ATL: INVEST 94L - DISCUSSION

[Frank2]

That's disappointing - but I smelled rain this morning, and often that means rain within 24 hours, so we'll see...

Frank

[wxman57]

That's disappointing - but I smelled rain this morning, and often that means rain within 24 hours, so we'll see...

Frank

Check if your neighbor was watering his lawn, Frank. Maybe some of the disturbance's moisture will provide a little rain for Florida by Friday.

[cycloneye]

This is today's TCPOD for missions on Tuesday and Wednesday. Of course,the way 94L is behaving, they may never fly towards that system.

Code: Select all

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1015 AM EDT MON 06 JUNE 2011
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
         VALID 07/1100Z TO 08/1100Z JUNE 2011
         TCPOD NUMBER.....11-006

I.  ATLANTIC REQUIREMENTS
    1. SUSPECT AREA (CARIBBEAN)
       FLIGHT ONE -- TEAL 70
       A. 07/1800Z
       B. AFXXX 01AAA INVEST
       C. 07/1445Z
       D. 19.0N 82.0W
       E. 07/1745Z TO 07/2200Z
       F. SFC TO 10,000 FT

       FLIGHT TWO -- TEAL 71
       A. 08/0600Z
       B. AFXXX 0201A CYCLONE
       C. 08/0230Z
       D. 19.6N 82.3W
       E. 08/0530Z TO 08/0900Z
       F. SFC TO 10,000 FT

    2. SUCCEEDING DAY OUTLOOK: CONTINUE 12-HRLY FIXES IF
       SYSTEM REMAINS A THREAT.
    3. REMARK: LOW-LEVEL INVEST MISSION FOR 06/1800Z AND FIX
       MISSION FOR 07/0600Z CANCELED BY NHC AT 06/1100Z.



[fci]

It smells like rain here in Fort Lauderdale this morning - also, contrary to this past week there's an arrival of numerous low clouds this morning, so apparently our rainy season is about to start in ernest, and that's good - nothing worse than being hot and dry...

I won't mind if Arlene doesn't form, but it'd be nice to get the rain associated with the disturbance...

Frank

Do you see any upper level W or SW winds today Frank?
If not, then I don't see the start to the rainy season.
We need that early summer W or SW flow to get the sea breeze storms to fire up and move to the East coast!

[cycloneye]

This morning's discussion about 94L by Dr Jeff Masters. I agree with him about it being 20% not 40%.

There is not much change to report on the large, wet, and disorganized tropical disturbance (Invest 94L) in the Western Caribbean, between Jamaica and Mexico's Yucatan Peninsula. The disturbance has brought intermittent heavy rains to Jamaica over the past two days, but nearby islands have thus far escaped the deluge. Satellite-estimated rainfall amounts of 1" per hour occurred in ocean regions just east of Jamaica this morning, but the heaviest rains have missed the island so far this morning. Visible satellite loops show no increase in organization of 94L in recent hours, and the storm's low-level spiral bands and upper-level outflow are poorly defined. The storm's center of low pressure is located about 130 miles south of Grand Cayman Island, in a region with no heavy thunderstorm activity. An intense clump of thunderstorms exists on either side of this low, near Jamaica, and just east of Mexico's Yucatan Peninsula. Water vapor satellite loops show the Caribbean has moistened over the past two days, and upper air balloon soundings from the Cayman Islands continue to show much moister air at mid levels of the atmosphere (2% humidity at 500 mb on Saturday, compared to 69% last night.) Wind shear remains in the moderate range, 15 - 20 knots, and is predicted by the SHIPS model to remain below 20 knots through tonight. Water temperatures in the Central Caribbean are about 1°C above average, 28 - 28.5°C, which is 2°C above the threshold needed to support development of a tropical storm.

Since 94L is so large and poorly organized, today's mission by the Hurricane Hunters has been cancelled. A new mission is scheduled for Tuesday afternoon at 2pm EDT. This morning's 00Z and 06Z model runs were unimpressed with 94L, with most of them showing little or no development. A band of very high wind shear of 30 - 50 knots lies over Cuba and the southern Bahama Islands. The GFS and ECMWF models show 94L pushing slowly northwest at about 5 mph, hitting this shear on Tuesday and Wednesday, preventing any further development. The NOGAPS model predicts that a gap may open up in the shear sufficient for the storm to organize into a tropical depression late this week. Given 94L's current disorganization, I doubt the storm will ever develop. NHC gave 94L a 40% chance of developing into a tropical depression by Wednesday, and I believe these odds should be lower, near 20%. Regardless of development, 94L is capable of bringing very heavy rains to Jamaica, Cuba, the Cayman Islands, and Haiti through Wednesday. These rains will probably spread northwards into South Florida and the Bahama Islands by Thursday or Friday.

[canes04]

Have to disagree with you guys. It appears to be coming together as we speak.

[otowntiger]

I agree with Frank2 in that I don't really care if it develops, rather it wouldn't but sure would like some rain out of it. I'm keeping my fingers crossed for some beneficial rains this week. I'm concerned that with the delay of the rainy season here in Florida that we may see a repeat of '98. It seems that the weather is truly odd this year.

[AdamFirst]

Melbourne NWS doesn't give the system much hope to bring us much rain according to their AFD

THU-SUN...NEAR-PERSISTENT FORECAST FOR THU AND FRI AS LONG FETCH
EASTERLIES CONTINUE WITH THE AXIS OF THE RIDGE REMAINING NORTH OF
FLORIDA. RAIN CHANCES WILL STAY SLIGHT AND JUST BARELY BETTER FOR
THE SOUTH FORECAST AREA THAN ELSEWHERE. MAX TEMPS IN THE UPPER 80S
TO LOW 90S. THEN FOR THE WEEKEND...TROPICAL MOISTURE SPREADS
NORTHWARD ACROSS CUBA TOWARD SOUTH FLORIDA ACCORDING TO BOTH THE GFS
AND ECMWF IN ASSOCIATION WITH A BROAD CARIBBEAN LOW PRESSURE SYSTEM.
THE GFS IS COMPARATIVELY MORE CONSERVATIVE IN ITS EXTENT OF THE
MOISTURE ADVECTION. NONETHELESS...BOTH CONTINUE THE TREND AND SERVE
TO ELEVATE RAINFALL HOPES DURING THE PERIOD. THE MOISTURE IS PART OF
AN AREA OF DISTURBED WEATHER THAT IS CURRENTLY LARGE AND
DISORGANIZED...BUT THERE IS A MEDIUM CHANCE THAT TROPICAL CYCLONE
DEVELOPMENT COULD OCCUR IN THE NEXT 48 HOURS BEFORE UPPER LEVEL
WINDS ENDEAVOR TO WORK AGAINST IT. FOR MORE INFORMATION...REFER TO
THE TROPICAL WEATHER OUTLOOK FROM THE NATIONAL HURRICANE CENTER.

[MGC]

If you want rain wash your car.....

94L looks like a train wreck to me...at least the atmosphere to the west of the CC has got rid of that dry air. So, have UL shear forecasts improved to say with any confidence that the shear over the W Carb is going to increase that much? 94L might just sit and fester for several more days before developing or dissipating....MGC

[NDG]

Have to disagree with you guys. It appears to be coming together as we speak.

I agree with you. I think some of the shear will actually help the system at least in the short term to develop more convection.

[ronjon]

The GFDL model actually predicts that 94L will sit around its same location for the next 2 days with perhaps a slow N-NW drift. In any case, if 94L doesn't develop, the low pressure system isn't going to go away, the deep tropical moisture will not vanish, and long range models like the Euro which do a decent job in the 3-5 day outlook show that this weather will push north up the FL peninsula. So the odds are the rainy season will start in earnest by the weekend for Floridians.

[wxman57]

I'm not seeing anything to indicate it's becoming better organized today. Pressure at the buoy near the weak LLC has risen 2mb since sunrise. Winds are from 5-15 kts around the weak circulation. Convection is pitiful, convergence is nonexistent, and it's heading into strong shear. Even a 20% chance of development now appears to be quite generous.

[AdamFirst]

All I want is for it to survive the upcoming shear gauntlet over Cuba and the Bahamas...have some resemblance of it intact so the southeast can get some needed rain somewhere

[boca]

The ULL over the BOC is drifting east and that will ultimately push 94L NE ward away from Florida You can clearly see that in the water vapor loop. If that ULL wasn't there 94L would be a player

http://www.ssd.noaa.gov/goes/east/watl/flash-wv.html

[GCANE]

Interesting convection SW of Grand Cayman


http://rammb.cira.colostate.edu/product ... 052315.GIF

http://rammb.cira.colostate.edu/product ... 061015.jpg

[HURAKAN]

very broad system

[Rgv20]

From Monday to Thursday evening 94L is going to be fighting some nasty shear especially near western Cuba in its path to the Gulf of Mexico.

[SouthFloridawx]

I'll start my post with this info.

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON JUN 06 2011


...SPECIAL FEATURE...

A 1008 MB LOW PRESSURE CENTER IS NEAR 17N81W...ABOUT 130 NM
SOUTH OF GRAND CAYMAN. THIS LOW CENTER IS CAUGHT UP IN THE BROAD
MONSOONAL TROUGH THAT EVENTUALLY EXTENDS FROM THE WESTERN
CARIBBEAN SEA ACROSS NICARAGUA INTO THE EASTERN PACIFIC OCEAN.
SCATTERED STRONG RAINSHOWERS AND THUNDERSTORMS ARE IN
THE WATERS THAT SURROUND JAMAICA WITHIN 180 NM FROM EAST TO
SOUTHWEST. NUMEROUS STRONG RAINSHOWERS AND THUNDERSTORMS ARE
ALSO FROM 16N TO 20N BETWEEN 83W AND 86W. BROAD SURFACE-TO-LOW
LEVEL CYCLONIC FLOW COVERS THE CARIBBEAN SEA TO THE WEST OF 75W.
THE EARLIER NUMEROUS STRONG RAINSHOWERS COVER NICARAGUA FROM
SIX HOURS AGO HAVE WEAKENED/DISSIPATED. OTHER RAINSHOWERS ARE
POSSIBLE ELSEWHERE IN THE WATERS THAT ARE TO THE WEST OF 70W.


In my personal opinion, as you can see above the system is caught in the eastern edge of a monsoon trough. As long as it's being fed it will continue to be even if it is weak.



The system is also sitting very near an Upper Level High pressure. The center of which is off the coast of Honduras and Nicaragua.



Since the system is very broad, due to the fact that it is being influenced very strongly by the monsoon trough. So a relocation of the main center could occur closer to the center of the ULH and very near where the eastern edge of the monsoon trough is. Since we have the two factors, the ULH and the Monsoon trough I think it will continue to persist even though, it is being influenced by shear by the ULL and the trough.

If we see a substantial blow up of thundestorms to day on the south side, I think we'll see it get better organized.

It also appears looking at the WV loop seen below that the Trough to it's Northeast is pulling out of the area.

http://rammb.cira.colostate.edu/ramsdis/online/loop_640.asp?product=tropical_ge_14km_wv

[Frank2]

I'm not seeing anything to indicate it's becoming better organized today. Pressure at the buoy near the weak LLC has risen 2mb since sunrise. Winds are from 5-15 kts around the weak circulation. Convection is pitiful, convergence is nonexistent, and it's heading into strong shear. Even a 20% chance of development now appears to be quite generous.

True, it doesn't look very impressive - but I'm hoping my old Indian instincts know that we might at least get some rain out of this - we need it...

Frank2

[canes04]

Give it 12 to 24 hours guys. The High is now in place, it just needs some time to consolidate.