000 AXNT20 KNHC 181753 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT MAY 18 2013 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. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 05N56W TO 11N52W MOVING W AT 15 KT. THE WAVE REMAINS LOW-AMPLITUDE AND HAS BROKEN AWAY FROM THE INFLUENCE OF THE ITCZ AXIS WHICH IS LOCATED TO THE SE. THE WAVE COINCIDES WITH A GLOBAL MODEL INDICATED AREA OF MAXIMUM POTENTIAL VORTICITY AT 315K WHICH HAS BEEN TRACKING WESTWARD OVER THE PAST FEW DAYS. TOTAL PRECIPITATABLE WATER AND SATELLITE IMAGERY ALSO INDICATE A MAXIMUM IN LOW-LEVEL MOISTURE CONVERGENCE AND CLOUDINESS IN THE VICINITY OF THE WAVE AXIS. ISOLATED MODERATE CONVECTION IS FROM 06N-11N BETWEEN 46W-60W. THIS CONVECTION IS LIKELY ENHANCED DUE TO UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE WESTERN PERIPHERY OF AN UPPER LEVEL RIDGE OVER THE TROPICAL ATLC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N14W TO 05N22W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 05N22W TO THE EQUATOR NEAR 4947W. SCATTERED MODERATE CONVECTION IS FROM 01N-03N BETWEEN THE PRIME MERIDIAN AND 02W. WIDELY SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 07N BETWEEN 08W-19W...AND FROM 01N-05N BETWEEN 26W-41W. ...DISCUSSION... GULF OF MEXICO... VISIBLE SATELLITE IMAGERY SHOWS THE GULF BASIN REMAINS UNDER FAIRLY TRANQUIL CONDITIONS THIS AFTERNOON. WATER VAPOR IMAGERY INDICATES UPPER LEVEL WEST-NORTHWESTERLY FLOW WITH MID-LEVEL RIDGING PROVIDING FOR OVERALL STABLE CONDITIONS. AT THE SURFACE...A RIDGE AXIS EXTENDS FROM THE SW NORTH ATLC REGION NEAR 31N73W TO 22N98W AND IS PROVIDING SE WINDS GENERALLY IN THE RANGE OF 5 TO 10 KT EAST OF 90W AND 10 TO 20 KT WEST OF 90W. THE RIDGING IS EXPECTED TO REMAIN NEARLY STATIONARY THROUGH THE REMAINDER OF THE WEEKEND INTO THE MIDDLE OF NEXT WEEK WITH LITTLE CHANGE REGARDING WIND SPEEDS AND DIRECTION AS NOTED ABOVE. FINALLY...OF NOTE...VISIBLE SATELLITE IMAGERY INDICATES MODERATELY DENSE SMOKE MOVING NORTH-NORTHWESTWARD OFF THE SOUTHERN MEXICO COAST THAT COVERS A PORTION OF THE SW GULF S OF 23N BETWEEN 91W-97W. THE SMOKE IS DUE TO SEVERAL AGRICULTURAL FIRES ACROSS SOUTHERN MEXICO AND NORTHERN CENTRAL AMERICA. CARIBBEAN SEA... DRY AND STABLE WEST-NORTHWESTERLY MIDDLE TO UPPER LEVEL FLOW IS NOTED ON WATER VAPOR IMAGERY ACROSS THE NW CARIBBEAN WITH UPPER LEVEL WINDS SHIFTING SLIGHTLY MORE WEST-SOUTHWEST OVER THE CENTRAL AND EASTERN CARIBBEAN E OF 78W. MODERATELY DRY AIR PREVAILS ALOFT E OF 78W...HOWEVER VISIBLE SATELLITE IMAGERY SHOWS A FEW PASSING CIRRUS CLOUDS OVER THIS AREA. SCATTERED SHOWERS AND TSTMS ARE OCCURRING S OF 12N BETWEEN 77W-84W AND LIKELY WILL PERSIST DUE TO LOW-LEVEL MOISTURE CONVERGENCE AND THE CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ACROSS PANAMA AND SOUTHERN COSTA RICA. OTHERWISE...TRADES CONTINUE IN THE RANGE OF 10 TO 20 KT WITH SLIGHTLY HIGHER WIND SPEEDS EXPECTED S OF 14N BETWEEN 69W-76W IN THE VICINITY OF THE COLOMBIA AND NW VENEZUELA COAST. A FEW AREAS OF ISOLATED SHOWERS ARE OCCURRING IN THE NW CARIBBEAN N OF 18N BETWEEN 78W-86W...AND REMAIN PRIMARILY WITHIN THE ADJACENT COASTAL WATERS SOUTH OF CUBA AND EAST OF THE YUCATAN PENINSULA. EASTERLY TRADES ARE EXPECTED TO PERSIST THROUGH THE WEEK AHEAD AS A SURFACE RIDGE REMAINS ANCHORED ACROSS THE SW NORTH ATLC TO THE NORTH OF THE BASIN. HISPANIOLA... CURRENTLY WESTERLY WINDS ALOFT ARE CONTINUING TO PROVIDE AN OVERALL STABLE ENVIRONMENT OVER THE ISLAND THIS AFTERNOON. WHILE THE TRADE WIND FLOW REGIME WILL REMAIN PERSISTENT THROUGH THE REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK...AND GIVEN A MODERATELY DRY UPPER LEVEL FLOW PATTERN IN PLACE...THE MOST LIKELY PRECIPITATION WILL CONTINUE TO BE ISOLATED SHOWERS AND TSTMS DURING THE AFTERNOON AND EARLY EVENING HOURS ACROSS THE ISLAND WHEN PEAK DAYTIME HEATING AND INSTABILITY OCCUR. ANY AREAS THAT RECEIVE MEASUREABLE AMOUNTS OF RAINFALL WILL LIKELY BE PRONE TO LOCALIZED FLOODING. ATLANTIC OCEAN... WEST-NORTHWESTERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY OVER MUCH OF THE SW NORTH ATLC. THIS RATHER STABLE REGIME ALOFT IS SUPPORTIVE OF A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH CENTERED NEAR 31N73W AND IS PROVIDING FOR OVERALL FAIR CONDITIONS. ON THE SOUTHERN AND WESTERN PERIPHERY OF THE RIDGE HOWEVER...A FEW ISOLATED SHOWERS AND TSTMS ARE POSSIBLE AS NOTED ON SATELLITE IMAGERY AND MOSAIC DOPPLER RADAR IMAGERY OFF THE COAST OF THE FLORIDA PENINSULA. FARTHER EAST...A WEAK MID-LEVEL SHORTWAVE TROUGH AXIS EXTENDS FROM 33N60W TO 29N69W AND IS SUPPORTING A STATIONARY ANALYZED FROM 32N56W TO 21N67W. ISOLATED SHOWERS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE BOUNDARY N OF 23N. IN ADDITION ACROSS THE CENTRAL ATLC...A WEAK SURFACE TROUGH IS ANALYZED FROM 26N44W TO 30N52W. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1033 MB HIGH CENTERED N-NW OF THE AZORES NEAR 41N30W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN