Atlantic INVEST 94L

[SouthFloridawx]

'Canefreak, You are correct as far as I know... It has always been my understanding that, Low Level Flow does steer a low level system. It would make no sense to me that, an low level system in the low, to mid level of the Troposphere, would be steered by the upper levels.

As I see it... Convection was and is being started by the ULL. Also at the same time, if during the summer months here in the Atlantic, sometimes when you get convection that is sustained over an area, it can form an area of low pressure in the lower levels.

CLOUDINESS AND SHOWERS OVER THE NORTHWESTERN CARIBBEAN SEA ARE
ASSOCIATED WITH A BROAD AND ELONGATED AREA OF LOW PRESSURE.
UPPER-LEVEL WINDS ARE CURRENTLY UNFAVORABLE FOR DEVELOPMENT...BUT
MAY BECOME MORE FAVORABLE DURING THE NEXT 48 HR AS THE SYSTEM
DRIFTS TOWARD THE NORTHWEST.

If there is no more convection associated with an area of low level pressure, then it will die off. The thunderstorms is pretty much the main part of what was and or is causing the low level pressure.

If the ULL is moving off to the East that doesn't mean that the the low level pressure will follow.

Lets look at the 00 hour of the 250mb wind/heights and the 500mb. These are two different levels of the atmosphere.

This first image we see the 200mb vorticity, we know the location of the upper level low and it shows up here on the this map.


Here is the 250 mb wind/heights 18Z GFS 00 Hour. We see currently that in the same area of the ull, winds are moving to the east and so is the ULL.


Here is the 500mb same run, same hour. There is not much wind in the area at all... Also we know that in high pressure rotates clockwise in the Northern Hemisphere. Looking at weak tropical systems in the tropics, it's usually the best to look at the mid to low level steering. In this case, our system is parked on the Western side of the High Pressure, with nothing to steer it out.



At the same time, if the thing that was sparking the convection, The ULL pulls out of the area and the low pressure isn't very strong, and there is no convergence at the surface, this area will die off and the the spin will die down.

We'll have to see how much longer convection is in the area and if it isn't then it won't.

But, please know this low level pressure is not going to shoot off to the north and east... Just the ULL, the thing that is sparking the convection is.

[Recurve]

Right. Will be a stormy Saturday in Miami with a moisture plume pulled up over the Keys and south florida.

[bahamaswx]

By tomorrow it will be a Bahamas system.

It wouldn't be a Bahamas system because the surface low pressure center is in the NW Caribbean, and it will not be moving to the NE right now. Surface & mid level ridge are moving in from the east, surface pressures across the Bahamas have been on the rise since the past 24 hrs.

Pft. We claim this one!

[Rainband]

poof. I don't see anyhting worth an invest??

[Thunder44]

This "invest" doesn't appear to be getting any better organzied this morning. Most of the shower and thunderstorm activity has shifted south or over Western and Central Cuba. That and the ULL over the western tip of Cuba appears to be moving ENE. I don't see the NW movement the TPC was expecting last night and TC development looks unlikely to me to occur today.

[caneman]

next

[Chacor]

000
ABNT20 KNHC 150902
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 AM EDT FRI JUN 15 2007

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

CLOUDINESS AND SHOWERS OVER THE NORTHWESTERN CARIBBEAN SEA ARE
ASSOCIATED WITH A BROAD AND ELONGATED AREA OF LOW PRESSURE.
UPPER-LEVEL WINDS ARE CURRENTLY UNFAVORABLE FOR DEVELOPMENT...BUT
MAY BECOME MORE FAVORABLE DURING THE NEXT 48 HOURS AS THE SYSTEM
DRIFTS TOWARD THE NORTHWEST. AN AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT IS SCHEDULED TO INVESTIGATE THE SYSTEM THIS AFTERNOON...
IF NECESSARY.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BEVEN

[N2FSU]

Looks pretty pitiful this morning.

[wxman57]

By tomorrow it will be a Bahamas system.

It wouldn't be a Bahamas system because the surface low pressure center is in the NW Caribbean, and it will not be moving to the NE right now. Surface & mid level ridge are moving in from the east, surface pressures across the Bahamas have been on the rise since the past 24 hrs.

I didn't say it'll be a "Bahamas system" but that the convection will track across the Bahamas with the upper low. All we had in the western Caribbean was a very weak tropical wave, too weak to even sustain convection without the upper low. Now that the upper low is leaving, there won't be enough lift to fire off convection. Of course, pressures will continue to be lower in the SW-W Caribbean as they always are this year. Eventually, another wave down the line will spark more convection, perhaps under more favorable conditions. But that could be weeks from now.

You know, as I look at the water vapor I can see that the first wave is already well to the west around 92-93W. The second wave we've been tracking westward through the Caribbean (no convection either) is what's causing some storms just SE of the upper low. This second wave axis is along 85W-86W and moving westward at 10-15 mph. Once it passes, there's yet another wave along 80W crossing Central America. But most of its energy is way down south, probably too far south to enhance thunderstorms east of the Yucatan.

[DanKellFla]

I guess Sunday won't be a beach day in South Florida.

[TampaFl]

From NWS Melbourne:

000
FXUS62 KMLB 150720
AFDMLB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
320 AM EDT FRI JUN 15 2007

.DISCUSSION...TODAY...STUBBORN UPPER TROUGH OFF NEW ENGLAND WILL
FINALLY LOOSEN ITS GRIP ALONG THE EASTERN SEABOARD. WITH BUILDING
HEIGHTS...LATEST GFS SHOWS 500 MB TEMPS RISING THROUGH THE DAY TO
AROUND -6C DURING THE AFTERNOON. SYNOPTIC ENVIRONMENT IS NOT ALL
THAT FAVORABLE FOR ORGANIZED CONVECTION AND THE ATMOSPHERE WILL
NEED TO RELY ON THE EAST COAST SEA BREEZE TO GENERATE LIFT AND
LOW-LEVEL MOISTURE CONVERGENCE. GIVEN THE LACK OF DEEP MOISTURE
AND A LIGHT ONSHORE FLOW (RESULTING IN A FASTER DEVELOPING EAST
COAST SEA BREEZE)...WILL RUN WITH RAIN CHANCES BETWEEN 20 AND 30
PERCENT...HIGHEST ACROSS THE SOUTHERN AND INTERIOR COUNTIES.
HOWEVER...ANY STORMS THAT DO FORM WILL STILL BE CAPABLE OF
PRODUCING HEAVY RAIN...FREQUENT LIGHTNING AND STRONG WINDS.

TONIGHT...GFS HAS BACKED OFF ON THE MOISTURE ADVECTION AND PRECIP
CHANCES. THIS IS NOT SURPRISING...GIVEN THE FACT THAT THE DEEPEST
MOISTURE BETWEEN THE YUCATAN AND CUBA APPEARS TO BE MAKING MORE
PROGRESS EASTWARD THAN NORTHWARD. COMBINE THIS WITH THE FACT THAT
THE MODEL MAY NOT HAVE INITIALIZED THE LOCATION OF THE YUCATAN 500
MB TROUGH TOO FAR WEST...WILL AGAIN RUN WITH POPS BELOW MAV GUIDANCE.

WEEKEND...EASTERN U.S. MID-LEVEL CYCLONE FINALLY DEPARTS INTO THE
ATLANTIC...ALLOWING DEEP TROPICAL MOISTURE TO STREAM NORTHWARD
BETWEEN WESTERN CARIBBEAN ANTICYCLONE AND UPPER LOW OVER TEXAS.
SUITE OF HEMISPHERIC MODELS PRESENTLY AGREE THAT TROPICAL
DISTURBANCE NEAR THE YUCATAN CHANNEL WILL NOT CONSOLIDATE INTO A
DISCRETE/DEEP SURFACE LOW...BUT INSTEAD SEVERAL PACKETS OF MID-LEVEL
VORTICITY WILL LIFT NORTHEAST ACROSS FLORIDA/BAHAMAS...PRODUCING A
SERIES OF WEAK LOWS. LOW LEVEL BOUNDARY/QUASI-FRONT CURRENTLY OVER
THE KEYS WILL ALSO WORK NORTHWARD TOWARD CENTRAL CWA AND SHOULD RESULT
IN A DIVIDING LINE BETWEEN HIGHER RAIN CHANCES TO THE SOUTH AND
LOWER TO THE NORTH. IN ADDITION...BOUNDARY MAY PROVIDE ENHANCED
SHEAR TO FOCUS A FEW STRONGER/ORGANIZED STORMS. WILL CONTINUE WITH
ABOVE NORMAL RAIN CHANCES OVER THE WEEKEND (MAINLY DIURNAL) WITH
SCATTERED-NUMEROUS SHOWERS/STORMS SOUTH AND SCATTERED NORTH. WITH
PRECIPITABLE WATER VALUES LIKELY REACHING WELL OVER 2 INCHES...
SOME PERIODS OF HEAVY RAINFALL EXPECTED...ESPECIALLY NEAR
LOCATION OF BOUNDARY/QUASI-FRONT. MAX TEMPS AT OR SLIGHTLY BELOW
CLIMO WITH MINS NEAR NORMAL.



$$

SHORT TERM/AVIATION...HIRSCH
LONG TERM....SPRATT

[wxman57]

Taking a look at the NW Caribbean with GARP, I can see straight SE winds across the NW Caribbean by buoys/ships. The buoy near 20N/80W has a pressure up 5mb from last night, now 1010.5mb. Thunderstorms are moving across Cuba toward the Bahamas. The discussion just above says it all. Just some packets of vorticity moving NE causing rain in south FL and the Bahamas over the weekend.

[HURAKAN]

It seems the bottom line is a lot of rain but no Barry-like system from this disturbance.

[tgenius]

I find it funny how everyone complained about no rain in miami.. and midway through June we have about 7 inches already!

[dizzyfish]

I'll take some of your rain! We still need it badly up here.

[benny]

ugh. this sucker is really dead. nothing to talk about for a while.. maybe not until July with the active convection phase of the MJO entering the western Pacific soon.

[Hyperstorm]

Just because a disturbance loses some convection for a while doesn't mean it's dead or that the chances of development have greatly diminished. Yesterday, many were excited about the possibility of development. Now today, we're seeing complete negativism among most. Come on, people...remember how the tropics can change in an instant. They've done it before!

I'm currently seeing a disturbance that has all the potential to become a player during the next few days. In fact, latest satellite images do indicate popcorn-type convection firing up just to the S of Isla Juventud. This system does have the look of one that wants to separate from the trough to the NE and be "left behind". This is a scenario that is typically quite favorable for development as these types of systems tend to find better upper-levels as the trough pulls away. There also seems to be some kind of mid-level twisting to the S and SW of Isla Juventud, which is definitely sparking my interest.

I do expect the recon mission today to be cancelled, but don't be surprised if it's re-scheduled for tomorrow afternoon, as it appears that the upper-levels will continue to become more favorable over the next 24-36 hours. It seems like the pieces are coming together for a low pressure center to form rather soon. Keep an eye on it...

[DESTRUCTION5]

Just because a disturbance loses some convection for a while doesn't mean it's dead or that the chances of development have greatly diminished. Yesterday, many were excited about the possibility of development. Now today, we're seeing complete negativism among most. Come on, people...remember how the tropics can change in an instant. They've done it before!

I'm currently seeing a disturbance that has all the potential to become a player during the next few days. In fact, latest satellite images do indicate popcorn-type convection firing up just to the SE and S of the Cayman Islands. This system does have the look of one that wants to separate from the trough to the NE and be "left behind". This is a scenario that is typically quite favorable for development as these types of systems tend to find better upper-levels as the trough pulls away. There also seems to be some kind of mid-level twisting near Grand Cayman, which is definitely sparking some interest in me today.

I do expect the recon mission today to be cancelled, but don't be surprised if it's re-scheduled for tomorrow afternoon, as it appears that the upper-levels will continue to become more favorable over the next 24-36 hours. It seems like the pieces are coming together for a low pressure center to form rather soon. Keep an eye on it...

I agree Completely..

[boca]

I see a new area SW of that ball of convection over Cuba starting to fire up 200 miles SE of Cozemel. Not dead yet but not a Florida player.

http://www.ssd.noaa.gov/goes/east/watl/loop-avn.html

[Hyperstorm]

I made an edit above regarding the location. I meant to reference Isla Juventud and NOT Cayman Islands.