000 AXNT20 KNHC 221745 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT OCT 22 2011 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... AN AREA OF LOW PRESSURE COVERS THE SW CARIBBEAN FOCUSED NEAR A 1007 MB LOW ANALYZED NEAR 13N82W. A STATIONARY FRONTAL BOUNDARY LINGERS TO THE NORTH FROM 21N78W TO 17N84W KEEPING THIS LOW WITHIN A TROPICAL AIRMASS WITH PLENTIFUL MOISTURE AND STABILITY. HOWEVER...ALOFT AN UPPER LEVEL ANTICYCLONE IS POSITIONED TO THE NORTH CENTERED OVER THE NW CARIBBEAN NEAR 18N84W WHICH IS PROVIDING MODEST NORTHERLY WIND SHEAR TO THE ONGOING CONVECTION. ISOLATED STRONG CONVECTION IS WITHIN 90 NM OF THE CENTER OF THE LOW WITH SCATTERED MODERATE CONVECTION COVERING A LARGER AREA FROM 09N-19N BETWEEN 79W-86W. WHILE CONVECTIVE DEVELOPMENT REMAINS UNORGANIZED AT THIS TIME...THE DEVELOPMENT OF A TROPICAL DEPRESSION IS STILL POSSIBLE OVER THE NEXT DAY OR TWO. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 15N17W TO 07N33W. SCATTERED MODERATE CONVECTION IS FROM 04N-09N BETWEEN 22W-28W...AND FROM 02N-06N BETWEEN 31W-37W. ...DISCUSSION... GULF OF MEXICO... NEARLY ZONAL WESTERLY FLOW ALOFT IS IN CONTROL ACROSS THE GULF THIS AFTERNOON WITH WATER VAPOR IMAGERY INDICATING A VERY DRY AND STABLE AIRMASS IN PLACE. THIS IS SUPPORTIVE OF A SURFACE RIDGE ANCHORED BY A 1024 MB HIGH CENTERED OVER NW ALABAMA WHICH EXTENDS S-SW TO 29N91W TO 20N97W. STRATOCUMULUS CLOUDS ARE NOTED ON VISIBLE SATELLITE IMAGERY WITH ONLY A FEW ISOLATED SHOWERS OCCURRING OVER THE SW GULF S OF 20N. THE RIDGE AXIS IS FORECAST TO REMAIN NEARLY STATIONARY DRIFTING A NW SLIGHTLY BY MONDAY PROVIDING THE BASIN WITH MOSTLY FAIR CONDITIONS AND LIGHT NE WINDS THROUGH TUESDAY. CARIBBEAN SEA... WATER VAPOR IMAGERY INDICATES THAT AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE NW CARIBBEAN NEAR 18N84W THAT IS SUPPORTIVE OF SCATTERED SHOWERS AND TSTMS ASSOCIATED WITH A STATIONARY FRONTAL BOUNDARY ANALYZED FROM EASTERN CUBA NEAR 21N78W TO OFFSHORE OF NORTHEASTERN HONDURAS NEAR 17N84W. SOUTH OF THIS BOUNDARY AND NORTH OF THE SPECIAL FEATURES LOW PRESSURE AREA OFFSHORE OF CENTRAL NICARAGUA NEAR 13N82W IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 09N-19N BETWEEN 79W-86W. AS THE LOW DRIFTS SLOWLY NORTHWARD OVER THE NEXT 24-36 HOURS...CONTINUED RAINFALL... LOCALLY HEAVY AT TIMES...WILL PRESENT THE POSSIBILITY OF FLOODING AND MUDSLIDES OVER INTERIOR PORTIONS OF NICARAGUA AND HONDURAS. FARTHER EAST...SW MONSOONAL WINDS ACROSS PANAMA AND INTO THE SOUTH-CENTRAL CARIBBEAN ARE PROVIDING FOR AN AREA OF LOW-LEVEL MOISTURE CONVERGENCE FOCUSED ALONG A SURFACE TROUGH ANALYZED FROM 11N62W TO 15N72W. SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS ARE OCCURRING FROM 12N-15N WEST OF THE SURFACE TROUGH TO 78W. OTHER LINGERING ISOLATED SHOWERS ARE NOTED ON SATELLITE IMAGERY OCCURRING FROM 15N-18N BETWEEN 68W-72W. ATLANTIC OCEAN... A BROAD LONGWAVE UPPER LEVEL TROUGH IS LOCATED ACROSS THE EASTERN CONUS IN SUPPORT OF A STATIONARY FRONT EXTENDING INTO THE DISCUSSION AREA NEAR 32N70W TO THE CENTRAL BAHAMAS NEAR 24N76W TO EASTERN CUBA NEAR 21N77W. SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT. AN UPPER LEVEL RIDGE AXIS EXTENDS FROM THE NW CARIBBEAN TO 30N70W PROVIDING UPPER LEVEL DIFFLUENCE TO THE CONVECTION ALONG AND EAST OF THE FRONTAL BOUNDARY. FARTHER EAST...WATER VAPOR IMAGERY INDICATES AN ELONGATED UPPER LEVEL LOW IS CENTERED NEAR 24N66W THAT IS REFLECTED AS A TROUGH AT THE SURFACE ANALYZED FROM EAST OF PUERTO RICO NEAR 18N66W TO 27N67W. LOW-LEVEL CONVERGENCE AND MIDDLE TO UPPER LEVEL LIFTING DYNAMICS ARE GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 20N-27N BETWEEN 63W-67W...AND FROM 25N-32N BETWEEN 56W-64W. ELSEWHERE... ASIDE FROM A 1027 MB SUBTROPICAL RIDGE CENTERED NORTH OF THE AREA NEAR 35N45W...DEEPER INTO THE TROPICS WEAK TROUGHING EXTENDS FROM A 1007 MB LOW CENTERED NEAR 10N56W E-NE TO A 1011 MB LOW CENTERED NEAR 15N42W. THESE FEATURES ARE LOCATED PRIMARILY ON THE SOUTHERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 18N48W THAT IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS NEAR THE WESTERN-MOST LOW WITHIN 180 NM OF THE CENTER. THIS LOW IS FORECAST TO GRADUALLY DRIFT NW OVER THE NEXT 24-36 HOURS AND BRING INCREASED CHANCE OF PRECIPITATION TO THE WINDWARD ISLANDS THROUGH THE EARLY PORTION OF NEXT WEEK. FINALLY...A 1013 MB LOW IS CENTERED SW OF THE CANARY ISLANDS NEAR 25N24W. THIS LOW IS SUPPORTED BY AN UPPER LEVEL TROUGH AXIS WHICH EXTENDS FROM THE IBERIAN PENINSULA SW TO 20N33W. THE LOW IS EXPECTED TO DISSIPATE OVER THE NEXT 24 HOURS...HOWEVER MIDDLE TO UPPER LEVEL MOISTURE AND DIFFLUENCE CONTINUE TO PROVIDE ISOLATED SHOWERS AND TSTMS WITHIN 240 NM EITHER SIDE OF A LINE FROM SOUTHERN MOROCCO NEAR 28N11W TO 15N35W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN