000 AXNT20 KNHC 041804 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI FEB 04 2011 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... SATELLITE IMAGERY AND GFS ANALYSIS SUGGEST THE AXIS EXTENDS FROM COASTAL GULF OF GUINEA MEANDERING W-SW TO 01N16W TO NEAR THE EQUATOR ALONG 27W TO THE COAST OF S AMERICA NEAR 03S43W. ACTIVE CNVTN WAS OCCURRING N OF THIS ANALYZED ITCZ...WHERE SCATTERED TO NUMEROUS MODERATE TO STRONG CNVTN WAS NOTED WITHIN 240 NM N OF THE AXIS...WHILE SCATTERED MODERATE TO STRONG CNVTN WAS NOTED WITHIN 180 NM S OF THE AXIS AND EXTENDED ACROSS THE EQUATOR INTO THE SRN HEMI BETWEEN 24W AND 35W. SCATTERED CLUSTERS OF DEEP CNVTN WERE OCCURRING ALONG COASTAL PORTIONS OF THE GULF OF GUINEA...S OF THE MONSOON TROUGH. ...DISCUSSION... THE GULF OF MEXICO... THE BROAD RIDGE ACROSS THE GULF HAS SHIFTED E TO ALONG 70W THIS MORNING AS DEEP LAYERED CYCLONE ACROSS THE SW U.S. AND OKLATEX REGION HAS REORGANIZED OVERNIGHT AND BECOME MORE NE TO SW ELONGATED. THE LINGERING FRONTAL BOUNDARY ACROSS THE GULF REMAINS DIFFICULT TO IDENTIFY PRECISELY...BUT HAS DRIFTED NW ACROSS N AND NE PORTIONS OF THE GULF AND INTO THE GULF STATES COASTAL WATERS FROM SE LOUISIANA TO THE FLORIDA PANHANDLE. SHARP CYCLONIC TURNING IN BUOY AND OIL RIG OBS OFF OF MS AND LA COASTS INDICATE AN E TO W WARM FRONT ACROSS THE NE GULF FROM N OF TARPON SPRINGS TO JUST E OF THE MOUTH OF THE MISSISSIPPI THEN STATIONARY FRONT S-SW TO NEAR 26N91W CONTINUING INTO THE CENTRAL BAY OF CAMPECHE. DENSE OVERCAST LOW AND MIDDLE CLOUD CONTINUE W OF THE FRONTAL BOUNDARY...PRODUCING FOG...LIGHT RAIN...DRIZZLE AND SOME FREEZING LIGHT RAINS ACROSS W AND NW PORTIONS. OVERRUNNING SW FLOW AT MID LEVELS IS PRODUCING A MIXED BAG OF PRECIPITATION IN MODERATE CONVECTION ACROSS LOUISIANA...MS...AND ALABAMA SPREADING NE INTO THE SE U.S. AN ASCAT PASS YESTERDAY SHOWED A SHARP HORIZONTAL WIND GRADIENT IN THE W BAY OF CAMPECHE...SUGGESTING THE FRONTAL BOUNDARY MAY HAVE REMAINED THERE FOR THE PREVIOUS 24 HOURS...AND MOST RECENT WIND OBSERVATION FROM COATZACOALCOS MEXICO IN THE S CENTRAL BAY OF CAMPECHE WAS FROM THE SOUTH. OUR FRONTAL POSITION FOR THE S END OF THE FRONT MAY HAVE BEEN TOO FAR E FOR THE PAST 48 HOURS AND SOME ADJUSTMENTS WILL BE MADE OF THE 18Z MAP. ALTHOUGH PRES ANALYSIS ACROSS THE GULF THIS MORNING SHOWS BROAD AND ELONGATED LOW PRES ALONG THE FRONT...THERE IS YET LITTLE EVIDENCE FOR A SYNOPTIC SCALE LOW AS GLOBAL MODELS HAD BEEN FORECASTING. THE WAVE OR DOUBLE POINT OFF THE MOUTH OF THE MS WILL BE THE LIKELY GENESIS REGION FOR ANY FORMATION OF A SURFACE LOW. NW TO N WINDS OF 20-30 KT PREVAIL TO THE W OF THE FRONT AND W OF 90W...WITH MINIMAL GALES OVER WRN PORTIONS EARLY THIS MORNING THROUGH LATE MORNING...WHICH HAVE LIKELY DIMINISHED BY NOW. DEEP LAYERED LOW MOVING ACROSS THE OKLATEX REGION IS FORECAST BY GLOBAL MODELS TO ELONGATE WITH JET ENERGY LIFTING OUT TO THE NE NEXT 24 HOURS... WITH ANOTHER SURFACE LOW BEING GENERATED AND MOVING IN SYNC. THIS WILL PROVIDE SUPPORT TO MOVE THE COLD FRONT CURRENTLY STALLED ACROSS THE GULF...AND DRAG IT E AND SE ACROSS THE BASIN...WITH A NEWLY INVIGORATED COLD FRONT EXPECTED TO REACH FROM THE FLORIDA BIG BEND REGION SW TO THE ERN BAY OF CAMPECHE BY SAT MORNING. NORTHERLY FLOW OF 20-25 KT IS FORECAST TO SPILL ACROSS THE W HALF OF THE BASIN TO OFFSHORE OF THE MOUTH OF THE MS TONIGHT BEHIND THE EWD MOVING BOUNDARY AND THEN DIMINISH QUICKLY BY FRI AFTERNOON AS HIGH PRES MOVES INTO THE NW GULF. THE CARIBBEAN SEA... SINKING AIR AND SUBSIDENCE CONTINUES TO DOMINATED ALL BUT THE FAR NW PORTIONS OF THE CARIB BASIN...ON THE S SIDE OF THE GULF OF MEXICO UPPER RIDGE. WATER VAPOR IMAGERY REVEALS A MID LEVEL TROUGH AXIS MEANDERING FROM THE CENTRAL ATLC DEEP LAYERED LOW TO NEAR 10N61W THEN CONTINUES WWD TO A WEAKENING MID LEVEL CYCLONE NEAR 11N77W. FAIR WEATHER AND MODERATE TO FRESH E-NE TRADES THUS DOMINATE THE BASIN. RECENT SCATTEROMETER PASSES SHOW STRONGEST TRADES CONTINUING FROM S AND SW OF THE MONA PASSAGE TO OFFSHORE OF COLOMBIA AT AROUND 25 KT...WITH WINDS 30 TO NEAR 35 KT WITHIN 120 NM OF THE COLOMBIA COAST. DEEP LAYERED TROUGH E OF THE LESSER ANTILLES HAS CARVED OUT A BROAD SURFACE REFLECTION IN THE PAST FEW DAYS...HELPING TO PRODUCE A DECIDEDLY NE FLOW ACROSS THE E AND SE CARIB. A FEW CLUSTERS OF SHALLOW MOISTURE AND MODERATE SHOWERS WERE SEEN EMBEDDED IN THESE TRADES MOVING WSW ACROSS THE BASIN. LITTLE CHANGE IN THE OVERALL LLVL PATTERN IS EXPECTED THROUGH FRI MORNING...WITH AN INCREASE IN MOISTURE AND SHOWERS EXPECTED ACROSS THE NE CARIB BY MIDDAY FRI. THE ATLANTIC OCEAN... AS STATED ABOVE...UPPER RIDGING ACROSS THE GULF OF MEXICO HAS SHIFTED E TO ALONG 70W...YIELDING MID TO UPPER CONVERGENCE AND SINKING MOTION S OF 27N AND W OF 60W. GENERALLY ZONAL FLOW PREVAILS N OF THE AREA OVER THE RIDGE...WITH A TUTT AXIS EXTENDING FROM A MID TO UPPER CYCLONE NEAR 34N23W TO THE CENTRAL ATLC DEEP LAYERED TROUGH AND WEAKENING CYCLONE NEAR 17.5N53W. STRONG DIRECTIONAL CONVERGENCE ALONG THE ITCZ CONTINUES TO YIELD GOOD CONVECTION OFF FROM 01N TO 05N E OF 40W AND IS MAINTAINING THE UPPER RIDGING S OF THE TUTT. HOWEVER CONVECTION HAS DIMINISHED IN THE PAST HOUR OR SO. GULF FRONTAL BOUNDARY WAS ILL DEFINED ACROSS FLORIDA...BUT STRETCHED ACROSS N FLORIDA SW TO NW...WITH A SMALL WEAK LOW ALONG THE FRONT NEAR 31N79W MOVING E-NE...AND WEAK ANTICYCLONIC FLOW TO THE E. THIS WEAK HIGH WAS TRAPPED TO THE S OF AN OLD FRONTAL BOUNDARY STRETCHED OUT ACROSS N PORTIONS OF THE AREA FROM THE SURFACE LOW TO 30N70W TO 33N56W AND BEYOND. EXCEPT FOR SCATTERED MODERATE CONVECTION OCCURRING ACROSS THE E AND SE SEMICIRCLES OF THE DEEP LAYERED CENTRAL ATLC TROUGH...HIGH PRES AND FAIR WEATHER GENERALLY PREVAIL ACROSS THE ATLC OFF THE ITCZ. A 1040 MB HIGH NEAR NEAR 40N14W ANCHORS THE ATLANTIC HIGH PRES RIDGE. METEOSAT IMAGERY THIS MORNING SHOWS VERY STABLE NE LLVL FLOW BLOWING OFF OF W AFRICA TO 30W TURNING CYCLONICALLY INTO THE WEAK BUT PERSISTENT MONSOONAL CIRCULATION ACROSS TROPICAL AFRICA. DRY CLEAR AIR CONTINUED OFF THE W COAST OF AFRICA TO THE CAPE VERDES...WITH ANOTHER PLUME OF AFRICAN DUST SEEN EXITING THE CONTINENT ALONG 19N. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ STRIPLING