000 AXNT20 KNHC 212326 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT MAR 21 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2215 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N9W 2N18W ALONG THE EQUATOR FROM 27W-46W THEN S INTO NE BRAZIL NEAR 1S49W. NO SIGNIFICANT CONVECTION. ...DISCUSSION... GULF OF MEXICO... BROAD DEEP LAYERED TROUGH COVERS THE E US AND THE E GULF OF MEXICO E OF 90W INTO THE W ATLC WITH MODERATE/STRONG SUBSIDENCE OVER THE SAME AREA. THE ASSOCIATED COLD FRONT IS IN THE W ATLC. THE W GULF IS UNDER NEAR ZONAL WESTERLY FLOW. THE SURFACE IS DOMINATED BY A RIDGE EXTENDING FROM OVER NEW ENGLAND COVERING THE ENTIRE GULF. SOME UPPER LEVEL MOISTURE IS MOVING ACROSS THE W GULF IN THE FORM OF THIS HIGH CLOUDS N OF 22N FROM 92W-96W. THE REMNANTS OF THE FRONT IN THE W ATLC IS SPARKING OFF LOW LEVEL SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS OVER THE S FLORIDA PENINSULA AND MOVING INTO THE SE GULF WITHIN 60 NM OF THE FLORIDA PENINSULA BETWEEN TAMPA AND THE FLORIDA KEYS. OTHERWISE THE REMAINDER OF THE GULF REMAINS UNDER FAIR WEATHER CLOUDS THIS EVENING. CARIBBEAN SEA... BROAD UPPER RIDGE DOMINATES THE CARIBBEAN ANCHORED OVER SOUTH AMERICA AND THE AXIS EXTENDING ALONG 65W INTO THE W TROPICAL ATLC. A JET STREAM WITH WINDS OF 90 TO 110 KT IS WITHIN 200 NM OF LINE EXTENDING FROM S OF JAMAICA NEAR 16N78W OVER HISPANIOLA INTO THE W ATLC INCLUDING PUERTO RICO AND THE VIRGIN ISLANDS. MODERATE/STRONG EASTERLY TRADE WINDS ARE OVER THE S CARIBBEAN WITH THE STRONGEST WINDS ALONG THE COAST OF COLOMBIA. THE TYPICAL NE FLOW OVER THE SW CARIBBEAN IS BANKING LOW LEVEL CLOUDS WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS INLAND AND WITHIN 90 NM ALONG THE COAST OF W PANAMA AND COSTA RICA S OF 11N W OF 80W. THE SAME EASTERLY TRADE WINDS ARE BANKING SIMILAR CLOUDS/ACTIVITY IN THE GULF OF HONDURAS TO INLAND OVER HONDURAS AND THE YUCATAN S OF 18N W OF 86W. TYPICAL AFTERNOON SHOWERS AND POSSIBLE THUNDERSTORMS HAVE DEVELOPED OVER THE JAMAICA...HISPANIOLA...AND PUERTO RICO. OTHERWISE THE REMAINDER OF THE CARIBBEAN IS UNDER FAIR WEATHER CLOUDS THIS EVENING. ATLANTIC OCEAN... THE DEEP LAYERED TROUGH OVER THE E US AND E GULF OF MEXICO COVERS THE W ATLC W OF 61W WITH THE ASSOCIATED COLD FRONT ENTERING THE AREA JUST E OF BERMUDA AND EXTENDING ALONG 27N73W WEAKENING AS IT REACHES THE FLORIDA COAST NEAR MIAMI. HOWEVER... IT IS GENERATING LOW LEVEL SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 25N-28N W OF 79W AND OVER THE N BAHAMA ISLANDS BETWEEN 76W-79W. EMBEDDED WITHIN THE DEEP LAYERED TROUGH IS A WEAKENING 1014 MB LOW NEAR 28N66W WITH A SURFACE TROUGH EXTENDING S ALONG 22N67W THEN SW OVER HISPANIOLA TO 19N72W AND A WEAK WARM FRONT EXTENDING FROM THE LOW ALONG 29N63W TO 27N61W. THE BROAD UPPER RIDGE THAT COVERS THE CARIBBEAN EXTENDS INTO THE W AND CENTRAL ATLC NEAR 20N65W THEN NE TO BEYOND 32N48W. AN EMBEDDED JET STREAM WITH WINDS OF 90 TO 110 KT EXTENDS WITHIN 200 NM OF A LINE FROM THE CARIBBEAN ACROSS HISPANIOLA TO 21N59W. UPPER LEVEL DIFFLUENCE TO THE W OF THE UPPER RIDGE IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE FROM 25N64W TO BEYOND 32N59W. A SECOND DEEP LAYERED TROUGH IS OVER THE E/CENTRAL ATLC N OF 20N BETWEEN 26W-43W WITH AN ASSOCIATED COLD FRONT ENTERING THE REGION NEAR 32N34W EXTENDING SW ALONG 26N39W TO 22N46W BISECTING THE SURFACE RIDGE THAT COVERS MOST OF THE E AND CENTRAL ATLC. A SURFACE TROUGH EXTENDS FROM THE SURFACE LOW WELL N OF THE REGION INTO THE AREA THROUGH 32N39W TO 27N46W. BOTH THE FRONT AND SURFACE TROUGH ARE EMBEDDED WITHIN SOME RATHER DRY AIR...THUS ONLY LOW LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE WITHIN 60 NM OF EITHER FEATURE. $$ WALLACE