[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101131
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...SPECIAL FEATURES...

TROPICAL WAVE IS ALONG 24W FROM 9N TO 18N WITH A 1008 MB LOW
ALONG THE WAVE NEAR 14N MOVING W NEAR 10 KT. FIRST VISIBLE
SATELLITE IMAGERY INDICATES THE LOW/MID LEVEL CYCLONIC
CIRCULATION REMAINS WELL DEFINED WITH AN AREA OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION NEAR AND TO THE SW OF THE
LOW LEVEL CIRCULATION FROM 10N-15N BETWEEN 23W-28W. 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 REMAINS TILTED NW TO SE FROM 17N47W 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 CONVECTION ARE WITHIN 60 OF 15N BETWEEN
41W-50W.

TROPICAL WAVE IS FROM ALONG 57W/58W 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 14N. CLUSTERS OF
SCATTERED MODERATE CONVECTION WITHIN 60 NM OF LINE FROM 15N55W
TO 14N60W.

TROPICAL WAVE IS ALONG 68W/69W S OF 16N MOVING W NEAR 15 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 89W S OF 16N MOVING W NEAR 10 KT. THIS
WAVE IS NOW INLAND OVER CENTRAL AMERICA AND IN THE E PACIFIC
REGION.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 18N16W 11N32W 12N39W...THEN
ALONG 8N43W 13N55W INTO THE CARIBBEAN ACROSS THE WINDWARD
ISLANDS TO 11N63W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS INLAND AND WITHIN 150 NM ALONG THE COAST OF W AFRICA FROM
7N-10N. CLUSTERS OF SIMILAR CONVECTION ARE FROM 8N-12N BETWEEN
30W-35W AND WITHIN 120 NM ALONG OF LINE FROM 6N41W 7N47W TO
8N54W.

...DISCUSSION...

GULF OF MEXICO...
LARGE UPPER RIDGE ANCHORED OFF THE CAROLINA COASTS EXTENDS OVER
THE W ATLC AND THE E GULF N OF 25N E OF 90W WITH A SURGE OF DRY
AIR ALOFT SWEEPING ACROSS N FLORIDA AND THE NE GULF N OF 27N
CAPPING THUNDERSTORM DEVELOPMENT AND PUSHING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS OVER THE CENTRAL GULF N OF 24N TO
OVER THE LOUISIANA COAST BETWEEN 88W-92W WITH ISOLATED SHOWERS
DOTTING THE AREA S OF 26N E OF 86W OVER THE S TIP OF
FLORIDA...THE FLORIDA KEYS...AND THE STRAITS OF FLORIDA. AN
UPPER RIDGE IS ANCHORED OVER S MEXICO NEAR 20N97W COVERING THE W
GULF DRAWING UPPER LEVEL MOISTURE FROM THE TROPICS ACROSS MEXICO
AND S TEXAS INTO THE FAR W GULF. UPPER LEVEL DIFFLUENCE COUPLED
WITH LOW LEVEL CONVERGENCE IS GENERATING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS OVER THE W BAY OF CAMPECHE S OF 21N W OF
94W.

CARIBBEAN SEA...
THE W CARIBBEAN IS DOMINATED BY AN UPPER LOW CENTERED SW OF THE
CAYMAN ISLANDS NEAR 18N83W GENERATING ISOLATED SHOWERS/
THUNDERSTORMS S OF 21N W OF 83W. THE E CARIBBEAN IS DOMINATED BY
AN UPPER HIGH NEAR PUERTO RICO. 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 COLOMBIA
CROSSING COSTA RICA INTO THE E PACIFIC REGION IS GENERATING
SCATTERED SHOWERS/THUNDERSTORMS S OF 12N W OF 76W TO OVER THE
AREA FROM COLOMBIA TO NICARAGUA WITH SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60 NM OF LINE FROM 14N67W
ACROSS THE WINDWARD ISLANDS TO 14N60W. A SMALL AREA OF UPPER
DIFFLUENCE IS OVER THE N/CENTRAL CARIBBEAN GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 18N-20N BETWEEN 73W-77W.

ATLANTIC OCEAN...
THE UPPER RIDGE THAT COVERS THE E GULF OF MEXICO COVERS THE W
ATLC N OF 24N W OF 65W WITH DRY AIR ALOFT SUPPRESSING ANY
SHOWERS/THUNDERSTORMS. HOWEVER...A NARROW UPPER TROUGH EXTENDS
FROM 27N61W ACROSS E CUBA TO THE UPPER LOW OVER THE E CARIBBEAN.
A NARROW BAND OF UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER RIDGE
AND TROUGH IS PRODUCING A SURFACE THAT EXTENDS FROM 29N60W TO
26N73W AND GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS WITHIN 60/75 NM OF LINE FROM 28N66W TO 30N56W. A
SECOND WEAKER SURFACE TROUGH IS TO THE SE AND EXTENDS FROM
26N58W TO 20N62W AND NOT PRODUCING ANY SIGNIFICANT WEATHER. HIGH
PRESSURE DOMINATES THE W ATLC INTO THE GULF OF MEXICO ANCHORED
BY A 1022 MB HIGH OFF GEORGIA COAST NEAR 31N79W AND A SECOND
SURFACE RIDGE OVER THE E ATLC ANCHORED BY A 1026 MB HIGH JUST W
OF THE AZORES. THE REMAINDER OF THE ATLC REMAINS TRANQUIL THIS
MORNING WITH A BROAD AREA OF SAHARAN DUST COVERING MOST OF THE
AREA E OF 53W.

$$
WALLACE




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