ATL: TROPICAL DEPRESSION ALEX - DISCUSSION

[Aquawind]

I just don't anything looking like organization.. Plenty of outflow boundries but, zero rotation.. Cyclonic or LL in the orange arrows..

[KWT]

is it just me, or does the convection mass appear to be moving towards Hispanola?

Yeah it does seem like the MLC is moving WNW/NW, probably also the convergence region shifting northwards a little bit allowing more convection to develop further north. Got to be worried about flooding in DR/Haiti as well...

[srainhoutx]

HPC thoughts...

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
257 PM EDT TUE JUN 22 2010

VALID 12Z FRI JUN 25 2010 - 12Z TUE JUN 29 2010



FINAL...

THE 12Z/22 GFS AND GEFS MEAN ARE CLOSER TO THE LARGE SCALE PATTERN
DEPICTED BY THE 00Z/22 ECENS MEAN OVER EASTERN NORTH AMERICA DAY 6
THAN THE GEM GLOBAL AND UKMET...WHICH SHOW A MORE AMPLIFIED
POSITIVE PNA PATTERN. SEE NO GOOD REASON TO DEVIATE FROM THE
RELIABLE ECENS THERE...WITH THE TROUGH COMING INTO THE NORTHWEST
NOT A MAJOR POINT OF CONTENTION. COORDINATION WITH TPC ON THE LOW
IN THE GULF THIS PERIOD RESULTED IN A SLIGHTLY FASTER
FORECAST...WITH THE CIRCULATION APPROACHING THE UPPER TEXAS COAST
DAY 7.

CISCO

[BigA]

Looks to me like a surface circulation is trying to form at turtle speed to the southeast of Jamaica. Looks a bit more concentrated there than 3 hours ago, and the 850mb vorticity (5000 feet/1500 meters) seems to indicate that something's trying to bore down to the surface. I bet it will happen more quickly one then Mesoscale mid level low runs aground over Hispanola

[tolakram]

I just don't anything looking like organization.. Plenty of outflow boundries but, zero rotation.. Cyclonic or LL in the orange arrows..

Put the loop on the last 5 frames and observe the clouds south of the system. Notice how they are no longer streaming west? Rock the image back and forth to better demonstrate what I mean. Something is going on down there. Ignore the 'MLC' spin, it was a distraction.

http://rammb.cira.colostate.edu/ramsdis ... _floater_1

For comparison observe the low cloud motion above the islands.

[littlevince]

In MIMIC there are 2 distinct areas of vorticity at middle levels, one close to 75W and other perhaps close to 63W.
The first one (associated to 93L) is more robust today than it was yesterday at this time.

(click to loop 18z-18z)

[tolakram]

Trying my hand at a quick youtube video ... sat pic rocking back and forth. This is the same area mimic-tpw is showing the best spin as well.

Horrible quality ... will have to find a better codec next time i try this.

[youtube]http://www.youtube.com/watch?v=h-rvd1ZFA9U[/youtube]

[Ivanhater]

Mobile/Pensacola AFD

"LONG TERM (SATURDAY THROUGH TUESDAY)...
VERY LITTLE CHANGE IN THE OVERALL PATTERN WILL EXIST THROUGH THE
WEEKEND AS VERY WARM AND HUMID CONDITIONS PERSIST WITH ISOLD/SCT
MAINLY DAYTIME CONVECTION. ATTENTION TURNS TO THE TROPICS AS A WAVE
OF LOW PRESSURE POTENTIALLY ORGANIZES IN THE EASTERN CARIBBEAN...
BETWEEN CUBA AND THE YUCATAN PENINSULA. AS IS COMMON WITH DEVELOPING
TROPICAL SYSTEMS IN THE LONGER RANGE TIME FRAME...THE OPERATIONAL
MODELS ARE NOT IN AGREEMENT. IN FACT...THE 12Z/22 ECMWF AND 12Z GFS
ARE ON NEARLY OPPOSITE ENDS OF THE SPECTRUM. THE FORECAST WILL BE
DEPENDANT ON THE POSITIONING OF THE UPR HIGH WHICH WILL LIKELY MOVE
JUST OFF THE SOUTHEAST COAST AS AN UPR TROUGH DIGS ACROSS THE UPR
MIDWEST/NORTHEAST REGION.

ASSUMING CURRENT TROPICAL WAVE CAN REMAIN INTACT...THERE REMAINS A
CHANCE THAT FURTHER DEVELOPMENT COULD OCCUR AS THE WAVE DRIFTS
NORTHWEST INTO THE SOUTHERN GULF THIS WEEKEND INTO EARLY NEXT WEEK.
WILL HAVE TO SEE OVER THE NEXT COUPLE DAYS IF MEDIUM RANGE MODELS
SHOW BETTER RUN-TO-RUN CONSISTENCY...WHICH DOES NOT EXIST AT THE
MOMENT."

[Aquawind]

Ok I will give ya "Something is going on down there."

[srainhoutx]

AFD's are coming in from the TX NWS offices this afternoon...FYI: Houston is running late...

Corpus Christi...


FORECAST NEXT WEEK HIGHLY DEPENDENT ON TROPICAL SYSTEM CURRENTLY IN
THE CARIBBEAN SEA. IT DOES APPEAR NOW PER THE ECMWF/GFS/CANADIAN
THAT THE RIDGE ACROSS THE NORTHERN GULF AND SOUTHEAST U.S. WILL
WEAKEN AS A TROUGH DIGS THROUGH THE GREAT LAKES INTO THE EASTERN
CONUS. THIS WOULD ALLOW THE TROPICAL SYSTEM TO GAIN LATITUDE THROUGH
THE GULF. WILL FOLLOW CLOSE TO THE LEAD OF NHC/HPC MEDIUM RANGE
COORDINATION...WHICH CALLS FOR THE LOW CENTERED IN THE CENTRAL GULF
12Z MONDAY AND TOWARDS THE UPPER TEXAS COAST 12Z TUESDAY. INTRODUCED
LOW POPS INTO THE FORECAST FOR DAY 7 ON TUESDAY. IT SHOULD BE
STRESSED...IT IS STILL TOO EARLY TO SPECULATE ON EXACTLY WHERE AND
HOW THIS SYSTEM WILL IMPACT THE GULF OF MEXICO NEXT WEEK...AND THE
FORECAST FOR THE MIDDLE TEXAS COAST COULD CHANGE SIGNIFICANTLY.
THOSE WITH INTERESTS IN THE WESTERN GULF SHOULD CONTINUE TO MONITOR
THE PROGRESS AND DEVELOPMENT OF THIS WAVE THROUGH THE CARIBBEAN SEA
OVER THE COMING DAYS.

Austin/San Antonio

BEGINNING NEXT WEEK NUMERICAL MODEL GUIDANCE DEVELOP SEVERAL AREAS
OF LOW PRESSURE ACROSS THE WESTERN CARIBBEAN/GULF OF MEXICO. AT THIS
TIME...THEIR SOLUTIONS ARE A BIT DIFFERENCE...HOWEVER...FOR THE LAST
TWO DAYS...THE ECMWF MODEL HAS SHOWED SOME SORT OF TROPICAL
DEVELOPMENT OVER THE GULF OF MEXICO TOWARDS THE END OF THE FORECAST
CYCLE.

LOOKING A HISTORICAL TROPICAL CYCLONE DATA FOR THE LAST WEEK OF JUNE
(21-30)...MOST OF THE TROPICAL CYCLONES FORMED NEAR THE YUCATAN
PENINSULA AND OVER THE DEEP GULF. THE ONES FORMED NEAR OR OVER THE
YUCATAN TEND TO MOVE NNE AFFECTING AREAS FROM LOUISIANA EASTWARD TO
THE WESTERN FLORIDA COAST. THOSE THAT FORMED OVER THE DEEP GULF TEND
TO TRACK NORTH AND THEN WEST NORTHWEST AFFECTING THE SOUTH TEXAS
COASTLINE FROM WEST OF GALVESTON TO BROWNSVILLE.

WILL KEEP MONITORING AND ADJUSTING THE FORECAST AS NEW MODEL RUNS
COME IN. SO FAR...THIS TROPICAL MOISTURE IS EXPECTED TO
SIGNIFICANTLY INCREASE SHOWERS AND THUNDERSTORMS ACROSS THE SOUTH
COASTAL PLAINS AND SOUTH CENTRAL TEXAS NEXT TUESDAY AND WEDNESDAY
AND MAYBE INTO THURSDAY. FORTUNATELY...THE FORTH OF JULY WEEKEND
LOOKS GOOD AS STRONG HIGH BUILDS OVER THE CENTRAL PLAINS.

[HURAKAN]

If there has been any progress from yesterday is that there is more vorticity and convection is more persistent.

[Ivanhater]

Hmm..structure improving around the 18z track. Looks to be slowly organizing just as expected.

[CourierPR]

Looks to me like a surface circulation is trying to form at turtle speed to the southeast of Jamaica. Looks a bit more concentrated there than 3 hours ago, and the 850mb vorticity (5000 feet/1500 meters) seems to indicate that something's trying to bore down to the surface. I bet it will happen more quickly one then Mesoscale mid level low runs aground over Hispanola

It sure seems that something is happening in the general vicinity of 15N and 75W.

[AdamFirst]

What is that spin around 17N-72W? Could that be a center trying to form?

[cycloneye]

Definitly,something is trying to get going at the 18z Position 155N, 744W.

[Aquawind]

Well that's were it's suppose to be so maybe it's Cyclonic but I still don't see much LL organization.. Birthday Man broke me down..

[Aric Dunn]

Vorticity has definitely increased where the 18z track is focusing on

which is what I mentioned earlier happen south of Jamaica today .. the 18z is perfect if your looking any surface feature to form and its looks better now than it did this morning.. there is some very very broad turning now with some slight sw low level flow.

[PTrackerLA]

It does appear that vorticity is increasing based on the visual satellite loop. Anyone else thinking this could become quite a large TC if it were to form? The wave envelope is huge.

[Aric Dunn]

Now if the convection that is starting to firing near the 18z position continues to increase the vorticity will also increase and a surface circ may begin to take shape tonight. also the upper ridge is still in place over or near the 18z position so the shear is not a problem atm

[Wx_Warrior]

Those towns along the GOM (Mobile, Pensacola) that rely on vacationers to those beautiful beaches......this is so crucial.