000 AXNT20 KNHC 172342 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON MAR 17 2008 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 3N16W 1N26W CROSSING THE EQUATOR NEAR 36W TO NE BRAZIL NEAR 3S42W. SCATTERED MODERATE AND EMBEDDED ISOLATED STRONG CONVECTION IS WITHIN 180 NM EITHER SIDE OF THE AXIS BETWEEN 13W-21W. ISOLATED MODERATE CONVECTION IS WITHIN 150 NM N OF THE AXIS W OF 36W. ...DISCUSSION... GULF OF MEXICO... A SUBSIDENT MID TO UPPER RIDGE IS LOCATED OVER THE REGION WITH A MEAN AXIS ALONG 86W. THIS UPPER SYSTEM FEATURE IS PROVIDING LIMITED SUPPORT FOR THE TAIL END OF A QUASI-STATIONARY WEAKENING FRONT FROM THE FLORIDA STRAITS TO S MISSISSIPPI. ONLY PATCHY LOW-LEVEL CLOUDS ARE ASSOCIATED WITH THIS BOUNDARY. STRONG SE WINDS ARE OCCURRING IN THE WRN GULF DUE TO A TIGHT PRESSURE GRADIENT BETWEEN A 1035 MB HIGH OVER SRN VIRGINIA AND A LOW PRES TROUGH OVER TEXAS AND MEXICO. THESE WINDS ARE LIKELY TO REACH GALE FORCE WITHIN THE NEXT 18 HOURS AS THE LOW PRES AREA...AND ASSOCIATED COLD FRONT...NEARS THE NW PORTION. CARIBBEAN SEA... A WELL DEFINED COLD FRONT LIES JUST N OF THE CARIB SEA ACROSS THE SRN BAHAMAS AND NRN CUBA. LOW-LEVEL CLOUDS AND EMBEDDED SHOWERS ARE ALONG AND JUST AHEAD OF THE FRONT...WITH GUSTY NLY WINDS BEHIND IT. ALOFT...A MID TO UPPER RIDGE...BEING STRETCHED BY A SHORTWAVE IN THE ATLC...EXTENDS FROM NRN VENEZUELA TO THE YUCATAN PENINSULA. WIDESPREAD DRY STABLE AIR IS ASSOCIATED WITH THIS SYSTEM ESPECIALLY E OF 80W....SUPPRESSING THE DEVELOPMENT OF DEEP CONVECTION. TYPICAL PATCHES OF LOW-LEVEL CLOUDS ARE STEERED WWD BY THE TRADES...MOST ORGANIZED OVER THE WINDWARD ISLANDS WHERE THERE IS A WEAK LOW-LEVEL TROUGH. ATLANTIC OCEAN... A POWERFUL 966 MB LOW LOCATED WELL N OF THE REGION NEAR 40N57W PULLS A COLD FRONT INTO THE AREA FROM 32N52W TO 23N67W AND INTO THE FLORIDA STRAITS. THIS FRONT IS VERY WELL DEFINED WITH AN IMPRESSIVE ROPE CLOUD EVIDENT ON VISIBLE IMAGERY AND A WIDESPREAD AREA OF STABLE STRATOCUMULUS CLOUDS BEHIND IT. LIGHTNING DATA DEPICTS WIDELY SCATTERED TSTM ACTIVITY WITHIN 60 NM E OF THE FRONT N OF 26N. HOWEVER...THE BIG STORY IS THE WINDS REACHING HURCN FORCE N OF THE AREA AND TO GALE FORCE IN OUR FORECAST AREA N OF 25N. THE REMAINDER OF THE ATLC IS FAIRLY QUIET. A WEAK SFC TROUGH ALONG 33W FROM 26N-31N...WHICH LIES BENEATH A WEAKENING UPPER TROUGH...IS PRODUCING PATCHY CLOUDS AND A FEW EMBEDDED SHOWERS N OF 28N BETWEEN 27W-35W. OTHERWISE...A WEAK SFC PRES PATTERN AND FAIRLY FLAT UPPER FLOW IS KEEPING CONDITIONS TRANQUIL. $$ CANGIALOSI/WALTON