000 AXNT20 KNHC 031029 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI OCT 03 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 45W/46W S OF 18N MOVING W 10-15 KT. WAVE REMAINS EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE AS INDICATED BY MIMIC TPW ANIMATION. SCATTERED SHOWERS ARE FROM 13N-16N BETWEEN 44W-50W. TROPICAL WAVE IS ALONG 56W S OF 18N MOVING W 10-15 KT. WELL DEFINED INVERTED-V CURVATURE IS OBSERVED IN THE LOW LEVEL CLOUDS N OF 13N ON SATELLITE IMAGERY AND COINCIDES WITH A MAXIMUM IN MIMIC TPW ANIMATION. SCATTERED MODERATE/STRONG CONVECTION IS FROM 9N-13N BETWEEN 53W-60W WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 8N-11N BETWEEN 58W-62W. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 13N15W 8N26W 5N41W 5N55W. CLUSTERS OF SCATTERED STRONG CONVECTION ARE WITHIN 150 NM N OF THE ITCZ E OF 19W TO JUST INLAND OVER SENEGAL. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM N OF THE ITCZ FROM 19W-27W AND CLUSTERS OF SIMILAR CONVECTION ARE FROM 2N-11N BETWEEN 10W-21W. ...DISCUSSION... GULF OF MEXICO... A DEEP LAYERED TROUGH CONTINUES TO DOMINATE THE E US AND GULF PROVIDING DRY STABLE AIR OVER THE GULF WATERS WITH THE EXCEPTION OF THE FLORIDA STRAITS E OF 81W. THIS DEEP TROUGH CONTINUES TO SUPPORT A QUASI-STATIONARY FRONT EXTENDING ACROSS S FLORIDA NEAR NAPLES ALONG THE N COAST OF THE YUCATAN NEAR 90W TO NEAR 21N93W. LOW LEVEL CONVERGENCE CONTINUES IN THE BAY OF CAMPECHE AND IS SUPPORTING LOW CLOUDS AND POSSIBLE ISOLATED SHOWERS S OF 21N ACROSS THE BAY. THE REMAINDER OF THE GULF REMAINS CLEAR AGAIN THIS MORNING WITH DEW POINTS IN THE 50 DEG RANGE ACROSS THE GULF N OF 26N E OF 96W. CARIBBEAN SEA... A WEAKENING SURFACE TROUGH EXTENDS FROM A 1009 MB SURFACE LOW NEAR 18N84W NE ACROSS CENTRAL CUBA NEAR 22N80W INTO THE W ATLC AND S TO INLAND OVER HONDURAS WITH SCATTERED STRONG CONVECTION COVERING THE AREA WITHIN A 60 NM RADIUS OF THE LOW. AN UPPER RIDGE ANCHORED OVER THE CAYMAN ISLANDS COVERS THE W CARIBBEAN AND COUPLED WITH THE DEEP LAYERED TROUGH OVER THE GULF IS BRINGING MOIST SW FLOW ALOFT TO THE NW CARIBBEAN AND GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ACROSS THE REMAINDER OF THE AREA W OF 80W TO OVER W CUBA AND CENTRAL AMERICA. AN UPPER LOW IS IN THE S/CENTRAL CARIBBEAN NEAR 13N76W WITH SCATTERED MODERATE/STRONG CONVECTION WITHIN 120 NM ALONG THE COAST OF COLOMBIA FROM 73W-77W AND ISOLATED SHOWERS ELSEWHERE S OF 13N FROM 72W-80W. THE UPPER RIDGE ANCHORED IN THE W ATLC COVERS THE VIRGIN ISLANDS TO HISPANIOLA WITH AN UPPER LOW IN THE W TROPICAL ATLC EXTENDING OVER THE LESSER ANTILLES BRINGING MODERATE SUBSIDENCE AND DRIER AIR TO THE E CARIBBEAN E OF 70W LIMITING DEEP CONVECTION AND CLOUD FORMATION. HOWEVER... SCATTERED LOW LEVEL SHOWERS ARE BEING USHERED ACROSS THE E CARIBBEAN ON MODERATE TRADE WINDS WITHIN 90 NM OF LINE FROM 13N63W TO 15N72W. ATLANTIC OCEAN... DEEP LAYERED TROUGH OVER THE E US AND GULF OF MEXICO CONTINUES TO PUSH E OVER THE W ATLC WITH A STATIONARY FRONT ENTERING THE REGION FROM A 1011 MB LOW NEAR 31N76W ALONG 29N75W EXTENDING ACROSS FLORIDA JUST S OF WEST PALM BEACH INTO THE GULF OF MEXICO. DRY STABLE AIR IS W OF THE FRONTAL BOUNDARY WITH MOIST SW UPPER FLOW FROM THE CARIBBEAN ACROSS CUBA AHEAD OF THE FRONT AND W OF A LINE FROM 32N65W ALONG 28N72W TO HAITI NEAR 20N72W. A WEAKENING SURFACE TROUGH IS BENEATH THIS SW UPPER FLOW ALONG FROM THE BAHAMAS NEAR 25N76W ACROSS CENTRAL CUBA INTO THE W CARIBBEAN NEAR 22N80W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 25N TO THE N COAST OF CUBA BETWEEN 77W-80W AND POSSIBLE ISOLATED SHOWERS ACROSS THE REMAINDER OF THE AREA UNDER THE SW MOIST UPPER FLOW. AN UPPER RIDGE COVERING THE REMAINDER OF THE W ATLC ANCHORED NEAR 29N62W IS BEGINNING TO PULL NORTHWARD WITH THE AXIS EXTENDING NE TO BEYOND 32N58W AND SW TO HISPANIOLA. AN UPPER LOW CONTINUES TO UNDERCUT THE UPPER RIDGE OVER THE W ATLC CENTERED IN THE W TROPICAL ATLC NEAR 17N59W MOVING OVER THE LEEWARD ISLANDS. A SECOND CUT-OFF UPPER LOW IN THE CENTRAL ATLC IS BEGINNING TO MOVE SW CENTERED NEAR 25N45W WITH A SURFACE TROUGH EXTENDING FROM 32N41W ALONG 27N43W TO 22N43W GENERATING ISOLATED SHOWERS FROM 22N-26N BETWEEN 40W-45W. DIFFLUENCE ALOFT TO THE SE OF THIS UPPER LOW IS GENERATING SCATTERED MODERATE/ ISOLATED STRONG CONVECTION FROM 20N-24N BETWEEN 36W-39W. AN UPPER TROUGH IS BEGINNING TO PUSH S OVER THE NE ATLC EXTENDING FROM 32N20W SW TO 27N25W COVERING THE AREA FROM THE CANARY ISLANDS TO 30W. THE TYPICAL E/W UPPER RIDGE CONTINUES TO DOMINATE THE REMAINDER OF THE TROPICAL ATLC ALONG 14W/15N FROM AFRICA TO 50W. THE FIRST VISIBLE SATELLITE IMAGES SHOW THE AFRICAN DUST COMING OFF AFRICA IS DIMINISHING WITH THE DENSEST AREA NOW FROM 8N-18N BETWEEN 20W-35W. $$ WALLACE