ATL: TROPICAL DEPRESSION ALEX - DISCUSSION

[USTropics]

93L with shear overlay.

[lonelymike]

62 pages over this disorganized mess What's the record on the board for a particular system?

[KWT]

Shear still looks a little on the high side there though there is convection over the center of the system.

However this shows just how 100-200 miles away from the upper high conditions aren't nearly as condusive for development.

[cycloneye]

Here is an excerpt from the Hurricane Darby discussion related to 93L.

THE TRACK FORECAST IS HEAVILY DEPENDENT ON THE EVOLUTION OF THE AREA
OF LOW PRESSURE CURRENTLY OVER THE WESTERN CARIBBEAN. NEARLY ALL
OF THE GLOBAL MODELS SHOW DEVELOPMENT OF THIS SYSTEM BY THE TIME IT
GETS TO THE WESTERN GULF OF MEXICO IN A FEW DAYS...AND THESE MODELS
STALL DARBY BY DAY 2 FOLLOWED BY A NORTHEASTWARD ACCELERATION ON
DAYS 4 AND 5...MOST NOTABLY INDICATED BY THE ECMWF AND UKMET. THE
OFFICIAL FORECAST FOLLOWS THIS GENERAL PATTERN...BUT DOES NOT
INDICATE A POSITION AS FAR TO THE EAST ON DAY 5 AS THE MODEL
CONSENSUS TVCN...WHICH IS BEING INFLUENCED BY THE ECMWF AND UKMET
OUTLIERS. ON ANOTHER NOTE...THE GFS SHOWS ALMOST NO DEVELOPMENT OF
THE CARIBBEAN LOW AND THEREFORE KEEPS DARBY ON THE WESTERN SIDE OF
THE RATHER HELTER-SKELTER GUIDANCE ENVELOPE. ESSENTIALLY...THE
STRONGER THE CARIBBEAN LOW GETS WHILE IN THE GULF OF MEXICO...THE
FARTHER TO THE EAST DARBY COULD BE LOCATED BY THE END OF THE
FORECAST PERIOD.

[ronjon]

Buoy near the COC has pressure now at 29.71 with a SE wind of 21 kts gusting to 25 kts.

http://www.ndbc.noaa.gov/show_plot.php?station=42057&meas=wdpr&uom=E&time_diff=-4&time_label=EDT

[tolakram]

Though it has yet to reach TD status I think it's notable that MIMIC-TPW indicated pretty much exactly where this would develop, just follow the swirl.



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[HURAKAN]

06z

[Thunder44]

Shear still looks a little on the high side there though there is convection over the center of the system.

However this shows just how 100-200 miles away from the upper high conditions aren't nearly as condusive for development.

Yeah, it hasn't been able to really co-located under the core of the upper-level ridge. Which is why it's has remained disorganzied for the days. At this rate, I would not be suprised to see it not get upgraded before moving inland over the Yucatan or Central America. The ECMWF Ensemble Mean has had the best handle on this system this week, keeping it relatively weak,disorganized, and further south.

[HURAKAN]

Discussion:

...SPECIAL FEATURES...

AT 0900 UTC...A TROPICAL WAVE REMAINS OVER THE W CARIBBEAN
EXTENDING FROM OVER THE FLORIDA KEYS ACROSS CUBA ALONG 20N82W
THROUGH A 1006 MB SURFACE LOW NEAR 16N82W TO 12N81W.
SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 45 NM OF THE
TROUGH AXIS FROM 14N-17N WITH CLUSTERS OF SCATTERED MODERATE/
STRONG CONVECTION FROM 13N-17N BETWEEN 79W-84W.

THIS SYSTEM
HAS CHANGED LITTLE IN ORGANIZATION DURING THE PAST SEVERAL
HOURS. HOWEVER...UPPER LEVEL WINDS ARE GRADUALLY BECOMING MORE
CONDUCIVE FOR DEVELOPMENT AS THE LOW DRIFTS SLOWLY NW...AND THE
SYSTEM COULD BECOME A TROPICAL DEPRESSION BEFORE IT REACHES THE
YUCATAN PENINSULA IN A COUPLE OF DAYS. THERE IS A HIGH CHANCE OF
THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

[cycloneye]

70%

ABNT20 KNHC 251142
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT FRI JUN 25 2010

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

A LOW PRESSURE AREA CENTERED BETWEEN THE NORTHEAST COAST OF HONDURAS
AND GRAND CAYMAN CONTINUES TO SHOW SIGNS OF ORGANIZATION. SHOWER
ACTIVITY HAS BECOME A LITTLE MORE CONCENTRATED THIS MORNING...AND
SURFACE PRESSURES ARE FALLING. UPPER-LEVEL WINDS ARE GRADUALLY
BECOMING MORE CONDUCIVE FOR DEVELOPMENT...AND THE SYSTEM IS LIKELY
TO BECOME A TROPICAL DEPRESSION BEFORE IT REACHES THE YUCATAN
PENINSULA IN A COUPLE OF DAYS. THERE IS A HIGH CHANCE...70
PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS. AN AIR FORCE RECONNAISSANCE PLANE IS SCHEDULED TO
INVESTIGATE THIS DISTURBANCE LATER TODAY TO DETERMINE IF A TROPICAL
CYCLONE HAS FORMED.

A LARGE BUT DISORGANIZED AREA OF CLOUDINESS AND SHOWERS CENTERED
JUST EAST OF THE NORTHERN LEEWARD ISLANDS IS ASSOCIATED WITH A
TROPICAL WAVE INTERACTING WITH AN UPPER-LEVEL TROUGH. THIS ACTIVITY
IS EXPECTED TO MOVE TOWARD THE NORTHWEST AND ADDITIONAL
DEVELOPMENT...IF ANY...WILL BE SLOW TO OCCUR. THERE IS A LOW
CHANCE...10 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS.

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

$$
FORECASTER AVILA/ROBERTS

[KWT]

Yeah, it hasn't been able to really co-located under the core of the upper-level ridge. Which is why it's has remained disorganzied for the days. At this rate, I would not be suprised to see it not get upgraded before moving inland over the Yucatan or Central America. The ECMWF Ensemble Mean has had the best handle on this system this week, keeping it relatively weak,disorganized, and further south.

It is going to have to lift out somewhat soon if its going to get into the BoC or Gulf, looks like they are expecting that WNW/NW motion to kick in soon, esp with the LLC being present...however as you say the upper ridge is still shunted off to the west.

[HURAKAN]

YES!!!! WE HAVE RECON!!!

[KWT]

Hardly a shock w ehave recon, they'd e nuts not to send it in with land so close and a at least convection close to where the center was...

[pepeavilenho]

A LARGE BUT DISORGANIZED AREA OF CLOUDINESS AND SHOWERS CENTERED
JUST EAST OF THE NORTHERN LEEWARD ISLANDS IS ASSOCIATED WITH A
TROPICAL WAVE INTERACTING WITH AN UPPER-LEVEL TROUGH. THIS ACTIVITY
IS EXPECTED TO MOVE TOWARD THE NORTHWEST AND ADDITIONAL
DEVELOPMENT...IF ANY...WILL BE SLOW TO OCCUR. THERE IS A LOW
CHANCE...10 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS.

[Iune]

62 pages over this disorganized mess What's the record on the board for a particular system?

216 pages for 94L (pre-Dolly)

[srainhoutx]

Trailing wave

[KWT]

There was also an invest that got over 100 pages and never was upgraded...so we are still very low...esp compared to Fay, Gustav and Ike from 2008 which each went well over 500 pages...Ike ended up with just under 1000 pages when it was all combined...

Anyway yeah thats off topic, the first Vis imagery will be very interesting to see as it'll be our first chance to have a guess at whether we have any LLC down there yet or not. Its presentation does look sheared to me still though I have to admit.

[gatorcane]

A LARGE BUT DISORGANIZED AREA OF CLOUDINESS AND SHOWERS CENTERED
JUST EAST OF THE NORTHERN LEEWARD ISLANDS IS ASSOCIATED WITH A
TROPICAL WAVE INTERACTING WITH AN UPPER-LEVEL TROUGH. THIS ACTIVITY
IS EXPECTED TO MOVE TOWARD THE NORTHWEST AND ADDITIONAL
DEVELOPMENT...IF ANY...WILL BE SLOW TO OCCUR. THERE IS A LOW
CHANCE...10 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS.

Yes been tracking this wave and there is a thread already where we are discussing it. Models hinting at some development as it heads WNW to somewhere east of the Bahamas but development will be slow to occurr. Could be 94L in the next couple of days. I imagine 93L will steal the show though!

Topic:
viewtopic.php?f=31&t=108284

[HURAKAN]

Vorticity

[HURAKAN]

Somewhere around there, a LLC could be hiding!