000 AXNT20 KNHC 080005 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT APR 07 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N11W 2N25W EQ47W AND INTO NE BRAZIL NEAR 1S53W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS OVER AFRICA AND ADJACENT ATLC WATERS FROM 3N-12N BETWEEN 1W-9W. ISOLATED MODERATE IS WITHIN 220 NM EITHER SIDE OF THE AXIS BETWEEN 20W-40W. STRONGER ACTIVITY HAS AGAIN FLARED UP OVER NE SOUTH AMERICA S OF 6S W OF 40W. ...DISCUSSION... THE GULF OF MEXICO... A DEVELOPING SFC TROUGH IS OVER THE WRN GULF ALONG 27N95W 22N95W. THIS...ALONG WITH DYNAMICS AHEAD OF A MID TO UPPER SHORTWAVE TROUGH CURRENTLY EXTENDING SSW THROUGH EL PASO TX AND INTO NRN MEX...IS SUPPORTING THE OVERCAST MULTILAYERED CLOUDINESS WITH NUMEROUS SHOWERS IN THE NW GULF N OF 24N W OF 90W. MESSY WEATHER TO PERSIST IN THE WRN GULF THROUGH SUN AS LOWER PRESSURE MEANDERS OFF THE TX COAST. SFC WINDS ARE CURRENTLY AND WILL REMAIN STRONGEST IN THE NRN GULF...ESPECIALLY N OF 26N W OF 90W...AS THE TROUGHING INTERACTS WITH HIGH PRES OVER THE SRN/SE U.S. THE ERN GULF IS CURRENTLY MUCH QUIETER ASIDE FROM THE UNSEASONABLY COOL AIR MASS OVER THE AREA. INCREASING MID TO HIGH CLOUD COVER IS APPROACHING FLORIDA FROM THE WEST WITH WLY FLOW ALOFT WHICH WILL LIMIT RADIATIONAL COOLING TONIGHT BUT CHILLY TEMPS STILL ANTICIPATED...SEE STATEMENTS FROM LOCAL FORECAST OFFICES FOR MORE INFO. THE CARIBBEAN SEA... A DISSIPATING STATIONARY FRONT IS OVER THE NW CARIB ALONG 20N76W TO THE GULF OF HONDURAS NEAR 16N87W. A PREFRONTAL TROUGH IS BETWEEN HAITI AND 13N78W. THE LATTER BOUNDARY SEEMS TO BE GENERATING MORE MOISTURE WITH POSSIBLE SHOWERS WITHIN 60 NM OF THE TROUGH...WITH DEEPER MOISTURE/SHOWERS NOTED OVER HISPANIOLA AND ADJACENT ATLC WATERS. THESE SFC FEATURES HAVE LED TO A WEAKNESS IN THE PRESSURE GRADIENT AND LIGHTER THAN NORMAL WINDS ACROSS MUCH OF THE BASIN...THOUGH HIGH PRES WILL REBUILD N OF THE AREA THROUGH EARLY NEXT WEEK ALLOWING MORE TYPICAL MODERATE TO FRESH TRADE FLOW TO RESUME. LINGERING LOW LEVEL CONFLUENCE WILL SUPPORT SCATTERED SHOWER ACTIVITY BETWEEN COSTA RICA/PANAMA AND HISPANIOLA OVER THE NEXT DAY OR SO THOUGH. UPSLOPE FLOW...SPEED CONFLUENCE...AND THE EPAC ITCZ WILL SUPPORT DEEPER CONVECTION AND SHOWER/TSTM ACTIVITY IN THE FAR SW CARIBBEAN AND OVER COSTA RICA/PANAMA INTO EARLY NEXT WEEK AS WELL. ALOFT...BROAD AREA OF SW/WSW FLOW DOMINATES NE OF A PRONOUNCED ANTICYCLONE OVER NE SOUTH AMERICA. VERY DRY/STABLE UPPER AIR IS OVER THE FAR NW CARIB WHILE SCATTERED HIGH CLOUDS ARE OVER THE MIDDLE AND ERN PORTIONS OF THE BASIN...DOWNSTREAM FROM CONVECTION OVER THE EPAC ITCZ AND S AMERICA. THE ATLANTIC OCEAN... LARGE DEEP LAYERED LOW CONTINUES TO SPIN OVER THE ERN U.S. A RAPIDLY INTENSIFYING SFC LOW JUST E OF DELMARVA HAS A TRAILING COLD FRONT THAT ENTERS THE AREA NEAR 32N70W AND CONTINUES SW TO SRN FLORIDA. COLD AIR ADVECTION PATTERN BEHIND THE FRONT HAS BROKEN STRATOCUMULUS CLOUDS OVER THE WRN ATLC...MAINLY N OF 27N. ANOTHER COLD FRONT REMAINS AHEAD OF THIS BETWEEN 32N60W TO THE TURKS AND CAICOS. A PREFRONTAL TROUGH IS ALONG 27N61W 22N67W TO THE COAST OF HISPANIOLA AT 20N71W. THIS SFC TROUGH HAS SCATTERED SHOWERS/ISOLD TSTMS WITHIN 60 NM EITHER SIDE...AND IS ALSO BEING SUPPORTED BY UPPER DIFFLUENCE BETWEEN THE LARGE TROUGH OVER THE ERN U.S. AND RIDGING OVER THE CENTRAL ATLC. THE WRN ATLC SFC BOUNDARIES EXPECTED TO GRADUALLY CONSOLIDATE INTO A REMNANT FRONTAL FRONT BETWEEN THE WINDWARD PASSAGE AND 32N57W AS WEAK HIGH PRES BUILDS INTO THE WRN ATLC THRU MON. MUCH OF THE E AND CENTRAL ATLC IS DOMINATED BY THE SRN PERIPHERY OF A 1025 MB HIGH NEAR 31N43W. A WEAK SFC TROUGH IS OVER THE FAR NE PORTION OF THE DISCUSSION AREA ALONG 30N18W 24N27W...WHICH IS A REFLECTION OF THE UPPER TROUGHING OVER THE AREA. $$ WILLIS