000 AXNT20 KNHC 162359 TWDAT TROPICAL WEATHER DISCUSSION... NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED APR 16 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 2345 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 7N11W 3N18W 0.5N30W CROSSING THE EQUATOR NEAR 34W TO 1S48W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE AXIS E OF 16W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM N OF THE AXIS BETWEEN 24W-26W AND 35W-38W. ISOLATED MODERATE CONVECTION IS WITHIN 240 NM N OF THE AXIS W OF 40W. ...DISCUSSION... GULF OF MEXICO... SFC HIGH PRES CONTINUES TO SHIFT E...CURRENTLY 1026 MB CENTERED OVER GEORGIA...ALLOWING LOW-LEVEL RETURN FLOW TO BECOME ESTABLISHED ACROSS THE WRN WATERS. THIS FLOW HAS GREATLY MODIFIED THE COOL AIRMASS THAT WAS IN PLACE EARLIER THIS WEEK. THE COOL AIRMASS IS STILL HANGING ON OVER THE ERN WATERS ENHANCED BY LOW PRES OVER THE W ATLC. SCATTERED STRATOCUMULUS CLOUDS ARE SLOWLY THINNING BETWEEN 86W-93W. IN THE MID AND UPPER LEVELS...TROUGHING EXTENDS ACROSS FLORIDA AND INTO THE E GULF WHILE A BUILDING RIDGE EXTENDS OVER MEXICO AND THE W WATERS. THIS PATTERN IS PRODUCING A DRY STABLE ENVIRONMENT...ESPECIALLY N OF LINE FROM CORPUS CHRISTI TO HAVANA...PROVIDING WIDESPREAD FAIR WEATHER. THIS FAIR WEATHER REGIME WILL CONTINUE THRU TOMORROW. THEREAFTER...THE NEXT COLD FRONT IS EXPECTED TO ENTER THE NW WATERS ON FRI...BUT THIS ONE IS NOT EXPECTED TO BE NEARLY AS STRONG AS THE PREVIOUS. CARIBBEAN SEA... THE TAIL END OF A POTENT COLD FRONT LIES OVER HISPANIOLA WITH DENSE LOW-LEVEL CLOUDS AND SCATTERED SHOWERS ALONG AND TO THE W OF THE BOUNDARY N OF 18N BETWEEN 70W-78W. SIMILAR CLOUDS/SHOWERS ARE OVER THE SW WATERS S OF 12N W OF 80W AND IN THE GULF OF HONDURAS. THIS MOISTURE IS BEING POOLED IN THESE AREAS...DRIVEN BY N/NE WINDS...AND THEN ENHANCED BY CONVERGENCE ALONG THE COAST AND INLAND TERRAIN. ALOFT...THE PATTERN REMAINS FAIRLY FLAT WITH WATER VAPOR IMAGES INDICATING SLIGHT TROUGHING OVER THE NW PORTION AND SLIGHT RIDGING OVER THE SW AND E CARIB...LEADING TO A MODESTLY DRY ENVIRONMENT. TRADE WINDS ARE FAIRLY RELAXED E OF THE FRONT BUT SHOULD BE ON THE INCREASE TOMORROW AND FRI AS HIGH PRES BUILDS N OF THE REGION. ATLANTIC OCEAN... A VERTICALLY STACKED LOW PRES SYSTEM IS SPINNING OVER THE W ATLC WITH SFC OBSERVATIONS INDICATING A MIN PRES OF 1001 MB NEAR 30N71W. WHILE WINDS ARE JUST BELOW GALE FORCE IN OUR FORECAST WATERS THE TIGHT PRES GRADIENT BETWEEN THIS LOW AND HIGH PRES OVER GEORGIA IS PRODUCING STORM FORCE WINDS N OF THE AREA. IR IMAGES AND LIGHTNING DATA REVEAL SCATTERED SHOWERS AND TSTMS MAINLY N OF THE LOW CENTER AND ALONG AND N OF A TRAILING TROUGH AXIS FROM 28N-31N BETWEEN 74W-76W. THIS DEEP LAYER LOW PRES SYSTEM HAS ALSO BEEN SUPPORTING A PAIR OF FRONTS. HOWEVER...IT NOW APPEARS THAT THE SECOND BOUNDARY HAS MERGED WITH THE LEADING ONE ALONG 31N64W 22N68W TO HISPANIOLA. SCATTERED TSTM ACTIVITY IS N OF 26N BETWEEN 60W-65W ENHANCED BY UPPER DIFFLUENCE. SCATTERED SHOWERS ARE ELSEWHERE WITHIN 120 NM E AND 180 NM W OF THE FRONT. THE REMAINDER OF THE ATLC BASIN IS RATHER TRANQUIL THANKS TO A NEARLY STATIONARY SPRAWLING DEEP LAYER HIGH PRES SYSTEM CENTERED NEAR 30N35W. THE SFC CENTER...ANALYZED 1029 MB...IS PRODUCING N TO NE 20-25 KT WINDS NEAR THE COAST OF AFRICA FROM 19N-26N AND MAINLY 15-20 KT NE/E WINDS ACROSS THE REMAINDER OF THE TROPICS. AN UPPER LOW IS SPINNING NEAR 20N56W...BUT PRODUCING LITTLE WEATHER AT THE MOMENT. A RETREATING UPPER TROUGH EXTENDS ACROSS NW AFRICA TO 20N16W THEN WWD TO 19N37W. STRONG WLY UPPER FLOW BETWEEN THIS TROUGH AND A FLAT UPPER RIDGE OVER THE TROPICS IS SPREADING A PLUME OF HIGH LEVEL CLOUDINESS S OF 15N. $$ CANGIALOSI