000 AXNT20 KNHC 231027 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 61W/62W S OF 21N MOVING W 10-15 KT. THE N END OF THE WAVE IS JUST TO THE E OF A DEVELOPING UPPER LOW WHILE THE REMAINDER OF THE 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 12N-18N BETWEEN 52W-59W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N12W 7N21W 9N45W 8N53W 10N61W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG TO SCATTERED STRONG CONVECTION ARE FROM 3N-10N BETWEEN 12W-40W. DISCUSSION... GULF OF MEXICO... STRONG COLD FRONT CONTINUES TO MOVE ACROSS THE GULF EXTENDING FROM A 1005 MB LOW OVER N MISSISSIPPI ACROSS EXTREME SE LOUISIANA INTO THE GULF NEAR 30N89W ALONG 24N92W INTO MEXICO JUST S OF VERACRUZ TO THE E SLOPES OF THE SIERRA MADRE MOUNTAINS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 60 NM E OF THE FRONT N OF 26N AND WITHIN 90/120 NM W OF THE FRONT S OF 26N. DEEP LAYERED EASTERLY FLOW ACROSS THE YUCATAN AND E BAY OF CAMPECHE ARE GENERATING HEAVY SHOWERS AND STRONG THUNDERSTORMS W OF A LINE TO THE FRONT FROM 26N90W TO OVER S MEXICO NEAR 18N92W. 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 ACROSS THE MISSISSIPPI VALLEY AND INCLUDING THE W GULF. STORM FORCE NORTHERLY SURFACE WINDS ARE W OF THE FRONT. AN UPPER HIGH IN THE W ATLC EXTENDS A RIDGE ACROSS FLORIDA COVERING THE E GULF. LOW LEVEL SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE MOVING ACROSS S FLORIDA AND THROUGH THE FLORIDA STRAITS IN THE RETURN FLOW AROUND A SURFACE HIGH IN THE W ATLC S OF 26N E OF 85W. CARIBBEAN SEA... AN UPPER LEVEL SHEAR AXIS BISECTS THE CARIBBEAN EXTENDING ACROSS THE VIRGIN ISLANDS ALONG 16N70W 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 VERY MOIST TROPICAL AIR WITH S AND W UPPER FLOW IS TO THE S. AN AREA OF CONVERGENCE BETWEEN THE SW UPPER FLOW AND LOW LEVEL EASTERLY SURFACE FLOW IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 12N-18N BETWEEN 78W-85W INCLUDING THE COAST OF N NICARAGUA/E HONDURAS. THE ITCZ AXIS CROSSES THE N PORTION OF SOUTH AMERICA AND PANAMA INTO THE E PACIFIC REGION GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 13N BETWEEN THE WINDWARD ISLANDS AND 80W. 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 IS JUST OFF THE NE FLORIDA COAST NEAR 31N80W GIVING THE W ATLC S TO SW 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 INTO THE CARIBBEAN ACROSS THE VIRGIN ISLANDS FROM A DEVELOPING UPPER LOW ROUGHLY LOCATED NEAR 20N63W. A NARROW SWATH OF DRY STABLE AIR IS S OF 23N OVER THE GREATER ANTILLES W OF 63W. AN UPPER RIDGE OVER THE W TROPICAL ATLC EXTENDS ALONG 54W TO 23N ENHANCING ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE AND PROVIDING ENOUGH DIFFLUENCE TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 125 NM OF A LINE FROM 21N54W TO 26N66W. A LARGE CUT-OFF UPPER LOW IS IN THE E/CENTRAL ATLC NEAR 27N35W WITH A 1009 MB SURFACE LOW CENTERED NEAR 29N37W AND A SURFACE TROUGH EXTENDING S TO 20N40W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS COVERS A BROAD AREA FROM 18N TO BEYOND 32N BETWEEN 29W-38W. WEAK UPPER HIGH IS ALONG THE COAST OF WESTERN SAHARA/MAURITANIA BORDER COVERING THE REMAINDER OF THE E ATLC. WEAK SURFACE RIDGE COVERS THE REMAINDER OF THE E ATLC WITH DRY STABLE AIR. $$ WALLACE