000 AXNT20 KNHC 071752 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI MAR 07 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 7N10W 1N20W 1N30W THEN ALONG THE EQUATOR BETWEEN 25W-35W TO 3S46W. CLUSTERS OF MODERATE TO STRONG CONVECTION ARE FROM 1N TO THE SW COAST OF AFRICA BETWEEN THE PRIME MERIDIAN AND 10W. SIMILAR CONVECTION IS SEEN WITHIN 120 NM EITHER SIDE OF AXIS EAST OF 15W. SCATTERED MODERATE CONVECTION IS FROM FROM EQ-6N BETWEEN 42W-50W. ...DISCUSSION... THE GULF OF MEXICO... A STRONG COLD FRONT IS MOVING ACROSS THE GULF FOLLOWED BY GALE FORCE WINDS. A DEEP LAYERED TROUGH OVER THE CENTRAL CONUS AND NE MEXICO SUPPORTS THE FRONT. AS OF 1500 UTC...THE COLD FRONT EXTENDS FROM A 1004 MB LOW LOCATED OVER SOUTHERN ALABAMA TO NEAR VERACRUZ MEXICO. THE CITY OF VERACRUZ IS NOW REPORTING SUSTAINED WINDS OF 40 KT WITH GUSTS UP TO 50 KT. A GALE WARNING IS IN EFFECT BEHIND THE FRONT...BUT WINDS ARE EXPECTED TO GRADUALLY DIMINISH TONIGHT. THE FRONTAL SYSTEM WILL EXTEND FROM THE FLORIDA BIG BEND TO THE EASTERN YUCATAN PENINSULA THIS EVENING AND SHOULD SWEEP THROUGH THE REMAINDER OF THE GULF BY SAT MORNING. THE COMBINATION OF LOW-LEVEL CONVERGENCE AND A DIFFLUENT PATTERN ALOFT IS PRODUCING ACTIVE WEATHER AHEAD OF THE FRONT. SATELLITE IMAGERY AND DOPPLER RADAR SHOW A BAND OF STRONG SHOWERS AND TSTMS EXTENDING FROM 24N90W THROUGH THE FLORIDA BIG BEND TO SE GEORGIA. A SQUALL LINE IS ANALYZED IN THIS AREA. COLD AIR STRATOCUMULUS CLOUDS ARE FOUND OVER THE NW PORTION OF THE GULF. AN EARLY MORNING QUIKSCAT PASS AND SFC WIND OBSERVATIONS INDICATE THAT S TO SW WINDS OF 20-25 KT ARE BLOWING AHEAD OF THE FRONT OVER THE EASTERN GULF...THE FLORIDA KEYS AND SOUTH FLORIDA. THE CARIBBEAN SEA... LARGE MID TO UPPER HIGH DOMINATES THE REGION EXCEPT FOR THE FAR E PORTION WHERE UPPER TROUGHING IS INDUCED BY A LARGE CUT OFF LOW CURRENTLY LOCATED IN THE EASTERN ATLANTIC NEAR 28N38W AT 500 MB. WIDESPREAD SUBSIDENCE IS ASSOCIATED WITH THESE UPPER SYSTEMS. THIS FAIRLY STABLE ENVIRONMENT ALOFT IS CAPPING THE TYPICAL LOW-LEVEL CLOUD PATCHES...WHICH ARE MOST ORGANIZED IN BANDS OVER THE EASTERN CARIBBEAN JUST SOUTH OF PUERTO RICO. THE SAN JUAN DOPPLER RADAR SHOWS SCATTERED SHOWERS AND ISOLATED TSTMS ON THE CARIBBEAN SIDE. HIGH PRES OVER CENTRAL ATLC MAINTAINS MODERATE TO FRESH TRADE WINDS ACROSS MOST OF BASIN. THESE WINDS WILL PERSIST DURING THE UPCOMING WEEKEND. THE COLD FRONT THAT IS NOW MOVING ACROSS THE GULF OF MEXICO WILL REACH THE NW CARIBBEAN EARLY SAT WITH FRESH NLY FLOW AND BUILDING SEAS BEHIND IT. THE ATLANTIC OCEAN.... THE MAIN WEATHER FEATURE ACROSS THE FORECAST AREA IS A 1005 MB LOW SPINNING NEAR 28N37W. THIS LOW REMAINS QUASI-STATIONARY. THE AIR MASS AROUND THIS LOW HAS BECOME MORE HOMOGENEOUS DURING THE LAST 24 HOURS...AND THERE ARE NO FRONTS ASSOCIATED WITH THIS CYCLONE ANY LONGER. INSTEAD...A SFC TROUGH IS ANALYZED FROM THE SFC LOW TO 20N41W. SCATTERED SHOWERS AND TSTMS ARE MOST ORGANIZED IN BANDS N AND NE OF THE LOW. TIGHT PRES GRADIENT BETWEEN THIS CYCLONE AND HIGH PRES OVER THE CENTRAL ATLC IS PRODUCING A LARGE AREA OF MODERATE TO STRONG NE WINDS IN THE NW SEMICIRCLE OF THE LOW. ACCORDING TO THE GFS COMPUTER MODEL...THE LOW WILL SLOWLY DRIFT SW AND WEAKEN DURING THIS WEEKEND. MOST OF THE WEST AND CENTRAL ATLC ARE UNDER THE INFLUENCE OF A RIDGE ANCHORED ON A 1031 MB HIGH LOCATED NEAR 36N52W. FRAGMENTS OF LOW LEVEL CLOUDS ARE OBSERVED ACROSS THE AREA WITH SLY RETURN FLOW ACROSS THE BAHAMAS AND THE WESTERN ATLC WEST 0F 70W. ALOFT...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE AREA. A JET STREAM BRANCH WITH CORE WINDS OF 90-130 KT LIES BETWEEN THE PREVIOUSLY MENTIONED LARGE CUT-OFF LOW OVER THE EASTERN ATLC AND A BROAD UPPER-LEVEL HIGH LOCATED SE OF THE CAPE VERDE ISLANDS NEAR 9N18W. UPPER SLY FLOW ON THE WESTERN SIDE OF THE HIGH IS ADVECTING PATCHY HIGH LEVEL CLOUDS FROM N SOUTH AMERICA ACROSS THE TROPICAL ATLC. THESE WINDS ARE ALSO ENHANCING SCATTERED MODERATE CONVECTION N OF THE ITCZ AXIS AND WEST OF 40W. $$ GR