[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 052357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED AUG 05 2009

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 27W S OF 16N MOVING W NEAR 8 KT. THIS
WAVE REMAINS EMBEDDED WITHIN THE ITCZ AS SCATTERED SHOWERS ARE
WITHIN 180 NM EITHER SIDE OF THE AXIS.

A TROPICAL WAVE IS ALONG 41W S OF 17N MOVING W NEAR 15 KT. THIS
WAVE REMAINS ON THE LEADING EDGE OF A MAXIMUM IN DEEP LAYER
MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP
CONVECTION IS ASSOCIATED WITH THIS WAVE.

A TROPICAL WAVE IS ALONG 60W S OF 20N MOVING W NEAR 20 KT. ON
THE TOTAL PRECIPITABLE WATER IMAGERY THIS WAVE EXHIBITS A
MOISTURE MAXIMUM THAT IS BEGINNING TO IMPACT THE LESSER
ANTILLES. ALTHOUGH NO DEEP CONVECTION IS OBSERVED ON SATELLITE
IMAGERY...ISOLATED SHOWERS ARE WITHIN 200 NM OF THE WAVE AXIS.

A TROPICAL WAVE IS ALONG 79W S OF 21N MOVING W NEAR 15 KT. THIS
WAVE HAS BEEN REPOSITIONED TO THE WEST AND REMAINS RATHER
ILL-DEFINED AS IT HAS TRACKED ACROSS THE CENTRAL CARIBBEAN THE
PAST 24 HOURS. NO DEEP CONVECTION IS NOTED AS TRACES OF SAHARAN
DUST FOLLOW TO THE EAST OF THE WAVE AXIS.

...ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 12N16W 13N32W 12N35W 9N40W 8N43W
8N59W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 9N-15N
BETWEEN 13W-21W. A 1012 MB LOW IS CENTERED NEAR 12N34W MOVING W
AT 10 KT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
PRIMARILY NW OF THE CENTER FROM 12N-16N BETWEEN 34W-38W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL TROUGH IS ACROSS THE NE GULF OF MEXICO WITH AXIS
OVER THE WRN FLORIDA PANHANDLE NEAR 31N86W TO 26N91W. AT 2100
UTC...THIS UPPER TROUGH SUPPORTS A PAIR OF SURFACE TROUGHS THAT
ARE POSITIONED ALONG THE GULF COAST BETWEEN 85W-92W. LOW-LEVEL
CONVERGENCE ALONG AND S OF THESE SURFACE TROUGHS IS GENERATING
SCATTERED SHOWERS AND TSTMS N OF 30N ACROSS MOST OF THE INTERIOR
GULF COAST. UPPER DIFFLUENCE TO THE E OF THE UPPER TROUGH AXIS
IS SUPPORTING ISOLATED SHOWERS OVER THE CENTRAL GULF FROM
25N-29N BETWEEN 85W-92W. ACROSS THE WRN GULF...NLY UPPER LEVEL
FLOW AND STRONG SUBSIDENCE ALOFT IS SUPPORTING A 1019 MB SURFACE
HIGH CENTERED NEAR 27N93W. A FRACTURED PORTION OF THE TROPICAL
WAVE ALONG 79W IS ANALYZED AS A SURFACE TROUGH AND EXTENDS FROM
FORT MYERS FLORIDA TO WRN CUBA NEAR 22N85W. LOW-LEVEL
INSTABILITY AND CYCLONIC FLOW FOCUSED NEAR THE SURFACE TROUGH
AXIS IS GENERATING SCATTERED SHOWERS AND TSTMS OVER THE SRN
FLORIDA PENINSULA...SE GULF...WRN CUBA AND THE YUCATAN PENINSULA
N OF 19N. ELSEWHERE...A FEW ISOLATED SHOWERS ARE OBSERVED ON
SATELLITE IMAGERY ACROSS THE FAR WRN BAY OF CAMPECHE DUE TO
UPPER LEVEL DIFFLUENCE ON THE SE PERIPHERY OF AN UPPER LEVEL
HIGH CENTERED OVER NW MEXICO.

CARIBBEAN SEA...
AN UPPER LEVEL DIFFLUENT PATTERN IS OVER CENTRAL AMERICA AND THE
SW CARIBBEAN GENERATING SCATTERED SHOWERS AND STRONG TSTMS FROM
8N-16N BETWEEN 78W-86W. THIS ACTIVITY IS BEING ENHANCED BY
LOW-LEVEL SPEED CONVERGENCE OF THE ELY TRADES AND THE PRESENCE
OF THE TROPICAL WAVE ALONG 79W. AN UPPER LEVEL LOW IS CENTERED
NEAR 21N87W AND ALONG WITH A SURFACE TROUGH EXTENDING ACROSS WRN
CUBA IS PRODUCING SCATTERED SHOWERS AND TSTMS OVER MUCH OF
CUBA...THE YUCATAN CHANNEL AND NRN YUCATAN PENINSULA. ACROSS THE
ERN CARIBBEAN...A SHARP UPPER LEVEL TROUGH EXTENDS FROM THE SW
NORTH ATLC ACROSS PUERTO RICO TO NEAR ARUBA. DRY AIR AND
SUBSIDENCE ALOFT IS PROVIDING FAIR WEATHER ACROSS THE BASIN
BETWEEN 66W-78W. HOWEVER...THIS UPPER TROUGH SUPPORTS A SURFACE
TROUGH THAT EXTENDS ACROSS CENTRAL PUERTO RICO AND IS GENERATING
SCATTERED SHOWERS N OF 17N E OF THE MONA PASSAGE. ALSO AS THE
TROPICAL WAVE ALONG 60W APPROACHES THE LESSER ANTILLES...AND
COMES UNDER THE INFLUENCE OF THE UPPER LEVEL TROUGHING ACROSS
THE NE CARIBBEAN...INCREASED SHOWERS AND TSTM ACTIVITY IS
EXPECTED ACROSS THE ERN CARIBBEAN OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
UPPER LEVEL DIFFLUENCE IS OVER THE SW NORTH ATLC WATERS N OF 27N
DUE TO AN ANTICYCLONIC CIRCULATION CENTERED OVER THE NW BAHAMAS
NEAR 25N78W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ALONG THE
ERN FLORIDA COAST N OF 26N W OF 79W. ANOTHER AREA OF SCATTERED
SHOWERS IS FROM 27N TO BEYOND 32N BETWEEN 70W-76W. FARTHER TO
THE SE...A SURFACE TROUGH IS ANALYZED FROM PUERTO RICO NWD TO
25N64W. THIS SURFACE FEATURE ALONG WITH AN UPPER LEVEL LOW
CENTERED NEAR 23N67W IS GENERATING SCATTERED SHOWERS AND
ISOLATED TSTMS FROM 20N-28N BETWEEN 61W-67W. ELSEWHERE ACROSS
THE CENTRAL AND ERN ATLC...RELATIVELY TRANQUIL CONDITIONS
CONTINUE AS A RIDGE OF HIGH PRESSURE STRETCHES FROM THE CANARY
ISLANDS TO NEAR 75W. THIS RIDGE IS ANCHORED ON A 1027 MB SURFACE
HIGH CENTERED N OF THE DISCUSSION AREA NEAR 35N48W.

$$
HUFFMAN




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