000 AXNT20 KNHC 031757 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU FEB 03 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 OFFSHORE OF W AFRICA NEAR 06N13W THEN MEANDERS W-SW TO 02N32W TO NEAR THE EQUATOR ALONG 43W. VERY 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... A BROAD AND RELATIVELY FLAT MID TO UPPER RIDGE CONTINUED ACROSS THE GULF OF MEXICO THIS MORNING EXTENDING E TO 70W. A MID TO UPPER CYCLONE ACROSS THE SW U.S. WAS DIGGING SLOWLY S INTO NRN MEXICO WHILE THE ASSOCIATED TROUGH AXIS OF THE CYCLONE WAS ROTATING CYCLONICALLY. THIS DEEP LAYERED LOW IS FORECAST TO SHIFT E-SE AND MOVE ACROSS NRN MEXICO AND THE W HALF OF TEXAS NEXT 24 HOURS BEFORE SRN STREAM JET ENERGY SHEARS AND ELONGATES THIS LOW NE TO SW BY FRI EVENING. THIS WILL SHIFT THE UPPER RIDGE EWD AND AMPLIFY IT ACROSS THE WRN ATLC. THE COLD FRONT ACROSS THE GULF HAS BECOME STATIONARY OVERNIGHT...WITH MULTILAYERED CLOUDS MAKING IT DIFFICULT TO IDENTIFY PRECISELY. GFS ANALYSIS AND OBSERVATIONS SUGGEST THE FRONT WAS LOCATED FROM JUST S OF TAMPA BAY W TO NEAR 27N85.5W THEN ARCHING SW TO THE BAY OF CAMPECHE NEAR 18N93W. MID LEVEL FLOW ACROSS THE S CENTRAL AND SW GULF HAS BECOME S TO SW AND APPEARS TO BE SLOWLY NUDGING THE FRONT BACK TOWARDS THE N AND NW. WIDESPREAD STRATIFORM PRECIP IS LIKELY OCCURRING ACROSS THE SW AND CENTRAL PORTIONS OF THE GULF NW OF THE FRONT AS AMPLE LOW AND MID LEVEL MOISTURE OVERRUNS THE BOUNDARY. A FEW ISOLATED DEEP TSTMS WERE NOTED NEAR THE BOUNDARY ACROSS THE NE GULF NEAR 27N. NLY FLOW 20-25 KT IS ASSUMED TO BE OCCURRING ACROSS MUCH OF THE WRN GULF TO THE NW OF THE FRONT...WITH THE POTENTIAL FOR WINDS TO 30 KT WITHIN 120 NM OF THE MEXICAN COASTLINE. SCATTEROMETER PASSES LATER THIS MORNING SHOULD PROVIDE INSIGHT INTO THE WIND FIELD AROUND THE FRONT BUT MAY MISS THE FAR W GULF COAST. THE FRONT IS FORECAST TO DRIFT NW AND W THROUGH 12Z FRI AND IS EXPECTED TO ALLOW A FRONTAL WAVE TO DEVELOP ACROSS THE CENTRAL OR S CENTRAL GULF AND SHIFT GRADUALLY NE ALONG THE BOUNDARY THROUGH FRI NIGHT. GLOBAL MODEL GUIDANCE REMAINS SOMEWHAT IN DISAGREEMENT ON THE LOCATION OF THIS LOW DEVELOPMENT. HOWEVER GFS AND ECMWF ENSEMBLES SUGGEST THAT THIS LOW WILL EVENTUALLY DEVELOP AND SHIFT TO NEAR 25N92W AROUND 12Z FRI. THIS WILL ALLOW FOR A VERY TIGHT PRES GRADIENT AND DAMMING OF WINDS ALONG THE MEXICAN COAST...AND NLY GALES ARE EXPECTED ACROSS PORTIONS OF THE W GULF BY 12Z. THE CARIBBEAN SEA... SINKING AIR AND SUBSIDENCE GENERALLY DOMINATES THE ENTIRE CARIB BASIN...ON THE S SIDE OF THE GULF OF MEXICO UPPER RIDGE. WATER VAPOR IMAGERY REVEALS A MID LEVEL TROUGH AXIS MEANDERING FROM A CENTRAL ATLC DEEP LAYERED LOW TO NEAR 10N60W THEN WWD TO A MID LEVEL CYCLONE NEAR 12N75W. FAIR WEATHER AND MODERATE TO FRESH E-NE TRADES THUS DOMINATE THE BASIN. RECENT SCATTEROMETER PASSES SHOW NE TRADES 20-25 KT EXTENDING FROM THE WATERS S AND SW OF PUERTO RICO TO THE SW CARIB ALONG 80W...WITH 25-30 KT WINDS WITHIN 180 NM OF THE COLOMBIAN COASTLINE. THESE FRESH TRADES ARE BLOWING ACROSS CENTRAL AMERICA AND PRODUCING GAP WIND EVENTS OF 20-25 KT IN THE TYPICAL EXIT REGIONS OF THE EPAC...INCLUDING NLY WINDS IN THE GULF OF PANAMA. ENHANCED LLVL MOISTURE WILL MOVE FROM THE TROPICAL N ATLC W-SW ACROSS THE S HALF OF THE WINDWARDS DURING THE NEXT 24 HOURS TO PRODUCE SCATTERED SHOWERS AND ISOLATED TSTMS. THE ATLANTIC OCEAN... STRONG UPPER RIDGING ACROSS THE GULF OF MEXICO EXTENDS E INTO THE SW N ATLC TO 70W...WITH UPPER FLOW BECOMING CONFLUENT NEAR 70W...AND JET ENERGY CONTINUING E-NE ACROSS THE CENTRAL ATLC AND A PORTION OF THE FLOW DIVERTING SE THEN S INTO THE BACKSIDE OF A DEEP LAYERED CYCLONE NEAR 21N54W. CONVERGENCE ACROSS THE BROAD W SEMICIRCLE OF THE LOW WAS YIELDING SUBSIDENCE FROM THE NE CARIB NE AND E TO NEAR 55W. A MID TO UPPER HIGH WAS CENTERED JUST NE OF THE SE BAHAMAS NEAR 23N70W. THE COLD FRONT ACROSS THE GULF OF MEXICO WAS SOMEWHAT ILL DEFINED ACROSS THE FLORIDA PENINSULA BUT WAS SOMEWHERE NEAR FORT PIERCE EXTENDING NE TO NEAR 30N77.5W. A 1024 MB HIGH NEAR 29N68W WAS THE SW LOBE OF THE ATLC RIDGE THAT EXTENDED SW TO SRN FLORIDA. FAIR WEATHER AND LIGHT TO MODERATE ANTICYCLONIC FLOW PREVAILED ACROSS THE SW N ATLC...THE BAHAMAS AND INTO FAR SRN FLORIDA...W OF 67W. THE REMNANTS OF A SURFACE LOW SPAWNED BY THE DEEP LAYERED CYCLONE WERE STILL EVIDENT NEAR 25.5N61W AND MOVING W...WHILE THE CURRENT LOCATION OF THE UPPER CYCLONE ALONG 54W CONTINUED TO CARVE OUT A LLVL WEAKNESS AND TROUGHING DOWN TO THE SURFACE S OF 21N ALONG 54/55W. LOW TO MID LVL CONVERGENCE ACROSS THE SRN SEMICIRCLE OF THIS CYCLONE WAS PRODUCING BANDS OF SCATTERED SHOWERS AND ISOLATED TSTMS...WITH BEST CONVECTION OCCURRING ACROSS THE SE QUADRANT OF THE UPPER CYCLONE WHERE A JET SEGMENT WAS ENHANCING UPPER SPEED DIVERGENCE. STRONG HIGH PRES ACROSS THE NE ATLC WAS HELPING TO PRODUCE A BROAD AREA OF FRESH NE TO E TRADES ACROSS THE REMAINDER OF THE ATLC E OF 55W BETWEEN 25-30N ACROSS THE E ATLC AND 08N IN THE DEEP TROPICS. VIS STLT IMAGES THIS MORNING SHOWED GENERALLY FAIR WEATHER ACROSS THIS LARGE AREA WITH COLD AIR STRATOCU. ELONGATED CONVERGENCE BANDS BETWEEN 40W AND 50W WERE PRODUCING SCATTERED SHALLOW CONVECTION. METEOSAT IMAGERY THIS MORNING SHOWS VERY STABLE NE LLVL FLOW BLOWING OFF OF W AFRICA TURNING CYCLONICALLY INTO THE WEAK BUT PERSISTENT MONSOONAL CIRCULATION ACROSS TROPICAL AFRICA. DRY CLEAR AIR WAS MOVING W OFF THE W COAST AND HAD BEGUN TO REACH THE CAPE VERDES...WITH TWO PLUMES OF AFRICA DUST BECOMING EVIDENT BETWEEN 16N AND 22N. WARM WATERS ACROSS THE EQUATORIAL ATLC AND GOOD LLVL CONVERGENCE DUE TO N TO NE FLOW ACROSS THE N ATLC...CONTINUE TO PRODUCE SIGNIFICANT CNVTN ALONG THE ATLC ITCZ E OF 45W...WHICH IS THEN ACTING TO MAINTAIN UPPER RIDGING ACROSS THE TROPICAL ATLC. 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