Gulf of Mexico low growing more organized
The large extratropical storm that has been drenching Florida over the past few days continues to pour rain on the state as it treks slowly west-northwestward over the Gulf of Mexico. Rainfall amounts as high as 23.75 inches have been measured in Northern Florida at the Flagler County Fairgrounds over the past four days, and Daytona Beach has seen over 14 inches, forcing closure of numerous roads. Another 1 - 3 inches are expected in Northeast Florida today from the storm, along with beach erosion, 7 - 10 foot waves, and tides 2 - 3 feet above normal. The bad weather in Northeast Florida should gradually subside Friday and the rains should diminish substantially on Saturday, when the center of the storm is expected to move ashore over Louisiana.
Figure 1. Storm total rainfall estimated from the Melbourne radar.
Latest visible satellite loops show that the circulation of the low has grown more circular and better defined, and heavy thunderstorm activity is starting to build off the Gulf Coast of Florida on the low's east side. These thunderstorms are beginning to form spiral bands characteristic of a developing tropical depression. Water vapor satellite imagery shows that the low is moving into an area of dry continental air, though, and this dry air will slow development. Wind shear is about 20 knots, which is low enough to allow development. While none of the computer models develop the storm, they generally predict the storm should move northwestwards towards Louisiana over the next two days, and the shear is lower to the north. The low is currently over Sea Surface Temperatures (SSTs) of about 27°C in the Loop Current, which is about 1°C (1.8°F) warmer than average. SSTs of at least 26°C are typically needed to support a tropical storm, so I expect the low will continue to develop through Friday. By Friday night, the low will be approaching the Louisiana coast, and SSTs will cool to 26°C. Still, with wind shear expected to drop, this low has a medium (30 - 50%) chance of developing into a subtropical or tropical depression before its expected landfall Saturday over Louisiana. Since there will be strong winds from the west creating wind shear over the storm, plus dry air to the storm's west, most of the heavy rain should be confined to the east of the storm's center, along a stretch of coast from New Orleans to Pensacola. Rainfall totals of 3 - 6 inches can be expected.
Figure 2. Latest satellite image of the Gulf of Mexico storm.
I'll have an update Friday morning, or sooner if NHC declares this storm an area of interest (an "Invest").
Jeff Masters
Taken last night with a 16mm lense. Enjoy
Mark
www.shockpic.smugmug.com
Reader Comments
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There's plenty of humidity at the surface,if the sun breaks out it w/further distablize things by heating the humid air mass and w/general lower pressures in the area the airmass is much more boiant,as the storms build and punch into the drier are above w/could have some isolated severe wx...and that will also moderate the drier air in the UL this afternoon,tonight most of that dry air in the UL should be gone to the south of the low,IMO...
Sorry my bad.......but I didn't say ULL I said upper-level vortex.....and if you look at the same map I linked you'll see a kink in the wind barbs off the SC/Georgia coast. That is the spin evident in WV imagery.
Gulf of Mexico - AVN Color Infrared Loop
3" so far in the last week here on siesta key in the ol'rain gauge.....
Lol....I'm not the firstest one to use that term around here. It is just basically the processes that govern the function of non-tropical storms in the mid-latitudes. Thunderstorms along fronts like the ones near Jamaica form as a result of difference in temperature in the airmasses on both sides of the front and converging air. Thunderstorms driven by tropical processes derive their energy directly from the heat an moisture available from the ocean.
MARK
25.8N/86.0W
movement nw
..Runn,REUnn,..Runn..
Wow straight to name calling all over a little sports trash talking, you must be all of 3 years old.
Pounded huh, you better take cover LOL!
Link
cool
Yeah you're right, my bad on loosely using the term "front". Those t-storms are still not "tropical" though, and therefore pose no threat for development into a tropical system.
It has also begun to take on the cloud structure of Andrea, with multiple bands of parallel convection.
No its ok because without looking at surface obs, it would appear to be frontal in nature. Yea they are not tropical in nature since they being created by upper level forcing, ie. baroclinic processes.
It looks very similar to Andrea.
Be Back Later
there is a weak surface trough there???:
The system is still mostly extratropical, and therefore the highest winds are located far from the center. The strongest winds are gales northeast of the system in the strong bands that have been affecting Florida over the last couple days.
I see that as well. But will that convection persist? It could just be temporary b/c of the warm loop eddy. However, if the firing up of convection persists - we will see our next invest - or STS Ana - my prediction is later tonight or early Fri morning.
Not wishcasting - just IMO.
If it was August or September we would not be talking about a subtropical storm. That's for sure.
Again this system is still for the most part extratropical in nature. Dry air and wind shear are not hindering factors for such systems. It is likely that if a truly tropical system of this strength entered this environment right now it would have very little chances of doing much. Right now as this system attempts to go warm-core it will moisten up the environment a little bit at a time as thunderstorms form and fizzle over and over again.
The problem for this system is that by the time it becomes warm-core, it will be over water temperatures less than 26c south of Louisiana. The irony of this is that when the system is finally nameable, it will no longer be able to be supported in its environment. In any case, the worst that this system will ever have to offer has probably already happened in Florida as an unnamed system. Ironic huh?
Nuff said about football...
307. I'm glad you guys got some needed rain up there...send some down here. We've gotten about a half inch in the last week here in North Fort Myers. Getting ready for a band rolling in now though. Hopefully it'll stay together today...
Here you go, I hope you can see that well enough, it's not the best zoom-in, but I thought you'd like lat/lon lines on it. Paste the image url into your browser if you want it full size. There is a very weak vortex southwest of the main center, but I doubt there will be any more centers to compete with the main one in the near future.
...DISCUSSION...
THE GULF OF MEXICO...
A 1006 MB LOW IS OVER THE E GULF OF MEXICO NEAR 26N86W. BANDS OF
WIDELY SCATTERED MODERATE CONVECTION ARE OVER THE NE GULF OF
MEXICO AND FLORIDA FROM 24N-29N BETWEEN 80W-86W. A TIGHT
PRESSURE GRADIENT OVER THE NE GULF IS PRODUCING 20-25 KT WINDS N
OF 27N E OF 90W. THE W GULF OF MEXICO W OF 90W HAS PARTLY CLOUDY
SKIES WITH 10-15 KT N WINDS. IN THE UPPER LEVELS...AN UPPER
LEVEL LOW IS CENTERED OVER THE E GULF NEAR 28N85W. THE NE GULF
AND FLORIDA HAS ABUNDANT UPPER AIR MOISTURE WHILE STRONG
SUBSIDENCE IS OVER THE REMAINDER OF THE GULF. EXPECT...THE
SURFACE LOW TO DRIFT NW TO THE CENTRAL GULF OF MEXICO OVER THE
NEXT 24 HOURS WITH CONVECTION MOSTLY N OF THE CENTER.
They don't seem concerned at all and I don't foresee an invest anytime soon.
Tropical Cyclone Outlook (0600z 21MAY)
===========================================
Convective clouds are seen over Andaman Sea, south Bay of Bengal, and parts of southeast Arabian Sea
MONSOON WATCH
===================
Conditions are becoming favourable for onset of monsoon over Kerala and further advance over some parts of south Arabian Sea, some more parts of south Bay of Bengal and some parts of central Bay of Bengal during next 2-3 days.
Chief Meteorologist Forecast Outlook (1200z 21MAY)
==================================================
Current meteorological analysis indicate that a low pressure area is likely to form over southwest and adjoining southeast Bay of Bengal by tomorrow.
Joint Typhoon Warning Center
Tropical Disturbance Summary (1800z 21MAY)
========================================
An area of convection (98B) located at 13.9N 88.1E or 515 NM south of Kolkata, India. Recent animated infrared satellite imagery shows a broad, poorly organized area of convection to the southeast of a formative low level circulation center. Earlier imagery showed the area had multiple circulation centers, but the system has consolidated into a single circulation in last 12 hours. A 1138z Windsat image shows 10-15 knot winds close to the low level circulation center with a broad region of 20-25 knot southwesterly winds to the southeast of the low level circulation center. A 1126z SSMIS image shows a broad low level circulation center with scattered pockets of deep convection near the center and to the southeast of the low level circulation center. The system is located under the upper level ridge axis and environmental analysis indicates the system is in an area of favorable sea surface temperatures and low vertical wind shear.
Maximum sustained winds near the center is 12-17 knots with a minimum sea level pressure of 1007 MB. The potential for this disturbance to form inot a significant tropical cyclone within the next 24 hours is POOR.
Due to the pressure gradient more than anything.
Apology accepted. I agree, back to weather related items, we'll save the football talk until the fall and only when the tropics are quiet LOL!
Is that where the Black Pearl is?
'Ere there be treasure!
How much rain do you think SE Louisiana will see from this system by Tuesday?
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