000 AXNT20 KNHC 271049 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU AUG 27 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... TROPICAL STORM DANNY IS CENTERED NEAR 27.4N 72.1W AT 27/0900 UTC OR ABOUT 320 NM ENE OF NASSAU AND ABOUT 500 NM SSE OF CAPE HATTERAS NORTH CAROLINA MOVING NW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 26N-29N BETWEEN 67W-72W. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 24W S OF 20N MOVING W NEAR 15 KT. THIS WAVE COINCIDES WITH A BROAD AREA OF LOW-LEVEL CYCLONIC CURVATURE AND CIMSS WAVETRAK GUIDANCE DEPICTS A MAXIMUM AREA OF 850 MB VORTICITY IN THE VICINITY OF THE WAVE AXIS AND ACROSS THE CAPE VERDE ISLANDS. AN AREA OF SCATTERED MODERATE TO STRONG CONVECTION IS SW OF THE WAVE AXIS FROM 7N-13N BETWEEN 25W-31W AND IS POSSIBLY THE RESULT OF LOCALIZED LOW-LEVEL CONVERGENCE W OF THE AXIS AND ALONG THE ITCZ AXIS. THIS CONVECTION IS FURTHER ENHANCED BY UPPER LEVEL DIFFLUENCE ON THE SRN PERIPHERY OF AN ERN TROPICAL ATLC UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 19N29W. TROPICAL WAVE IS ALONG 46W S OF 20N MOVING W NEAR 20 KT. THE WAVE CONTINUES TO MOVE BENEATH AN VERY DRY AIR MASS ALOFT AS AN UPPER LEVEL RIDGE EXTENDS TO 40W ACROSS THE TROPICAL ATLC. STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY...HOWEVER...AN UPPER LEVEL LOW IS CENTERED N OF THE WAVE AXIS AND IS STRETCHING AN AREA OF POSSIBLE SHOWERS NWD FROM 19N-24N BETWEEN 43W-50W. OTHER POSSIBLE SHOWERS ARE MOSTLY EMBEDDED WITHIN THE ITCZ AXIS FROM 10N-14N BETWEEN 42W-49W. TROPICAL WAVE IS ALONG 77W S OF 19N MOVING W NEAR 12 KT. WAVE REMAINS WITHIN AN AREA OF MAXIMUM DEEP LAYER MOISTURE AS OBSERVED ON THE TOTAL PRECIPITABLE WATER IMAGERY...HOWEVER DRY...SUBSIDENT NELY FLOW ALOFT IS OVER THE CENTRAL CARIBBEAN AND THUS INHIBITING ANY DEEP CONVECTION OR SHOWER ACTIVITY. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 15N16W 14N23W 12N27W 12N44W 11N47W 10N63W. WIDELY SCATTERED MODERATE CONVECTION IS ALONG THE W AFRICA COAST FROM 8N-14N BETWEEN 13W-17W. ASIDE FROM THE AREA OF CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 24W... SCATTERED SHOWERS ARE WITHIN 200 NM EITHER SIDE OF THE AXIS BETWEEN 37W-56W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH IS ANALYZED ACROSS THE ERN GULF AND EXTENDS FROM 28N86W TO THE TIP OF THE NW YUCATAN PENINSULA NEAR 22N90W. THIS SURFACE TROUGH IS SUPPORTED BY AN UPPER LEVEL LOW CENTERED OVER ERN LOUISIANA. THE SURFACE TROUGH ALONG WITH MIDDLE TO UPPER LEVEL DIFFLUENCE SE OF THE UPPER LOW IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS MUCH OF THE NE GULF N OF 25N AND E OF 90W. AN UPPER LEVEL RIDGE COVERS THE REMAINDER OF THE GULF ANCHORED BY AN UPPER LEVEL ANTICYCLONE CENTERED OVER THE YUCATAN CHANNEL. BETWEEN THESE TWO UPPER LEVEL FEATURES... MOIST SWLY FLOW EXTENDS FROM E/CENTRAL MEXICO TO THE NE GULF AND NRN FLORIDA WITH POSSIBLE SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE OF A LINE FROM TAMPICO MEXICO THROUGH 24N90W TO THE BIG BEND REGION OF FLORIDA. A WEAK RIDGE OF HIGH PRESSURE IS FORECAST TO REMAIN ACROSS THE WRN GULF WATERS AHEAD OF THE NEXT FRONTAL BOUNDARY THAT IS EXPECTED TO STALL ALONG THE LOUISIANA AND TEXAS GULF COAST BY EARLY SUNDAY. CARIBBEAN SEA... AN UPPER LEVEL RIDGE IS ACROSS THE NW CARIBBEAN AND NRN PORTIONS OF CENTRAL AMERICA ANCHORED OVER THE YUCATAN CHANNEL WHILE UPPER LEVEL TROUGHING COVERS THE CENTRAL CARIBBEAN ANCHORED BY AN UPPER LOW CENTERED NEAR 15N75W. THE UPPER DIVERGENT FLOW ACROSS THE FAR WRN CARIBBEAN AND PORTIONS OF CENTRAL AMERICA ARE GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS OVER CENTRAL AMERICA...THE GULF OF HONDURAS AND THE YUCATAN PENINSULA. SIMILAR CONVECTION HAS INCREASED OVER THE PAST 6 HOURS IN THE SW CARIBBEAN IN CLOSE PROXIMITY TO THE ITCZ AXIS WHICH LIES ACROSS PANAMA. MOST OF THE ACTIVITY HOWEVER IS REMAINING S OF 10N. THE REMAINDER OF THE CARIBBEAN IS UNDER DRY STABLE AIR AND MOSTLY CLEAR SKIES. ATLANTIC OCEAN... THE PRIMARY CONCERN FOR THE ATLC IS TROPICAL STORM DANNY LOCATED OVER PORTIONS OF THE SW NORTH ATLC. THE UPPER LEVEL LOW OVER THE CENTRAL CARIBBEAN EXTENDS UPPER LEVEL TROUGHING N TO NEAR T.S. DANNY WHILE UPPER RIDGING IS LOCATED TO THE E AND W OF THE SYSTEM. THE CONVECTION PRIMARILY ASSOCIATED WITH DANNY IS LOCATED IN THE NW QUADRANT OF AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 24N64W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 26N-29N BETWEEN 67W-72W. THE REMAINDER OF THE SW NORTH ATLC IS UNDER NE TO ELY SURFACE FLOW WITH ISOLATED SHOWERS FROM 24N-31N MOVING WWD ACROSS THE BAHAMAS AND INLAND ACROSS THE FLORIDA PENINSULA. AN UPPER LEVEL LOW IS CENTERED OVER THE CENTRAL ATLC NEAR 27N48W. UPPER LEVEL DIFFLUENCE LOCATED E OF THE UPPER LOW AND A SURFACE TROUGH ANALYZED FROM 32N47W TO 26N51W IS GENERATING SCATTERED SHOWERS FROM 25N-33N BETWEEN 44W-50W. FARTHER TO THE EAST...A WEAKENING UPPER LEVEL TROUGH WITH AXIS N OF 22N ALONG 37W IS PRODUCING POSSIBLE SCATTERED SHOWERS FROM 22N-32N BETWEEN 31W-35W. ELSEWHERE ACROSS THE CENTRAL AND ERN ATLC...A SURFACE RIDGE REMAINS IN PLACE AND IS ANCHORED BY A 1025 MB HIGH CENTERED N OF THE DISCUSSION AREA NEAR 35N32W. $$ HUFFMAN