000 AXNT20 KNHC 282351 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI SEP 28 2012 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... HURRICANE NADINE IS CENTERED NEAR 30.1N 35.0W AT 28/2100 UTC OR ABOUT 615 NM SW OF THE AZORES MOVING NW AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 988 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SCATTERED MODERATE CONVECTION IS FROM 29N-33N BETWEEN 31W-37W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 11N19W TO 17N17W MOVING W AT 10 KT. EXAMINING A HOVMOLLER DIAGRAM AND UPPER AIR TIME SECTION ANALYSES...IT APPEARS THE WAVE PASSED DAKAR SENEGAL AROUND 28/1200 UTC AND NOW REMAINS EMBEDDED WITHIN A MONSOONAL GYRE OFF THE COAST OF AFRICA NEAR 11N19W. TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATES DEEP LAYER MOISTURE IN THE VICINITY OF THE WAVE AXIS FROM 09N-17N E OF 22W. MOST DEEP CONVECTION REMAINS OVER INLAND PORTIONS OF W AFRICA WITH SCATTERED MODERATE CONVECTION FROM 10N-13N BETWEEN 11W-17W. TROPICAL WAVE EXTENDS FROM 09N37W TO 16N34W MOVING W AT 10 KT. THE WAVE COINCIDES WITH A WEAK 700 MB TROUGH NOTED IN GLOBAL MODEL GUIDANCE BETWEEN 32W-39W. TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATES THE WAVE LIES WITHIN A DEEP LAYER MOISTURE MAXIMUM FROM 10N-18N BETWEEN 26W-38W. NO SIGNIFICANT CONVECTION IS NOTED IN THE VICINITY OF THE WAVE AXIS. TROPICAL WAVE EXTENDS FROM 13N80W TO 21N82W MOVING W AT 5-10 KT. THE WAVE COINCIDES WITH VERY BROAD 700 MB TROUGHING OVER THE WESTERN CARIBBEAN AS TOTAL PRECIPITABLE WATER VALUES REMAIN ELEVATED ACROSS THE REGION BETWEEN 69W-84W. WITH AN UPPER LEVEL TROUGH OVER THE FLORIDA PENINSULA WITH AXIS ALONG 81W...ENERGY CONTINUES TO FRACTURE NORTHWARD WHILE SOME ENERGY CONTINUES WESTWARD. SCATTERED MODERATE CONVECTION IS FROM 20N-24N BETWEEN 73W-84W AND IS LIKELY ENHANCED DUE TO CLOSE PROXIMITY OF THE UPPER LEVEL TROUGHING. ALSO SCATTERED MODERATE CONVECTION IS OCCURRING OVER A LARGE PORTION OF THE WESTERN CARIBBEAN SEA FROM 07N-17N BETWEEN 75W-85W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO 11N19W TO 08N36W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N36W TO 10N49W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 04N-09N BETWEEN 15W-30W. A SURFACE TROUGH IS ANALYZED FROM 09N-15N ALONG 50W AT THE WESTERN EXTENT OF THE ITCZ AXIS. SCATTERED MODERATE CONVECTION IS FROM 07N-17N BETWEEN 42W-52W...AND IS LIKELY ENHANCED DUE TO AN UPPER LEVEL TROUGH NOTED BETWEEN 45W-60W OVER THE TROPICAL ATLC. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG 81W TO A BASE OVER THE NW CARIBBEAN SEA. WHILE WATER VAPOR IMAGERY INDICATES FAIRLY DRY AIR ALOFT OVER THE FAR EASTERN GULF...THE REMAINDER OF THE GULF IS UNDER NORTH-NORTHWESTERLY FLOW ALOFT DUE TO BROAD UPPER LEVEL RIDGING OVER MUCH OF MEXICO AND THE SOUTH-CENTRAL CONUS STRETCHING EASTWARD TO 85W. MIDDLE TO UPPER LEVEL MOISTURE CONTINUES TO SPILL OVER THE TOP OF THE RIDGE PROVIDING NW PORTIONS OF THE GULF WITH BROKEN TO OVERCAST CLOUDINESS THIS EVENING. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE ALSO FOUND NW OF A LINE FROM MOBILE BAY NEAR 30N88W TO NEAR TAMPICO MEXICO. AT THE SURFACE...A RIDGE EXTENDS FROM THE SE CONUS ANCHORED BY A 1019 MB HIGH CENTERED OVER CENTRAL GEORGIA TO THE SW GULF NEAR 19N96W WITH PRIMARILY LIGHT EAST TO SOUTHEASTERLY SURFACE FLOW. OTHERWISE...THE UPPER LEVEL TROUGH ALONG 81W IS PROVIDING FOR OVERALL BROAD SURFACE TROUGHING ACROSS THE FLORIDA PENINSULA AND SW NORTH ATLC REGION THAT SUPPORTS EARLY EVENING SCATTERED SHOWERS AND TSTMS ACROSS THE SOUTHERN FLORIDA PENINSULA AND PORTIONS OF THE FLORIDA STRAITS. CARIBBEAN SEA... AN UPPER LEVEL TROUGH EXTENDS FROM OVER THE FLORIDA PENINSULA INTO THE NW CARIBBEAN AND CONTINUES TO ADVECT MIDDLE TO UPPER LEVEL MOISTURE NORTHWARD BETWEEN 70W-83W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER THIS AREA FROM PANAMA AND NORTHERN COLOMBIA NORTHWARD TO CUBA AND PORTIONS OF HISPANIOLA. TO FURTHER AID IN LOW TO MIDDLE LEVEL CONVERGENCE AT THE SURFACE AND DIFFLUENCE ALOFT... A TROPICAL WAVE ALONG 82W IS ALSO ADDING ATMOSPHERIC ENERGY TO THE CONVECTIVE EQUATION THIS EVENING. OVERALL...VERY BROAD SYNOPTIC SCALE SURFACE TROUGHING IS ACROSS THE SW NORTH ATLC REGION AND MUCH OF THE CARIBBEAN WHICH IS A FAVORABLE ENVIRONMENT FOR THE CONVECTION. EAST OF 70W...AN UPPER LEVEL RIDGE AXIS EXTENDS ALONG 67W AND PROVIDES THE EASTERN CARIBBEAN AND LESSER ANTILLES WITH A DRY AND SUBSIDENT NW FLOW ALOFT. A FEW ISOLATED SHOWERS ARE NOTED OVER THE NE CARIBBEAN AND PUERTO RICO THIS EVENING...HOWEVER COVERAGE AND INTENSITY LESSENED DUE TO THE DRIER AIR IN PLACE ALOFT. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH AXIS IS LOCATED OVER THE FLORIDA PENINSULA THIS EVENING PROVIDING MUCH OF THE SW NORTH ATLC WITH MOIST SOUTHWESTERLY UPPER LEVEL FLOW BETWEEN 69W-80W. WHILE NO SPECIFIC SURFACE FRONTAL BOUNDARIES ARE PRESENT...SCATTERED SHOWERS AND TSTMS ARE OCCURRING W OF 73W. THE OVERALL LARGER SCALE SYNOPTIC SURFACE TROUGHING EXTENDS FARTHER EAST TO 52W AND REMAINS S OF 30N. A SURFACE TROUGH IS ANALYZED FROM 20N62W TO 25N57W AND CONTINUES TO PROVIDE FOCUS FOR WEAK LOW-LEVEL MOISTURE CONVERGENCE AND ISOLATED SHOWERS AND TSTMS FROM 19N-28N BETWEEN 52W-58W...AND FROM 20N-25N BETWEEN 60W-67W. FARTHER SE...AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG 30N47W TO 20N50W TO A BASE NEAR 12N55W. AS MENTIONED IN THE ITCZ SECTION...THIS TROUGHING IS LIKELY ENHANCING SCATTERED SHOWERS AND TSTMS PRIMARILY EAST OF A SURFACE TROUGH S OF 15N ALONG 50W. THE ACTIVITY IS OCCURRING FROM 07N-17N BETWEEN 42W-52W. OTHERWISE... HURRICANE NADINE IS LOCATED IN THE VICINITY OF 30N35W AND IS EXPECTED TO EXPERIENCE SOME UPPER LEVEL WIND SHEAR DUE TO THE PREVIOUSLY MENTIONED MIDDLE TO UPPER LEVEL TROUGH. THE UPPER LEVEL TROUGH IS ANCHORED BY AN UPPER LEVEL LOW CENTERED NEAR 34N48W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN