000 AXNT20 KNHC 151157 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU OCT 15 2009 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 1015 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 65W/66W S OF 15N MOVING W NEAR 15 KT. WAVE IS AT THE LEADING EDGE OF AN AREA OF DEEP MOISTURE AS INDICATED IN THE TOTAL PRECIPITABLE WATER IMAGERY AND REMAINS AT A LOW AMPLITUDE. ISOLATED SHOWERS ARE S OF 15N TO INLAND OVER VENEZUELA BETWEEN 60W-68W INCLUDING THE WINDWARD ISLANDS. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N13W 7N27W 8N37W 7N44W 10N55W 10N62W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ ALONG 38W/39W FROM 5N-9N WITH A SECOND SURFACE TROUGH ALSO EMBEDDED WITHIN THE ITCZ ALONG 52W FROM 9N-15N. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 5N-13N E OF 18W TO THE COAST OF W AFRICA AND FROM 9N-13N E OF 24W TO INLAND OVER W AFRICA. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 6N-10N BETWEEN 25W-39W AND FROM 7N-12N BETWEEN 52W-60W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE CONTINUES TO DOMINATE THE GULF ANCHORED OVER N/CENTRAL MEXICO WITH AN AXIS EXTENDING E ACROSS EXTREME S FLORIDA INTO THE W ATLC. MOSTLY DRY STABLE AIR DOMINATES THE AREA WITH SOME LINGERING ISOLATED SHOWERS OVER THE NE GULF N OF 26N E OF 87W AS A RESULT OF AN UPPER LEVEL SHORTWAVE TROUGH MOVING ACROSS FAR NE FLORIDA INTO THE W ATLC. THE REMAINDER OF THE GULF IS EXPERIENCING FAIR WEATHER WITH REMARKABLY CLEAR SKIES AGAIN THIS MORNING WITH A WEAK 1013 MB HIGH OFF THE FLORIDA COAST NEAR 26N83W. THE NEXT FRONT TO ENTER THE GULF WATERS WILL BE ON FRI. CARIBBEAN SEA... THE BROAD UPPER RIDGE THAT COVERS MOST OF THE ATLC AND GULF OF MEXICO IS GIVING THE CARIBBEAN UPPER EASTERLY WINDS N OF A SHEAR AXIS THAT ENTERS THE CARIBBEAN OVER THE LESSER ANTILLES OVER DOMINICA ALONG 13N74W TO W PANAMA NEAR 9N82W PRODUCING PATCHES OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 17N-20N BETWEEN THE LEEWARD ISLANDS AND JAMAICA AND WITHIN 60 NM ALONG THE S COAST OF CUBA FROM 79W-82W AND IN THE SW CARIBBEAN S OF 12N BETWEEN 75W-82W TO INLAND OVER COLOMBIA AND PANAMA. THE REMAINDER OF THE CARIBBEAN IS UNDER A VERY DRY AND STABLE AIRMASS GIVING THAT AREA CLEAR SKIES AGAIN THIS MORNING. ATLANTIC OCEAN... THE UPPER LEVEL SHORTWAVE TROUGH IS MOVING ACROSS NE FLORIDA INTO THE W ATLC N OF 28N W OF 73W AND IS SUPPORTING A 1007 MB LOW OFF THE COAST OF SOUTH CAROLINA NEAR 32N78W AND A COLD FRONT EXTENDING SW TO OVER THE SE US NEAR THE FLORIDA/GEORGIA BORDER. A SECOND BROADER UPPER LEVEL TROUGH IS FURTHER TO THE E BUT N OF 30N FROM 45W-55W SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N51W EXTENDING ALONG 27N63W BECOMING STATIONARY TO 29N74W THEN WARM TO THE 1007 MB LOW OFF THE COAST OF SOUTH CAROLINA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 60 NM OF LINE FROM 27N58W TO BEYOND 32N47W WITH CLUSTERS OF SIMILAR ACTIVITY OVER THE FAR W ATLC N OF 25N W OF 70W. A WEAK 1015 MB HIGH IS ANCHORED OVER THE CENTRAL ATLC NEAR 24N40W. A BROAD UPPER RIDGE CONTINUES TO DOMINATE THE ATLC S OF 30N W OF 50W EXTENDING AN AXIS FROM ACROSS THE GULF OVER EXTREME S FLORIDA ALONG 25N AND IS PROVIDING DIFFLUENCE ALOFT TO ENHANCING THE ACTIVITY ASSOCIATED WITH THE FRONT ABOVE. A BROADENING UPPER TROUGH DIGS S INTO THE E ATLC N OF 15N FROM THE CANARY ISLANDS TO 50W SUPPORTING A WEAKENING SURFACE TROUGH EXTENDING THROUGH 32N22W 29N23W THEN W TO 27N30W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 200 NM E OF THE SURFACE TROUGH. A LINGERING SHEAR AXIS EXTENDS FROM THE BASE OF THE UPPER TROUGH NEAR 15N31W ALONG 20N48W INTO THE S CARIBBEAN OVER DOMINICA IN THE LESSER ANTILLES. $$ WALLACE