000 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