000 AXNT20 KNHC 041138 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SUN MAR 04 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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 1115 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 3N25W 1N40W CROSSING THE EQUATOR AT 48W INTO NE BRAZIL. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 50 NM ON EITHER SIDE OF THE AXIS BETWEEN 18W AND 25W...AND WITHIN 80 TO NM N OF THE AXIS BETWEEN 25W-35W. ...DISCUSSION... GULF OF MEXICO... A COLD FRONT IS MOVING SLOWLY ACROSS THE FLORIDA KEYS AND THE SE PORTION OF THE GULF EARLY THIS MORNING. A LINE OF SCATTERED SHOWERS OVER THE STRAITS OF FLORIDA DEFINES THE LEADING EDGE OF THE FRONT WHILE A SURGE OF COLD AIR AND EXTENSIVE CLOUDINESS ARE FOUND BEHIND THIS FRONTAL SYSTEM. A BROAD MID-UPPER LEVEL TROUGH THAT EXTENDS FROM QUEBEC SOUTHWESTWARD TO THE TEXAS PANHANDLE SUPPORTS THIS FRONTAL BOUNDARY. VERY STRONG UPPER LEVEL WINDS ASSOCIATED WITH A SUBTROPICAL JETSTREAM AHEAD OF THE TROUGH ARE TRANSPORTING UPPER LEVEL MOISTURE FROM THE EPAC ACROSS N MEXICO AND THE NORTH GULF STATES INTO THE W ATLC. DRY AIR/STRONG SUBSIDENCE IS NOTED OVER THE GULF S OF THE STRONG JET/27N...WITH 250 MB WINDS INDICATING CORE SPEEDS OF 130 TO 150 KT. AT THE SURFACE BUILDING HIGH PRESSURE OVER TEXAS AND THE NW CORNER OF THE GULF CONTINUES TO PUSH THE ABOVE MENTIONED COLD FRONT SLOWLY SEWD. THIS FEATURE IS EXPECTED TO BUILD FURTHER INTO THE W GULF TODAY WITH STRONG NORTHERLY WINDS INCREASING TO GALE FORCE OVER THE SW GULF THIS AFTERNOON. NLY WINDS OF 20 TO 25 KT ARE ALREADY BLOWING ACROSS THE W GULF BEHIND THE FRONT. BROKEN TO OVERCAST LOW LEVEL CLOUDS WITH LIGHT RAIN/DRIZZLE ARE BANKED UP ALONG THE E SLOPE OF THE SIERRA MADRE MOUNTAINS AND A STATIONARY FRONT IS INDICATED THERE. CARIBBEAN... A MID/UPPER LEVEL HIGH IS CENTERED BETWEEN E CUBA AND HISPANIOLA NEAR 19N73W WITH THE ASSOCIATED RIDGE AXIS EXTENDING ENE INTO THE SW ATLC. THIS FEATURE COVERS THE ENTIRE CARIBBEAN AND IS ACCOMPANIED BY VERY STRONG SUBSIDENCE/DRY AIR ESPECIALLY OVER THE E CARIBBEAN IN THE VICINITY OF AN UPPER LEVEL TROUGH AXIS WHICH IS UNDERCUTTING THE RIDGE AXIS AND EXTENDS THROUGH 15N61W TO 13N74W. PRESSURE GRADIENT BETWEEN THE SURFACE RIDGE OVER THE ATLC AND THE 1005 MB SFC LOW PRESSURE LOCATED OVER N COLOMBIA IS GENERATING STRONG EASTERLY TRADE WINDS ACROSS THE AREA. PATCHES OF LOW LEVEL MOISTURE WITH EMBEDDED SHOWERS DRIVEN BY THESE WINDS ARE MOVING WWD FROM THE TROPICAL N ATLC INTO THE E CARIBBEAN. SOME OF THEM ARE NOW AFFECTING THE VIRGIN ISLANDS... PUERTO RICO AND HISPANIOLA AS WELL AS JAMAICA AND PARTS OF CUBA. THE ATLC RIDGE WILL CONTINUE TO MOVE EWD AND THE COLD FRONT CURRENTLY OVER THE SE GULF WILL REACH THE NW CARIB/W CUBA TONIGHT FOLLOWED BY STRONG GUSTY N WINDS. ATLANTIC... STRONG ZONAL FLOW SOUTH OF THE BROAD TROUGH OVER THE E CONUS IS SWEEPING OVER THE ATLC N OF 28N W OF 65W. BROAD UPPER RIDGE EXTENDS FROM THE CARIBBEAN INTO THE W AND CENTRAL ATLC TO BEYOND 32N55W COVERING THE AREA W OF 50W. STRONG SUBSIDENCE AND VERY DRY UPPER AIR DOMINATE THE REGION S OF 27N W OF 45W LIMITING SHOWERS ACTIVITY E OF A COLD FRONT THAT ENTERS THE FORECAST AREA NEAR 31N70W AND CROSSES THE N BAHAMAS AND THE FLORIDA KEYS. A SURFACE RIDGE EXTENDS FROM A 1028 MB HIGH LOCATED NEAR 35N37W SOUTHWEST TO NEAR 25N72W. A MID/UPPER LEVEL TROUGH EXTENDS FROM THE CANARY ISLANDS SW TO A DEVELOPING CYCLONIC CIRCULATION NEAR 18N45W. THE TAIL END OF THE ASSOCIATED COLD FRONT CLIPS THE REGION THROUGH 30N25W TO 28N30W. A WEAKENING SURFACE TROUGH IS APPROACHING THE LESSER ANTILLES. IT LIES ALONG 59/60W FROM 12N-21N. ONLY ISOLATED LOW TOP SHOWERS ARE OCCURRING WITH THIS TROUGH. AN UPPER RIDGE IS DOMINATING THE FAR E ATLC. WV IMAGERY REVEALS A BAND OF TRANSVERSE HIGH CLOUDS ASSOCIATED WITH A TROPICAL JETSTREAM OVER THE DEEP TROPICS E OF 50W CROSSING S OF THE CAPE VERDE ISLANDS. $$ GR