000 AXNT20 KNHC 171122 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SAT FEB 17 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA... CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA... NORTHEASTERN 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 3N25W 1N34W...CROSSING THE EQUATOR NEAR 39W...2S41W INTO NORTHEASTERN BRAZIL NEAR 3S45W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 180 NM EITHER SIDE OF THE AXIS E OF 17W AND W OF 32W. ISOLATED MODERATE IS WITHIN 120 NM EITHER SIDE BETWEEN 26W-32W. ...DISCUSSION... THE GULF OF MEXICO... FAIR WEATHER IS THE RULE ACROSS THE AREA THIS MORNING THANKS IN PART TO A 1023 MB HIGH PRES SYSTEM IN THE CENTRAL GULF NEAR 25N90W. NEARLY ALL OF THE LOW TO MID LEVEL CLOUD DECK THAT PLAGUED THE SRN GULF OVER THE PAST FEW DAYS HAS THINNED AND PUSHED SWD WITH THE FRONT NOW IN THE NW CARIB. THE ONLY AREA OF NOTABLE CLOUD COVER IS IN THE WRN BAY OF CAMPECHE ASSOCIATED WITH SLY RETURN FLOW. SCATTERED COLD AIR STRATOCUMULUS CLOUDS ARE SEEN ON IR IMAGES OVER MOST OF THE ERN HALF OF THE REGION...NAMELY E OF THE SFC HIGH. THESE CLOUDS ARE AN INDICATION OF THE COLD AIRMASS IN PLACE. IN FACT...THIS MORNING IS THE COLDEST THIS WINTER FOR MANY LOCATIONS IN FLORIDA. SFC WINDS HAVE RELAXED A GREAT DEAL SINCE YESTERDAY AT THIS TIME DUE TO THE WEAK SFC PATTERN...BUT THEY WILL NOT STAY LIGHT FOR LONG AS A REINFORCED COLD FRONT...CURRENTLY DRAPED ACROSS THE CENTRAL U.S...ENTERS THE GULF THIS MORNING AND RACES ACROSS THE REGION CLEARING THE ENTIRE AREA BY TOMORROW MORNING. NLY WINDS WILL INCREASE BEHIND THE FRONT AS STRONG HIGH PRES BUILDS SWD IN ITS WAKE. THE CARIBBEAN SEA... THE TAIL END OF A WEAKENING COLD FRONT EXTENDS FROM CENTRAL CUBA TO HONDURAS ALONG 21N78W 18N83W 14N87W. THE FRONT IS MOST EASILY NOTED BY A SURGE IN NLY WINDS AS INDICATED BY A QSCAT PASS NEAR 00 Z. A WEAK PREFRONTAL TROUGH IS ANALYZED FROM 19N79W TO 14N81W SHIFTING THE WINDS FROM E/NE TO NW PRIOR TO THE FRONTAL PASSAGE. BROKEN PATCHES OF LOW TO MID LEVEL CLOUDS LIE OVER CUBA AND PARTS OF THE NW CARIB. THERE MAY BE ISOLATED SHOWERS EMBEDDED BUT NO ORGANIZED ACTIVITY AS SUGGESTED BY DOPPLER RADAR IN CUBA. ELSEWHERE THE MAIN WEATHER FEATURE IS A VERY BROAD STRONG UPPER LEVEL RIDGE STRETCHING ACROSS THE REGION. THE RIDGE HAS FLATTENED IN THE WRN CARIB IN RESPONSE TO A LARGE UPPER TROUGH ENCOMPASSING THE ERN U.S. THIS RIDGE CONTINUES TO SUPPLY AN ABUNDANT AMOUNT OF DRY AIR/SUBSIDENT FLOW ALOFT SUPPRESSING ANY SIGNIFICANT TSTM ACTIVITY. THE DRIEST AIR IS IN THE UPPER CONFLUENT ZONE BETWEEN HISPANIOLA AND VENEZUELA/COLOMBIA. BENEATH THE STRONG MID LEVEL CAP...SMALL PATCHES OF LOW-LEVEL MOISTURE ARE BEING STEERED BY LIGHT TO MODERATE ELY TRADES E OF THE PREFRONTAL TROF. LOOKING AHEAD FOR A DAY OR SO...THE STRONG NLY WINDS IN THE NW CARIB ARE EXPECTED TO SUBSIDE SLIGHTLY DURING THE DAY TODAY AND THEN QUICKLY RAMP UP AGAIN ON SUN BEHIND A QUICK MOVING REINFORCING COLD FRONT. THE ATLANTIC OCEAN... A COLD FRONT ENTERS THE AREA NEAR 32N56W AND CONTINUES SW ALONG 26N66W TO THE COAST OF CUBA NEAR 21N77W. LOW LEVEL LIFT NEAR THE FRONT ALONG WITH SOME UPPER ENERGY FROM A SUBTROPICAL JET RACING THRU THE AREA IS PRODUCING BROKEN TO OVERCAST MULTILAYERED CLOUDS WITH EMBEDDED SHOWERS ROUGHLY WITHIN 300 NM NW OF THE FRONT. A SFC TROUGH ENTERS THE AREA NEAR 32N61W AND CONTINUES WSW TO NE FLA NEAR 29N81W...ADDING A LITTLE CYCLONIC CURVATURE TO THE PREDOMINANT STRONG NW WINDS BLOWING OFFSHORE THE SE U.S. THE REMAINDER OF THE SFC PATTERN IN THE ATLC AREA IS DOMINATED BY THE SRN PERIPHERY OF A 1028 MB HIGH NEAR 36N24W. THIS IS SUPPLYING MOSTLY FAIR WEATHER AND MODERATE TRADES ACROSS A GOOD PORTION OF THE CENTRAL AND E ATLC. THE SFC WINDS ARE STRONGEST...SWLY GALE FORCE...WITHIN 240 NM E OF THE FRONT N OF 29N...IN THE TIGHT GRAD BETWEEN THE RIDGE AND THE FRONT. THE MID TO UPPER LEVEL PATTERN HAS AMPLIFIED A LITTLE DOMINATED BY A LARGE RIDGE OVER THE WRN AND CENTRAL ATLC W OF 45W AND A BROAD TROUGH E OF THERE. WHILE THE PATTERN IS MORE AMPLIFIED...THERE IS LITTLE SIGNIFICANT ASSOCIATED MOISTURE. THE ONLY AREA OF ANY SIGNIFICANT DEEP MOISTURE IS IN THE ITCZ...WHICH IS QUITE ACTIVE TODAY. STRONG SWLY WINDS IN THE UPPER LEVELS AND DIFFLUENCE IS FAVORING CONVECTION ALONG THE AXIS. $$ CANGIALOSI