000 AXNT20 KNHC 250002 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN AUG 24 2014 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 2345 UTC. ...SPECIAL FEATURES... TROPICAL STORM CRISTOBAL IS CENTERED NEAR 24.5N 73.0W AT 24/2100 UTC OR ABOUT 135 NM E-NE OF LONG ISLAND OR ABOUT 160 NM E-NE OF GREAT EXUMA ISLAND IN THE BAHAMAS. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. MAXIMUM SUSTAINED WINDS ARE 40 KT WITH GUSTS TO 50 KT. ON THE FORECAST TRACK...THE CENTER OF CRISTOBAL WILL PASS NEAR OR TO THE EAST OF THE CENTRAL BAHAMAS THROUGH MONDAY. SOME GRADUAL STRENGTHENING IS FORECAST DURING THE NEXT 48 HOURS. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 16N-27N BETWEEN 68W-78W...INCLUDING HISPANIOLA...JAMAICA...EASTERN CUBA AND ADJACENT WATERS. CRISTOBAL IS EXPECTED TO PRODUCE RAINFALL TOTALS OF 4 TO 8 INCHES OVER THE TURKS AND CAICOS ISLANDS...AS WELL AS THE SOUTHEASTERN AND CENTRAL BAHAMAS THROUGH TUESDAY...WITH ISOLATED AMOUNTS AROUND 12 INCHES POSSIBLE. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS EAST OF THE CAPE VERDE ISLANDS WITH AXIS EXTENDING FROM 18N21W TO 12N22W. THE WAVE IS EMBEDDED IN THE MONSOON TROUGH AND IS ASSOCIATED WITH MODERATE MOISTURE AT THE LOWER AND MIDDLE LEVELS. HOWEVER...DRY SAHARAN AIR AND DUST ARE OBSERVED IN THE WAVE ENVIRONMENT WHICH ALONG STRONG DEEP LAYER ENVIRONMENTAL SHEAR INHIBIT DEEP CONVECTION. ISOLATED SHOWERS ARE SE OF THE WAVE AXIS. A TROPICAL WAVE IS ON THE CENTRAL ATLC WITH AXIS EXTENDING FROM 17N33W TO A 1010 MB LOW NEAR 11N33W...MOVING W AT 20 KT. THE WAVE IS EMBEDDED IN THE MONSOON TROUGH AND DEEP LAYER HIGH MOIST ENVIRONMENT IS ASSOCIATED WITH IT S OF 13N WHERE SCATTERED MODERATE CONVECTION IS NOTED FROM 9N-13N BETWEEN 31W-36W. SAHARAN DRY AIR AND DUST ENGULFS THE NORTHERN PORTION OF THE IT...THUS HINDERING CONVECTION. A LOW AMPLITUDE TROPICAL WAVE IS FARTHER WEST WITH AXIS EXTENDING FROM 14N45W TO 9N45W...MOVING W AT 20 KT. THE WAVE IS DEVOID OF CONVECTION AS SAHARAN DRY AIR AND DUST IS IN ITS ENVIRONMENT. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC NEAR 19N16W AND THEN CONTINUES ALONG 14N22W TO A 1010 MB LOW NEAR 11N33W TO 8N37W. THE ITCZ BEGINS NEAR 8N37W AND CONTINUES TO 6N47W 8N54W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...A CLUSTER OF MODERATE CONVECTION IS FROM 8N-12N BETWEEN 38W-41W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL TROUGH IS ON THE WESTERN ATLC SUPPORTING A FRONTAL SYSTEM ANALYZED AS A BACKDOOR COLD FRONT ALONG THE NORTHERN FLORIDA PENINSULA. THIS FRONT ALONG A DIFFLUENT ENVIRONMENT ALOFT BEING GENERATED BY AN UPPER LEVEL INVERTED TROUGH COVERING MOST OF THE GULF SUPPORT SCATTERED HEAVY SHOWERS AND TSTMS ALONG THE WESTERN FLORIDA PENINSULA N OF 25N. SIMILAR CONVECTION IS NOTED ON THE EASTERN GULF FROM 23N-28N BETWEEN 84W- 89W. WEAK SURFACE RIDGING IS OVER THE WESTERN GULF PROVIDING ANTICYCLONIC WIND FLOW OF 5-10 KT. NORTHERLY FLOW OF THE SAME MAGNITUDE IS ON THE REMAINDER BASIN. MOISTURE ASSOCIATED WITH THE FRONTAL SYSTEM WILL CONTINUE TO SUPPORT RAINSHOWERS AND POSSIBLE TSTMS ACROSS THE FLORIDA PENINSULA THROUGH TUESDAY MORNING AND ACROSS THE NORTHERN AND EASTERN GULF BEYOND TUESDAY NIGHT. SURFACE RIDGING WILL DOMINATE ACROSS THE WESTERN GULF THROUGH WED NIGHT. CARIBBEAN SEA... A BROAD UPPER-LEVEL ANTICYCLONE DOMINATES THE WESTERN AND CENTRAL CARIBBEAN WHILE AN INVERTED UPPER TROUGH IS ON THE EAST OF THE BASIN. SOUTHERLY LOW-LEVEL WIND FLOW FEEDING T.S. CRISTOBAL ON THE SW N ATLC IS ENHANCING SCATTERED HEAVY SHOWERS ACROSS CENTRAL AND WESTERN HISPANIOLA...THE WINDWARD PASSAGE AND EASTERN CUBA. THIS SHOWER ACTIVITY EXTENDS TO 15N TO INCLUDE JAMAICA AND COASTAL WATERS OF THE ABOVE-MENTIONED TERRITORIES. SCATTEROMETER DATA DEPICTED A SURFACE TROUGH EXTENDING FROM EASTERN CUBA NEAR 20N75W SW TO 14N82W. THIS TROUGH IS ENHANCING ISOLATED SHOWERS ON THE NW CARIBBEAN BETWEEN 77W-85W. A DIFFLUENT ENVIRONMENT ALOFT BETWEEN THE RIDGE AND THE INVERTED TROUGH COULD SUPPORT ISOLATED SHOWERS AND THUNDERSTORMS ON PUERTO RICO. THE REMAINDER OF THE CARIBBEAN IS UNDER FAIR CONDITIONS TONIGHT. SHOWERS ASSOCIATED WITH CRISTOBAL WILL CONTINUE TO AFFECT HISPANIOLA AND CUBA THROUGH TUESDAY MORNING. THE NEXT TROPICAL WAVE WILL ENTER THE EASTERN CARIBBEAN WED MORNING. ...HISPANIOLA... MOIST LOW-LEVEL SOUTHERLY WIND FLOW FEEDING T.S. CRISTOBAL IS SUPPORTING SCATTERED HEAVY SHOWERS/ISOLATED THUNDERSTORMS OVER THE CENTRAL AND WESTERN ISLAND. RAINSHOWERS ARE FORECAST TO CONTINUE THROUGH TUE MORNING. ONAMET HAS ISSUED WEATHER ALERTS FOR FLASH FLOODS AND LANDSLIDES OVER PORTIONS OF THE ISLAND. PLEASE SEE ONAMET WEBSITE AT WWW.ONAMET.GOV.DO FOR MORE INFORMATION. ATLANTIC OCEAN... THE MAIN FEATURE ON THE BASIN IS T.S. CRISTOBAL JUST N OF THE SOUTHERN BAHAMAS ISLANDS. SEE SPECIAL FEATURES ABOVE. A BROAD UPPER TROUGH COVERS THE NW ATLC N OF 28N SUPPORTING A COLD FRONT ANALYZED ALONG 30N77W SW TO THE NE FLORIDA COASTLINE NEAR 29N81W. LOW-LEVEL MOISTURE CONVERGENCE ALONG WITH AN UPPER DIFFLUENT ENVIRONMENT ALOFT SUPPORT SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS AHEAD OF THE FRONT N OF 25N BETWEEN 64W-71W. THE REMAINDER OF THE ATLC BASIN IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1024 MB HIGH NEAR 33N29W. SHOWERS ARE EXPECTED ACROSS THE SW N ATLC BEYOND WED MORNING. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR