[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180538
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST TUE DEC 18 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N8W 3N18W 2N31W 1N50W EQ53W.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE N OF 2N TO
THE COAST OF SW AFRICA E OF 4W ACROSS THE PRIME MERIDIAN.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
WITHIN 60 NM OF THE ITCZ AXIS E OF 14W TO JUST INLAND OVER
AFRICA. BROAD AREA OF UPPER DIFFLUENCE COUPLED WITH TROPICAL
MOISTURE IS GENERATING AN AREA WITH CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION S OF 11N TO INLAND OVER
SOUTH AMERICA BETWEEN 43W-56W.

DISCUSSION...
GULF OF MEXICO...
ZONAL EASTERLY UPPER FLOW DOMINATES THE GULF TONIGHT WITH A
JETSTREAM OF WINDS ESTIMATED TO BE 90 TO 120 KT THE N GULF AND
THE SE US N OF 25N FROM TEXAS INTO THE W ATLC. A SURFACE RIDGE
DOMINATES THE GULF ANCHORED OVER THE E US WITH A 1029 MB HIGH
OVER S ALABAMA. RETURN FLOW AROUND THIS SURFACE RIDGE IS BANKING
LOW LEVEL CLOUDS WITH WIDELY ISOLATED SHOWERS OVER THE W GULF TO
THE SIERRA MADRE MOUNTAINS AND LEAVING REMARKABLE CLEAR SKIES E
OF 86W ACROSS FLORIDA. HIGH PRESSURE WILL REMAIN IN CONTROL OF
THE GULF WITH THE NEXT FRONT MOVING IN LATE IN THE WEEK.

CARIBBEAN SEA...
AN UPPER HIGH REMAINS IN THE GULF OF HONDURAS WITH THE RIDGE
AXIS EXTENDING ACROSS CENTRAL CUBA NEAR 21N78W INTO THE W ATLC
COVERING THE W CARIBBEAN W OF 75W. AN UPPER TROUGH COVERS THE
REMAINDER OF THE CARIBBEAN EXTENDING FROM THE VIRGIN ISLANDS TO
OVER COLOMBIA. MOSTLY DRY STABLE AIR REIGNS OVER THE CARIBBEAN.
HOWEVER...A WEAKENING COLD FRONT FROM THE W ATLC EXTENDS ACROSS
CENTRAL CUBA NEAR 20N77W BECOMING NEAR STATIONARY TO HONDURAS
NEAR 15N87W. A WEAK SURFACE TROUGH EXTENDS FROM 17N81W TO OFF
PANAMA NEAR 10N81W. BROKEN/OVERCAST LOW CLOUDS WITH ISOLATED
SHOWERS COVER THE AREA W OF THE FRONT N OF 17N AND W OF THE
TROUGH S OF 17N. MODERATE/STRONG N TO NE WINDS ARE W OF THE
FRONT WITH MODERATE/STRONG EASTERLY TRADE WINDS ACROSS THE
REMAINDER OF THE REGION. THE REMAINDER OF THE CARIBBEAN HAS
WIDELY SCATTERED LOW LEVEL CLOUDS BUT REMAINS RATHER TRANQUIL
TONIGHT.

ATLANTIC OCEAN...
THE DEEP LAYERED TROUGH THAT COVERS THE FAR E US AND THE W ATLC
W OF 65W WITH THE ASSOCIATED COLD FRONT ENTERING THE REGION E OF
BERMUDA NEAR 32N62W ACROSS THE S BAHAMA ISLANDS THEN CONTINUING
INTO THE CARIBBEAN OVER CUBA NEAR 20N77W. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE WITHIN 60/75 NM OF THE FRONT N OF 25N
WITH ISOLATED SHOWERS S OF 25N OVER THE BAHAMAS INTO THE
CARIBBEAN. A JETSTREAM WITH WINDS ESTIMATED TO BE 80 TO 110 KT
COVERS THE W ATLC N OF 24N W OF THE FRONT. AN UPPER RIDGE
ANCHORED IN THE CARIBBEAN EXTENDS ACROSS CUBA NEAR 21N78W TO
26N59W WITH A SECOND UPPER HIGH CENTERED IN THE CENTRAL ATLC
NEAR 30N51W. A DEEP LAYERED TROUGH IS OVER E ATLC N OF 20N E OF
30W WITH THE ASSOCIATED COLD FRONT ENTERING THE REGION NEAR
32N18W EXTENDING ALONG 28N25W TO 25N33W THEN DISSIPATING ALONG
24N40W THEN NW TO 29N50W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE E OF THE FRONT N OF 26N BETWEEN THE COAST OF
AFRICA AND THE FRONTAL BOUNDARY INCLUDING THE CANARY AND MADEIRA
ISLANDS. A SURFACE RIDGE IS BRIDGING THE WEAKENING FRONT
COVERING THE AREA BETWEEN 30W-60W. UPPER WESTERLY ZONAL FLOW
COVERS THE TROPICS AND A WEAKENING JETSTREAM WITH ESTIMATED
WINDS OF 80 TO 100 KT EXTENDS FROM JUST N OF THE CAPE VERDE
ISLANDS NEAR 18N25W TO OVER AFRICA NEAR 20N16W. THE REMAINDER OF
THE ATLC UNDER RATHER TRANQUIL CONDITIONS AGAIN TONIGHT.

$$
WALLACE


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