LRandyB's Tropical Weather Discussion

Tropical Weather Discussion for Friday, June 22, 2012

By: LRandyB, 1:26 AM GMT on June 23, 2012

Things have been pretty quiet so far in the Atlantic after the early start. Hurricane Chris developed out over the open North Atlantic and stayed there without impacting land areas. Now we have Invest 96 in the Gulf to look at.

Let's take a look.....

In the Gulf of Mexico ......



Invest 96L is the news in the Gulf this weekend. 96L is actually a fairly large, broad area of low level circulation that is impacting most of the Gulf and the western Caribbean. Showers and thunderstorms are scattered from Central America and the Yucatan to western Cuba, the western Caribbean, and virtually all of Florida. The low level circulation covers nearly all the Gulf, and water vapor images show a fairly good upper level ridging pattern over the area. NHC reports that surface pressures are falling, and the system is becoming gradually better organized. Water temps in the Gulf are more than warm enough for development. Wind shear has been fairly high over the system for the last couple of days, but as the system moves northward into the central Gulf, shear should be somewhat less. While conditions aren't great for development, some development is possible.

The forecast for 96L is a bit problematic for the models at the moment. A lot depends on how well the system develops. Two basic scenarios emerge. One is the trough of low pressure in the Rockies picks the system up and drives it NE into N FL and into the Atlantic. The other is for the high pressure area over the southern plains to build eastward across the southeast US, preventing the trough from extending far enough south to pick up 96L and drive the system NW. I'm not placing any bets on the NE path for this system, but I also don't think it will have a lot of opportunity for development, so whatever makes it ashore should be little more than a rain event. For some parts of the Gulf Coast, that would be welcome. For some of us that have had a lot rain over the last week or so, not so much so. I'll keep on eye on the system as it progresses and update as needed here.


In the Caribbean .....



Most of the western Caribbean is dominated by the weather created by 96L and its broad circulation. The eastern Caribbean is enjoying quiet weather and hazy conditions as the result of a Saharan Air Layer that has moved into the region. I'll cover that more in the Atlantic discussion.

In the Atlantic ....



Most of the central and eastern Atlantic is under clear to partly cloudy skies with little in the way of weather. A fairly strong Saharan Air Layer is obvious on visible images as well as the Meteosat-9 SAL product covering a large part of the eastern Atlantic from the coast of Africa to the northeast Caribbean.



That broad circulation of 96L is impacting the weather over the western tropical Atlantic from the Bahamas to the GA coast. Another are of thunderstorms is seen associated with an upper level low 28N 68W with little movement to this low at the moment.

Have a great day!

Randy

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Tropical Weather Discussion for Sunday, June 3, 2012

By: LRandyB, 9:33 PM GMT on June 03, 2012

The 2012 Atlantic Hurricane Season officially began June 1st. We've already had two named systems, including the most intense ever recorded in pre-season activity. We haven't seen pre-season activity like this since 1908.

But the tropics have quieted a bit for the moment. Let's take a look.....

In the Gulf of Mexico ......



Weather in the Gulf of Mexico is fairly quiet today. In the low levels, high pressure over the SE US is producing the typical east to southeast trade winds we'd expect to see. The fact that that area of high pressure has shifted east into GA has helped to bring the normal southerly flow off the Gulf and helped to cool down the record high temps we were seeing last week along the SE coastal states when the high was in the mid-west giving a northerly flow.

In the mid and upper levels, high pressure over the western Caribbean is producing a westerly flow aloft over most of the Gulf. The upper level westerly flow over the low level east-southeast flow is producing very high wind shear in the range of 60 knots over most of the Gulf. Upper level difluence in the flow around the upper level high is producing a lot of high cloud cover over the Gulf but nothing in the way of real weather. There are some showers and thunderstorms over the Yucatan kicked off mainly by heating but aided by the upper level difluence.

In the Caribbean .....



Most of the Caribbean is experiencing very nice weather today with little cloud cover. There is a line of showers and thunderstorms associated with a weak tropical wave interacting with land moving ashore in Central America and this activity is aided by the difluence associated with an upper level high over Central America.

In the Atlantic ....



Most of the central and eastern Atlantic is under clear to partly cloudy skies with little in the way of weather. Visible satellite loops show a couple of mid-Atlantic tropical waves around 10N between 40W and 50W, but water vapor loops show little mid-level moisture or convection with these waves. Upper level shear is strong over most of the central Atlantic just east of the Lesser Antilles.

Over the western Atlantic a cold front is moving east and extends down into the central Bahamas. This front trails off into a stationary trough over the Florida Straights and western Cuba producing some showers and thunderstorms there.

The forecast models at the moment do not suggest any development for the next few days, but I'll update if anything looks like it has potential!

Have a great day!

Randy

Tropical

Updated: 11:48 PM GMT on June 05, 2012

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About LRandyB

I was an AF aviation weather forecaster for 12 years, then 15 years as a dropsonde systems operator with the AF Reserve Hurricane Hunters.

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