000 AXNT20 KNHC 101047 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU SEP 10 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. ...SPECIAL FEATURES... HURRICANE FRED IS CENTERED NEAR 15.9N 34.6W AT 10/0900 UTC OR ABOUT 610 NM W OF THE CAPE VERDE ISLANDS MOVING NW AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 970 MB. MAXIMUM SUSTAINED WIND SPEED IS 90 KT WITH GUSTS TO 110 KT. SCATTERED MODERATE/ STRONG CONVECTION IS FROM 15N-21N BETWEEN 31W-36W. WIDELY SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 13N-21N BETWEEN 29W-39W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 72W S OF 18N MOVING W NEAR 18 KT. THE WAVE COINCIDES WITH A NARROW MAXIMUM AREA OF DEEP LAYER MOISTURE OBSERVED IN THE TOTAL PRECIPITABLE WATER IMAGERY AND CONTINUES TO MOVE BENEATH UPPER LEVEL SWLY FLOW E OF AN UPPER LEVEL TROUGH AXIS LOCATED ACROSS THE CENTRAL CARIBBEAN. DEEP CONVECTION IS BEING INHIBITED BY DRY AIR ALOFT AS ONLY HIGH LEVEL CIRRUS IS NOTED ON SATELLITE IMAGERY. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N18W 15N28W 11N42W 8N60W. ASIDE FROM CONVECTION ASSOCIATED WITH HURRICANE FRED... ISOLATED MODERATE CONVECTION IS FROM WITHIN 90 NM EITHER SIDE OF THE AXIS BETWEEN 19W-27W. ELSEWHERE...SCATTERED MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF A LINE FROM 12N33W TO 10N43W. ...DISCUSSION... GULF OF MEXICO... NWLY UPPER LEVEL FLOW DOMINATES ACROSS THE GULF AS UPPER LEVEL TROUGHING IS ACROSS THE W ATLC AND FLORIDA PENINSULA WHILE AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE ERN PACIFIC EXTENDS UPPER RIDGING ACROSS CENTRAL MEXICO AND THE WRN GULF. A FAIR AMOUNT OF UPPER LEVEL MOISTURE IN THE FORM OF HIGH LEVEL CLOUDINESS IS NOTED ON INFRARED SATELLITE IMAGERY ACROSS THE GULF THIS MORNING. WITH THE LACK OF ANY SIGNIFICANT SURFACE FEATURES AND A WEAK PRESSURE GRADIENT PRESENT...UPPER DIFFLUENCE ASSOCIATED WITH THE UPPER LEVEL RIDGING IS GENERATING SCATTERED SHOWERS AND TSTMS ACROSS THE N/CENTRAL AND WRN GULF W OF A LINE FROM NEW ORLEANS LOUISIANA TO 20N96W. AS OF 0900 UTC...A SURFACE TROUGH EXTENDS FROM NEAR POMPANO BEACH FLORIDA THROUGH 24N83W TO NEAR CANCUN MEXICO AND REMAINS LOCATED NEAR THE BASE OF THE AFOREMENTIONED TROUGHING OVER THE W ATLC. LOW-LEVEL CONVERGENCE ALONG THE SURFACE TROUGH AND AN AREA OF UPPER LEVEL DIFFLUENCE OVER THE SE GULF ARE GENERATING SCATTERED SHOWERS AND TSTMS S OF 26N E OF 85W...INCLUDING THE STRAITS OF FLORIDA AND FLORIDA KEYS. CARIBBEAN SEA... A SURFACE TROUGH EXTENDS FROM THE SE GULF NEAR KEY WEST FLORIDA OVER THE YUCATAN CHANNEL TO CANCUN MEXICO. LOW-LEVEL CONVERGENCE NEAR THE SURFACE TROUGH AND UPPER LEVEL DIFFLUENCE LOCATED OVER CUBA IS SUPPORTING SCATTERED SHOWERS AND TSTMS OVER THE NW CARIBBEAN FROM 19N-23N BETWEEN 79W-85W. THE REMAINDER OF THE WRN AND CENTRAL CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER UNDER DRY SUBSIDENT AIR DUE TO NLY FLOW ALOFT ON THE ERN PERIPHERY OF AN UPPER LEVEL RIDGE OVER SRN MEXICO AND A LARGE PORTION OF CENTRAL AMERICA. UPPER LEVEL TROUGHING IS ACROSS THE CARIBBEAN E OF 82W AND CONTINUES DRAWING UPPER LEVEL MOISTURE ON SWLY WINDS FROM NRN SOUTH AMERICA AND PANAMA TO OVER THE S/CENTRAL CARIBBEAN NE TO PUERTO RICO. NEAR THE BASE OF THE UPPER LEVEL TROUGH OVER THE SW CARIBBEAN...SCATTERED SHOWERS AND ISOLATED TSTMS ARE S OF 13N BETWEEN 75W-82W. MODERATE TO FRESH TRADE WINDS CONTINUE ACROSS MUCH OF THE BASIN. ATLANTIC OCEAN... A SURFACE TROUGH ENTERS THE DISCUSSION AREA NEAR 32N71W AND EXTENDS SW TO NEAR POMPANO BEACH FLORIDA. LOW-LEVEL CONVERGENCE NEAR THE SURFACE TROUGH IS SUPPORTING SCATTERED SHOWERS AND TSTMS OVER MUCH OF THE SW NORTH ATLC S OF 30N BETWEEN 72W-81W... INCLUDING THE NW AND CENTRAL BAHAMAS AS WELL AS PORTIONS OF THE FLORIDA STRAITS. THIS ACTIVITY IS ALSO ENHANCED BY UPPER LEVEL DIFFLUENCE AND MOIST SWLY FLOW ALOFT AROUND AN UPPER LEVEL TROUGH THAT DIPS SWD FROM THE ERN CONUS OVER THE FLORIDA PENINSULA AND W ATLC WATERS TO 23N. FARTHER TO THE SE...AN UPPER LEVEL LOW IS CENTERED NEAR 26N65W AND HAS CONTINUED TO BE ABSORBED INTO THE MAIN WRN ATLC TROUGH OVER THE PAST 24 HOURS. UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE UPPER LOW IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 19N-23N BETWEEN 61W-70W. A 1018 MB SURFACE HIGH IS CENTERED NEAR 29N59W. A WEAKNESS IN THE SUBTROPICAL RIDGE ENTERS THE DISCUSSION AREA AS A SURFACE TROUGH NEAR 31N45W AND EXTENDS SW TO A 1016 MB LOW NEAR 28N50W. POSSIBLE ISOLATED SHOWERS ARE WITHIN THE AREA FROM 26N-30N BETWEEN 47W-51W. OVER THE CENTRAL ATLC...A SURFACE TROUGH EXTENDS FROM 16N47W TO 24N44W. ISOLATED SHOWERS ARE LOCATED WITHIN 60 NM EITHER SIDE OF THE TROUGH AXIS. THIS SURFACE TROUGH IS SUPPORTED ALOFT BY AN UPPER LOW CENTERED NEAR 22N46W. ELSEWHERE ACROSS THE TROPICAL ATLC...HURRICANE FRED REMAINS THE MAIN CONCERN. UPPER LEVEL ANTICYCLONIC FLOW IS OVER THE ERN ATLC S OF 25N E OF 41W AND CONTINUES TO ENHANCE THE CONVECTION AND OUTFLOW ASSOCIATED WITH HURRICANE FRED. $$ HUFFMAN