atlantic coast of Nova Scotia, with gusts to 40-60 mph across the remainder of the region. Rainfall totals of 2-5 inches may result in some localized flooding.

Teddy may produce strong winds across Atlantic Canada by the middle of next week. Image provided by WeatherBell.

Elsewhere, there are two other areas of note in the Atlantic. The first one is the extratropical remains of former Hurricane Paulette. This system will drift southward west of the Azores over the next few days, and as it moves over some warmer water, it could reacquire some tropical characteristics. There is also another tropical wave that will roll off the west coast of Africa on Saturday. Conditions may be favorable for some slow development as it makes its way across the Atlantic over the next week or so.

Weekend Outlook: September 18-21, 2020

Astronomical fall officially begins Tuesday morning at 9:31am. As far as the weather is concerned, fall is going to start tomorrow.

Temperatures are going to turn much cooler, but we’re still not expecting much, if any, rain for the next several days, so our drought situation will continue to get worse. A cold front will move across the region tonight, but it will be starved for moisture, so aside from a few very widely scattered showers, we’re not expecting any rain for most of us. There may be a few appreciable showers along the South Coast and across the Cape, but for the rest of us, you’ll probably be able to count the number of raindrops that fall on one hand.

Little to no rainfall is expected through Monday. Image provided by Weathermodels.com

After that, high pressure starts to build in behind the front on Friday and remains with us right through the weekend. This will give us plenty of sunshine for Saturday, Sunday, and Monday, but it will remain on the cool side. Some places may not even reach 60 during the afternoons. What about at night? If you’ve got some plants outside, or still growing in the garden, it’s time to bring them inside. There’s a good shot at the first frost for portions of the region. Welcome to Autumn.

Saturday morning looks quite cool, but Sunday morning could be a few degrees cooler. Image provided by WeatherBell.

Finally, we’ll briefly talk about the tropics, though we’re expecting to write a much more detailed post about them tomorrow. What’s left of Sally will bring heavy rain to the Carolinas today, then move offshore, sending some clouds our way tonight and early Friday, but the rain should stay to the south. A disturbance in the western Gulf of Mexico may become a Tropical Depression later today or tomorrow. What impact it has on Mexico and/or Texas remains to be seen. Tropical Depression Vicky should dissipate in the Central Atlantic today or tomorrow. Then there’s Hurricane Teddy. Teddy is going to become a pretty powerful storm in the next day or two. The current track brings it very close to Bermuda early Monday. Bermuda just got hit hard by Paulette, and here were are talking about another hurricane just a week later. Beyond that, Teddy likely heads northward, and could impact parts of Nova Scotia towards mid-week unless it hooks more quickly and heads out to sea. Now, you may have heard some of the media talking yesterday about the potential for Teddy to head our way. This is because one model (which has performed very poorly for several months now) showed a track that brought the storm closer, or even made landfall in Maine. In fact, one unnamed Boston TV meteorologist went so far as to show a map based on this model with a wind forecast for the region for next Tuesday (we can think of several words to describe this, but we’ll settle for STUPID). This is the equivalent of showing a model forecast snowfall map on Wednesday for a storm that one model shows might hit us next Tuesday. (Wait, they already do that too) The odds of Teddy impacting our area are extremely low (maybe not zero, but close enough). We long for the days when our local TV meteorologists just came on and provided a weather forecast for the next 3-5 days, and didn’t try and hype up everything.

There are still three named storms out there, though two of them are now tropical depression. Image provided by the Canadian Hurricane Centre.

Thursday night: Plenty of clouds, a few torrential sprinkles are possible, especially near the South Coast. Low 50-57.

Friday: Morning clouds, maybe even another raindrop or two across the Cape and the Islands, then skies start to clear out in the afternoon, but it will turn much cooler. High 58-65.

Friday night: Mostly clear and chilly. Low 37-44, a little warmer in the urban areas. A little patchy frost is possible in a few f the colder spots.

Saturday: Sunshine and possibly a few high clouds near the South Coast. High 57-64.

Saturday night: Clear and chilly again. Low 35-42, a little warmer in the urban areas. Some frost is possible, especially in the normally cooler locations.

Sunday: Wall-to-wall sunshine. High 56-63.

Sunday night: Clear skies, still chilly. Low 38-45, a little warmer in the urban areas.

Monday: Sunshine. Nothing but sunshine. High 58-65.

The Peak of Hurricane Season is Here

On average, the peak of hurricane season in the Atlantic is the middle of September. Right on cue, the 2020 season has seen a significant uptick to activity, with three active systems, a fourth likely to form in the next day or so, and possibly a fifth one a few days from now.

Tropical activity is picking up across the Atlantic. Loop provided by NOAA.

The most immediate threat to the US is Tropical Storm Sally. Tropical Depression 19 formed Friday evening just off the coast of southeastern Florida. The center of the system moved inland last night just south of Miami, producing wind gusts of up to 50 mph and heavy rain across south Florida. Early Saturday afternoon, the depression had strengthened into Tropical Storm Sally, and was centered about 35 miles south-southeast of Naples, Florida, moving toward the west at 7 mph. Maximum sustained winds were near 40 mph.

Tropical Storm Sally will head towards the northern Gulf Coast over the next few days. Image provided by Weathermodels.com

Sally is expected to track northwestward across the Gulf while strengthening over the weekend. It could become a hurricane by Monday. Current forecasts call for landfall in either southeastern Louisiana or southern Mississippi by early Tuesday. While storm surge and strong winds will obviously be a threat, rainfall will be the most significant issue residents of the Gulf Coast will need to prepare for. Sally will be a slow-mover, and could even stall out near or just after landfall. We’ve seen plenty of slow-moving tropical systems dump torrential rainfall on places in recent years, and this system will likely do the same. Rainfall totals of 10-20 inches and possibly heavier will create widespread significant flooding.

Torrential rainfall will produce flooding across parts of the Gulf Coast early next week. Image provided by WeatherBell.

Tropical Storm Sally isn’t the only storm that is threatening land at this time. Tropical Storm Paulette is centered about 510 miles southeast of Bermuda this afternoon, moving toward the northwest at 15 mph. It has maximum sustained winds near 70 mph, and it will likely become a hurricane later today or tonight. Additional strengthening is likely over the next couple of days as the storm continues northwestward before turning more toward the north. Unfortunately, that northerly turn will happen right around the time that Paulette reaches Bermuda’s longitude. A hurricane warning has been issued for Bermuda. Current forecasts call for the storm to pass very close to or right over the island late Sunday night and early Monday as a Category 2 hurricane. Paulette will also bring large waves to parts of the East Coast over the next several days, increasing the threat for rip currents at the beaches.

Forecast track for Tropical Storm Paulette. Image provided by the Bermuda Weather Service.

Bermuda is no stranger to tropical cyclones, as they are impacted by one per year on average. Last year, Hurricane Humberto produced wind gusts in excess of 120 mph on the island when the center passed just to the northwest. The last hurricane to make landfall in Bermuda was Hurricane Nicole in 2016. The only other storms to move directly across Bermuda in the 30 years before Nicole were Hurricane Fabian in 2003 and Hurricane Emily in 1987. One element of hurricanes that Bermuda doesn’t have to worry about is storm surge. Because the island is essentially a peak in the middle of the ocean, the water doesn’t have time to build up approaching the coast. The reef surrounding the island also helps to disperse some of the water before it reaches land. Humberto was a Category 3 storm that passed just northwest of the island last year, but only produced a storm surge of 2-3 feet. A similar storm impacting the US could produce a storm surge of 10-15 feet on average.

Forecast track for Tropical Depression Rene. Image provided by the National Hurricane Center.

In the eastern Atlantic, Tropical Depression Rene is slowly weakening this afternoon. It is centered about 1250 miles east of the Lesser Antilles, and maximum sustained winds have decreased to near 35 mph. Rene is expected to remain weak while meandering around in the central Atlantic for the next few days. Conditions won’t be that favorable, and it will likely dissipate over open water by early next week.

In addition to the 3 active systems, there are several other areas being watched for development this afternoon. Image provided by the National Hurricane Center.

Even farther to the east, there are two other systems that are being monitored at this time. The first system is several hundred miles southwest of the Cabo Verde Islands this afternoon. This system will likely become a tropical depression in the next 12-24 hours. It should continue across the Atlantic with some gradual strengthening likely over the next several days. It will not impact any land areas for at least another 5 or 6 days, if at all. Some of the models show the potential for this to become a significant storm, so we’ll keep an eye on it.

Forecast models show the potential for 2 more systems to develop in the eastern Atlantic. Image provided by the University at Albany.

Another area of disturbed weather is crossing the Cabo Verde Islands this afternoon. It will bring squally conditions to the islands today and tonight. There is some potential for this system to develop over the next few days as well. Once it moves past the islands, it will likely not be a threat to any land areas.

Record Heat and Cold, Snowstorms, Droughts, and Tropical Storms – What’s Next?

September is when we start to transition from Summer to Winter, but this September is starting off with a bang.

Intense heat has been common across much of the West for the past few days. Temperatures well over 100 degrees were widespread during Labor Day Weekend, especially across California, with numerous records set. One location, Richmond, on the eastern side of San Francisco Bay, reached 107 degrees Monday afternoon, tying their all-time record, originally set on September 15, 1971. Several other locations set monthly records for September as well. The worst of the heat has passed, but it will remain hot on Tuesday, with highs likely topping 100 across much of interior California and the Desert Southwest, possibly setting a few more records. Temperatures should gradually cool down a little more as we get toward the middle and latter portion of the week.

Another hot day is likely across interior California on Tuesday. Image provided by WeatherBell.

Heat was also common across the Plains and Rocky Mountains over the weekend, but big changes are developing thanks to a strong cold front. Denver set a record high of 97 on Sunday, then reached 93 on Monday. On Tuesday, that 93 will get reversed, with a daytime high closer to 39 (The high for the calendar day will be the 46-degree reading at midnight). On top of that, accumulating snow is likely. Even by Denver standards, this is quite early in the year for snow. Their all-time record for earliest snow is September 3, 1961, but on average Denver doesn’t see its first flakes until October 18. This won’t be the 1st time that Denver hit 90 one day and then had measurable snow the next. On September 12, 1993, Denver recorded a high of 92 degrees, and on September 13, they had 5.4″ of snow.

While a few inches of snow are likely in Denver and onto the adjacent High Plains of eastern Colorado and western Nebraska, heavier snow is likely across the mountains on Colorado and Wyoming. Across the higher elevations, snowfall totals in excess of a foot are likely. While the snow will likely last a while in the mountains, at the “lower” elevations on the Plains, it will disappear quickly. High temperatures in Denver will be back into the 60s by Friday, and near 80 by the end of the weekend.

Heavy snow is likely in the higher elevations of the Rockies. Image provided by the College of DuPage.

While the snow will get a lot of the headlines, the cold air behind the front will be making headlines of its own. The first frost and freeze of the season is likely across parts of the Dakotas, Montana, and northern Minnesota Tuesday and/or Wednesday morning, with lows in the upper 20s and 30s. The cold air will continue to push southward across the Great Plains during the day on Tuesday, with numerous record lows expected Wednesday morning as far south as the Texas Panhandle. The cold air will eventually spread eastward, but will be modified significantly before it reaches the Eastern United States.

Record lows are likely across the Plains and the Rockies Wednesday morning. Image provided by Weathermodels.com

While plenty of (frozen) precipitation is expected across the Rockies, the lack of precipitation is causing problems across the Northeast, specifically New England. Aside from a few showers with a cold front on Thursday, generally dry weather is expected across much of New England this week, and things don’t look that promising for much of next week either. This shouldn’t be a surprise, as precipitation has been generally below to well below normal across the region since the Spring. In some areas, the amount of rain has only been around 50-60% of normal since April 1. Drought conditions have developed across nearly all of New England, and for a good portion of the region, it is now considered a severe drought. What the region needs is a series of systems that can produce moderate rainfall to help alleviate the drought (too much at once won’t help that much), but prospects for that aren’t promising at this time. In fact, rainfall looks to remain below normal for much of the remainder of September.

Drought conditions are worsening across New England. Image provided by the National Drought Mitigation Center.

Meanwhile, as we approach the climatological peak of hurricane season, the Atlantic is once again getting more active. Tropical Storms Paulette and Rene both developed on Monday in the central and eastern Atlantic respectively. Paulette is expected to remain a tropical storm for the next several days while remaining over open water. It is not expected to be a threat to land. Meanwhile, Tropical Storm Rene moved into the Cabo Verde Islands Monday night and early Tuesday, producing heavy rain and gusty winds. It will likely strengthen over the next couple of days, possibly becoming a hurricane later this week. Once it pulls away from the Cabo Verde Islands, it is also expected to remain over open water for much of this week, presenting no additional threat to land.

Satellite loop showing Tropical Storms Paulette and Rene in the central and eastern Atlantic. Loop provided by Tropical Tidbits.

Those systems aren’t the only ones in the Atlantic that are being watched. An area of low pressure a couple of hundred miles west-southwest of Bermuda is expected to drift westward or northwestward over the next day or two. Some development of the system is possible. It may bring some rainfall into parts of the Carolinas and Southeast later this week. The other area that is being watched isn’t immediately apparent right now, as it is still over western Africa. A tropical wave is expected to emerge from the west coast of Africa later this week. Forecast models show the potential for this wave to develop rather quickly once it moves into the Atlantic. It could threaten the Cabo Verde Islands over the weekend.

The peak of hurricane season is during the middle to latter half of September. Given how active this season has been so far, there will likely be more systems developing. There are only 4 names left on this list for this season – Sally, Teddy, Vicky, and Wilfred. Once the list is exhausted, the Greek alphabet is used. This has only happened once before – in 2005. During that season, there were 28 named storms of which 15 became hurricanes.

Laura Bears Down on the Gulf Coast

Hurricane Laura is now a Category 3 hurricane with its sights set on the Gulf Coast.

Hurricane Laura has the appearance of a classic hurricane on satellite this morning. Loop provided by Tropical Tidbits.

As of 11am EDT, Hurricane Laura was centered about 225 miles south-southeast of Lake Charles, Louisiana, moving toward the northwest at 16 mph. Maximum sustained winds have increased to near 125 mph, making Laura a Category 3 Hurricane. A buoy in the central Gulf of Mexico reported sustained winds of 76 mph and a gust to 107mph as the center of Laura passed nearby this morning. Hurricane and Storm Surge Warnings are in effect for portions of the Texas and Louisiana coastline, with Tropical Storm Warnings, Hurricane Watches, and Storm Surge Watches for areas adjacent to the warning areas.

Numerous watches and warnings are in effect associated with Laura. Image provided by the National Hurricane Center.

The forecast for Laura is rather simple at this point. It will continue heading northwest towards a trough of low pressure moving across the nation’s mid-section. Landfall is expected tonight very close to the Texas/Louisiana border. The only question is, how strong will Laura get? Many forecast models bring Laura up to Category 4 intensity before landfall, which would mean sustained winds of 131-155 mph. However, intensity forecasts are notoriously poor. One thing that could limit intensity would be an eyewall replacement cycle. In stronger hurricanes, you’ll get a second eyewall that forms outside the center. That eyewall will eventually start to contract towards the eye, replacing the current eyewall. When this occurs, storms tend to weaken a bit. These are very hard to predict in advance.

Model forecasts for the track of Hurricane Laura. Image provided by the University of Wisconsin.

Laura presents many threats to the Gulf Coast. A storm surge of up to 15-20 feet will inundate coastal areas near and just to the east of where the center makes landfall. This will result in flooding across many of the bayous of southern Louisiana. Strong winds will obviously be a major hazard as well, mainly east of the center. The strong winds will likely penetrate well inland, as the storm will be powerful, though it should start to weaken fairly rapidly once inland.

Storm surge will be a significant threat along the Gulf Coast. Image provided by the National Hurricane Center.

By far, the biggest threat, as it is with most tropical systems, is heavy rain and the freshwater flooding it will produce. Rainfall totals of 10-15 inches and locally heavier are likely across extreme southeast Texas and western Louisiana. Since Laura is moving fairly quickly and not expected to stall out, we shouldn’t see a repeat of the 30-60 inches that Harvey produced in the same area 3 years ago this week.

Laura will produce very heavy rainfall through Friday evening. Image provided by Pivotal Weather.

Farther inland, rainfall totals of 3-6 inches are expected up into Arkansas. As the storm gets caught up in the jet stream and becomes extratropical, it will bring heavy rain to parts of the Ohio Valley and Mid-Atlantic states Friday into Saturday. Once it moves off the coast, it may strengthen a little, and could enhance some of the rain expected across New England and Atlantic Canada this weekend associated with a cold front.

Once Laura moves inland, the Atlantic should remain quiet for the next week or so. Plumes of Saharan Dust continue to move off the west coast of Africa and traverse the Atlantic and Caribbean. The very dry air associated with these plumes inhibits thunderstorm development, which means they also prevent tropical systems from developing.

Plumes of Saharan Dust will make their way across the Atlantic over the next several days. Loop provided by Weathermodels.com

Laura isn’t the only active storm in the tropics right now. This morning two separate tropical depressions have developed in the Eastern Pacific, off the southwestern coast of Mexico. Both are expected to become tropical storms in the next 24-36 hours, but remain relatively weak. Tropical Depression 13-E may bring some heavy rain and gusty winds to southern portions of Baja California late this week, but Tropical Depression 14-E should not impact any land areas.

Typhoon Bavi is expected to make landfall in North Korea this evening. Image provided by the Korean Meteorological Administration.

In the Western Pacific, Typhoon Bavi has maximum sustained winds near 110 mph as it moves into the Yellow Sea. The current forecast calls for the storm to make landfall in western North Korea this evening, then rapidly weaken as it moves inland into extreme northeastern China. As with Laura, strong winds and storm surge will have significant impacts on the region, but rainfall totals of 4-8 inches and locally heavier will result in flooding in many areas.

Gulf Coast Braces for Two Tropical Systems

This will not be a good week to take a vacation down along the Gulf Coast, especially from Louisiana into Texas, and COVID has nothing to do with it.

Tropical Storms Marco (left) and Laura (right) are both heading toward the Gulf Coast. Loop provided by Tropical Tidbits.

Tropical Storm Marco is the more immediate threat. As of 11am EDT Sunday, Marco was centered about 325 miles south-southeast of the mouth of the Mississippi River, moving toward the north-northwest at 14 mph. Maximum sustained winds were near 70 mph. Tropical Storm and Hurricane Watches and Warnings as well as Storm Surge Watches and Warnings are in effect for portions of the northern Gulf Coast.

Marco’s forecast is a bit complicated. The warm waters of the Gulf provide ample fuel for Marco to strengthen, and it could become a hurricane later today. However, as it heads northward, southwesterly shear will increase, which will help weaken the storm. Although hurricane warnings are in effect, Marco could weaken to a tropical storm before making landfall, likely along the Louisiana coast Monday afternoon or evening. Since there is little difference between a strong tropical storm and a weak hurricane, this has little impact on what will actually occur across the region.

Forecast track for Tropical Storm Marco. Image provided by the National Hurricane Center.

Marco will produce strong winds, mainly along the coast, and a storm surge of up to 6 feet will result in flooding along the coast and in the low-lying bayous of southern Louisiana. However, Marco’s biggest threat will be flooding from heavy rainfall. Rainfall totals of 3-6 inches and locally heavier will result in flooding in many areas. This is exacerbated in New Orleans, where much of the city itself is below sea-level and even heavy thunderstorms can produce flooding. We’re not expecting Katrina-level flooding, and the levees shouldn’t be tested too much by this storm, but widespread flooding is likely.

ECMWF model forecast for rainfall through Wednesday morning. Image provided by WeatherBell.

Marco is the initial threat, but Tropical Storm Laura is the more significant threat to the Gulf Coast. As of 11am EDT Sunday, Laura was centered about 95 miles southeast of the eastern tip of Cuba, moving toward the west-northwest at 21 mph. Maximum sustained winds were near 50 mph. Tropical Storm Warnings are in effect for parts of the Dominican Republic, Haiti, Cuba and the Southeastern Bahamas, with Tropical Storm Watches in effect for the Central Bahamas and the Florida Keys.

In the near-term, Laura is expected to traverse the entire length of Cuba for the next day or so, producing heavy rain and gusty winds. Heavy rains will diminish across the Dominican Republic and Haiti today as Laura pulls away.  With the center interacting with land, little strengthening is anticipated for the next 24-36 hours, and some weakening is possible. Once we get to late Monday, things become a bit more complicated.

Forecast track for Tropical Storm Laura. Image provided by the National Hurricane Center.

Laura is expected to move into the southeastern Gulf of Mexico Monday evening as a tropical storm. Once it does, it will find an environment that is favorable for strengthening. Water temperatures are well into the 80s, providing plenty of fuel for the system. (Tropical systems need water warmer than 80F/26C to survive and/or strengthen) A ridge of high pressure will also be building in aloft, resulting in very little wind shear. This is also an area that climatologically favors rapid intensification of tropical systems. Several models show the potential for Laura to quickly become a hurricane and possibly a major hurricane as it moves across the Gulf of Mexico on Tuesday. It should be noted that intensity forecasts for tropical systems, especially from forecast models, have been known to be rather poor.

The track forecast for Laura is also a bit uncertain. The ridge of high pressure building in will help steer Laura more towards the west-northwest. How strong that ridge actually is will help determine how far west Laura moves. While the models were nearly unanimous just 24 hours ago that Laura was heading towards the Central Gulf Coast, they have shifted westward, putting parts of Texas and western Louisiana in the crosshairs. Additional shifts are likely over the next day or two as the models adjust to what is actually going on in the atmosphere. For now, residents of the Gulf Coast from Central Texas to Alabama should keep a close eye on Laura’s progress.

There are no other systems in the Atlantic that are being monitored right now, but we are approaching the peak of Hurricane Season, so that will likely change soon. There are two systems in the Eastern Pacific that may become tropical depressions in the next day or two, and Typhoon Bavi will be a threat to Korea over the next 24-48 hours in the Western Pacific.

Forecast track for Typhoon Bavi. Image provided by the Korean Meteorological Admininstration.

As of 11am EDT, Typhoon Bavi was centered about 600 miles south-southwest of the southwestern South Korea, moving toward the northeast at 9 mph. Maximum sustained winds were near 80 mph. Bavi is expected to turn more toward the north over the next 12-24 hours, with some additional strengthening expected. The current forecast calls for Bavi to move into the Yellow Sea, and pass just west of South Korea, before making landfall in extreme northwestern North Korea, then it will move into extreme northeastern China where it will rapidly weaken. Strong winds and storm surge flooding are likely across the Korean Peninsula over the next few days, with heavy rain likely causing flooding along the Peninsula as well as in northeastern China. Parts of this region have received heavy rain recently, and some flooding has already occurred, so this will exacerbate it in some areas.

Double Trouble in the Tropics

The hype machine is getting cranked up again because we have two tropical systems in or near the Caribbean at the moment.

Tropical Depression 14 is located in the Western Caribbean while Tropical Storm Laura is moving into the Leeward Islands. Loop provided by Tropical Tidbits.

The media is already in a frenzy because some forecast models show both systems becoming hurricanes and moving into the Gulf of Mexico early next week. While this is certainly a possibility, it is far from a lock. As is usually the case, we’ll separate fact from fiction for you.

We’ll start with Tropical Storm Laura, as it is the “stronger” of the two systems at the moment, though you wouldn’t know it from looking at satellite pictures. As of 5pm EDT, Laura was centered about 40 miles east of Antigua with maximum sustained winds near 40 mph, and was moving toward the west at 17 mph. Tropical Storm Warnings are in effect for much of the northeastern Caribbean and Hispaniola, with a Tropical Storm Watch in effect for the southeastern Bahamas and the Turks and Caicos Islands. Laura does not have much thunderstorm activity associated with it, and the 40 mph estimate for winds may be very generous. Antigua has not reported winds higher than 10 mph all day long, though winds have gusted as high as 25 mph on Sint-Maarten.

Track forecasts for Tropical Storm Laura based on the ECMWF Ensemble. Image provided by the University at Albany.

The forecast for Laura is both simple and complicated at the same time. With a large ridge of high pressure over the Atlantic, Laura will continue west-northwestward for the next few days. That’s the simple part. Exactly where the center tracks has huge implications on its intensity. A track near or over Puerto Rico and then near or over Hispaniola and/or Cuba will mean the system remains very weak, if it even survives. However, if the center stays over water, especially if it remains far enough away from land, then it may have a chance to strengthen. The official forecast from the National Hurricane Center calls for it to become a hurricane late Monday or early Tuesday while moving into the southeastern Gulf of Mexico. While this is certainly possible, we’ve got a long way to go before determining how likely this scenario is.

In the short term, we can expect some heavy rain and gusty winds across the northeastern Caribbean and into Puerto Rico and Hispaniola over the next couple of days. Rainfall totals of 3-6 inches and locally heavier will lead to flooding and mudslides.

Heavy rain will produce flooding and mudslides from Puerto Rico into Hispaniola this weekend. Image provided by WeatherBell.

Meanwhile, in the western Caribbean we have Tropical Depression 14. As of 5pm, it was centered about 255 miles southeast of Cozumel, Mexico with maximum sustained winds near 35 mph, and was moving toward the northwest at 13 mph. A Tropical Storm Warning and Hurricane Watch are in effect for the Yucatan Peninsula of Mexico from Punta Herrero to Cancun. The Tropical Storm Warning actually extends along the north coast of the Yucatan to Dzilam.

The depression appeared to have 2 low-level centers this morning based on reconnaissance information, but they have now consolidated into one center. Despite that, the system has been slow to strengthen, despite seemingly favorable conditions with warm waters and low wind shear. The forecast from the National Hurricane Center calls for some strengthening before the storm makes landfall in the northeastern Yucatan Saturday night. Assuming it becomes a Tropical Storm, it will be named Marco.

ECMWF Ensemble forecasts for the track of Tropical Depression 14. Image provided by Weathernerds.org

Once it emerges into the Gulf of Mexico, the questions increase. Will it continue northwestward or bend more toward the west-northwest? This will be determined by how strong the ridge over the Atlantic is. Some models show it building westward into the Gulf, which would send TD 14 (and also TS Laura) on a more west-northwestward track. How strong will TD 14 get? There’s plenty of warm water over the Gulf, but wind shear is forecast to increase, which will limit the strengthening of the system.

The ECMWF model shows up to 50 knots of southwesterly shear in the western Gulf of Mexico Sunday night. That is not conducive for a strengthening tropical system. Image provided by Weathermodels.com

So, despite the media hype of “2 hurricanes in the Gulf at the same time” for early next week, the odds seem to be just as good that we may not have any hurricanes in the Gulf. There could be 2 tropical storms, or maybe 1 hurricane, or maybe only 1 storm. At this point, it is just to early to make that call. The other ridiculous statement we’ve heard is that the storms could collide. This just doesn’t happen. If two storms get close to each other, we get what is called the Fujiwhara Effect. Essentially, they start to rotate around each other. Alternately, if they get close to each other and one is considerably stronger than the other, the circulation around it could create enough wind shear to essentially destroy the weaker of the two storms.

Finally, another tropical wave is approaching the Cabo Verde Islands. It has some potential for development, and will be watched as it crosses the Atlantic over the next several days.

Weekly Outlook: August 3-9, 2020

The forecast for the upcoming week is both complex and simple at the same time.

Barring a surprise, Isaias will almost certainly track to our west. Image provide by Tropical Tidbits.

We start the week off with a hot and humid day today, thanks to high pressure located over the Atlantic (more on that in a bit). Temperatures will get into the upper 80s and 90s across the region this afternoon. When you combine that with dewpoints generally in the 60s, it’ll feel like it’s in the mid 90s during the afternoon. Clouds will quickly start to stream in at night, making for a rather warm and muggy evening.

The heaviest rain from Isaias will stay well to our west. Image provided by Weathermodels.com

As we head into Tuesday, we turn our eyes to the southwest and Tropical Storm Isaias. The combination of a trough of low pressure approaching from the west and that high pressure over the Atlantic will steer Isaias into the Carolinas late tonight or early Tuesday. After that, it will start to quickly move north-northeastward, likely passing west of the region late Tuesday night or early Wednesday. Most of the heavy rain will be located west of the track, but we’ll still have some showers and tropical downpours around here late Tuesday and Tuesday night. The storm should also be weakening and passing far enough to our west to spare us from any significant wind issues. It’ll be breezy, with some gusts to 40 mph or so possible, especially along the South Coast, but overall, it really shouldn’t be too big of a deal. Once again, the hype will be likely worse than the reality.

The potential exists for wind gusts to 50 mph, but they’ll likely be lower. Image provided by WeatherBell.

By Wednesday morning, Isaias is out of here and skies will clear out, with drier air settling in as high pressure builds into the region. That high should remain in place for the rest of the week and into the weekend, with seasonably warm temperatures and comfortable humidity levels.

Dry weather for the latter half of the week will not help with the developing drought. Image provided by the National Drought Mitigation Center.

Monday: Partly to mostly sunny, breezy, and hot. High 86-93.

Monday night: Becoming mostly cloudy with a few showers possible. Low 67-74.

Tuesday: Cloudy and becoming windy with showers likely, some of them may be briefly heavy. High 79-86.

Tuesday night: Mostly cloudy and windy with showers ending, skies may start to clear late at night. Low 67-74.

Wednesday: Becoming partly to mostly sunny. High 81-88.

Thursday: A mix of sun and clouds. High 79-86.

Friday: Partly sunny. High 78-85.

Saturday: Sunshine and a few clouds. High 79-86.

Sunday: Partly to mostly sunny. High 82-89.

Tropical Storm Isaias Nears Florida, Heads for the Carolinas

While crossing the Bahamas on Saturday, Hurricane Isaias weakened to a tropical storm, but it remains a threat to much of the East Coast.

Tropical Storm Isaias continues to spin off the Florida Coast this afternoon. Loop provided by NOAA.

As of 2pm Sunday, Tropical Storm Isaias was centered about 45 miles east-southeast of Vero Beach, Florida, moving toward the north-northwest at 9mph. Maximum sustained winds were near 65 mph, and should remain near that level for the next day or two, with some fluctuations in strength possible. Tropical Storm Warnings are in effect from Jupiter Inlet, Florida to Surf City, North Carolina, with a Tropical Storm Watch north of Surf City to Duck, North Carolina, including Albemarle and Pamlico Sounds. A Storm Surge Watch is in effect from Edisto Beach, South Carolina to Cape Fear, North Carolina.

Isaias moved across the Bahamas as a hurricane late Friday into early Saturday, before weakening to a Tropical Storm Saturday afternoon. The combination of southwesterly wind shear and some dry air due to Saharan Dust contributed to the weakening. Isaias is maintaining its strength this afternoon despite the presence of more wind shear.

Forecast track for Tropical Storm Isaias. Image provided by the National Hurricane Center.

Isaias should continue to head towards the north today, in between a large area of high pressure of the east, and an approaching trough of low pressure from the west. As the trough continues to move towards the East Coast, it will help turn Isaias more towards the north-northeast and eventually northeast. On this track, Isaias will parallel the coast of Florida and Georgia today and tomorrow, then likely make landfall in either South Carolina or North Carolina late Monday night or early Tuesday. Once inland, Isaias will continue northeastward, and although it will weaken a bit, it should maintain some strength as it moves up the coast, as it starts to transition into an extratropical storm.

Storm surge will be a threat along the Carolina coast, near and east of where the center makes landfall. A surge of up to 4 feet above normal tide levels could result in some coastal flooding. Strong winds will also be a threat, mainly east of the storm’s center. Winds have been gusting as high as 50 mph along the Florida coast this afternoon. As it moves northward, some strong winds will be likely across eastern North Carolina as the storm moves inland, and possibly across eastern New England late Tuesday into early Wednesday as the system moves across the Northeast.

Most of the strongest winds should remain offshore. Image provided by WeatherBell.

By far, the biggest threat with Isaias is heavy rainfall and the resulting flooding. Some bands of heavy rain have moved across parts of Florida, and that will continue through tonight. Rainfall totals of 1-3 inches are possible across parts of Florida and Georgia over the next 24-36 hours. As you head north, heavier rain is likely from the Carolinas into the Mid-Atlantic states and the Northeast, mainly along and west of the storm’s track. Rainfall totals of 3-6 inches and locally heavier are likely, which will produce flooding in many areas. The storm’s relatively quick motion will preclude even heavier totals. East of the storm’s track, rainfall will be much lighter, with many places likely seeing less than 1 inch.

Isaias will produce heavy rainfall across much of the East Coast over the next few days. Image provided by WeatherBell.

Elsewhere, we’re keeping an eye on a tropical wave located a few hundred miles east of the Leeward Islands. Conditions could become favorable for it to develop into a tropical depression in a few days. Model forecasts show it heading northwestward, staying north of the Caribbean over the next few days. By mid-week, most forecasts show it stalling out about midway between Bermuda and the Bahamas. It does not look like a threat to any land areas at this time.