000 AXNT20 KNHC 261728 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED AUG 26 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC. ...SPECIAL FEATURES... THE SURFACE TROUGH NE OF THE BAHAMA ISLANDS HAS BEEN UPGRADED TO TROPICAL STORM DANNY AT 26/1500 UTC. TROPICAL STORM DANNY IS CENTERED NEAR 24.9N 70.3W OR ABOUT 390 NM E OF NASSAU AND ABOUT 675 NM SSE OF CAPE HATTERAS NORTH CAROLINA AT 26/1500 UTC MOVING WNW AT 16 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/ WTPZ25 KNHC FOR MORE DETAILS. THE LOW LEVEL CENTER IS PARTIALLY EXPOSED DUE TO THE INTERACTION OF AN UPPER TROUGH IS TO THE S AND AN UPPER RIDGE TO THE NE OF DANNY. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS COVER THE AREA FROM 22N-27N BETWEEN 63W-70W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 40W/41W S OF 25N MOVING WNW NEAR 15 KT. WAVE APPEARS TO BE WRAPPING AROUND A DRY AIR SLOT THUS THE WNW MOVEMENT OVER THE PAST 24 HOURS. WAVE IS AT THE LEADING EDGE OF A DEEP LAYER MOISTURE MAXIMUM OBSERVED ON THE TOTAL PRECIPITABLE WATER IMAGERY THAT IS N OF THE ITCZ. ISOLATED SHOWERS ARE WITHIN 60 NM OF 18N BETWEEN 34W AND THE WAVE AXIS. TROPICAL WAVE IS ALONG 72W/73W S OF 19N MOVING W NEAR 15 KT. WAVE REMAINS WITHIN AN AREA OF UPPER LEVEL MOISTURE AS OBSERVED ON THE TOTAL PRECIPITABLE WATER IMAGERY...HOWEVER THE LOWER LEVELS REMAIN DRY AND STABLE. THEREFORE NO ASSOCIATED SHOWERS/CONVECTION. TROPICAL WAVE IS ALONG 89W/90W S OF 16N MOVING W NEAR 15 KT. THIS WAVE IS COMPLETELY INLAND OVER CENTRAL AMERICA. WAVE REMAINS EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE MAXIMUM AS OBSERVED IN THE TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER ALL ACTIVITY IS IN THE E PACIFIC REGION. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 14N16W 13N21W 16N33W 10N44W 8N53W 9N62W. SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF SCATTERED STRONG CONVECTION COVER THE AREA WITHIN 150 NM OF LINE FROM 14N18W TO 10N27W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 90 NM OF THE ITCZ BETWEEN 39W-59W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH REMAINS IN THE GULF EXTENDING FROM TALLAHASSEE FLORIDA ALONG 26N86W TO 22N92W. SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE NE GULF N OF 25N E OF 86W AND WITHIN 90 NM NW OF THE SURFACE TROUGH E OF 90W. THIS SURFACE TROUGH IS SUPPORTED BY AN UPPER LOW OVER SW MISSISSIPPI WITH AN UPPER TROUGH EXTENDING S OVER THE N GULF. THE UPPER LOW IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 25N-2N BETWEEN 91W-94W. AN UPPER RIDGE COVERS THE REMAINDER OF THE GULF ANCHORED BY AN UPPER HIGH OVER THE YUCATAN PENINSULA. THE SURFACE TROUGH IS EXPECTED TO DISSIPATE BY THU AS WEAK HIGH PRESSURE WILL BUILD ACROSS THE N GULF THROUGH FRI. THE NEXT WEAK FRONTAL TROUGH WILL POSSIBLY MOVE INTO THE NW GULF EARLY SUN. CARIBBEAN SEA... AN UPPER RIDGE IS OVER THE W CARIBBEAN ANCHORED OVER THE YUCATAN PENINSULA WHILE AN UPPER TROUGH COVERS THE CENTRAL CARIBBEAN ANCHORED BY AN UPPER LOW OVER HAITI EXTENDING SSW TO E PANAMA. THIS UPPER FLOW COUPLED WITH MODERATE TO FRESH TRADE WINDS ACROSS THE CARIBBEAN ARE DEVELOPING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS SW OF A LINE FROM 19N85W TO PANAMA NEAR 9N77W WITH THE HIGHEST CONCENTRATION OF THUNDERSTORMS JUST OFF NE HONDURAS AND NE NICARAGUA. THE REMAINDER OF THE CARIBBEAN IS UNDER DRY STABLE AIR AND MOSTLY CLEAR SKIES. ATLANTIC OCEAN... THE PRIMARY CONCERN FOR THE ATLC THIS AFTERNOON IS THE NEWLY DEVELOPED TROPICAL STORM DANNY. THE UPPER LOW OVER HAITI EXTENDS AN UPPER TROUGH N TO NEAR T.S. DANNY WHILE AN UPPER RIDGE IS TO THE NE OF DANNY ALONG 63W TO E OF BERMUDA. THIS IS KEEPING THE ACTIVITY ASSOCIATED WITH T.S. DANNY TO THE E AND KEEPING THE REMAINDER OF THE W ATLC CLEAR TO THE FLORIDA COAST. A SERIES OF UPPER LOWS ARE OVER THE CENTRAL AND E ATLC BUT DUE TO THE DRY STABLE AIR IS NOT PRODUCING ANY SIGNIFICANT WEATHER. A SURFACE RIDGE DOMINATES THE ATLC TO OVER THE SE US ANCHORED BY SERIES OF HIGHS N OF THE REGION. $$ WALLACE