Cristobal Threatens the Gulf Coast

After dumping feet of rain on portions of southern Mexico and Central America, Cristobal is now starting to take aim on the Gulf Coast.

Cristobal is become a little better organized this afternoon. Loop provided by NOAA.

Early Friday afternoon, Cristobal had strengthened back into a Tropical Storm and was located about 35 miles south-southeast of Merida, Mexico, moving toward the north at 12 mph. Maximum sustained winds have increased to near 40 mph. Cristobal should continue moving toward the north, with the center of circulation moving back over the Gulf of Mexico later today or tonight. Once that happens, the system should strengthen a bit more.

Cristobal is a bit of a lopsided system right now, with most of the rainfall along with the strongest winds all located east of the center of the storm. While some of the rainfall will eventually rotate around to the western side of the storm, the overall structure of the system likely won’t change much over the weekend. This has important implications that we’ll get to in a little bit.

As Cristobal moves away from Mexico tonight and Saturday, some additional strengthening is expected. The waters of the Gulf are very warm, which will help the storm intensify, but the presence of dry air aloft and some wind shear will act to inhibit significant strengthening. Cristobal should strengthen a bit more on Saturday, but at this time, it does not look like it will become a hurricane before approaching the central Gulf Coast Sunday night.

Model forecasts for the track of Cristobal. Image provided by WeatherBell.

The current forecast calls for Cristobal to make landfall as a tropical storm along the coastline of Louisiana Sunday evening. A Tropical Storm Warning is already in effect for the coast of Mexico from Punta Herrero to Rio Lagartos, where tropical storm conditions are expected into Saturday. A Tropical Storm Watch has been issued from Intracoastal City, Louisiana to the Alabama/Florida border, including Lakes Ponchatrain and Maurepas. A Storm Surge Watch has also been issued from Grand Isle, Louisiana to Ocean Springs, Mississippi, including Lake Borgne, and also along the coast of Florida from Indian Pass to Arepika.

As we mentioned earlier, Cristobal is a bit lopsided, and this should still be the case as the storm moves inland Sunday night. That’s not to say that areas west of the center will escape without issues, but they shouldn’t be as problematic. There will still be some heavy rain, and wind gusts to 30-40 mph, but this isn’t anything the region hasn’t experienced plenty of times before. Near and east of the center are where the problems will become more numerous.

Storm surge of 2-4 feet is expected along parts of the Gulf Coast as Cristobal moves inland. Image provided by the National Hurricane Center.

Cristobal should have sustained winds of 50-60 mph near the center at landfall, but these winds will only be experienced over a small area along the coast. The remainder of the area will likely have sustained winds of 30-40 mph, with some gusts to 50-60 mph. Along the coast, a storm surge of 2-4 feet will result in flooding of some areas, especially the low-lying locations near the Mississippi River entrance. By far, the biggest threat is heavy rain.

GFS forecast for rainfall from Saturday through Tuesday morning across the Gulf Coast, Image provided by WeatherBell.

Rainfall totals of 4-8 inches are expected across a wide area, with isolated totals to 12 inches possible. This will lead to flooding across much of the region. Flood watches have already been issued. Parts of the Gulf Coast have actually been in a drought recently, but too much rain in a short period isn’t a good thing. Once inland, Cristobal should weaken and head northward, bringing heavy rain to parts of the Mississippi Valley and the Great Lakes early next week.

Tropical Depression Three formed in the Bay of Campeche Monday afternoon and strengthened into Tropical Storm Cristobal Tuesday afternoon. It made landfall along the coast of Mexico Wednesday morning, and has been drifting around southeastern Mexico and Guatemala for the past 48 hours. Cristobal has produced torrential rainfall, with 15-25 inches of rain reported across much of the region, resulting in widespread flooding. Another 3-6 inches of rain, possibly more, is expected across this region before the system pulls away over the weekend.

Weekend Outlook: June 4-8, 2020

Lots of changes are coming over the next few days, but overall, we’re not expecting anything too significant.

It is a fantastic early June afternoon across the region. Loop provided by the College of DuPage.

We’ve got a sunny and warm afternoon in progress, with a frontal boundary stalled out to the south and high pressure trying to build in from the north. That front will start to lift northward again tonight, bringing some clouds back in along with the threat for a few showers and possibly a rumble of thunder. It will also bring more humid air back in. This will set up a very warm and humid Friday. A few showers and thunderstorms may pop up during the afternoon, but they’ll be widely scattered, and probably won’t be that strong.

Dewpoints will rise into the upper 60s across the region Friday afternoon. Image provided by WeatherBell.

Saturday could be a different story. It will be another warm and humid day to start, but a cold front will move across the region. This front will likely produce showers and thunderstorms, some of which could be strong, but a lot will depend on the timing of the front. If it moves through in the morning or around midday, we’ll just have some garden-variety showers and thunderstorms in the morning, then we’ll start to dry out in the afternoon. If the front doesn’t move through until mid-to-late afternoon, then the atmosphere may have more time to destabilize, and we’ve got a better shot at some stronger thunderstorms. Right now, we’re leaning towards an earlier passage of the front, but obviously we’ll keep an eye on it. High pressure then builds in for Sunday and Monday with much drier and cooler conditions, though some low clouds may move in from the ocean on Saturday.

Conditions have become abnormally dry across parts of the area, the first step towards a drought. Image provided by the National Drought Mitigation Center.

As for the tropics, Cristobal is still over land, southern Mexico to be specific, and has weakened to a tropical depression. It will continue to produce heavy rain and flooding across the area, but the current forecast calls for it to move back over water on Friday or Saturday, and head northward while strengthening. It will become an increasing threat to the central Gulf Coast by late in the weekend. We’ll have a full blog post about Cristobal and the threat to the Gulf Coast tomorrow.

Current Forecast for Tropical Depression Cristobal. Image provided by the National Hurricane Center.

Thursday night: Becoming mostly cloudy with a chance for some showers, possibly a thunderstorm. Low 60-67.

Friday: More clouds than sunshine, showers and thunderstorms are possible during the afternoon. High 79-86.

Friday night: Partly to mostly cloudy, some lingering showers along the south coast. Low 62-69.

Saturday: A mix of sunshine and clouds, chance for some more showers and thunderstorms. High 79-86, cooler along the south coast.

Saturday night: Becoming mostly clear and less humid. Low 53-60.

Sunday: Intervals of clouds and sunshine. High 66-73, coolest along the coast.

Sunday night: Becoming mostly clear. Low 49-56.

Monday: Sun, sun, and more sun. High 72-79, a little cooler along the coast.

Tropical Depression Three Develops

Yesterday was the first day of the official hurricane season in the Atlantic. It also saw the formation of the third system of the season.

Tropical Depression Three developed in the Bay of Campeche Monday afternoon. Loop provided by NOAA.

Tropical Depression Three developed in the Bay of Campeche Monday afternoon. The system is the remnants of Eastern Pacific Tropical Storm Amanda, which moved into southern Guatemala on Saturday. It has been producing heavy rainfall across portions of Guatemala, El Salvador, Honduras, and southeastern Mexico since Friday, and that will likely continue for another couple of days as the system mills around in the Bay of Campeche. As of early Tuesday morning, the system was centered about 100 miles west of Campeche, Mexico with maximum sustained winds near 35 mph, and was moving toward the west at 5mph. Conditions are favorable for additional strengthening, and the system could be upgraded to Tropical Storm Cristobal on Tuesday. Since this seems likely, the government of Mexico has issued a Tropical Storm Warning from Campeche to Puerto de Veracruz.

Rainfall totals of 10-20 inches and locally heavier will likely produce flooding and mudslides across the region this week. Image provided by WeatherBell.

This season is the 6th one since 1851 that has seen 2 named storms form before June 1 (1887, 1908, 1951, 2012, and 2016 are the others). If this system is named in the next few days, it will be the earliest we’ve ever had a “C” storm in the Atlantic. The previous record was June 5, 2016, when Tropical Storm Colin was born.

The forecast for the system is fairly straightforward for the next few days. The system should mill around in the Bay of Campeche, producing heavy rainfall across southeastern Mexico and neighboring countries, with some strengthening likely. This will produce significant flooding, and mudslides in mountainous areas. As we get into the latter half of the week, things gets significantly more complicated. There are two distinct scenarios presented by the various computer models at this time. The first option is that the system turns northward, and moves across the Gulf of Mexico, heading towards the northern Gulf Coast towards next weekend while strengthening. The second option is that the system moves into southeastern Mexico and dissipates, then a new storm forms near or north of the Yucatan Peninsula, and heads northward later in the week. Either way, residents of the Gulf Coast should pay attention to the progress of this system as as the week goes on.

The 51 members of the ECMWF Ensemble show a wide range in the location and strength by thr end of this weekend for what is currently TD 3. Image provided by Weathermodels.com

Most of the forecast models do not show this system reaching hurricane strength before moving towards the Gulf Coast, but a few do. This is consistent with early-season storms that impact the United States. Since 1851, only 18 hurricanes have made landfall during the month of June in the United States, and only one (Audrey in 1957) did so as a major hurricane. A hurricane hasn’t made landfall in the United States before July 1 since Hurricane Bonnie came ashore as a minimal hurricane near the Texas/Louisiana border on June 26, 1986. The earliest in the season that a hurricane has ever made landfall in the United States was June 9, 1966, when Hurricane Alma made landfall in the Florida Panhandle.

Weekly Outlook: June 1-7, 2020

June has arrived, which means that we are now officially in meteorological summer. It also means that Hurricane Season has officially begun in the Atlantic.

June is starting on a rather cool note with some frost across portions of Northern New England. Image provided by WeatherBell.

We start the week off on a cool note with high pressure at the surface and upper-level trough of low pressure moving across the region. This trough may help produce a few pop-up showers this afternoon, but will also help keep temperatures well below normal today. Another cool night is expected tonight, but not as cool as it was this morning. By Tuesday a warm front will be moving towards the area, with clouds streaming in ahead of it, and possibly a shower or two.

Warmer air moves in on Wednesday as low pressure heads toward the St. Lawrence Valley. With the warm air will be some shower activity and possibly a thunderstorm or two. We’ll remain warm and humid through Thursday and into Friday before another low pressure system passes north of the region. This will bring in more showers and thunderstorms late Friday and Friday night.

Dewpoints will rise into the middle to upper 60s by Friday afternoon. Image provided by WeatherBell.

A cold front moves through early Saturday, but we’ll remain on the warm side with developing sunshine during the afternoon. Drier air will filter in behind the front, then high pressure builds in for Sunday with cooler conditions.

Over the weekend, we published our annual look at the upcoming hurricane season, which also contained some stats about how overdue we are for a storm up here, or, as a colleague said “me thinks our clock be tick’n!” We’ve already had 2 named storms this season (we’re still not convinced that “Bertha” was actually a tropical storm), but another system could be brewing in the Bay of Campeche. Conditions will be favorable for a system to develop later this week, and a majority of the forecast models do show a system developing, but they don’t agree on how strong it could get or where it could go. Obviously, we’ll keep an eye on it, and if it develops, we’ll keep you updated, but it will likely have little to no impact up here, except for possibly some rain as whatever is left of the system moves through, but that would be a good 10 or more days away, if at all.

The 51 members of the ECMWF Ensemble show a wide range in location and strength of a potential tropical system in the Gulf next weekend. Image provided by Weathermodels.com.

Monday: Early sun, then clouds develop, with a chance for a few afternoon showers. High 59-66.

Monday night: Clear to partly cloudy. Low 43-50.

Tuesday: Thickening clouds, a few showers are possible late in the day. High 66-73.

Tuesday night: Partly to mostly cloudy with scattered showers. Low 51-58.

Wednesday: Intervals of clouds and sunshine, chance for a few showers, especially along the south coast. High 73-80.

Thursday: A mix of sun and clouds. High 77-84.

Friday: Becoming partly to mostly cloudy, chance for a few showers. High 79-86.

Saturday: Morning showers, then becoming partly to mostly sunny. High 77-84.

Sunday: A mix of sun and clouds. High 67-74.

Hurricane Season 2020 Starts Monday

Earlier this month, Tropical Storm Arthur grazed the Outer Banks of North Carolina and “Tropical Storm Bertha” moved into South Carolina, marking the 6th year in a row that we had at least one named tropical system in the Atlantic before the “official” start of Hurricane Season, which runs from June 1 through November 30. That’s just the start of what looks to be an active hurricane season.

The list of Tropical Cyclone Names for the Atlantic for this season. Image provided by the National Hurricane Center.

Arthur produced wind gusts of up to 45 mph across the Outer Banks of North Carolina, with rainfall of 3-5 inches resulting in some flooding. Otherwise, it was a rather unremarkable storm, which is rather typical for early-season storms. Earlier this week, “Bertha” (we’re skeptical that it was really a tropical storm) brought heavy rain into parts of South Carolina. This is the 6th time since 1851 that we’ve had 2 named storms form before June 1 (1887, 1908, 1951, 2012, and 2016 are the others). Despite the early start for the past several years, the average date for the first named storm in the Atlantic is still in late June or early July. Over 97% of all named storms in the Atlantic form between June 1 and November 30. Like our first two storms this year, most early season storms tend to be on the weaker side. A hurricane hasn’t made landfall in the United States before July 1 since Hurricane Bonnie came ashore as a minimal hurricane near the Texas/Louisiana border on June 26, 1986.

Based on climatology, the most likely spots for an early season storm are in the Gulf of Mexico or northwest Caribbean. Image provided by the National Hurricane Center.

An early start is not always a harbinger of what the season will bring. NOAA issued their seasonal hurricane outlook last Wednesday, and it calls for a 60 percent chance for an above normal season, a 30 percent chance for a normal season, and a 10 percent chance for a below normal season. Many of the other hurricane outlooks issued by various outlets are also expecting a busy season, due to a number of factors. An average season consists of 12 named storms, of which 6 become hurricanes and 3 become major hurricanes (Category 3 or higher on the Saffir-Simpson scale). NOAA’s forecast for this season calls for 13-19 named storms, 6-10 hurricanes, and 3-6 major hurricanes. The Tropical Meteorology Project at Colorado State, the first group to forecast how active a hurricane season would be, originally led by Dr. Bill Gray, will issue their forecast on June 4. Their initial forecast from April called for 16 named storms, 8 hurricanes, and 4 major hurricanes. They also pegged the chance at a storm making landfall in the United States at 69% (52% is the average in any given year), and the odds of a storm making landfall along the East Coast at 45% (31% is the average). The last 5 seasons have all featured above normal activity across the Atlantic.

The 2019 Hurricane Season was an active one across the Atlantic Basin. Image provided by the National Hurricane Center.

A busy season does not always mean that multiple storms (or any storms for that matter) will impact the United States. In 2010, 19 named storms were observed in the Atlantic, 12 of them became hurricanes, and 5 were major hurricanes. Only one storm made landfall in the United States, and that was Bonnie, which was a minimal tropical storm at landfall. On the flip side, an inactive year doesn’t mean much for landfall probabilities as well. Only 7 named storms formed in 1992, and the 1st one didn’t develop until August 16. That storm, however, was named Andrew, and it made landfall just south of Miami as a category 5 storm.

Here in New England, we should always pay attention when a storm is nearing the Bahamas, as those are the ones that have the potential to impact us, and we are very overdue for a system to impact us. Using data back to 1851, here are some stats that show how overdue we are:

  • Since 1851, 36 storms of tropical storm strength of greater have made landfall in New England or Long Island, an average of one every 4.7 years. The longest we’ve ever gone without one is 11 years, between 1897 and 1908 and also between 1923 and 1934. We’re at 9 years since Irene, the last one to do so.
  • Since 1851, 28 strong tropical storms (maximum sustained winds of 60 mph or more) have made landfall in New England or Long Island, an average of one every 6 years. The longest we’ve ever gone without one is 20 years, between 1991 and 2011. We’re at 9 years since Irene, the last one to do so.  
  • Since 1851, a hurricane has made landfall in New England or Long Island 18 times, an average of one every 9.4 years. The longest we’ve ever gone between hurricane landfalls is 38 years, between 1896 and 1934. It’s been 29 years since Bob, our 2nd longest drought on record.
  • Since 1851, 9 hurricanes of Category 2 intensity or stronger have made landfall in New England or Long Island, an average of one every 18.8 years. The longest we’ve gone between hits by storms of that intensity is 69 years, between 1869 and 1938. We’re at 29 years since Bob, the last one to do so.
  • Since 1851, New England/Long Island has had 3 Major Hurricanes (Category 3 or higher) make landfall – an unnamed storm in October of 1869, the infamous 1938 Long Island Express, and Hurricane Carol in 1954. That’s an average of 1 every 56.3 years, and the longest time between 2 major hurricanes is 69 years (1869-1938). We’re at 66 years since Carol. There are also 3 documented storms from before 1851 – The Great Colonial Hurricane of 1635, the 1815 New England Hurricane, and the Norfolk and Long Island Hurricane of 1821. That’s it. That changes the numbers to 6 in 385 years, or one every 64.2 years, with a longest drought of 180 years.
Satellite photo of Hurricane Bob approaching New England. Bob was the last hurricane to make landfall in New England – 27 years ago. Image provided by NOAA.

We all saw what Sandy did in 2012, and that was a minimal hurricane that eventually made landfall in southern New Jersey. When (not if) the next big storm comes up the coast, much of this region will not be prepared for the storm or its aftermath.

The Atlantic is quiet right now, but some of the models show the potential for a system to develop over the next 7-10 days in the western Caribbean or the Bay of Campeche (we’re ignoring the cluster of cumulus clouds in the central Atlantic that the National Hurricane Center is “watching”). Even if something were to form off the East Coast in the next few weeks and head this way, the waters off of New England are much too cold to sustain a tropical system, so we’d see something more like a typical nor’easter. Only two tropical storms have ever made landfall in the Northeast before the end of June. The first was an unnamed minimal tropical storm that crossed extreme eastern Long Island and went into southeastern Connecticut on May 30, 1908. The other was Tropical Storm Agnes, which made landfall near New York City on June 22, 1972, then caused devastating flooding across parts of the Mid-Atlantic states. In terms of hurricanes, the earliest one to ever make landfall up this way was Hurricane Belle, which slammed into Long Island with 90 mph winds on August 9, 1976. We did have Hurricane Arthur pass just offshore of Nantucket on July 4, 2014. While it did not make landfall, it made for a rather wet and cool holiday, especially across Cape Cod and southeastern Massachusetts. Statistically, the most likely time for a hurricane to hit New England is between the middle of August and late September. Of the 18 hurricanes that made landfall in New England or Long Island since 1851, 16 of them have done so between August 19 and September 27.

The most likely time for a tropical system to impact our area is August of September. Image provided by the National Weather Service office in Norton, MA.

As always, you should get your weather information from a trusted source, especially when dealing with tropical systems. Much like with snowstorms in the winter, there will be plenty of hype and exaggeration on Twitter and Facebook, as well as people posting doom and gloom maps showing how a thunderstorm near the coast of Africa will develop into a Category 5 storm and head right for the East Coast in the next 2 weeks. We’re not among that group, we give you facts and our best forecasts, without any hype. If there’s reason to worry, we’ll let you know with plenty of advance warning. It’s always best to prepare ahead of the season. Chances are, you won’t have anything to worry about, but in case you do, it’s always good to be prepared, as we’ve learned recently.

Weekend Outlook: May 28-June 1, 2020

Changes are coming over the next few days. We’ve been dry for a while, but some rain is in the future. It’s been warm for much of the week, but cooler weather is on the horizon.

Despite plenty of cloudcover, it’s a warm afternoon across most of the region. Loop provided by NOAA.

We start off with high pressure still in control this afternoon and evening. A southerly flow around the offshore high pressure system continues to bring warm and humid air into southern New England. It’s also bringing plenty of cloudcover in. Aside from a few sprinkles here and there, it should remain dry through the afternoon. Low clouds and fog will move back in tonight, especially along the south coast, as the warm and humid air continues to flow into the region.

A cold front will start to move in from the west on Friday. Much of the day will be similar to today with plenty of clouds along with some warm and humid air. We could see a few showers around in the morning, but they’ll be light for the most part and very widely scattered. In the afternoon, as the cold front starts to get closer, strong to severe thunderstorms will likely start to develop across portions of New York down into the Mid-Atlantic states. These storms will move eastward, but once we get into the evening, they’ll start to weaken as they lose the heating of the sun. They move across our area overnight and early Saturday. For the most part, we’re just looking at scattered showers, with some embedded thunder and lightning, and a few heavy downpours.

Strong to severe storms are possible across parts of the Northeast on Friday, but the bulk of the severe weather should stay to our west. Image provided by Pivotal Weather.

The showers should come to an end by midday Saturday as the front finally pushes across the region, then drier air will start to move in. Skies should start to clear our late Saturday and Saturday night as high pressure builds in from Canada. Cooler air will start to settle in on Sunday despite plenty of sunshine. By Monday, an upper-level trough of low-pressure will be moving across the region, so we’ll see some additional clouds and possibly a few showers, but also even cooler conditions are expected.

Away from the South Coast very little rain has fallen over the past week, so we need all that we can get. Image provided by Weathermodels.com

Tonight: Mostly cloudy with some patchy fog, especially along the South Coast. Low 62-69.

Friday: Mostly cloudy and breezy with a few showers possible. High 72-79 south of the Mass Pike, 80-87 north of the Pike.

Friday night: Cloudy with showers likely, possibly some thunder. Low 60-67.

Saturday: Cloudy with showers ending by midday, some clearing takes place in the afternoon, especially north and west of Boston. High 77-84, cooler along the South Coast.

Saturday night: Becoming mostly clear. Low 54-61.

Sunday: Mostly sunny, cooler, and less humid. High 68-75.

Sunday night: Clear skies and cool. Low 44-51.

Monday: A mix of sun and clouds, chance for a few afternoon showers. High 61-68.

Weekly Outlook: May 25-June 1, 2020

Memorial Day is the “traditional start of summer”, and we’ll certainly have some summer-like weather this week, just not on Memorial Day.

The forecast for this week is actually fairly simple. We start the week out with plenty of low clouds and some fog for your Memorial Day morning. With high pressure east of Nova Scotia and low pressure south of New England, a light southeast flow is bringing in plenty of moisture in the form of cloud cover. Some patchy drizzle is possible along the coast as well. As we head into the afternoon, the clouds will start to break up away from the coast, allowing for some sunshine, but the low clouds and fog/drizzle may hang tough along the coast. The cloudcover, combined with winds blowing off the still-chilly Atlantic, will keep temperatures well below normal along the coast, but inland, temperatures will be much warmer, especially where sunshine develops. The low clouds and fog return Monday night, but things start to change in a big way on Tuesday.

The nighttime microphysics image from the GOES satellite shows the low clouds and fog spread across eastern Massachusetts Sunday evening and night. Loop provided by NOAA.

By Tuesday, high pressure will settle southward, with more of a south to southwest flow developing across the Northeast, this will allow warmer air to start to move in. Temperatures should jump into the 70s and lower 80s, but coastal locations, especially ones facing south, will stall cooler. Wednesday should feature even warmer weather. By Thursday, you’ll start to notice an increase in humidity, with a few pop-up showers possible in the afternoon.

Temperatures could approach 90 well inland on Wednesday. Image provided by WeatherBell.

As we head into Friday, a cold front will be approaching the region. This will bring in more cloudcover, with showers and thunderstorms expected, especially during the afternoon and evening. How much sunshine we get and when the front actually moves through will determine how warm we’ll get and how strong the storms will be. We’ll have more clarity on that situation on Thursday in our Weekend Outlook. Behind the front, high pressure builds in for the weekend with drier conditions.

Dewpoints could get into the middle to upper 60s across the region ahead of the cold front on Friday. Image provided by Weathermodels.com

Memorial Day: Low clouds and fog along with some patchy drizzle during the morning, then skies become partly sunny away from the coast in the afternoon. Some sunny breaks may develop along the coast late in the day. High 64-71, except 56-63 right along the coast.

Monday night: Low clouds and fog return. Low 50-57.

Tuesday: Becoming partly to mostly sunny. High 79-86, cooler along the coast.

Tuesday night: Clear to partly cloudy during the evening, low clouds and fog may move back in, especially along the coast. Low 56-63.

Wednesday: Partly to mostly sunny. High 83-90, cooler along the coast.

Thursday: Sunshine filtered through some high clouds, breezy, more humid, chance for a pop-up shower or thunderstorm in the afternoon. High 82-89, much cooler along the coast.

Friday: Partly to mostly cloudy, breezy, and humid with showers and thunderstorms likely during the late afternoon and evening. High 76-83.

Saturday: Becoming partly to mostly sunny. High 72-79.

Sunday: A mix of sun and clouds. High 68-75.

Weekend Outlook: May 21-25, 2020

Memorial Day weekend has arrived, and although the weather won’t be ideal, it could be a lot worse.

There weren’t many clouds across the region today, and Friday will be similar. Loop provided by NOAA.

High pressure remains in control on Friday, and it should result in probably the best day of the year thus far. We’ll have sunshine and temperatures getting into 80s away from the South Coast. Some clouds will start to move in during the afternoon though, the first sign of a significant change for Saturday.

Low pressure will pass south of the region on Saturday, with some showers likely along the South Coast, possibly as far north as the Mass Pike. For the rest of us, we’ll see plenty of clods, though there still may be some sunshine across parts of southern New Hampshire. The more noticeable effect will be on temperatures., With winds shifting into the east and northeast and blowing off of the still-cool Atlantic, temperatures will be 15-25 degrees cooler on Saturday compared to Friday.

Temperatures Saturday afternoon will be 20-25 degrees colder than at the same time Friday afternoon. Image provided by WeatherBell.

The system pulls away on Sunday and high pressure builds back in with sunshine returning, but temperatures will remain quite chilly for late May thanks to a wind off the water. We’ll start to moderate on Monday with high pressure still in control. Beyond that, it’s looking significantly warmer for the middle to end of next week, but we’ll get into more detail on that in our weekly outlook early Monday morning.

Warmer weather is expected across the Northeast for the end of next week. Image provided by the Climate Prediction Center.

Tonight: Clear to partly cloudy. Low 45-52.

Friday: Sunshine starts to fade behind increasing high clouds late in the day. High 78-85, cooler along the South Coast.

Friday night: Becoming mostly cloudy with showers developing after midnight across the South Coast. Low 52-59.

Saturday: Mostly cloudy and breezy with showers likely south of the Mass Pike, ending in the afternoon. Some sunny breaks may develop across southern New Hampshire during the afternoon, and skies may start to clear out late in the day north of Boston. High 63-70, but temperatures may drop during the afternoon, especially along the coast.

Saturday night: Becoming mostly clear. Low 40-47.

Sunday: Sunshine and some high clouds. High 60-67, cooler along the coast.

Sunday night: Partly cloudy, some patchy fog may develop. Low 40-47.

Memorial Day: A mix of sun and clouds. High 67-74, cooler along the coast.

Weekly Outlook: May 18-25, 2020

If we had written this forecast a few days ago, it would have looked rather cool and damp for a large chunk of the week. Instead, it’s now looking a lot drier, and likely a bit milder, especially late in the week.

We start the week off with a warm front trying to move into the region, producing a few light showers this morning , mainly north of the Mass Pike. The front won’t quite make it, so we’ll remain on the cool side, with plenty of clouds. The reason the front won’t make it is a large area of high pressure over eastern Quebec is going to slowly build in and drop southward. As the high builds in, we’ll start to clear out for Tuesday, with another cool day expected, especially along the coast.

Normal high temperatures are in the upper 60s to near 70 in mid-to-late May. Image provided by Weathermodels.com

As we had into the middle to latter portions of the week, that high pressure area will continue to slide southward and offshore, with winds shifting into the west and southwest. This will bring milder air back in, especially by Friday, when temperatures could top 80 degrees in spots.

By Friday night, a weak area of low pressure over the Mid-Atlantic states will start to push offshore south of New England. This will bring clouds back in along with a few showers. The more noticeable effect will be on temperatures, as winds will shift back into the east, bringing much cooler air back in off the chilly Atlantic. We’ll dry out Saturday night and Sunday as the low pulls away. High pressure should build back in for Memorial Day, with warmer weather returning.

At least one model is forecasting a rather warm Memorial Day. Image provided by WeatherBell.

Monday: Plenty of clouds, chance for a few showers in the morning, mainly north of the Mass Pike. High 60-67, cooler along the coast.

Monday night: Partly to mostly cloudy. Low 41-48.

Tuesday: A mix of sun and clouds, breezy. High 55-62, coolest along the coast.

Tuesday night: Becoming mostly clear. Low 38-45.

Wednesday: Plenty of sunshine. High 59-66, a little cooler along the coast.

Thursday: Sunshine and a few afternoon clouds. High 67-74, cooler along the South Coast.

Friday: Partly to mostly sunny. High 73-80, cooler along the South Coast.

Saturday: Intervals of clouds and sunshine, breezy, chance for a few showers. High 68-75, but temperatures may turn cooler in the afternoon, especially along the coast.

Sunday: Partly sunny. High 63-70, cooler along the coast.

Memorial Day: A mix of sun and clouds. High 70-77, cooler along the coast.

Tropical Storm Arthur will bring some rain and gusty winds to the Outer Banks of North Carolina today. Loop provided by NOAA.

Tropical Storm Arthur remains fairly weak off the Southeast coast early this morning. It will brush the Outer Banks of North Carolina later today with some gusty winds and heavy rainfall, but is expected to turn more toward the northeast and east and head out to sea while becoming extratropical on Tuesday. It may bring some gusty winds and rainfall to Bermuda later this week as an extra tropical system. After that, it may actually meander around in the central Atlantic for several days as an extratropical system, but won’t impact any land areas.

Another Early Start to Hurricane Season

For several days, most of the forecast models have been showing the potential for a tropical or subtropical system to develop in or near the Bahamas this weekend. Potential became reality Saturday evening when Tropical Depression One formed.

Satellite loop showing newly-formed Tropical Depression One. Loop provided by NOAA.

As of 8pm EDT, newly-formed Tropical Depression One was centered about 175 miles east-northeast of Melbourne, Florida, moving toward the northeast at 14 mph. Maximum sustained winds were near 35 mph. With favorable upper-level conditions and the system sitting over the warm waters of the Gulf Stream, strengthening is expected, and the system will likely be upgraded to Tropical Storm Arthur tonight or on Sunday.

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

A general north-to-northeast track is expected over the next few days, which could bring the center very close to the Outer Banks of North Carolina on Monday. As a result, a Tropical Storm Watch is now in effect for the coast of North Carolina from Surf City to Duck, including Pamlico and Albemarle Sounds.

Rain and gusty winds across the northwestern Bahamas and the east coast of Florida will wind down tonight, but rain should spread into the Carolinas later Sunday. The heaviest rain is expected from eastern North Carolina into the Delmarva Peninsula Monday into Tuesday, where as much as 2-4 inches could fall, leading to some localized flooding.

Rainfall forecast through Tuesday morning from the GFS. Image provided by WeatherBell.

Once it gets past the Carolinas, the official forecast track from the National Hurricane Center calls for the storm to turn toward the east-northeast and head out to sea while becoming extratropical, but this is far from a lock. An upper-level low pressure system will be moving into the Mid-Atlantic states and some models show the potential for the upper-low to capture the storm, and let it meander around near or just off the East Coast for several days as an extratropical system, with a large high pressure area to the north blocking it from moving farther up the coast. This would result in several days of damp and breezy conditions from the Carolinas possibly into Southern New England. Once we get towards Monday, we should hopefully have a better idea of what the storm will do.

While Hurricane Season in the Eastern Pacific Ocean starts on May 15, Hurricane Season in the Atlantic Basin does not officially start until June 1. However, as we’ve seen already several times, Mother Nature keeps her own calendar. This is actually the 6th year in a row that we’ve had a tropical system develop in the Atlantic Basin before June 1.

While Tropical Depression One will grab the weather headlines, it’s not the only tropical system that is active in the world right now. A much bigger threat has developed in the Bay of Bengal. Tropical Cyclone 01B (Amphan – pronounced UM-PUN) developed early Saturday, and is already strengthening quickly. As of late Saturday afternoon, the storm has maximum sustained winds near 50 mph, and is expected to continue strengthening rapidly while heading off towards the north. Current forecasts have the storm making landfall in either Bangladesh or extreme eastern India by Tuesday or Wednesday. By that point, maximum sustained winds could be in excess of 110 mph.

Forecast track for Tropical Cyclone 01B (Amphan). Image provided the India Meteorological Department

Strong winds would obviously be a significant hazard, but history has shown several times that the biggest threat with tropical cyclones in that part of the world is flooding, both from storm surge and torrential rainfall. Much of that region lies near sea-level and is very densely populated. In the past, storms that hit this area have resulted in tens of thousands, if not hundreds of thousands, of deaths. Given what is already going on around the world, this would make the situation exponentially worse.