[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 100532
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON AUG 10 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...SPECIAL FEATURES...

TROPICAL WAVE IS ALONG 23W FROM 10N TO 19N WITH A 1008 MB LOW
ALONG THE WAVE NEAR 14N DRIFTING WESTWARD. LATEST INFRARED
SATELLITE IMAGERY INDICATES A WELL DEFINED LOW/MID LEVEL
CYCLONIC CIRCULATION WITH A CLUSTERS OF SCATTERED MODERATE/
ISOLATED STRONG CONVECTION FLARING UP NEAR AND TO THE SW OF THE
LOW LEVEL CIRCULATION FROM 11N TO OVER THE THE SOUTHERN MOST
CAPE VERDE ISLANDS BETWEEN 22W-27W. CONDITIONS APPEAR FAVORABLE
FOR DEVELOPMENT OF THIS SYSTEM AND IT COULD BECOME A TROPICAL
DEPRESSION DURING THE NEXT DAY OR TWO. ASSOCIATED SHOWERS AND
THUNDERSTORMS WITH LOCALLY GUSTY WINDS COULD AFFECT PORTIONS OF
THE CAPE VERDE ISLANDS DURING THE NEXT 24 HOURS. SEE THE
TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS MIATWOAT/ABNT20
KNHC FOR ADDITIONAL DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS TILTED NW TO SE FROM 17N46W TO 8N39W MOVING W
10-15 KT. THE AXIS OF THE WAVE IS ORIENTED WITHIN A MOISTURE
MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY AND WELL
DEFINED CURVATURE IN THE LOW CLOUDS. SMALL CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 60 OF LINE FROM
14N38W TO 15N48W.

TROPICAL WAVE IS ALONG 56W/57W S OF 18N MOVING W 10-15 KT. WAVE
IS LOCATED ALONG A MOISTURE MAXIMUM OBSERVED IN THE TOTAL
PRECIPITABLE WATER IMAGERY AND LOW LEVEL CYCLONIC CIRCULATION IN
THE LOW CLOUDS ALONG THE WAVE AXIS NEAR 13N. SCATTERED SHOWERS
ARE FROM 14N-16N BETWEEN 55W-59W.

TROPICAL WAVE IS ALONG 67W/68W S OF 16N MOVING W 15-20 KT. WAVE
IS EMBEDDED WITHIN AN AREA OF MODERATE ELY TRADES OVER THE E
CARIBBEAN AND COINCIDES WITH A LOW AMPLITUDE MOISTURE MAXIMUM
OBSERVED IN THE TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...DUE
TO THE DRY STABLE CONDITIONS THERE IS NO ASSOCIATED SHOWER
ACTIVITY OR CONVECTION.

TROPICAL WAVE IS ALONG 88W S OF 17N MOVING W 10-15 KT. THIS WAVE
IS MOVING OUT OF THE CARIBBEAN AND OVER CENTRAL AMERICA AND IN
THE E PACIFIC REGION WITH NO SIGNIFICANT SHOWERS/CONVECTION IN
THE AREA.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N26W 7N43W 13N56W 11N65W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
INLAND AND WITHIN 120 NM ALONG THE COAST OF W AFRICA FROM 6N-9N
AND WITHIN 120 NM ALONG THE ITCZ FROM 41W-49W.

...DISCUSSION...

GULF OF MEXICO...
LARGE UPPER RIDGE ANCHORED OVER SOUTH CAROLINA EXTENDS OVER THE
E GULF N OF 24N E OF 88W WITH A SURGE OF DRY AIR ALOFT SWEEPING
ACROSS N FLORIDA AND THE NE GULF N OF 28N CAPPING THUNDERSTORM
DEVELOPMENT OVER FLORIDA AND PUSHING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS OVER THE E GULF FROM 24N-27N BETWEEN 83W-85W WITH
ISOLATED SHOWERS DOTTING THE AREA FROM 22N-28N BETWEEN 82W-90W.
AN UPPER RIDGE IS ANCHORED OVER S MEXICO NEAR 18N96W COVERING
THE W GULF DRAWING UPPER LEVEL MOISTURE FROM THE TROPICS ACROSS
MEXICO AND OVER THE FAR W GULF. UPPER LEVEL DIFFLUENCE COUPLED
WITH LOW LEVEL CONVERGENCE IS GENERATING ISOLATED SHOWERS/
THUNDERSTORMS OVER THE BAY OF CAMPECHE S OF 21N BETWEEN 92W-97W.

CARIBBEAN SEA...
THE W CARIBBEAN IS DOMINATED BY AN UPPER LOW CENTERED OVER
CAYMAN ISLANDS GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS N OF 21N TO OVER W CUBA BETWEEN 82W-85W. THE E
CARIBBEAN IS DOMINATED BY AN UPPER HIGH S OF PUERTO RICO NEAR
16N67W. VERY DRY AIR ALOFT IS NOTED OVER MUCH OF THE REGION WITH
THE EXCEPTION BEING ACROSS THE FAR S CARIBBEAN. THIS MOIST AIR
COUPLED WITH THE ITCZ AXIS THAT EXTENDS ACROSS THE ABC ISLANDS
THEN THE N PORTION OF VENEZUELA AND COLOMBIA CROSSING PANAMA
INTO THE E PACIFIC REGION IS GENERATING SCATTERED SHOWERS/
THUNDERSTORMS S OF 13N W OF 73W TO OVER THE AREA FROM COLOMBIA
TO NICARAGUA WITH ISOLATED SHOWERS OVER THE WINDWARD ISLANDS S
OF 14N E OF 65W. A SMALL AREA OF UPPER DIFFLUENCE IS OVER HAITI
AND THE ADJACENT COASTAL WATERS GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 18N-20N BETWEEN 72W-76W.

ATLANTIC OCEAN...
THE UPPER RIDGE THAT COVERS THE E GULF OF MEXICO COVERS THE W
ATLC N OF 24N W OF 69W WITH DRY AIR ALOFT SUPPRESSING ANY
SHOWERS/THUNDERSTORMS. HOWEVER...A NARROW UPPER TROUGH EXTENDS
FROM 27N62W ACROSS E CUBA TO AN UPPER LOW OVER THE CAYMAN
ISLANDS. A NARROW BAND OF UPPER LEVEL DIFFLUENCE BETWEEN THE
UPPER RIDGE AND TROUGH IS GENERATING SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS WITHIN 90/120 NM S OF A SURFACE
TROUGH THAT EXTENDS FROM A COLD FRONT N OF THE REGION THROUGH
32N59W TO 28N73W. A SECOND SURFACE TROUGH IS TO THE E AND
EXTENDS FROM 28N55W TO 23N59W AND WILL CONTINUE WEAKENING AS THE
UPPER LEVEL SUPPORT HAS NOW MOVED N OF THE REGION. HIGH PRESSURE
HAS BEGUN TO DOMINATE THE ATLC BASIN WITH A SURFACE RIDGE OVER
THE W ATLC AND GULF OF MEXICO ANCHORED BY A 1021 MB HIGH OVER SW
GEORGIA AND A SECOND SURFACE RIDGE OVER THE E ATLC ANCHORED BY A
1027 MB HIGH JUST W OF THE AZORES. THE REMAINDER OF THE ATLC
REMAINS TRANQUIL TONIGHT WITH A BROAD AREA OF SAHARAN DUST
COVERING MOST OF THE AREA E OF 50W.

$$
WALLACE



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