000 AXNT20 KNHC 131047 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU AUG 13 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 1000 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION TWO IS CENTERED NEAR 14.0N 36.9W OR ABOUT 840 MILES...1350 KM...WEST OF THE SOUTHERNMOST CAPE VERDE ISLANDS AT 13/0900 UTC MOVING W AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. WWD MOTION IS EXPECTED TO CONTINUE OVER THE NEXT FEW DAYS WITH A GRADUAL BEND TO THE WNW AND AN INCREASE IN FORWARD SPEED. LITTLE CHANGE IN INTENSITY IS EXPECTED OVER THE NEXT 24 HRS. HOWEVER...THE DEPRESSION STILL COULD BECOME A TROPICAL STORM IN A FEW DAYS. LITTLE DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE SYSTEM...BUT SCATTERED SHOWERS ARE WITHIN 100 NM OF THE CENTER LOCATION. SEE LATEST NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 FOR MORE DETAILS. A STRONG TROPICAL WAVE IS ALONG 22W S OF 16N NEAR THE CAPE VERDE ISLANDS MOVING W NEAR 15 KT. RECENT VISIBLE SATELLITE IMAGERY...AS WELL AS A 0746 UTC QUIKSCAT PASS INDICATE LOW-LEVEL CYCLONIC CIRCULATION NEAR THE WAVE GIVING EVIDENCE OF A 1010 MB SURFACE LOW ANALYZED ALONG THE WAVE AXIS NEAR 12N. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM 8N-11N BETWEEN 21W-28W...AND FROM 12N-15N BETWEEN 21W-26W. THERE IS A 30-50 PERCENT CHANCE OF THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN THE NEXT 48 HRS. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS ALONG 21N67W T15N65 7N64W MOVING W NEAR 20 KT. SATELLITE IMAGERY INDICATES AN INVERTED-V STRUCTURE IN THE LOW-LEVEL CLOUD PATTERN. THE WAVE ALSO COINCIDES WITH A DEEP MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-7N BETWEEN 63W-65W...AND FROM 23N-25N BETWEEN 66W-71W. SCATTERED SHOWERS ARE WITHIN 250 NM E OF THE WAVE AXIS AFFECTING THE LESSER ANTILLES. THIS ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE. A TROPICAL WAVE IS ALONG 74W S OF 21N MOVING W NEAR 20 KT. CURRENT POSITION IS BASED ON CONTINUITY. STRONG SUBSIDENCE ALOFT IS INHIBITING ANY DEEP CONVECTION NEAR THE WAVE AXIS...EXCEPT FOR OVER COLUMBIA WHERE A LARGE CLUSTER OF SCATTERED MODERATE/STRONG CONVECTION IS FROM 5N-9N BETWEEN 73W-76W. A TROPICAL WAVE IS ALONG 88W S OF 20N MOVING W NEAR 18 KT. THE WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 15N-18N BETWEEN 86W-89W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 13N16W 12N25W 14N34W 10N48W 11N62W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS JUST OFF THE AFRICA COAST FROM 7N-12N BETWEEN 13W-17W. SCATTERED MODERATE CONVECTION IS FROM 10N-12N BETWEEN 42W-44W. ...DISCUSSION... GULF OF MEXICO... AS OF 0900 UTC...A SURFACE TROUGH IS ACROSS THE GULF OF MEXICO EXTENDING FROM A 1013 MB SURFACE LOW NEAR 30N83W TO 24N91W. THE TROUGH IS SUPPORTED BY AN UPPER LEVEL TROUGH ACROSS THE ERN CONUS EXTENDING ACROSS THE ERN GULF TO 24N87W. UPPER LEVEL DIFFLUENCE ALONG WITH SURFACE CONVERGENCE NEAR THE SURFACE TROUGH ARE SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE CENTRAL GULF WITH 100 NM EITHER SIDE OF THE TROUGH AXIS. ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE FAR NW GULF N OF 27N W OF 92W. THIS ACTIVITY IS SUPPORTED BY A STATIONARY FRONT EXTENDING ACROSS THE GULF COAST FROM 31N88W TO 30N95W...AS WELL AS UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER LEVEL TROUGH OVER THE ERN GULF AND AN UPPER LEVEL RIDGE OVER TEXAS AND NRN MEXICO. ISOLATED SHOWERS ARE ACROSS THE BAY OF CAMPECHE S OF 21N BETWEEN 90W-95W SUPPORTED BY UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL RIDGE CENTERED OVER BELIZE NEAR 17N89W AND AN UPPER LEVEL TROUGH CENTERED S OF MEXICO NEAR 16N103W. EXPECT THE SURFACE TROUGH TO REMAIN ACROSS THE CENTRAL GULF...AND A TROPICAL WAVE E OF THE YUCATAN PENINSULA TO REACH THE SW GULF LATER TODAY. CARIBBEAN SEA... THREE TROPICAL WAVES ARE AFFECTING THE CARIBBEAN SEA AND CENTRAL AMERICA...SEE ABOVE. ISOLATED SHOWERS/THUNDERSTORMS ARE ACROSS THE WRN CARIBBEAN FROM 9N-21N BETWEEN 78W-84W DUE TO UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL HIGH OVER BELIZE NEAR 17N89W AND AN UPPER LEVEL LOW OVER WRN HISPANIOLA NEAR 19N73W. STRONG SUBSIDENCE ALOFT IS OVER THE CENTRAL CARIBBEAN INFLUENCED BY CONVERGENCE NEAR THE UPPER LEVEL LOW...INHIBITING CONVECTION NEAR THE TROPICAL WAVE ALONG 74W. UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER LEVEL LOW AND AN UPPER LEVEL RIDGE E OF 68W IS SUPPORTING CONVECTION NEAR THE TROPICAL WAVE IN THE ERN CARIBBEAN. MODERATE TO FRESH TRADEWINDS ARE OVER MUCH OF THE BASIN...BECOMING STRONG NEAR THE COAST OF COLUMBIA. EXPECT SHOWERS/ISOLATED THUNDERSTORMS OVER THE CARIBBEAN DUE TO THE TROPICAL WAVES OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE FAR W ATLC N OF 24N W OF 78W DUE TO SURFACE CONVERGENCE AHEAD OF A SURFACE TROUGH OVER THE GULF OF MEXICO EXTENDING ACROSS NRN FLORIDA TO NEAR 31N82W...AS OF 0900 UTC. UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL TROUGH W OF 78W AND AN UPPER LEVEL RIDGE BETWEEN 57W-78W IS ALSO SUPPORTING THE SHOWER ACTIVITY. SCATTERED SHOWERS/THUNDERSTORMS ARE N OF PUERTO RICO AND HISPANIOLA ASSOCIATED WITH A TROPICAL WAVE IN THE ERN CARIBBEAN...SEE ABOVE. A SURFACE TROUGH EXTENDS FROM 28N74W TO 30N64W SUPPORTING A FEW ISOLATED SHOWERS WITHIN 50 NM N OF THE TROUGH AXIS. ISOLATED SHOWERS/THUNDERSTORMS ARE FROM 27N-32N BETWEEN 49W-58W DUE TO UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER LEVEL RIDGE BETWEEN 57W-78W AND AN UPPER LEVEL LOW NEAR 28N45W. ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A 1026 MB HIGH NEAR 39N26W. A BROAD UPPER LEVEL RIDGE DOMINATES THE ERN ATLC E OF 40W. $$ WALTON