[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 241754
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI AUG 24 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1730 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 22W/23W S OF 16 KT. THE WAVE PASSAGE WAS
EVIDENT IN THE DAKAR RAOB DATA AROUND 22/1200 UTC...WHICH
SUGGESTS THE WAVE IS MOVING W JUST UNDER 10 KT. THE WAVE IS
OVERALL DIFFICULT TO LOCATE WITH CONVENTIONAL SATELLITE IMAGERY.
HOWEVER...THE WAVE AXIS IS EVIDENT IN METSAT-9 LOW TO MID LEVEL
CLOUD DRIFT WINDS. THIS...ALONG WITH THE SURGE OF MOISTURE NOTED
IN THE UW-CIMSS TPW PRODUCT...WERE THE MAIN TOOLS USED IN
PLACING THE WAVE AXIS. THERE IS A CLUSTER OF SCATTERED MODERATE
CONVECTION E OF THE AXIS FROM 12N-15N BETWEEN 18W-21W...BUT WITH
THE PERSISTENT ELY SHEAR OVER THE AREA IT IS HARD TO SAY THIS IS
ASSOCIATED WITH THE WAVE.

A LOW AMPLITUDE TROPICAL WAVE IS ALONG 47/48W S OF 14N MOVING
10-15 KT. LOW LEVEL CYCLONIC TURNING IS EMBEDDED IN THE ITCZ
FROM 8N-12N BETWEEN 44W-51W. SCATTERED SHOWERS/ISOLATED TSTMS
ARE WITHIN 150NM EITHER SIDE OF THE AXIS S OF 11N. THERE
CONTINUES TO BE WHAT APPEARS TO BE A HIGHER AMPLITUDE INVERTED V
PATTERN JUST E OF THE LESSER ANTILLES...BUT THE EVOLUTION OF
THIS FEATURE IS A LITTLE BLURRY AND COULD BE MORE IN RESPONSE TO
THE LIFT ASSOCIATED WITH THE UPPER LOW NEAR 21N56W...IN ADDITION
TO CONFLUENT LOW LEVEL FLOW BETWEEN THE PAIR OF WEAK ATLC SFC
HIGHS ANALYZED ON TODAY'S 1200 UTC MAP.

TROPICAL WAVE PREVIOUSLY ALONG 71W WAS RELOCATED TO 76W S OF 18N
MOVING W NEAR 20 KT. THE RELOCATION WAS PRIMARILY BASED ON QUICK
WWD MOVING SURGE OF MOISTURE NOTED IN THE UW-CIMSS TPW
PRODUCT...WHICH WERE THE SHOWERS/TSTMS NOTED MOVING THROUGH THE
ABC ISLANDS AROUND THIS TIME YESTERDAY. SCATTERED MODERATE TO
STRONG CONVECTION IS S OF 11N BETWEEN 76W-81W.

TROPICAL WAVE IS ALONG 87W S OF 23N MOVING W NEAR 15 KT. WAVE
HAS BECOME A LITTLE MORE DIFFICULT TO LOCATE TODAY BUT MOISTURE
HAS INCREASED IN THE NW CARIBBEAN AND SRN GULF OVER THE LAST 24
HOURS...WITH SCATTERED SHOWERS/TSTMS NOTED FROM 17N-26N BETWEEN
83W-87W...WHICH ARE ALSO BEING SUPPORTED BY THE UPPER LOW OVER
THE MIDDLE GULF NEAR 25N87W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N15W 9N20W 7N25W 9N46W 10N65W.
SCATTERED MODERATE CONVECTION IS AFFECTING
TRINIDAD...TOBAGO...AND ADJACENT WATERS FROM 9N-13N BETWEEN
57W-64W. OUTSIDE OF THIS ACTIVITY AND THAT DESCRIBED WITH THE
TROPICAL WAVES...THE AXIS IS PRETTY QUIET.

DISCUSSION...

GULF OF MEXICO...
THE NRN PORTION OF THE TROPICAL WAVE ALONG 87W IS OVER THE S
CENTRAL GULF AS DESCRIBED ABOVE. A WEAK SFC TROUGH IS OVER THE
BAY OF CAMPECHE ALONG 24N96W 19N93W. AN INVERTED UPPER TROUGH
ALSO EXTENDS NE FROM THE COAST OF MEXICO TO JUST OFF THE S TEXAS
COAST. THESE FEATURES ARE SUPPORTING A CLUSTER OF SCATTERED
MODERATE CONVECTION NEAR 24N95W. THE DOMINANT UPPER FEATURE IS
THE UPPER LOW SPINNING NEAR 25N87W THAT HAS SCATTERED TSTMS FROM
THE YUCATAN CHANNEL TO 28N BETWEEN 84W-88W. SCATTERED TSTMS ARE
ALSO NOTED ALONG AND S OF THE LOUISIANA COAST N OF 25N BETWEEN
91W-94W. WEAK SFC RIDGING WILL PERSIST ALONG 30N OVER THE NEXT
COUPLE OF DAYS AS WEAK TROUGHING MEANDERS IN THE SW PORTION.

CARIBBEAN SEA...
THE MOST ACTIVE WEATHER IN THE BASIN IS IN THE SW CARIB OFF THE
COAST OF PANAMA/COLOMBIA...WITH SCATTERED MODERATE TO STRONG
CONVECTION S OF 11N BETWEEN 75W-81W. IN ADDITION TO THE TROPICAL
WAVE MOVING INTO THE AREA THIS ACTIVITY IS BEING SUPPORTED BY
SPEED CONVERGENCE DOWNSTREAM FROM THE STRONGER TRADES OFF THE N
COAST OF COLOMBIA. AN UPPER HIGH HAS BUILD OVER CENTRAL CUBA AND
DOMINATES THE WRN CARIB...WHILE AN ELONGATED UPPER TROUGH
DOMINATES THE ERN PORTION OF THE CARIBBEAN. THIS TROUGHING IN
ADDITION TO SOME WEAK SFC TROUGHING IN THE VICINITY IS
SUPPORTING THE SCATTERED MODERATE CONVECTION AFFECTING PUERTO
RICO AND NRN CARIB N OF 16N BETWEEN 64W-68W. SIMILAR ACTIVITY IS
OVER THE FAR SE CARIBBEAN NEAR THE SRN WINDWARD ISLANDS...AND IN
THE VICINITY OF GUADELOUPE.

ATLANTIC OCEAN...
A BUNCH OF WEAK SFC FEATURES ARE AFFECTING THE ATLC TODAY. THE
FIRST OF THESE FEATURES IS THE DISSIPATING 1015 MB LOW JUST OFF
THE COAST OF CENTRAL FLORIDA...WHICH APPEARS TO BE OPENING UP
INTO A TROUGH AND DRIFTING N. A SMALL CLUSTER OF MODERATE
CONVECTION ASSOCIATED WITH THIS IS NEAR 30N79W. A SFC TROUGH IS
ALONG 28N72W 21N74W THAT HAS SCATTERED SHOWERS/ISOLATED TSTMS
MOVING THROUGH THE SRN BAHAMAS. A 1018 MB HIGH IS NEAR 26N66W
WITH A 1016 MB HIGH NEAR 24N44W. THE HIGHS HAVE MOVED S OVER THE
LAST 24 HOURS IN RESPONSE TO THE COLD FRONT THAT ENTERS THE AREA
FROM A 1008 MB LOW NEAR 32N46W...CONTINUES SW TO 27N57W...THEN
NW TO 32N66W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE GENERALLY
WITHIN 60 NM OF THIS BOUNDARY. THIS AFTERNOONS VISIBLE IMAGERY
SUGGESTS ANOTHER LOW MAY BE FORMING ALONG THE FRONT NEAR 28N54W.
THE FRONT IS ASSOCIATED WITH A SHARP UPPER TROUGH ALONG 50W N OF
27N. TYPICAL UPPER RIDGING DOMINATES THE E ATLC OUT TO NEAR 50W.
SFC RIDGING ALSO DOMINATES THE ERN ATLC...S OF A 1032 MB HIGH
OFF OF WRN EUROPE. THESE FEATURES ARE PRODUCING MOSTLY FAIR
WEATHER AND LIGHT WINDS N OF 15N E OF 40W.


$$
WILLIS




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