000 AXNT20 KNHC 201749 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED JUN 20 2012 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... TROPICAL STORM CHRIS IS CENTERED NEAR 38.1N 51.3W AT 20/1500 UTC OR ABOUT 520 NM S OF CAPE RACE NEWFOUNDLAND MOVING E AT 19 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 90 NM OF CENTER IN THE NORTHERN SEMICIRCLE. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 09N22W TO 16N19W MOVING W AT 10-15 KT. THE WAVE IS EMBEDDED WITHIN THE MONSOON TROUGH AXIS AND COINCIDES WITH A VERY WEAK 700-850 MB TROUGH THAT HAS PROGRESSED OFF THE AFRICAN COAST. NO CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS TIME DUE TO SAHARAN DUST THAT COVERS MUCH OF THE TROPICAL NORTH ATLC WATERS. ANY CONVECTION TO THE SW OF THE WAVE AXIS IS LIKELY ASSOCIATED WITH THE MONSOON TROUGH AXIS. TROPICAL WAVE EXTENDS FROM 11N64W TO 18N62W MOVING W-NW AT 20-25 KT. THE WAVE CONTINUES TO MOVE AROUND THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL RIDGE CENTERED OVER THE CENTRAL ATLC NEAR 24N50W AND IS QUICKLY BECOMING EMBEDDED WITHIN THE LOW-LEVEL TROUGHING THAT IS LOCATED ACROSS THE SW NORTH ATLC...FLORIDA STRAITS...AND SE GULF OF MEXICO. NO SIGNIFICANT DEEP CONVECTION IS NOTED ON SATELLITE IMAGERY. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 15N17W TO 07N28W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N28W TO 06N34W TO 07N43W TO 04N51W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 05N-08N BETWEEN 22W-50W. ...DISCUSSION... GULF OF MEXICO... WEST TO SOUTHWESTERLY UPPER LEVEL FLOW IS OVER THE GULF THIS AFTERNOON BETWEEN AN UPPER LEVEL LOW CENTERED NEAR 26N99W AND AN UPPER LEVEL RIDGE WITH AXIS EXTENDING FROM OVER SOUTHERN MEXICO NEAR 16N94W E-NE TO NEAR 23N76W. UPPER LEVEL MOISTURE CONTINUES TO ADVECT FROM THE PACIFIC OCEAN REGION ACROSS MEXICO AND INTO THE WESTERN GULF W OF 90W AND PORTIONS OF THE EASTERN GULF E OF 85W. UPPER LEVEL DIFFLUENCE IS MAXIMIZED OVER THESE AREAS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS SW OF A LINE FROM 29N95W TO 21N88W...AND EAST OF A SURFACE TROUGH ANALYZED FROM 27N81W TO 20N88W. WHILE THE MIDDLE TO UPPER LEVEL DYNAMICS ARE IN PLACE FOR CONVECTION TO PERSIST OVER THE NEXT 36 TO 48 HOURS...THE SURFACE TROUGH IS FORECAST TO MOVE NORTHWESTWARD OVER THE NEXT 24 HOURS AND LIKELY STALL ACROSS THE EASTERN AND CENTRAL PORTIONS OF THE GULF...POTENTIALLY AS A BROAD SURFACE LOW...PROVIDING AN ENHANCEMENT TO CONVECTIVE ACTIVITY THROUGH THE UPCOMING WEEKEND ACROSS THE EASTERN GULF AND FLORIDA PENINSULA. IN THE MEANTIME...A SURFACE RIDGE ANCHORED ACROSS SW NORTH CAROLINA IS SLOWLY ERODING AS THE SURFACE TROUGH SHIFTS NW AND IS PROVIDING THE GULF WITH BRISK EAST TO SOUTHEAST WINDS IN THE RANGE OF 15 TO 20 KT. CARIBBEAN SEA... AN UPPER LEVEL RIDGE AXIS EXTENDS FROM OVER SOUTHERN MEXICO NEAR 16N94W E-NE TO NEAR 23N76W WITH UPPER LEVEL DIFFLUENT FLOW MAXIMIZED OVER THE NW CARIBBEAN AND CUBA INTO PORTIONS OF THE SW NORTH ATLC N OF 17N W OF 72W. THIS AREA ALOFT ALONG WITH A SURFACE TROUGH ANALYZED ACROSS THE YUCATAN CHANNEL IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 18N-23N BETWEEN 80W-86W. THE SURFACE TROUGHING IS EXPECTED TO CONTINUE MOVING TOWARDS THE NW THROUGH THE REMAINDER OF THE WEEK WITH PERSISTENT PRECIPITATION FORECAST OVER PORTIONS OF CUBA AND THE YUCATAN PENINSULA THE NEXT FEW DAYS. LOCALLY HEAVY RAINFALL WITH THE HIGH POTENTIAL FOR FLOODING AND MUDSLIDES WILL CONTINUE BE THE PRIMARY IMPACT. OTHERWISE...THE REMAINDER OF THE CARIBBEAN IS FAIRLY QUIET DUE TO NORTHEASTERLY UPPER LEVEL WINDS AND MODERATE TO FRESH E-SE TRADES. A TROPICAL WAVE ALONG 63W ACROSS THE EASTERN CARIBBEAN IS QUICKLY BECOMING EMBEDDED WITHIN THE SURFACE TROUGHING THAT EXISTS ACROSS THE SW NORTH ATLC AND NW CARIBBEAN AND IS EXPECTED TO DISSIPATE OVER THE NEXT 24 TO 36 HOURS. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH COVERS THE WESTERN NORTH ATLC N OF 28N BETWEEN 60W-78W WITH AN AXIS EXTENDING FROM 34N60W TO 29N77W. THIS TROUGHING SUPPORTS A SURFACE TROUGH ANALYZED FROM 32N60W TO 29N70W TO THE FLORIDA COAST NEAR 27N80W. MIDDLE TO UPPER LEVEL DIFFLUENCE IS MAXIMIZED SOUTHEAST OF THE TROUGH AXIS WITH SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS OCCURRING FROM 22N-31N BETWEEN 59W-75W...AND FROM 20N-28N BETWEEN 75W-82W. TO THE NORTH OF 30N...HIGH PRESSURE CONTINUES TO PROVIDE FAIR WEATHER CONDITIONS NW OF THE SURFACE TROUGH AXIS AS A 1024 MB HIGH IS CENTERED OFF THE CAROLINA COAST NEAR 35N70W. OTHERWISE THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A PAIR OF 1023 MB HIGHS ONE CENTERED NEAR 28N57W AND THE OTHER CENTERED NEAR 31N38W. FAIR WEATHER CONDITIONS PERSIST PRIMARILY E OF 55W. A COLD FRONT IS ANALYZED INTO THE DISCUSSION AREA FROM 32N20W TO 27N30W WITH ONLY ISOLATED SHOWERS POSSIBLE WITHIN 45 NM EITHER SIDE OF THE FRONT. OF NOTE...EXAMINING THE GOES-R PROVING GROUND DUST PRODUCT IMAGERY...METEOSAT-9 VISIBLE IMAGERY...AND THE CIMSS SAHARAN AIR LAYER TRACKING PRODUCT...A LARGE AREA OF SAHARAN DUST IS ACROSS A LARGE PORTION OF THE TROPICAL ATLC FROM 08N-23N E OF 64W. AN ENHANCED AREA CENTERED NEAR 20N58W HAS REACHED THE LESSER ANTILLES AND CONTINUES MOVING TO THE W-NW WHICH WILL LIKELY PROVIDE HAZY SKY CONDITIONS OVER THE NEXT FEW DAYS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN