000 AXNT20 KNHC 272346 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI MAY 27 2011 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS FROM 04N TO 11N ALONG 52W MOVING W-NW AT 10-15 KT. THE LAST FEW VISIBLE SATELLITE IMAGES OF THE DAY SHOW AN INVERTED-V STRUCTURE WITH CYCLONIC FLOW ABOUT THE AXIS IN THE LOW-LEVEL CLOUD PATTERN. TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATES A NORTHWARD EXTENSION OF LOW-LEVEL MOISTURE TO 11N IN THE VICINITY OF THE WAVE AXIS. HOWEVER...DRY NW FLOW IN THE MIDDLE TO UPPER LEVELS ABOVE THE LOW-LEVEL WAVE SIGNATURE IS INHIBITING ANY SIGNIFICANT CONVECTION WITH THE WAVE THIS EVENING. TROPICAL WAVE IS FROM 04N TO 12N ALONG 60W SE OF THE WINDWARD ISLANDS AND TRINIDAD AND TOBAGO MOVING W-NW AT 10-15 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOWS DEEPER MOISTURE IN THE VERTICAL AND A MORE DIFFLUENT ATMOSPHERE ALOFT THAN THE PREVIOUSLY MENTIONED WAVE WHICH IS RESULTING IN SCATTERED SHOWERS AND ISOLATED MODERATE CONVECTION FROM 05N-11N BETWEEN 57W-63W. ...ITCZ... ITCZ AXIS IS ALONG 09N13W 03N35W 04N50W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM NORTH OF THE AXIS BETWEEN 16W-27W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES A VERY DRY AIRMASS IS ASSOCIATED WITH A MIDDLE TO UPPER LEVEL TROUGH POSITIONED ACROSS THE GULF THIS EVENING. THE UPPER LEVEL TROUGH AXIS EXTENDS FROM NORTHERN FLORIDA NEAR 29N82W TO NORTH OF THE YUCATAN PENINSULA NEAR 22N90W AND SUPPORTS A STATIONARY FRONT EXTENDING ACROSS THE WESTERN FLORIDA PANHANDLE AND GULF COASTAL PLAIN ALONG 30N BETWEEN 87W-92W. THE FRONT HAS INITIATED A FEW ISOLATED SHOWERS IN THE VICINITY OF THE FLORIDA BIG BEND REGION HOWEVER THE LACK OF SURFACE FORCING AND DRY AIR ALOFT IS ACTING QUICKLY TO DIMINISH THE ACTIVITY. THE REMAINDER OF THE FLORIDA PENINSULA IS EXPERIENCING ISOLATED SHOWERS AND TSTMS N OF 26N DUE TO SEABREEZE INTERACTION AND PEAK DAYTIME HEATING. AREAL COVERAGE OF THIS ACTIVITY SHOULD BEGIN TO WANE OVER THE NEXT 3 TO 6 HOURS WITH LOSS OF MAXIMUM INSTABILITY. ELSEWHERE...THE REMAINDER OF THE GULF WATERS REMAIN NEARLY CLOUDLESS WITH FAIR CONDITIONS AS A SURFACE RIDGE ANCHORED BY A 1014 MB HIGH CENTERED NEAR 27N87W RETAINS HOLD OVER AN OVERALL STABLE ATMOSPHERE. LASTLY...WHILE SKIES REMAIN CLEAR...THE LAST FEW VISIBLE SATELLITE IMAGES OF THE DAY INDICATE A HAZY ATMOSPHERE W OF 90W DUE TO THE ADVECTION OF SMOKE FROM SOUTHERN MEXICO WILDFIRES. VISIBILITIES BELOW 10 STATUTE MILES...OR 8.7 NM ARE PREVALENT IN OBSERVATIONS ACROSS THE SW GULF WATERS AND ALONG THE MEXICO GULF COAST S OF 26N. CARIBBEAN SEA... ZONAL WESTERLY FLOW ALOFT IS NOTED ACROSS MUCH OF THE CARIBBEAN SEA THIS EVENING AS MOSTLY DRY AIR IS EVIDENT ON WATER VAPOR IMAGERY N OF 17N W OF 70W. FAIR CONDITIONS AND RELATIVELY CLEAR SKIES PREVAIL OVER MUCH OF THE NW CARIBBEAN WHILE ISOLATED SHOWERS AND TSTMS IN ASSOCIATION WITH PEAK DAYTIME HEATING AND INSTABILITY CONTINUE ACROSS INTERIOR PORTIONS OF CUBA AND HISPANIOLA...AS WELL AS IN THE VICINITY OF JAMAICA. THIS ACTIVITY IS EXPECTED TO DIMINISH OVER THE NEXT 3 TO 6 HOURS. ELSEWHERE...CONVERGENT TRADEWIND FLOW IN THE LOW-LEVEL ALONG WITH UPPER LEVEL DIFFLUENCE EAST OF AN UPPER LEVEL TROUGH AXIS SKIRTING ACROSS SOUTHERN MEXICO IS GENERATING WIDELY SCATTERED SHOWERS AND TSTMS OVER THE SW CARIBBEAN S OF 16N AND W OF A LINE FROM 16N83W TO NORTHERN COLOMBIA NEAR 12N73W. THIS CONVECTION REMAINS ENHANCED OVER INTERIOR PORTIONS OF GUATEMALA... HONDURAS...EL SALVADOR...AND NORTHERN NICARAGUA DUE TO THE CLOSE PROXIMITY OF THE EASTERN PACIFIC OCEAN ITCZ AXIS. ATLANTIC OCEAN... A SURFACE RIDGE COVERS THE WESTERN ATLC W OF 65W KEEPING CONDITIONS MOSTLY FAIR THIS EVENING. HOWEVER...A FEW ISOLATED SHOWERS AND TSTMS OVER THE INTERIOR FLORIDA PENINSULA ARE DRIFTING INTO THE COASTAL ZONES OFF OF THE EAST COAST N OF 26N. FARTHER EAST...A BROAD UPPER LEVEL LOW CONTINUES TO SPIN NEAR 32N51W SUPPORTING A PAIR OF 1015 MB SURFACE LOWS CENTERED NEAR 30N51W AND 30N57W. A SURFACE TROUGH EXTENDS FROM THE EASTERNMOST LOW ALONG 27N52W 25N60W TO 24N65W SUPPORTING ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE OF THE SURFACE TROUGH AXIS. A SHEAR LINE EXTENDS AROUND THE SYSTEM ALONG 32N48W 28N46W 23N49W TO 20N55W. SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS COVER A VAST AREA FROM 18N-35N BETWEEN 38W-55W. THE PRESSURE GRADIENT WITH THIS SYSTEM REMAINS STRONGEST IN THE NORTHEAST SEMICIRCLE IN THE VICINITY OF 33N49W WITH GALE FORCE E-SE WINDS EXPECTED TO CONTINUE OVER THE NEXT 24 HOURS. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE EXTENDING SOUTHWARD INTO THE DISCUSSION AREA ALONG 37W. FINALLY...AN ELONGATED UPPER LEVEL LOW IS CENTERED NE OF THE MADEIRA ISLANDS NEAR 35N15W. THIS DEEP LAYER TROUGH REFLECTS AS A 1011 MB LOW CENTERED NEAR 33N15W WITH A SURFACE TROUGH EXTENDING FROM THE LOW TO 28N21W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN