Tropical Weather, Weekly Outlook

Weekly Outlook: August 28-September 4, 2017

“Summer’s going fast, nights growing colder”

 

Neil Peart wrote that line (and the rest of the song) 30 years ago, but it’s appropriate right now, as we’re coming up on Labor Day weekend, the “traditional” end of summer. Of course, meteorological summer ends on Thursday, so, we really are getting closer to fall. Just for completeness, the autumnal equinox occurs at 4:02pm on September 22. Of course, we’ve had plenty of hot weather in September before, so don’t start putting away the shorts just yet.

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Rainfall totals across southeastern Texas through Sunday afternoon. Image provided by the National Weather Service Office in Houston.

 

Before we get to the forecast around here, we’d like to discuss Harvey a little. In our post a few days ago, we mentioned the possibility that some locations could see 30-40 inches of rain over the span of a week as Harvey stalled across the region. Well, it looks like we underestimated that. Much of the area, especially right around Houston, has already seen 15-30 inches of rain, leading to catastrophic flooding across the region. Some of the pictures of the flooding have been just incredible. Unfortunately, with Harvey expected to move very little over the next few days, another 15-30 inches may fall across the region.

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Rainfall forecast for the next 7 days across Texas and the Lower Mississippi Valley. Image provided by WeatherBell.

 

As for around here, the week will start off dry and cool, which is how the last week ended. High pressure remains in control, which will give us some sunshine for one more day. High clouds will start to stream in on Tuesday ahead of a tropical system off the East Coast (more on that in a minute). That system will pass south and east of the region Tuesday night and Wednesday as it becomes a post-tropical system. It will likely pass close enough to spread some gusty winds and maybe some showers into Cape Cod and possible southeastern Massachusetts. A cold front then swings through the region on Thursday, bringing in more showers and maybe some thunderstorms. High pressure then returns will dry and cool conditions for Friday and Saturday. Clouds start to move back in on Sunday, and unfortunately, Labor Day isn’t looking that great right now, as a storm system moving in from the Great Lakes may bring us more showers. However, it’s a week away and things can change, so don’t go cancelling any plans just yet.

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We’ll start the week off with a cool Monday morning. These readings are 5-10 degrees below normal. Image provided by WeatherBell.

 

As we mentioned a moment ago, we may have a tropical system to deal with off the East Coast. As early early Monday morning, Potential Tropical Cyclone 10 was centered about 165 miles south-southwest of Charleston, South Carolina. The system doesn’t have a well-defined circulation yet, which is why it’s only a “potential” tropical cyclone. If it does get its act together, it will be named Irma. The current forecast is for that to happen while the storm starts moving northeastward. Since it will likely bring gusty winds and heavy rain to parts of the Carolinas, a Tropical Storm Watch has been issued from the South Santee River in South Carolina northward to Duck, North Carolina, including the Pamlico and Albemarle Sounds. Once it passes the Outer Banks of North Carolina, it will likely accelerate east-northeastward out into the open Atlantic while slowly strengthening, but also losing its tropical characteristics.

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Computer model forecasts for the track of Potential Tropical Cyclone 10. Image provided by the National Center for Atmospheric Research.

 

Monday: Sunshine and some afternoon clouds. High 70-77.

Monday night: Some high clouds may start to spread across the region. Low 52-59.

Tuesday: Sunshine filtered through high clouds to start, but clouds start to thicken up during the afternoon. High 66-73.

Tuesday night: Mostly cloudy, becoming breezy across Cape Cod. Some showers are possible, mainly across Cape Cod and southeastern Massachusetts. Low 53-60.

Wednesday: Some showers possible in the morning across Cape Cod and southeastern Massachusetts, then skies clear out in the afternoon. High 66-73.

Thursday: A sunny start, then clouding back up with showers and maybe some thunderstorms late in the day. High 77-84.

Friday: Sunshine and a few clouds. High 65-72.

Saturday: Partly to mostly sunny. High 69-76.

Sunday: Intervals of clouds and sunshine. High 76-83.

Labor Day: Mostly cloudy and breezy with a chance of showers. High 78-85.

Longer range: Aside from a system bringing in some showers towards midweek, much of next week looks dry and cool.

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Tropical Weather

Houston Might Have a Problem Named Harvey

A week ago, Tropical Storm Harvey produced wind gusts as high as 44 mph in the Windward Islands. It moved into the eastern Caribbean and fell apart a few days later, degenerating into a tropical wave. Four days after that,  Harvey has regenerated into a tropical storm over the Bay of Campeche. Now, it’s setting it sights on Texas.

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Sorry, wrong Harvey. This Harvey isn’t a problem at all. Image provided by WCVB.

As of early Thursday morning, Tropical Storm Harvey was centered about 410 miles southeast of Port Mansfield, Texas with maximum sustained winds near 45 mph. Harvey was moving toward the northwest at 7 mph. A hurricane watch is in effect for the coast of Texas from Port Mansfield, to San Luis Pass. Tropical Storm Watches have also been issued from Port Mansfield southward to Boca de Catan, Mexico, and from San Luis Pass northward to High Island, Texas. A Storm Surge Watch is also in effect from Port Mansfield to High Island.

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Harvey certainly looks to be heading towards the Texas coastline. Once it gets there, where it goes is a question that really can’t be answered yet. Image provided by Tropical Tidbits.

Current indications are that Harvey should continue to head northwestward while strengthening over the next day or two. Harvey should be approaching the Lower or Middle Texas coast on Friday. With warm water and low wind shear, there is a chance that Harvey could rapidly intensify on Thursday, and should become a hurricane before landfall, possibly a strong hurricane.

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This Harvey is a problem for Gotham City, not Houston. Image provided by DC Comics Database.

Once Harvey makes landfall, it will start to slow down and its movement could become erratic as there will be little in the way of upper-level wind flow to steer the storm. Many models are now showing a turn towards the west or southwest for a day or two, others show the storm nearly stationary once inland, and still others have the storm drift off towards the east or northeast after landfall. There’s also the chance that Harvey stalls before moving inland. The exact track that Harvey takes will have a huge impact on the region for obvious reasons.

While wind and storm surge are obviously threats to Texas, especially along the coast near where Harvey makes landfall, by far, the bigger threat at this point is flooding from heavy rainfall. The slow movement once inland means that heavy rain will continue across portions of the region for several days, leading to widespread, severe flooding, especially across parts of south and southeast Texas.

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GFS model forecast for rainfall across Texas for the 7 days ending Wednesday August 30. That’s a LOT of water. Image provided by Pivotal Weather.

Some models, such as the one above, are showing the possibility for 10-20 or more inches of rain across parts of the area over the next week. Some models are showing extreme totals of 30-40 or more inches during the same time frame. While these numbers seem unbelievable, they wouldn’t be unprecedented. Hurricanes that move out of the Gulf of Mexico are usually loaded with tropical moisture and if they are moving slow enough, can produce several months worth of rainfall in a matter of days. In 1978, Tropical Storm Amelia dropped 48 inches of rain on Medina, Texas. This is the most rainfall recorded from a single storm anywhere in the United States. Just one year later, Tropical Storm Claudette made landfall near the Texas/Louisiana border. In Alvin, Texas, just west of Houston, a total of 42 inches of rain was recorded in just 24 hours. This set a new record for 24-hour rainfall in the contiguous United States. More recently, in 2001, Tropical Storm Allison produced 20-40 inches of rain on portions of southeastern Texas and Louisiana.

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NAM model forecast for rainfall across Florida through Sunday morning. Some flooding seems like a possibility south of I-4. Image provided by WeatherBell.

Meanwhile, a trough of low pressure is drifting across Florida this morning. This system will produce heavy rain across portions of the Sunshine State over the next few days, which could lead to some localized flooding. Once it drifts back into the Atlantic, it will need to be watched for signs of development. While the most likely track for the system, if it develops at all, is to head northeastward out into the open Atlantic, there are some models that show the potential for the system to impact portions of the East Coast early this weekend or next week, as we mentioned at the end of our Weekly Outlook on Sunday. We’ll continue to keep an eye on this system, just in case it does become a threat.

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An out-to-sea track still looks most likely, but the potential for trouble along the East Coast still exists. Image provided by the National Center for Atmospheric Research.

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Severe Weather, Tropical Weather, Weekly Outlook

Weekly Outlook: August 21-27, 2016

As we start a new week all eyes will literally be looking at the sky. As you may have heard, there’s an eclipse today. The weather will cooperate, as high pressure provides us with sunshine, so viewing it shouldn’t be a problem. You’ve probably also heard plenty of people warning you not to look directly at the sun during the eclipse. Since you’ve heard it enough already, we won’t say it. Besides, if you want to look at the sun, we won’t stop you. Eyesight is overrated anyways. Plenty of people live without it. If that’s what you want, who are we to stop you? You’ll still be alive and free to go golfing in the middle of the thunderstorms we’re expecting on Tuesday. Don’t worry, they’ll likely be coming at night, so even if you were golfing, you wouldn’t be able to find the ball if you had eyesight.

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Cloud cover forecast from the HRRR model for 2pm Monday. Just a few clouds around, which shouldn’t impact eclipse viewing much. Image provided by WeatherBell.

 

Now that we’ve given you the teaser and the sarcasm, let’s get to the details. We start the week off with high pressure, giving us a fantastic Monday. A cold front approaches on Tuesday, producing showers and thunderstorms, mainly at night. A few of these storms could be quite strong, but with the activity mostly expected at night, that should limit the potential for severe weather. Of course, that doesn’t mean you should let your guard down. These storms still could produce heavy downpours, but severe weather is still possible at night. In fact, Tuesday marks the one year anniversary of the tornado that impacted Concord, MA at 3:20 in the morning.

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A rare overnight tornado impacted Concord, MA one year ago tomorrow. Image provided by the National Weather Service office in Taunton, MA.

The showers and thunderstorms will taper off and end early Wednesday as a cold front crosses the region, then things get quiet again. We’ll dry out Wednesday afternoon but it will remain warm. We’ll cool off a little more on Thursday as an upper-level trough of low pressure settles into the Northeast while high pressure does at the surface, which will result in some cool days for Friday and the weekend.

Monday: Sunshine and a few afternoon clouds, dimmed for a while by a passing moon in the afternoon. High 82-89.

Monday night: High clouds overspread the region. Low 64-71.

Tuesday: Clouds thicken up, with some showers and thunderstorms possible late in the day. High 85-92.

Tuesday night: Showers and thunderstorms likely, some of which could contain heavy downpours and gusty winds. Low 68-75.

Wednesday: Showers and thunderstorms end in the morning, then skies clear out in the afternoon. High 78-85.

Thursday: Sunshine and some afternoon clouds. High 74-81.

Friday: A sunny start, then clouds start to pop up with a slight chance for a spot shower in the afternoon. High 71-78.

Saturday: A mix of sunshine and clouds. High 70-77.

Sunday: Partly to mostly sunny. High 70-77.

Finally, we get to a topic that doesn’t impact this week’s forecast, but could have an impact early next week. For several days now, the Canadian model has been extremely insistent on a tropical disturbance developing near the Bahamas and eventually moving northward, up the East Coast early next week. There have been a few reasons to ignore this for the past few days:

  1. This was the only model showing this feature.
  2. The Canadian model always seems to take every little ripple in the tropics and blow it up into a hurricane.

So, why are we mentioning it now? There are a few reasons.

  1. Other models are starting to show the potential for something to develop near the Bahamas or Florida late this week or early next week.
  2. The Canadian model has been slightly better than many of the other models in regards to the tropics so far this season.
  3. It’s had this feature with very little variation for at least 6 consecutive model runs.

That last point is the main reason why we at least feel the need to mention it. This model has not really wavered much at all, and consistency is one of the things we look for in a model before we start to trust its solution. Add in the fact that other models are starting to come around, and well, it’s something we need to keep an eye on. This does not mean that a massive hurricane is going to wipe out the East Coast just before Labor Day. If anything does materialize, we’ll obviously keep you informed, but for now, it’s just something to keep in the back of your mind. (Of course, now that we’ve mentioned it, the next run of the Canadian model will likely change its tune completely)

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Forecast for Atlantic Disturbance 92L based on the Canadian GEM model initialized Sunday evening. Loop provided by Tropical Tidbits.

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Tropical Weather, Weekly Outlook

Weekly Outlook: August 14-20, 2017

We’ve actually got a fairly straightforward forecast for much of this week, so we’ll get right to it.

The week starts off with high pressure bringing us sunshine and seasonable temperatures for Monday. A cold front moves through on Tuesday, with some showers and thunderstorms expected. A few of them could be on the strong side, but the bulk of the activity will remain to the north and west of most of the people reading this. Drier weather returns behind the front on Wednesday. Clouds return on Thursday ahead of another system. This is where we get to our question mark of the week – when will it rain?

Some models have the rain come in for Thursday night and Friday, others for Friday into Friday night. The timing of the rain and the cold front will also have implications on the temperatures, especially on Friday. These questions really can’t be answered yet. Things start to improve on Saturday, though another shower can’t be ruled out. High pressure then returns for Sunday.

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Some pretty big waves are possible along south-facing beaches by Wednesday as Tropical Storm Gert passes well offshore. Image provided by WeatherBell.

Turning our attention to the tropics, we have Tropical Storm Gert, which is in between the East Coast and Bermuda. Unless you are a boater or are planning a cruise to Bermuda this week, you have nothing to worry about. Gert will strengthen some more, possibly even becoming a hurricane in a day or two. It will head northward, then make a sharp right turn and head out into the open Atlantic without threatening any land areas.

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Model forecast for the track of Tropical Storm Gert. Image provided by Tropical Tidbits.

Perhaps you’ve heard rumblings of another system in the Atlantic? Yes, there is a wave that came off of Africa recently, and will be monitored as it makes it’s journey westward. Yes, it’s true that some of the models show it strengthening and possibly even threatening the East Coast. Here’s the thing, and we have mentioned this before. The models suck at predicting these things until they actually form. Even then, they’re not that much better. For example, the GFS model, which is the one that most people look at because it goes out 16 days had the storm that eventually became Gert. As we mentioned earlier, Gert is about halfway between the East Coast and Bermuda, and has a central pressure of 1009mb. If you go back and look at the GFS forecast from 11 days ago, it had Gert this evening centered about 50 miles east of Vero Beach, FL as a Category 5 hurricane with a central pressure of 926 mb. If this were the winter, that’d be the equivalent of a forecast of 4 feet of snow and you actually get sunshine. (We don’t want to hear any snide remarks – our forecasts has never been that bad) We’ll step off of our soapbox now, but please keep in mind, unless there’s actually a storm out there, ignore what the computers and especially the Facebook Forecasters have to say.

Monday: Sunshine and some high clouds. High 79-86.

Monday night: Becoming partly to mostly cloudy. Low 61-68.

Tuesday: Mostly cloudy with a chance of showers and thunderstorms. High 79-86.

Tuesday night: Clearing skies. Low 60-67.

Wednesday: Sunshine and a few clouds. High 80-87.

Thursday: Clouds slowly thicken up throughout the day. High 77-84.

Friday: Cloudy with showers likely. High 72-79.

Saturday: Intervals of clouds and sun, another shower or two possible. High 76-83.

Sunday: Partly to mostly sunny. High 74-81.

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Weekly Outlook

Weekly Outlook: August 7-13, 2017

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We lost a true legend of the meteorological community a few days ago. RIP Dick Albert. Image provided by WCVB.com

As we get into the middle of August, we are at the traditional end of the so-called “Dog Days of Summer“. Most of this week is not going to live up to that name though. Instead, we’re going to be stuck with “MOTS” as the late, great Dick Albert used to say. That stands for “More Of The Same”. In other words, not much heat, but more rain.

The week starts off with low pressure passing south of New England. That means were in for some rain and cool conditions later Monday into Tuesday. In some places, it might be more than “some” rain, and could be “a lot” of rain. High pressure then builds in for Wednesday, Thursday, and possibly Friday, meaning we get to use another one of Dickie’s favorite expressions to describe those days – “F and D”, which means “Fine and Dandy.” Next weekend could be unsettled, as we’ll have a frontal system in the neighborhood, so the possibility for showers and thunderstorms will increase.

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Rainfall forecast through Tuesday evening based on the NAM model. Image provided by Pivotal Weather.

Monday: Cloudy with rain developing during the afternoon. High 72-79.

Monday night: Periods of rain and showers, possibly heavy at times, especially along the South Coast. A rumble of thunder is also possible. Breezy at times, mainly south of Boston. Low 58-65.

Tuesday: Showers taper off and end in the morning. Some sunny breaks may develop late in the day.  High 70-77.

Tuesday night: Becoming mostly clear. Low 55-62.

Wednesday: Sunshine and a few afternoon clouds. High 77-84.

Thursday: Partly to mostly sunny. High 79-86.

Friday: A mix of sun and clouds. High 76-83.

Saturday: Partly sunny, chance for a few showers and thunderstorms. High 75-82.

Sunday: Intervals of clouds and sun with a chance for showers and thunderstorms. High 74-81.

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Computer model forecasts for the track of Tropical Storm Franklin. Image provided by the National Center for Atmospheric Research.

The tropical Atlantic is finally waking up from its long slumber. Tropical Storm Franklin formed late Sunday evening in the western Caribbean. As of early Monday morning, it was centered just off the coastline of Nicaragua and Honduras. Maximum sustained winds were near 45 mph. The current forecast calls for the storm to move into the Yucatan Peninsula Monday evening, then move back into the Gulf of Mexico on Tuesday. From there, it will likely head westward, towards the eastern coast of Mexico. Landfall is likely towards the middle to latter half of the week. The majority of the forecast models are showing that Franklin should make its second landfall as a strong tropical storm. We’re not so sure about that. For one, the models that predict intensity of tropical systems are, shall we say, not that good. OK, they suck. Maybe not as much as the New York Jets or the UMass Hockey team, but they’re not that good. Also, the water in the western Gulf of Mexico is some of the warmest water you’ll find in the Western Hemisphere right now. That could provide plenty of fuel to strengthen a system. There are plenty of other factors involved, starting with the potential for the system to not even survive its trip across the Yucatan. Having said that, we wouldn’t be surprised at all if Franklin approached the coast of Mexico as a Category 1 or 2 hurricane later this week.

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Plenty of bathwater in the western Gulf of Mexico can help fuel a strengthening tropical system. Image provided by WeatherBell.

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