000 AXNT20 KNHC 290524 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON SEP 20 2008 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0500 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS MOVING ACROSS THE CAPE VERDE ISLANDS ALONG 24W SOUTH OF 17N. THE WAVE IS MOVING WESTWARD NEAR 10 KT. THE SSMI-DERIVED TPW INDICATES A MOISTURE MAXIMUM JUST OVER THE CAPE VERDE ISLANDS. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 150 NM WEST OF THE AXIS FROM 12N-15N. A TROPICAL WAVE IS ALONG 41W SOUTH OF 19N MOVING WEST 10 TO 15 KT. BROAD LOW LEVEL CIRCULATION IS VISIBLE ON SATELLITE IMAGERY NEAR 15N. CLUSTERS OF MODERATE CONVECTION IS BEHIND THE AXIS TO 35W NORTH OF 15N. SCATTERED MODERATE CONVECTION IS ALONG THE AXIS BETWEEN 39W-42W FROM 7N-10N. A TROPICAL WAVE IS ALONG 53W SOUTH OF 17N MOVING WEST NEAR 10 KT. AN UPPER-LEVEL LOW SPINNING EAST OF THE LESSER ANTILLES IS PRODUCING MODERATE TO STRONG UPPER-LEVEL SWLY FLOW OVER THE WAVE. NO SIGNIFICANT CONVECTION IS ASSOCIATED WITH THIS WAVE. A TROPICAL WAVE IS OVER NICARAGUA ALONG 84W SOUTH OF 16N MOVING WEST 10 TO 15 KT. CONVECTION ASSOCIATED WITH THIS WAVE IS NOW OVER THE EASTERN PACIFIC. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N13W 8N25W 8N35W 9N45W AN INTO SOUTH AMERICA NEAR 9N61W. IN ADDITION TO CONVECTION ASSOCIATED WITH TROPICAL WAVES...A LARGE CLUSTER OF MODERATE TO STRONG CONVECTION IS MOVING OFF THE WEST COAST OF AFRICA AND EXTENDS TO 20W FROM 11N-14N. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM SOUTH OF THE AXIS BETWEEN 33W-37W. ...DISCUSSION... THE GULF OF MEXICO... A BROAD LOW PRESSURE SYSTEM OVER THE YUCATAN PENINSULA IS GENERATING NUMEROUS SHOWERS AND THUNDERSTORMS OVER THE SE GULF. AS OF 0300 UTC...THE 1010 MB LOW WAS ANALYZED NEAR 21N90W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTER NORTHWARD TO NEAR 22N90W THEN NORTHEASTWARD ALONG 25N85W...CROSSING THE FLORIDA PENINSULA NEAR TAMPA BAY. CONVECTIVE ACTIVITY EXTENDS UP TO 200 NM SE OF THE TROUGH COVERING THE YUCATAN CHANNEL...WESTERN CUBA...FLORIDA STRAIGHTS...AND SOUTH FLORIDA INTO THE W ATLC. THE LOW IS FORECAST TO EMERGE INTO THE SOUTH-CENTRAL GULF OF MEXICO AND MOVE RAPIDLY NE...REACHING THE FLORIDA PENINSULA NEAR TAMPA BAY EARLY TUE. E TO SE WINDS OF 10-15 KT ARE OBSERVED IN THIS REGION. PRES GRADIENT BETWEEN THIS LOW PRESSURE AREA AND HIGHER PRESSURE OVER THE WESTERN GULF IS PRODUCING NLY WINDS OF 15-20 KT OVER THE SW PORTION OF THE GULF INCLUDING THE BAY OF CAMPECHE. NE WINDS 10-15 KT COVER THE REMAINDER OF THE GULF. ALOFT...A MID/UPPER LEVEL TROUGH LIES OVER THE WESTERN HALF OF THE GULF WITH ITS AXIS ALONG 94W. UPPER-LEVEL SWLY WINDS AHEAD OF THIS TROUGH ARE LIMITING THE DEVELOPMENT OF THE AFOREMENTIONED SFC LOW. THE CARIBBEAN SEA... SCATTERED SHOWERS AND THUNDERSTORMS IN THE EXTREME NW CARIBBEAN ARE ASSOCIATED WITH A 1010 MB SURFACE LOW OF THE YUCATAN PENINSULA. UPPER LEVEL DIFFLUENCE ALONG THE SOUTHERN PERIPHERY OF AN UPPER HIGH NE OF THE BAHAMAS IS GENERATING A LARGE CLUSTER OF MODERATE TO STRONG CONVECTION OVER THE WINDWARD PASSAGE BETWEEN HAITI AND CUBA. A SHORTWAVE TROUGH OVER THE CENTRAL CARIBBEAN IS PRODUCING WIDELY SCATTERED SHOWERS W OF 74W TO THE COAST OF NICARAGUA SOUTH OF 16N. THE EASTERN CARIBBEAN REMAINS VERY DRY UNDER STRONG SUBSIDENCE ALOFT. MODERATE TRADE WINDS PERSIST THROUGHOUT THE CENTRAL AND EASTERN CARIBBEAN. THE ATLANTIC OCEAN... A LARGE NON-TROPICAL LOW LOCATED OVER THE NORTH-CENTRAL ATLANTIC NEAR 37N46W IS SHOWING SIGNS OF ORGANIZATION. THIS SYSTEM IS SLOWLY ACQUIRING TROPICAL CHARACTERISTICS AND HAS THE POTENTIAL TO BECOME A SUBTROPICAL OR TROPICAL CYCLONE OVER THE NEXT DAY OR TWO AS IT MOVES GENERALLY WESTWARD NEAR 10 KT. A DISSIPATING FRONTAL BOUNDARY ASSOCIATED WITH THIS LOW EXTENDS TO NEAR 29N37W. SCATTERED SHOWERS ASSOCIATED WITH THE LOW AND THE FRONTAL BOUNDARY EXTEND SOUTHWARD TO 26N BETWEEN 31W-51W. A WEAK SFC RIDGE COVERS THE WEST-CENTRAL ATLC. THE ONLY CONVECTIVE ACTIVITY IN THE REGION IS LOCATED BETWEEN THE EAST COAST OF FLORIDA AND THE BAHAMAS. SCATTERED SHOWERS AND THUNDERSTORMS IN THIS AREA ARE ASSOCIATED WITH A SFC TROUGH EXTENDING UP THE FLORIDA PENINSULA FROM A LOW PRESSURE OVER THE YUCATAN. THE EASTERN ATLC IS DOMINATED BY A SFC RIDGE EXTENDING FROM OVER THE AZORES. A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE UPPER LEVELS. THE WESTERN RIDGE IS CENTERED ON AN UPPER HIGH SITUATED TO THE NE OF THE BAHAMAS NEAR 26N72W. A TROUGH CONNECTS AN UPPER LOW NEAR 30N47W TO A SECOND LOW EAST OF THE ANTILLES. THE EASTERNMOST RIDGE IS CENTERED ON AN UPPER HIGH NEAR 18N23W. THIS RIDGE IS ENHANCING CONVECTION ALONG THE ITCZ. $$ WADDINGTON