000 AXNT20 KNHC 161752 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 31W S OF 18N MOVING W AT 15 KT. RECENT SATELLITE IMAGERY DEPICTS A LOW TO MIDDLE LEVEL CYCLONIC CIRCULATION ALONG THE WAVE AXIS NEAR 10N. AN EARLIER ASCAT PASS AROUND 1150 UTC ALSO CAPTURED A BROAD LOW-LEVEL CIRCULATION NEAR 10N WHICH REMAINS EMBEDDED WITHIN THE ITCZ AXIS. SCATTERED MODERATE CONVECTION IS FROM 6N-13N BETWEEN 27W-33W. A TROPICAL WAVE IS ALONG 47W S OF 17N MOVING W AT 13 KT. THIS WAVE COINCIDES WITH A RELATIVELY 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 250 NM EITHER SIDE OF THE WAVE AXIS FROM 10N-18N. A HIGHLY-AMPLIFIED TROPICAL WAVE IS OVER CENTRAL CUBA AND THE WRN CARIBBEAN ALONG 21N77W 15N80W 5N81W MOVING W NEAR 25 KT. THIS WAVE IS FOLLOWED BY A STRONG ELY 600-700 MB JET...WITH CORE WINDS OF 40-50 KT. TRANSLATING TO THE SURFACE...AN EARLIER SCATTEROMETER PASS AROUND 1130 UTC DEPICTED STRONG ELY TRADE WINDS OF UP TO GALE FORCE ACROSS THE CENTRAL CARIBBEAN. THE WAVE REMAINS ON THE LEADING EDGE OF AN AREA OF ABUNDANT DRY LOW TO MIDDLE LEVEL SAHARAN AIR...ALONG WITH HAZY CONDITIONS ACROSS MUCH OF THE CENTRAL AND ERN CARIBBEAN. THE DRY AIR...ALONG WITH STABLE ATMOSPHERIC CONDITIONS BENEATH NELY FLOW ALOFT OVER THE WRN CARIBBEAN...ARE INHIBITING THE DEVELOPMENT OF DEEP CONVECTION NEAR THE WAVE...WITH ISOLATED SHOWERS S OF 17N W OF 80W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 10N29W 9N33W 10N45W 10N49W 10N63W. SCATTERED MODERATE CONVECTION IS WITHIN 200 NM EITHER SIDE OF THE AXIS BETWEEN 19W-27W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL HIGH IS OVER THE FLORIDA PANHANDLE CENTERED NEAR 30N84W WITH A SURFACE RIDGE ACROSS THE CENTRAL GULF ALONG 27N AND ANCHORED ON A 1021 MB SURFACE HIGH NEAR 27N84W. STABLE ATMOSPHERIC CONDITIONS AND SUBSIDENCE ASSOCIATED WITH THE SURFACE HIGH AND SURFACE RIDGE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS A MAJORITY OF THE GULF. HOWEVER...A MIDDLE LEVEL SHORTWAVE TROUGH IS POSITIONED ACROSS NRN LOUISIANA AND ERN TEXAS AND IS GENERATING SCATTERED SHOWERS AND TSTMS ACROSS THE NW GULF N OF 23N BETWEEN 88W-95W. WINDS REMAIN LIGHT IN THE VICINITY OF THE SURFACE RIDGE ACROSS THE N GULF...WITH ANTICYCLONIC FLOW AROUND THE RIDGE SUPPORTING AN SWATH OF SE WINDS OF 10-15 KT ACROSS PORTIONS OF THE SW GULF. THESE CONDITIONS ARE FORECAST TO CONTINUE DURING THE NEXT SEVERAL DAYS AS THE SURFACE RIDGE HOLDS NEARLY STATIONARY. 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. CARIBBEAN SEA... FRESH TO STRONG TRADE WINDS ARE OCCURRING BETWEEN THE RIDGE OF HIGH PRESSURE OVER THE CENTRAL ATLC AND A BROAD TROUGH OVER NRN SOUTH AMERICA...WITH THE STRONGEST FLOW NEAR THE COAST OF COLOMBIA. THE QSCAT PASS AROUND 1130 UTC INDICATED A LARGE AREA OF E-NE 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 WRN CARIBBEAN AND CENTRAL AMERICA. ATMOSPHERIC INSTABILITY ASSOCIATED WITH A WEAK UPPER LEVEL SHORTWAVE TROUGH OVER THE SE CARIBBEAN IS SUPPORTING SCATTERED SHOWERS AND TSTMS S OF 13N BETWEEN 61W-64W. ALSO...ISOLATED SHOWERS ARE OCCURRING ACROSS THE LEEWARD ISLANDS N OF 15N E OF 63W. ATLANTIC OCEAN... DEEP LAYER MOISTURE IS COMBINING WITH UPPER LEVEL DIFFLUENCE IN NWLY FLOW ALOFT TO RESULT IN SCATTERED SHOWERS AND ISOLATED TSTMS N OF 28N BETWEEN 54W-72W. SUBSIDENCE AND GENERALLY FAIR WEATHER ARE PRESENT ACROSS MUCH OF THE CENTRAL AND E ATLC AROUND A BROAD SURFACE RIDGE ANCHORED ON A 1032 MB HIGH CENTERED N OF THE AZORES NEAR 42N26W. ACROSS THE TROPICAL N ATLC...AN UPPER LEVEL RIDGE EXTENDS FROM 10N60W TO 17N41W 16N17W...WITH UPPER LEVEL DIVERGENCE SUPPORTING THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 31W. $$ HUFFMAN