000 AXNT20 KNHC 042339 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST TUE MAR 04 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 5N9W 3N21W 1N30W CROSSING THE EQUATOR NEAR 35W TO 2S43W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180 NM EITHER SIDE OF AXIS BETWEEN 17W-21W AND 30W-37W. SIMILAR CONVECTION IS FROM 1N-4N BETWEEN 37W-48W AND FROM 4N-6N E OF 10W. ...DISCUSSION... GULF OF MEXICO... STRONG COLD FRONT...ASSOCIATED WITH A DEEP LAYER LOW PRES SYSTEM OVER THE OHIO VALLEY...EXTENDS FROM THE FLORIDA PANHANDLE TO THE YUCATAN PENINSULA ALONG 30N85W 21N88W. RADAR DATA INDICATES LINES OF SCATTERED SHOWERS AND TSTMS N OF 24N E OF THE FRONT. ISOLATED ACTIVITY EXISTS S OF 24N E OF THE FRONT. W OF THE FRONT...GALE FORCE WINDS HAVE LIKELY ENDED OR WILL VERY SHORTLY AS WEAK HIGH PRES HAS NOW ENTERED THE W GULF WATERS...GREATLY RELAXING THE PRES GRADIENT. CLEAR SKIES ARE EVIDENT ON SATELLITE IMAGES ACROSS THE NW WATERS DUE TO VERY DRY AIR ON THE BACK SIDE OF THE DEEP LAYER LOW. LOOKING AHEAD A DAY OR SO...THE FRONT WILL CONTINUE TO MOVE SE THROUGH EARLY TOMORROW AS IT WEAKENS. THEREAFTER...IT WILL LIFT BACK TOWARD THE NW AS A WARM FRONT WITH ATTENTION THEN DRAWN TO THE NEXT FRONT ENTERING THE NW GULF LATE THU. CARIBBEAN SEA... WEAK UPPER SHORTWAVE EXTENDS FROM THE VIRGIN ISLANDS TOWARD THE N SHORE OF COLOMBIA WHILE A MID TO UPPER RIDGE CONTROLS THE PATTERN ALOFT IN THE W CARIB. WIDESPREAD SUBSIDENCE IS ASSOCIATED WITH THESE UPPER SYSTEMS KEEPING THE TYPICAL LOW-LEVEL MOISTURE PATCHES SHALLOW. VISIBLE/SW IR IMAGES INDICATE THAT THE THICKEST CLOUD PATCHES ARE OVER THE NRN LEEWARD ISLANDS AND MUCH OF THE CENTRAL PORTION N OF 14N BETWEEN 65W-78W. AS USUAL...ISOLATED TO SCATTERED QUICK MOVING SHOWERS AND LOW TOPPED TSTMS ARE LIKELY EMBEDDED IN THESE PATCHES. A COLD FRONT OVER THE WRN YUCATAN IS STILL MAKING SLOW E PROGRESS BUT IT IS NOT EXPECTED TO MOVE MUCH FARTHER SE...SO LITTLE IMPACT IS ANTICIPATED OVER THE NW WATERS. TRADE WINDS REMAIN ON THE STRONG SIDE...ESPECIALLY IN THE TYPICAL ENHANCED ZONE NEAR THE COLOMBIAN COAST WHERE SUSTAINED WINDS ARE TO 30 KT. THESE CONDITIONS ARE EXPECTED TO CHANGE LITTLE OVER THE NEXT COUPLE OF DAYS. ATLANTIC OCEAN.... FAIRLY POTENT VERTICALLY STACKED LOW PRES SYSTEM OVER THE OHIO VALLEY IS PRODUCING SCATTERED SHOWER AND TSTM ACTIVITY OVER AND OFF THE ERN SEABOARD N OF 29N W OF 80W. THIS WILL SPREAD E BUT LIKELY WEAKEN SOME LATER TONIGHT AND TOMORROW AS THE LOW AND ITS ASSOCIATED FRONT MOVE OFFSHORE. A STACKED RIDGE LIES OVER THE W ATLC WITH THE SFC CENTER ANALYZED 1030 MB NEAR 35N57W. FAIRLY QUIET CONDITIONS ARE BENEATH THIS RIDGE EXCEPT FOR AN AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS FROM 24N-28N BETWEEN 62W-70W....LIKELY DUE TO A SMALL WEAK MID-LEVEL DISTURBANCE. AN UPPER LOW IS DROPPING S IN THE CENTRAL ATLC...STILL N OF THE AREA NEAR 39N39W. A RELATED COLD FRONT CLIPS THE N PORTION OF THE REGION EXTENDING FROM 32N36W TO 28N41W. LITTLE SIGNIFICANT WEATHER IS ASSOCIATED WITH THE FRONT ITSELF...BUT THERE IS A BAND OF SCATTERED SHOWERS N OF 27N BETWEEN 30W-35W IN AN UPPER DIFFLUENT AREA. IN THE TROPICS...AN E-W STRETCHED RIDGE IS CENTERED NEAR 4N23W. DIFFLUENCE ALOFT ASSOCIATED WITH THIS RIDGE IS AIDING CONVECTION IN THE ITCZ. FOR MORE DETAILS SEE ABOVE. STIFF WLY FLOW ALOFT AND A WEAK PRES PATTERN IS PROVIDING A VERY TRANQUIL ENVIRONMENT FOR MUCH OF THE REGION N OF 10N E OF 40W. $$ CANGIALOSI