Belize Tropical Weather Outlook: May 21, 2018

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Belize NMS Forecast

May 21, 2018

Tropical cyclone formation is not expected in the North Atlantic, Caribbean Sea or Gulf of Mexico during the next 48 hours.

USA National Weather Service Forecast

May 21, 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Tropical cyclone formation is not expected during the next 5 days.

Routine issuance of the Tropical Weather Outlook will resume on June 1, 2018. During the off-season, Special Tropical Weather Outlooks will be issued as conditions warrant.

Tropical Weather Discussion

...Special features...

An upper-level trough extends across the eastern Gulf of Mexico and western Caribbean, with diffluent flow aloft prevailing across the Florida Peninsula, the western Atlantic, and Caribbean, to the east of the upper trough's axis. This pattern is drawing deep tropical moisture northward from the SW Caribbean between 76W and 84W and is supporting scattered to numerous moderate convection along this corridor. This activity is expected to continue through at least Tuesday, with heavy rainfall and flooding possible over the land areas affected.

...Tropical waves...

An eastern central Atlantic tropical wave has an axis that extends from 13N31W to 00N33W, moving W at 10 to 15 kt. This wave is embedded in a sharp 700 mb trough. Although deep moisture accompanies the wave, subsidence from aloft is inhibiting convection except over the southern portion. Scattered moderate convection is from 00N to 04N between 29W and 35W.

A central Atlantic tropical wave has an axis that extends from 17N56W to 05N57W, moving W at 5 to 10 kt. This wave continues to appear as a 700 mb trough and has a poleward surge in moisture associated with it. Scattered showers and isolated thunderstorms are within 300 nm of either side of the trough axis. This trough will enter the E Caribbean by Tuesday and then will become ill defined.

...The Caribbean Sea...

An upper-level trough extends over the eastern Gulf of Mexico and western Caribbean. A surface trough is over the western Caribbean and as of 0300 UTC had an axis extending from 21N85W to 11N83W. The combination of upper- level diffluence on the eastern side of the upper-level trough and convergence associated with the surface trough is supporting scattered to numerous moderate convection across the Caribbean waters between 78W and 84W. Broad high pressure over the subtropical Atlantic continues to support moderate to fresh tradewinds over most of the basin, except fresh to strong winds over the central Caribbean. Wave heights of 8 to 9 ft persist over the central Caribbean as confirmed by both satellite altimeters and current buoy data.

Over the next day or so, the upper-level trough and surface trough will remain nearly stationary enhancing shower and thunderstorm activity over the western Caribbean. The surface ridging pattern over the Atlantic will persist, keeping a similar wind profile in place across the basin into the middle of this week.

48 Hour Forecast - Favorable Environmental Conditions For Tropical Development

Infrared Satellite in Belize City

No current reports
Accuweather

5/18/2018

May 19, 2017

The Threat For Northwestern Caribbean Tropical Development Remains On The Table For The Middle To Late Parts Of Next Week: It still looks like we may see tropical development in the northwestern Caribbean as we get into the middle and later parts of next week. Any tropical system that does form in the northwestern Caribbean is currently forecast to move into the eastern Gulf of Mexico next weekend. This type of track would bring even more heavy rainfall and flooding to the Florida Peninsula next weekend along with the possibility of severe weather and tropical storm conditions.

Looking at the latest model guidance – All of the major global model guidance are in agreement in showing tropical development in the northwestern Caribbean between Wednesday and Friday of next week. What the guidance are not in agreement with right is the potential track of this system as they all show very different possible tracks.

The GFS and the GFS ensemble guidance show a more easterly track taking this system across southeastern Florida and near the coast of eastern Florida next weekend. This appears to be a bias with the GFS model and I suspect we will see a more westerly track than what these models show.

The Canadian model guidance is much quicker in its forecast track and shows a track into the eastern Gulf of Mexico by Friday followed by a track into the Big Bend area of northwest Florida next Saturday.

The European model guidance is the furthest west and weakest of the model suite and shows a very broad low pressure system to track northward into the central Gulf of Mexico on Thursday and Friday. By next weekend, the European model guidance forecasts this system to strengthen into a tropical storm as it moves into the northern Gulf of Mexico and into southeastern Louisiana next Monday.

The NAVGEM model is similar to the Canadian model in that it shows a track into the eastern Gulf of Mexico late next week followed by a track across western and northern Florida on Friday.

The multi-model (GFS, Canadian and European) ensemble tropical cyclone genesis probability charts currently forecast a 30-40 percent chance for tropical development in the northwestern Caribbean during the middle part of next week.

Here Are My Thoughts: I still think that we are going to have to keep an eye on the northwestern Caribbean for tropical development between Wednesday and Friday of next week. The convection that is currently occurring from the southwestern Caribbean northward through Jamaica to central Cuba is associated with a frontal boundary along the eastern United States. I do think that once this frontal system pulls away early next week, it will leave behind a piece of energy over the western Caribbean. At the same time, a tropical wave currently located to the east of the southern Lesser Antilles between 50 and 55 West Longitude will push westward over the next several days reaching the western Caribbean by about the middle of next week. What looks to occur is that the combination of the piece of energy being left behind and this westward moving tropical wave will potentially set off tropical development in the northwestern Caribbean during the middle and later parts of next week.

The very strong wind shear that is currently present across the entire Caribbean is forecast to decrease somewhat next week as the ribbon of strong wind shear lifts northward and is replaced by a upper level high pressure ridge. I think that the environmental conditions will be favorable enough to allow for tropical development to occur over the northwestern Caribbean. With that said, the environmental conditions will not be at all optimal, so we’re probably going to be looking at a very messy, east weighted tropical system.

Another factor that favors tropical development is that the upward motion pulse of the Madden Julian Oscillation will be placed right over the western Caribbean and Gulf of Mexico throughout next week. This should promote the development of widespread shower and thunderstorm activity from the western Caribbean into the Gulf of Mexico and also will assist in this potential tropical development.

As of right now, I still think that there is about a 20 percent chance for tropical development in the northwestern Caribbean between Wednesday and Friday of next week. The reason why I am not tacking on a higher chance for development is for a couple of reasons – The first is that the environmental conditions are forecast to be just be favorable enough for development and any changes in this will mean that conditions will be unfavorable and tropical development will not occur. The second reason is that while sea surface temperatures are sufficiently warm enough for tropical development over the northwestern Caribbean, analysis indicates that sea surface temperatures over the eastern Gulf of Mexico are not warm enough to support development. This means that anything that tries to form in the northwestern Caribbean may not maintain itself as it pushes into the eastern Gulf of Mexico.

I think that the European model is too far west with its forecast track and that the GFS model guidance is too far east with its forecast track.

So, overall, I think that we will see a track that brings a potential tropical storm from the northwestern Caribbean on Wednesday into Thursday through the eastern Gulf of Mexico just barely offshore of the west coast of Florida around Friday of next week. This potential tropical storm, I think, may make landfall in the eastern Florida Panhandle or the Big Bend area of northwestern Florida sometime next weekend. This is a favored storm track this time of year and based on all of the latest data, it is the type of track that seems most possible right now.

As I already mentioned, I think that this system will be a east weighted very messy tropical cyclone and heavy rainfall and flooding will be the main threat with this system. The entire Florida Peninsula will likely see another round of very heavy rainfall and flooding late next week through next weekend. Given that conditions are already very wet across the Florida Peninsula, heavy rainfall connected to a tropical cyclone could bring some significant to major flooding across a large part of the Florida Peninsula during the Memorial Day Holiday weekend. In addition, severe weather and tornadoes is also a potential concern across a large part of the Florida Peninsula next weekend.

In addition to this, there will be heavy rainfall and storminess starting in the southwestern Caribbean this weekend and spreading into the northwestern Caribbean next week. This heavy rainfall and storminess is expected to impact much of Nicaragua, Honduras, Guatemala, Belize and the Yucatan Peninsula.

The next tropical weather discussion will be issued on Monday Morning or sooner if conditions warrant.

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