[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 081041
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED OCT 08 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 24W/25W S OF 13N MOVING W 5-10 KT. WAVE
IS BEGINNING TO LOSE ITS IDENTITY DUE TO THE AFRICAN DUST THAT
HAS COME OFF COAST COVERING THE AREA FROM 10N-23N E OF 30W. NO
ASSOCIATED DEEP CONVECTION.

TROPICAL WAVE IS ALONG 37W S OF 15N WITH A WEAK 1011 MB LOW
ALONG THE WAVE NEAR 12N MOVING W 5-10 KT. SMALL LOW LEVEL SWIRL
IS ASSOCIATED WITH THE LOW WITH CLUSTERS SCATTERED MODERATE/
ISOLATED STRONG CONVECTION FROM 11N-13N BETWEEN 35W-37W.

TROPICAL WAVE IS ALONG 53W/54W S OF 16N MOVING W 10-15 KT. BROAD
MID LEVEL INVERTED-V CURVATURE IS OBSERVED ON SATELLITE IMAGERY.
SCATTERED SHOWERS ARE FROM 11N-14N BETWEEN 52W-56W.

TROPICAL WAVE IS ALONG 72W/73W S OF 18N MOVING W NEAR 15 KT.
WAVE REMAINS BENEATH AN UPPER RIDGE WITH UPPER DIFFLUENCE
GENERATING HIGH CLOUDS AND SHOWER ACTIVITY OVER THE AREA...THUS
MASKING ANY SATELLITE SIGNATURE.

TROPICAL WAVE IS ALONG 81W/82W S OF 20N MOVING W NEAR 15 KT. THE
WAVE IS MOVING BENEATH AN UPPER LOW ENHANCING ANY SHOWER
ACTIVITY IN THE VICINITY.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 13N16W 7N26W 11N35W 9N43W 11N51W
10N62W. A SMALL 1012 MB LOW IS N OF THE ITCZ CENTERED NEAR
14N33W GENERATING SCATTERED MODERATE/ISOLATED STRONG CONVECTION
FROM 13N-17N BETWEEN 30W-34W. CLUSTERS OF SIMILAR CONVECTION ARE
FROM 5N-11N BETWEEN 17W-23W. SMALL CLUSTERS OF SCATTERED
MODERATE CONVECTION DOT THE REMAINDER OF THE AREA FROM 2N-13N
ACROSS THE ENTIRE ATLC.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH COVERS THE CENTRAL US WITH AN UPPER LOW
MOVING OVER THE LOWER MISSISSIPPI VALLEY EXTENDS INTO THE NW
GULF N OF 27N W OF 90W. THE ASSOCIATED COLD FRONT ENTERS THE
GULF ACROSS LOUISIANA OVER THE VERMILION BAY EXTENDING SW TO
JUST S OF BROWNSVILLE TEXAS. MOIST TROPICAL AIR IS TO THE SE OF
THE FRONT WITH STRONG SUBSIDENCE AND DRY STABLE AIR NW OF THE
FRONT...THUS CLEAR SKIES ALONG THE TEXAS AND W LOUISIANA COASTS.
A BROAD UPPER RIDGE COVERS THE REMAINING GULF WATERS ANCHORED
ALONG THE COAST OF MEXICO NEAR 20N97W. UPPER DIFFLUENCE E OF THE
FRONT IS GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS OVER WITHIN 90/120 NM OF LIEN FROM MEXICO NEAR
TAMPICO ALONG 28N88W TO OVER FLORIDA NEAR 30N84W. MODERATE/
STRONG EASTERLY WINDS ARE OVER THE E GULF USHERING IN ISOLATED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS THROUGH THE FLORIDA
STRAITS S OF THE FLORIDA KEYS E OF 85W.

CARIBBEAN SEA...
AN UPPER LOW COVERS THE W CARIBBEAN CENTERED ALONG THE COAST OF
HONDURAS NEAR 16N86W. AN UPPER TROUGH COVERING THE W ATLC DIPS S
JUST OVER THE N CARIBBEAN ISLANDS FROM THE PUERTO RICO TO
HISPANIOLA WHILE THE REMAINDER OF THE CARIBBEAN IS DOMINATED BY
A BROAD UPPER RIDGE ANCHORED OVER VENEZUELA E OF 81W TO ACROSS
THE LESSER ANTILLES. DIFFLUENCE ALOFT COUPLED WITH AN ABUNDANCE
OF TROPICAL MOIST AIR ARE GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ACROSS THE AREA WITH THE EXCEPTION OF THE YUCATAN
CHANNEL WHERE CLEAR SKIES PREVAIL. THE STRONGEST ACTIVITY IS IN
THE GULF OF HONDURAS AND OVER THE ABC ISLANDS.

ATLANTIC OCEAN...
BROAD DEEP LAYERED TROUGH COVERS THE W ATLC TO THE N CARIBBEAN
ISLANDS W OF 55W WITH THE ASSOCIATED COLD FRONT ENTERING THE
REGION NEAR 32N54W EXTENDING SW TO 26N72W WHERE IT BECOMES NEAR
STATIONARY TO OVER THE N BAHAMA ISLANDS NEAR 26N78W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 90 NM OF THE COLD
FRONT E OF 61W WITH ISOLATED SHOWERS WITHIN 60 NM S OF THE
REMAINDER OF THE FRONTAL BOUNDARY. AN UPPER RIDGE IS IN THE NE
ATLC ANCHORED NEAR 30N38W AND EXTENDS NE TO OVER THE AZORES. AN
UPPER LOW DOMINATES THE CENTRAL TROPICAL ATLC CENTERED NEAR
21N36W WITH A SURFACE TROUGH EXTENDING FROM 26N35W TO 29N37W.
BETWEEN THE DEEP LAYERED TROUGH OVER THE W ATLC AND THIS UPPER
LOW IS ENOUGH UPPER LEVEL DIFFLUENCE TO GENERATE AN AREA OF
SCATTERED SHOWERS/THUNDERSTORMS FROM 18N-29N BETWEEN 51W-55W. AN
UPPER RIDGE EXTENDS FROM AFRICA ACROSS THE E TROPICAL ATLC ALONG
15N S OF 23N TO NEAR 30W. A SURFACE RIDGE REMAINS OVER THE E
ATLC N OF 20N E OF 50W WITH A WEAKNESS IN THE IMMEDIATE VICINITY
OF THE SURFACE TROUGH. THE FIRST VISIBLE SATELLITE IMAGES SHOW A
SURGE OF AFRICAN DUST COVERING THE E ATLC FROM 10N-23N E OF 30W.

$$
WALLACE




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