[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121056
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST MON NOV 12 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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 66W/67W S OF 14N MOVING W NEAR 20 KT.
WAVE REMAINS EMBEDDED WITHIN A SURGE OF AFRICAN DUST THAT IS NOW
OVER THE E CARIBBEAN. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ARE S OF 13N BETWEEN 65W-69W INCLUDING THE ABC ISLANDS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 8N22W 8N38W 7N52W 7N60W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS
THE AREA FROM 2N-11N BETWEEN 11W-28W AND WITHIN 90/120 OT HE
ITCZ AXIS FROM 37W-45W.

DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE EXTENDS FROM THE W CARIBBEAN ACROSS THE
YUCATAN NEAR 21N88W TO OVER THE MISSISSIPPI VALLEY WITH DRY
STABLE AIR COVERING THE ENTIRE GULF. A SURFACE RIDGE EXTENDS
OVER THE GULF INTO THE W ATLC ANCHORED OVER NORTH CAROLINA IS
KEEPING THE W GULF IN RETURN FLOW AND PRODUCING SOME ISOLATED
LOW LEVEL SHOWERS MAINLY N OF 27N W OF 90W TO INLAND OVER
LOUISIANA. OTHERWISE MOSTLY FAIR SKIES DOMINATE THE GULF AGAIN
THIS MORNING.

CARIBBEAN SEA...
THE MAIN FOCUS TONIGHT REMAINS THE 1006 MB LOW IN THE SW
CARIBBEAN NEAR 11N82W WITH A SURFACE TROUGH EXTENDING N ALONG
16N82W TO THE CAYMAN ISLANDS NEAR 20N81W. THE LOW LEVEL CENTER
IS PARTIALLY EXPOSED AS THE SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE N AND W OF THE LOW WITHIN 75/90 NM OF LINE
FROM OVER NICARAGUA NEAR 13N84W TO 18N80W. THIS SYSTEM IS
EXPECTED TO CONTINUE TO DRIFT WESTWARD AND MOVE INLAND OVER
CENTRAL AMERICA LATER TODAY WITH NO SIGNIFICANT DEVELOPMENT.
HOWEVER...IT COULD PRODUCE LOCALLY HEAVY RAINFALL OVER PORTIONS
OF NICARAGUA AND HONDURAS OVER THE NEXT COUPLE OF DAYS. UPPER
RIDGE EXTENDS ACROSS THE CARIBBEAN FROM AN UPPER HIGH OVER THE
LESSER ANTILLES NEAR 15N62W. THIS IS PROVIDING ENOUGH UPPER
LEVEL DIFFLUENCE TO GENERATE OF SCATTERED SHOWERS/THUNDERSTORMS
WITHIN 60 NM OF LINE FROM 15N80W TO OFF THE COAST OF COLOMBIA
NEAR 11N76W WITH CLUSTERS OF SCATTERED SHOWERS AND WIDELY
ISOLATED THUNDERSTORMS DOTTING THE REMAINDER OF THE W CARIBBEAN
S OF 20N BETWEEN 75W-85W. AFRICAN DUST IS FILTERED OVER THE E
CARIBBEAN E OF 68W WITH AN AREA OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS PRECEDING IT FROM 14N-16N BETWEEN 69W-73W.

ATLANTIC OCEAN...
BROAD UPPER TROUGH COVERS THE W ATLC WITH THE UPPER LOW OVER THE
N CANADIAN MARITIMES AND EXTENDING W OF 50W TO THE E COAST OF
FLORIDA. THE ASSOCIATED COLD FRONT EXTENDS TO 32N56W WITH A
SURFACE TROUGH EXTENDING INTO THE REGION ALONG 27N67W OVER THE
BAHAMA ISLANDS TO THE E COAST OF FLORIDA NEAR 25N80W WITH BROKEN
TO OVERCAST LOW/MID CLOUDS AND ISOLATED SHOWERS N OF THE SURFACE
TROUGH. A REMNANT SURFACE TROUGH FROM AN UPPER SYSTEM THAT IS
WELL N OF THE REGION EXTENDS INTO THE CENTRAL ATLC NEAR 32N49W
SW ALONG 24N58W TO OVER HISPANIOLA NEAR 19N71W. SCATTERED
SHOWERS AND WIDELY ISOLATED THUNDERSTORMS ARE S OF 22N TO OVER
HISPANIOLA AND E CUBA BETWEEN 66W-75W. AN UPPER HIGH IS OVER THE
LESSER ANTILLES NEAR 15N62W EXTENDING AN UPPER RIDGE NE ALONG
23N49W TO BEYOND 32N40W WITH ENOUGH DIFFLUENCE TO GENERATE
SCATTERED SHOWERS AND WIDELY ISOLATED THUNDERSTORMS WITHIN 120
NM OF LINE FROM 24N56W TO BEYOND 32N43W. A WEAK UPPER TROUGH IS
UNDERCUTTING THE UPPER RIDGE ABOVE EXTENDING FROM 15N45W TO
7N52W. A NARROW UPPER TROUGH IS OVER THE FAR E ATLC N OF 20N E
OF 24W TO INLAND OVER W AFRICA WITH A SURFACE TROUGH EXTENDING
THROUGH 32N26W S TO 26N27W GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS WITHIN 150 NM E OF THE TROUGH. A SURFACE RIDGE IS
BUILDING SOUTHWARD OVER THE E/CENTRAL ATLC BETWEEN THE ABOVE
SURFACE TROUGHS TO 20N FROM 30W-48W WITH A WEAK 1018 MB HIGH
LOCATED NEAR 28N38W. THE TYPICAL E/W UPPER RIDGE CROSS THE
TROPICAL ATLC E OF 40W WITH THE AXIS ALONG 7N/8N. BROAD AREA OF
AFRICAN DUST COVERS MUCH OF THE TROPICS S OF 22N FROM 30W INTO
THE E CARIBBEAN.

$$
WALLACE



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