000 AXNT20 KNHC 230539 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT TUE OCT 23 2007 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 60W/61W S OF 21N MOVING W 10-15 KT. WAVE REMAINS BENEATH THE WESTERN EDGE OF A BROAD UPPER RIDGE PARTIALLY MASKING THE SATELLITE SIGNATURE AND DISPLACING THE DEEPEST CONVECTION TO THE E. SCATTERED MODERATE/STRONG CONVECTION IS FROM 13N-17N BETWEEN 53W-58W WITH CLUSTERS OF SCATTERED MODERATE CONVECTION COVERING A BROADER AREA FROM 11N-22N BETWEEN 50W-62W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N14W 6N29W 8N45W 11N63W. SCATTERED/NUMEROUS STRONG CONVECTION IS MOVING OFF AFRICA FROM 9N-12N E OF 17W TO INLAND OVER GUINEA BISSAU AND E GUINEA. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 3N-10N BETWEEN 10W-42W. DISCUSSION... GULF OF MEXICO... A STRONG COLD FRONT MOVED INTO THE GULF ON MONDAY AND EXTENDS FROM A 1008 MB LOW OVER NW MISSISSIPPI ACROSS SE LOUISIANA INTO THE GULF NEAR 29N91W ALONG 22N95W INTO MEXICO JUST S OF TAMPICO TO THE E SLOPES OF THE SIERRA MADRE MOUNTAINS. HEAVY SHOWERS AND STRONG THUNDERSTORMS ARE WITHIN 60/75 NM E OF THE FRONT WITH SCATTERED SHOWERS W OF THE FRONT...THE EXCEPTION IS ALONG THE COAST OF TEXAS WHERE RAPID CLEARING IS OCCURRING DUE TO THE DRY STABLE AIR ASSOCIATED WITH THE DEEP LAYERED TROUGH THAT IS CURRENTLY OVER THE CENTRAL PLAIN STATES TO THE MISSISSIPPI VALLEY AND INCLUDING THE FAR W GULF. GALE FORCE NORTHERLY SURFACE WINDS ARE W OF THE FRONT. AN UPPER HIGH IS CENTERED OVER NE FLORIDA NEAR 29N83W PROVIDING UPPER DIFFLUENCE TO THE W OF THE UPPER HIGH ENHANCING THE ACTIVITY ASSOCIATED WITH THE FRONTAL BOUNDARY. LOW LEVEL SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE MOVING ACROSS FLORIDA AND THROUGH THE FLORIDA STRAITS IN THE RETURN FLOW AROUND A SURFACE HIGH IN THE W ATLC E OF 85W. CARIBBEAN SEA... AN UPPER LEVEL SHEAR AXIS BISECTS THE CARIBBEAN EXTENDING ACROSS THE VIRGIN ISLANDS W OVER JAMAICA THEN SW TO AN UPPER LOW OVER THE W COAST OF NICARAGUA IN THE E PACIFIC REGION. DRY SOMEWHAT STABLE AIR IS N OF THE SHEAR AXIS WHILE MOIST TROPICAL AIR WITH S AND W UPPER FLOW IS TO THE S. A CONVERGENCE LINE BETWEEN THE SW UPPER FLOW AND LOW LEVEL EASTERLY SURFACE FLOW IS GENERATING SCATTERED SHOWERS/THUNDERSTORMS WITHIN 60 NM OF LINE FROM 10N80W TO 17N83W. THE ITCZ AXIS CROSSES THE N COAST OF SOUTH AMERICA AND EXTENDING ACROSS PANAMA AND COSTA RICA INTO THE E PACIFIC REGION GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 12N E OF 80W TO THE WINDWARD ISLANDS. LIGHT/MODERATE EASTERLY TRADE WINDS ACROSS THE CARIBBEAN ARE USHERING IN LOW LEVEL POPCORN TYPE SHOWERS ESPECIALLY E OF 80W. ATLANTIC OCEAN... THE UPPER HIGH OVER NE FLORIDA IS GIVING THE W ATLC SOUTHERLY UPPER FLOW W OF 65W. A SURFACE RIDGE COVERS THE W AND MOST OF THE CENTRAL ATLC N OF 23N W OF 45W ANCHORED BY A 1026 MB HIGH N OF BERMUDA NEAR 37N65W. AN UPPER SHEAR AXIS EXTENDS FROM THE CENTRAL ATLC NEAR 25N55W INTO THE CARIBBEAN OVER THE VIRGIN ISLANDS WITH A SWATH OF DRY STABLE AIR S OF 23N W OF 63W. A REMNANT OF A FRONTAL BOUNDARY REMAINS IN THE W/CENTRAL ATLC WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM OF 25N FROM 59W-67W. A LARGE CUT-OFF UPPER LOW IS IN THE E/CENTRAL ATLC NEAR 27N37W WITH A 1009 MB SURFACE LOW THAT DEVELOPED TO THE E OF THE UPPER LOW ON MONDAY CENTERED NEAR 28N35W AND A SURFACE TROUGH EXTENDING S TO 19N40W. CLUSTERS OF SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS COVERS A BROAD AREA FROM 17N TO BEYOND 32N BETWEEN 30W-40W. WEAK UPPER HIGH IS JUST OFF THE COAST OF WESTERN SAHARA S OF THE CANARY ISLANDS NEAR 24N19W COVERING THE REMAINDER OF THE E ATLC. WEAK SURFACE RIDGE COVERS THE E ATLC E OF 30W WITH DRY STABLE AIR COVERING THE SAME AREA. $$ WALLACE