000 AXNT20 KNHC 161042 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU JUL 16 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 1045 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 29W/30W S OF 15N MOVING W 10-15 KT. RECENT SATELLITE IMAGERY DEPICTS MID-LEVEL CYCLONIC CIRCULATION NEAR THIS WAVE. SATELLITE-DERIVED WINDS INDICATE CYCLONIC CURVATURE IN THE FLOW WITHIN THE 800-600 MB LAYER NEAR THIS WAVE. SCATTERED MODERATE CONVECTION IS FROM 5N-12N BETWEEN 27W-32W. A TROPICAL WAVE IS ALONG 44W/45W S OF 16N MOVING W 10-15 KT. THIS WAVE COINCIDES WITH A LOW AMPLITUDE MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. THE PRESENCE OF DRY LOW/MID-LEVEL SAHARAN AIR IS LIMITING DEEP CONVECTION NEAR THIS WAVE. HOWEVER...SCATTERED SHOWERS ARE OCCURRING WITHIN 240 NM E OF THE WAVE AXIS FROM 12N-16N. A HIGHLY-AMPLIFIED TROPICAL WAVE IS OVER THE SW NORTH ATLC AND CENTRAL CARIBBEAN ALONG 77W/78W S OF 23N MOVING W NEAR 25KT. UPPER AIR DATA FROM BARBADOS AND GUADELOUPE AT 15/0000 UTC INDICATE THAT THE WAVE IS FOLLOWED BY A STRONG EASTERLY 700-600 MB JET...WITH CORE WINDS OF 45-50 KT. THIS WAVE IS ALIGNED WITH A DISTINCT AND NARROW MAXIMUM IN TOTAL PRECIPITABLE WATER. THE WAVE IS LEADING AN AREA OF ABUNDANT DRY LOW/MID-LEVEL SAHARAN AIR...ALONG WITH HAZY CONDITIONS ACROSS MUCH OF THE CENTRAL AND E CARIBBEAN. THE DRY AIR...ALONG WITH STABLE ATMOSPHERIC CONDITIONS BENEATH AN UPPER LEVEL RIDGE OVER THE CENTRAL AND E CARIBBEAN...ARE INHIBITING THE DEVELOPMENT OF DEEP CONVECTION NEAR THE WAVE...WITH ISOLATED SHOWERS WITHIN 240 NM E OF THE WAVE AXIS. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 10N35W 11N47W 10N61W. SCATTERED MODERATE CONVECTION IS FROM 8N-12N E OF 22W. SCATTERED MODERATE IS WITHIN 90 NM N OF THE AXIS BETWEEN 48W-51W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL HIGH IS OVER THE NW GULF OF MEXICO CENTERED NEAR 27N97W WITH A SURFACE RIDGE ACROSS THE CENTRAL GULF AND A 1020 MB SURFACE HIGH NEAR 27N87W. STABLE ATMOSPHERIC CONDITIONS AND SUBSIDENCE ASSOCIATED WITH THE SURFACE HIGH AND SURFACE RIDGE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS THE GULF. WINDS ARE LIGHT AND VARIABLE IN THE VICINITY OF THE SURFACE RIDGE ACROSS THE N GULF...WITH ANTICYCLONIC FLOW AROUND THE RIDGE SUPPORTING A BROAD SWATH OF E WINDS OF 10-15 KT ACROSS THE S HALF OF THE GULF. THESE CONDITIONS ARE FORECAST TO CONTINUE DURING THE NEXT SEVERAL DAYS. HOWEVER...NE WINDS UP TO 20 KT ARE FORECAST TO OCCUR DURING THE LATE AFTERNOON AND EVENING HOURS FOR THE NEXT SEVERAL DAYS NEAR THE COAST OF THE YUCATAN PENINSULA. LITTLE CHANGE IS EXPECTED OVER THE NEXT COUPLE DAYS AS BOTH THE UPPER AND SFC RIDGE REMAIN IN PLACE. CARIBBEAN SEA... FRESH TO STRONG TRADE WINDS ARE OCCURRING BETWEEN THE SUBTROPICAL RIDGE OVER THE CENTRAL ATLC AND A BROAD TROUGH OVER NORTHERN SOUTH AMERICA...WITH THE STRONGEST FLOW NEAR THE COAST OF COLOMBIA. THE ASCAT PASS AROUND 16/0242 UTC INDICATED A LARGE AREA OF NE TO E WINDS OF 20 TO 30 KT ACROSS THE CENTRAL CARIBBEAN. COMPUTER MODEL GUIDANCE INDICATES THAT STRONGER WINDS TO GALE FORCE ARE OCCURRING NEAR THE COAST OF COLOMBIA. THESE WINDS WILL REMAIN STRONG OVER THE NEXT SEVERAL DAYS AS THE SUBTROPICAL RIDGE REMAINS IN PLACE AND A TROPICAL WAVE MOVES ACROSS THE AREA. IN FACT...GALE CONDITIONS ARE FORECAST TO CONTINUE DURING THE NEXT COUPLE DAYS NEAR THE COAST OF COLOMBIA...AS THE LOW LEVEL FLOW STRENGTHENS ACROSS THE CARIBBEAN AND INTERACTS THE LOCAL TOPOGRAPHICAL VARIATIONS NEAR THE COAST OF COLOMBIA. ATMOSPHERIC INSTABILITY ASSOCIATED WITH A WEAK UPPER LEVEL SHORTWAVE TROUGH OVER THE SE CARIBBEAN IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS S OF 13N BETWEEN 63W-66W. ATLANTIC OCEAN... DEEP LAYER MOISTURE IS COMBINING WITH UPPER LEVEL DIFFLUENCE IN NORTHWESTERLY FLOW ALOFT TO RESULT IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 28N BETWEEN 60W-67W. SUBSIDENCE AND GENERALLY FAIR WEATHER ARE PRESENT ACROSS MUCH OF THE CENTRAL AND E ATLC AROUND A BROAD SURFACE RIDGE WITH A 1023 MB HIGH NEAR 33N19W. ACROSS THE TROPICAL N ATLC...AN UPPER LEVEL RIDGE EXTENDS FROM 18N16W TO 15N47W 11N61W...WITH UPPER LEVEL DIVERGENCE SUPPORTING THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE EXTENDING FROM 16N26W TO 10N28W TO 5N28W. $$ COHEN/CANGIALOSI