[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151738
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI AUG 15 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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
1715 UTC.

...SPECIAL FEATURES...
TROPICAL WAVE IS IN THE W TROPICAL ATLC/E CARIBBEAN ALONG
67W/68W WITH A 1010 MB LOW ALONG THE WAVE IN THE MONA PASSAGE
NEAR 18.5N. THE SYSTEM IS MOVING W 10-15 KT. WHILE THIS SYSTEM
CONTINUES TO SHOW SIGNS OF ORGANIZATION...IT DOES NOT YET APPEAR
TO HAVE A WELL-DEFINED CENTER OF CIRCULATION AT THE SURFACE.
UPPER-LEVEL WINDS ARE FAVORABLE FOR DEVELOPMENT AND A TROPICAL
DEPRESSION COULD FORM AT ANY TIME WITHIN THE NEXT DAY OR SO.
BROAD AREA OF SCATTERED/HEAVY SHOWERS AND SCATTERED
THUNDERSTORMS ARE FROM 14N-24N BETWEEN 65W-72W. AN AIR FORCE
RESERVE HURRICANE HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE
THIS SYSTEM LATER THIS AFTERNOON. REGARDLESS OF DEVELOPMENT THE
HEAVY RAINS AND GUSTY WINDS WILL OCCUR OVER PORTIONS OF THE
VIRGIN ISLANDS...PUERTO RICO...AND HISPANIOLA TODAY AND
TONIGHT...AND OVER PORTIONS OF EASTERN CUBA...THE TURKS AND
CAICOS...AND THE SE BAHAMAS ON SATURDAY. THESE RAINS COULD CAUSE
LIFE-THREATENING FLASH FLOODS AND MUD SLIDES.

...TROPICAL WAVES...
TROPICAL WAVE OVER THE E TROPICAL ATLC IS ALONG 22W/23W S OF 17N
MOVING W 15-20 KT. THE SURFACE LOW IS NO LONGER DISCERNIBLE.
BROAD AREA OF DEEP LAYERED MOISTURE IS INDICATED BY MIMIC-TPW
ANIMATION BUT NO INDICATION OS DEEP CONVECTION. BROAD AREA OF
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS COVERS THE
AREA FROM 8N-16N BETWEEN 18W-26W INCLUDING THE CAPE VERDE
ISLANDS.

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC IS TILTED FROM 20N46W
THROUGH A WEAK 1011 MB LOW NEAR 15N48W TO 10N48W MOVING W NEAR
15 KT. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION
ARE FROM 15N-21N BETWEEN 41W-50W.

...THE ITCZ...
THE ITCZ IS CENTERED ALONG 15N16W 10N28W 10N35W 14N46W 11N62W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 4N-13N BETWEEN 28W-38W AND 6N-10N BETWEEN 45W-50W.

...DISCUSSION...

GULF OF MEXICO...
THE BROAD UPPER TROUGH OVER THE E U.S. INTO THE W ATLC WITH
ASSOCIATED FRONTAL BOUNDARY BOTH N OF THE REGION. HOWEVER...A
BAND OF SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE N GULF
WATERS WITHIN 75 NM OF LINE FROM THE TEXAS COAST NEAR CORPUS
CRISTI 29N89W TO ACROSS FLORIDA NEAR TAMPA. AN UPPER LEVEL RIDGE
EXTENDS ACROSS THE REMAINDER OF THE GULF ANCHORED OVER N/CENTRAL
MEXICO TO ACROSS S FLORIDA. WEAK SURFACE RIDGE EXTENDS ACROSS S
FLORIDA OVER THE E GULF WITH LIGHT/MODERATE RETURN FLOW. THE
REMAINDER OF THE GULF IS DOMINATED BY TRANQUIL CONDITIONS THIS
AFTERNOON. WEAK LOW PRESSURE SHOULD FORM ALONG THE N/CENTRAL ON
SAT AND REMAIN IN PLACE THROUGH MON BEFORE WEAKENING.

CARIBBEAN SEA...
THE BROAD UPPER RIDGE OVER THE GULF OF MEXICO COVERS THE NW
CARIBBEAN WITH NE UPPER FLOW W OF A LINE FROM HAVANA CUBA TO
OVER THE YUCATAN NEAR BELIZE. WEAK UPPER LOW REMAIN OVER CENTRAL
CUBA EXTENDING AN UPPER TROUGH SW TO THE N COAST OF HONDURAS
NEAR 16N85W. BROAD UPPER HIGH IS LOCATED OVER THE LOW PRESSURE
SYSTEM IN THE SPECIAL FEATURES SECTION ABOVE COVERING THE AREA N
OF THE ABC ISLANDS BETWEEN THE LESSER ANTILLES AND E CUBA. SE
UPPER FLOW COVERS THE SW CARIBBEAN PROVIDING UPPER LEVEL
DIFFLUENCE TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
OVER THE SW CARIBBEAN S OF 15 BETWEEN 75W-82W. SEE SPECIAL
FEATURES ABOVE FOR CONDITIONS OVER THE NE CARIBBEAN. OTHERWISE
THE REMAINDER OF THE CARIBBEAN REMAINS FAIRLY CLEAR THIS
AFTERNOON.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE E US. INTO THE W ATLC WITH THE
ASSOCIATED FRONTAL BOUNDARY BOTH N OF THE REGION. HOWEVER...A
BAND OF SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 75 NM OF LINE
FROM FROM ACROSS FLORIDA NEAR MELBOURNE NE TO BEYOND 32N75W. AN
UPPER LOW IS OVER E CUBA EXTENDING AN UPPER TROUGH NE ACROSS THE
BAHAMAS TO 26N73W. THIS UPPER LOW IS EMBEDDED WITHIN A FAIR
AMOUNT OF DRY AIR AND IS KEEPING SKIES MOSTLY CLEAR ACROSS CUBA
AND THE BAHAMA ISLANDS. TURKS AND CAICOS ARE BEGINNING TO
EXPERIENCE THE EFFECTS OF THE SYSTEM IN THE SPECIAL FEATURES
SECTION ABOVE. UPPER HIGH IS TO THE E OVER THE SYSTEM IN THE
SPECIAL FEATURES PROVIDING UNIFORM OUTFLOW. BROAD UPPER LOW IS
IN THE CENTRAL ATLC NEAR 25N53W AND IS ADVECTING SOME MID/UPPER
MOISTURE N PRODUCING ISOLATED SHOWERS/THUNDERSTORMS WITHIN
WITHIN 90 NM OF LINE FROM 29N48W TO 23N56W. A COUPLE OF BENIGN
UPPER LOWS ARE IN THE E ATLC WITH THE FIRST JUST W OF THE CANARY
ISLANDS NEAR 28N19W AND A SECOND NEAR 32N41W. THESE UPPER LOWS
ARE EMBEDDED WITHIN MODERATE/STRONG SUBSIDENCE AND DRY STABLE
AIR THAT COVERS MOST OF THE ATLC BASIN...THUS FAIR WEATHER
CONDITIONS ARE ACROSS THE REMAINDER OF THE ATLC. A SURFACE RIDGE
CONTINUES TO DOMINATE THE ATLC ANCHORED BY A 1028 MB HIGH N OF
THE REGION SW OF THE AZORES EXTENDING A RIDGE AXIS SW THROUGH
32N52W ACROSS FLORIDA TO OVER THE E GULF OF MEXICO.

$$
WALLACE




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