000 AXNT20 KNHC 132359 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST FRI FEB 13 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 1945 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG A LINE FROM 06N08W TO 04N14W TO 02N25W CROSSING THE EQUATOR AT 33W AND INTO NE BRAZIL NEAR 04S40W. SCATTERED MODERATE ISOLATED STRONG CONVECTION LIES WITHIN 90 NM N AND 150 NM S OF THE ITCZ AXIS E OF 17W. ...DISCUSSION... GULF OF MEXICO... THE STATIONARY BOUNDARY FROM SOUTH OF NEW ORLEANS OVER THE NE GULF OF MEXICO AND INTO FORT MYERS IS DISSIPATING THIS AFTERNOON/EVENING. SHOWERS AND ISOLATED THUNDERSTORMS CAN BE FOUND NEAR THE NORTHERN END OF THE DISSIPATING BOUNDARY MAINLY WITHIN 60 NM OF THE CENTRAL GULF COAST. OVER THE REST OF THE EASTERN GULF...LIGHT WINDS AND STABLE CONDITIONS SOUTH OF THE DISSIPATING STATIONARY FRONT WILL PROMOTE THE DEVELOPMENT OF FOG THROUGH SATURDAY. THE SW GULF IS MOSTLY CLOUD FREE ON THE WESTERN PERIPHERY OF A SFC RIDGE EXTENDS S OVER FLORIDA. SOUTHERLY FLOW AHEAD OF THE TROUGH OVER THE SOUTHERN PLAINS CURRENTLY DOMINATES THE WESTERN GULF OF MEXICO. THE COLD FRONT OVER THE SOUTHERN PLAINS WILL STRETCH EASTWARD...REACHING THE NORTHERN GULF COAST BY SATURDAY MORNING AND MEANDERING THERE OVERNIGHT UNTIL THE STEERING FLOW BECOMES MORE AMPLIFIED SUNDAY. A SURFACE WAVE WILL DEVELOP OVER THE NORTHERN GULF OF MEXICO MOVE EASTWARD INTO THE ATLC...SENDING THE ASSOCIATED COLD FRONT SOUTHWARD THROUGH THE GULF SUN/MON. CARIBBEAN SEA... THE CARIBBEAN IS VOID OF DEEP CONVECTION WITH STRONG SUBSIDENCE AND DRY AIR IN THE MID AND UPPER LEVELS COUPLED WITH CONFLUENT FLOW ALOFT BETWEEN THE RIDGING OVER CENTRAL AMERICAN AND THE SOUTHERN END OF THE TROUGH OVER THE WESTERN ATLC/EASTERN CARIBBEAN. TRADE WINDS HAVE DIMINISHED COMPARED TO YESTERDAY...WITH EASTERLY WINDS GENERALLY IN THE 20 TO 25 KT RANGE S OF 18N AND LESS THAN 20 KT ELSEWHERE ACCORDING TO THE 1440 UTC ASCAT PASS. WEAK TO MODERATE TRADE WINDS SHOULD CONTINUE OVER THE CARIBBEAN THROUGH THE WEEKEND...WITH ISOLATED TRADE SHOWERS MOVING WESTWARD ACROSS THE REGION. ATLANTIC OCEAN... THE ASCAT PASSES FROM 1120 AND 1300 UTC SHOW TRADE WINDS IN THE 20 TO 25 KT RANGE ACROSS MUCH OF THE ATLC FROM 05N TO 20N W OF 30W. WINDS ON THE WESTERN EDGE OF THIS SWATH SHOULD DIMINISH AS THE DEEP LAYER TROUGH OVER THE WESTERN ATLC APPROACHES AND THE SUBTROPICAL SURFACE HIGH...CURRENTLY 1022 MB NEAR 28N39N... WEAKENS SLIGHTLY AND PUSHES EASTWARD TOWARD 30W. THE SURFACE COLD FRONT ASSOCIATED WITH THIS DEEP LAYER TROUGH LIES OVER FORECAST WATERS FROM 31N58W TO 27N70W TO SOUTH OF PALM BEACH...FL. A COLDER AND MUCH DRIER AIRMASS HAS SETTLED INTO THE W ATLC BEHIND THE FRONT. SCATTERED SHOWERS CAN BE FOUND WITHIN 90 NM OF THE FRONT AND WINDS IN THE 25 TO 30 KT RANGE CAN BE FOUND WITHIN 90 NM OF THE FRONT OVER FORECAST WATERS E OF 65W ACCORDING TO THE 1436 AND 1256 UTC ASCAT PASSES. THE FRONT IS FORECAST TO DISSIPATE OVER WEST ATLC WATERS IN THE NEXT 24 HOURS AS HIGH PRESSURE BUILDS BETWEEN FLORIDA AND BERMUDA. AHEAD OF THE FRONT...FAIR WEATHER COVERS THE CENTRAL AND EAST ATLC NEAR THE AFOREMENTIONED HIGH PRESSURE CENTER. UPPER LEVEL MOISTURE IS BEING ADVECTED NORTHEASTWARD ACROSS THE ATLC S OF 20N BY FLOW ON THE LEADING EDGE OF A WEAK UPPER TROUGH OVER THE EAST ATLC. FARTHER SOUTH...DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 08N18W IS ENHANCING CONVECTION ALONG THE ITCZ. SCATTERED MODERATE ISOLATED STRONG CONVECTION LIES WITHIN 90 NM N AND 150 NM S OF THE ITCZ AXIS E OF 17W. $$ SCHAUER CLARK