000 AXNT20 KNHC 121133 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE JUL 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1100 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS INTRODUCED IN THE ERN TRPCL ATLC ALONG 13N25W TO 7N26W MOVING W 10-15 KT. WAVE IS LOW AMPLITUDE AND DIFFICULT TO DISCERN AT THE SURFACE. HOWEVER...SATELLITE HOVMOLLER DIAGRAMS INDICATE A TRACKABLE FEATURE BACK TO THE COAST OF AFRICA. UPPER AIR DATA FROM DAKAR SENEGAL ALSO INDICATES A CLEAR WAVE SIGNAL CROSSING THE STATION AROUND 10/1200 UTC. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE. TROPICAL WAVE IN THE WRN TRPCL ATLC EXTENDS FROM NEAR 17N54W TO 8N59W MOVING WNW 10-15 KT. WAVE CONTINUES TO PRECEDE A SURGE OF DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE IMAGERY ALSO INDICATES LOW LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-14N BETWEEN 55W-60W. TROPICAL WAVE IN THE WRN CARIBBEAN EXTENDS ACROSS ERN NICARAGUA/HONDURAS ALONG 84W FROM 13N-17N MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF ENHANCED MOISTURE ACROSS THE WRN CARIBBEAN. THE WAVE LIES UNDER DIFFLUENT FLOW ALOFT WHICH IS HELPING ENHANCE CONVECTION. IT IS DIFFICULT TO DETERMINE WHAT CONVECTION IS CAUSED BY THE WAVE...THE UPPER LEVEL INFLUENCE...AND ALSO THE MONSOON TROUGH TO THE S OF THE WAVE. NUMEROUS STRONG CONVECTION IS FROM 11N-13N BETWEEN 82W-84W. SCATTERED MODERATE/STRONG CONVECTION IS E OF THE WAVE AXIS FROM 12N-17N BETWEEN 81W-83W. SIMILAR ACTIVITY IS ALSO MOVING INTO THE YUCATAN PENINSULA AND BELIZE FROM 15N-20N BETWEEN 87W-90W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN AT 23N ALONG 22N12W 11N23W. THE ITCZ AXIS CONTINUES ON THE OTHER SIDE OF A TROPICAL WAVE ALONG 8N31W 5N44W 6N55W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM N...AND 75 NM S OF THE AXIS BETWEEN 30W-37W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING COVERS THE GULF OF MEXICO THIS MORNING CENTERED AROUND A 1018 MB HIGH OFF THE W CENTRAL COAST OF FLORIDA NEAR 28N83W SUPPORTING FAIR WEATHER AND LIGHT ANTI-CYCLONIC FLOW AROUND THE RIDGE. ALOFT...AN UPPER LEVEL RIDGE COVERS THE NRN GULF CENTERED OVER NRN ALABAMA. AN UPPER LEVEL TROUGH COVERS THE SW GULF EXTENDING FROM SRN MEXICO NEAR 18N95W TO 25N93W. A SHORTWAVE UPPER TROUGH IS ALONG IN THE N CENTRAL GULF FROM SE LOUISIANA TO 25N89W SUPPORTING A FEW ISOLATED SHOWERS/THUNDERSTORMS ALONG THE NRN GULF COAST BETWEEN 83W-89W. WATER VAPOR IMAGERY INDICATES DRY AIR IS WRAPPING AROUND THE SRN EXTENT OF THE UPPER RIDGE WHICH IS FURTHER SUPPORTING THE FAIR WEATHER. TOTAL PRECIPITABLE WATER IMAGERY STILL INDICATES ENHANCED MOISTURE IS ACROSS THE NRN GULF. WITH DAYTIME HEATING THIS WILL LIKELY MEAN SHOWERS/THUNDERSTORMS WILL POP UP LATER IN THE AFTERNOON TODAY. SHOWER/THUNDERSTORM ACTIVITY WILL ALSO LIKELY INCREASE OVER THE SE GULF AS MOISTURE FROM A TROPICAL WAVE IN THE WRN CARIBBEAN FLOWS INTO THE BASIN AS THE WAVE MOVES WWD. WEAK SURFACE RIDGING WILL CONTINUE OVER THE NRN GULF. CARIBBEAN SEA... MOIST DIFFLUENT FLOW ALOFT COVERS THE NW CARIBBEAN AROUND THE ERN SIDE OF AN INVERTED UPPER TROUGH OVER THE SRN GULF OF MEXICO...AND A NARROW UPPER RIDGE EXTENDING FROM NRN COLOMBIA TO NEAR 19N83W. THIS AREA OF DIFFLUENCE LIES OVER A TROPICAL WAVE ALONG 84W. THIS COMBINATION IS PRODUCING SHOWERS/ THUNDERSTORMS ACROSS THE WRN CARIBBEAN S OF 20N BETWEEN 80W-90W WITH THE STRONGEST ACTIVITY E OF THE WAVE AXIS...AND ACROSS SRN NICARAGUA. STRONG SHOWERS/THUNDERSTORMS ARE ALSO FROM 9N-12N BETWEEN 74W-86W INFLUENCED BY THE MONSOON TROUGH EXTENDING FROM THE ERN PACIFIC ACROSS NRN COSTA RICA TO NRN COLOMBIA. THE REMAINDER OF THE BASIN IS UNDER MOSTLY FAIR CONDITIONS WITH 15-20 KT ELY TRADEWIND FLOW. A FEW ISOLATED SHOWERS ARE NOTED IN THE NE CARIBBEAN N OF 15N E OF 71W. THIS AREA IS ALSO IN AN AREA OF MODERATE MOISTURE INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. A FEW ISOLATED SHOWERS ARE ALSO MOVING ACROSS THE SRN WINDWARD ISLANDS DUE TO MOISTURE ASSOCIATED WITH A TROPICAL WAVE E OF THE ISLANDS. SHOWER ACTIVITY IN THIS AREA WILL INCREASE AS THE WAVE MOVES WWD TOWARDS THE BASIN. ALOFT...A HORIZONTALLY ALIGNED UPPER LEVEL TROUGH IS ACROSS THE NRN CARIBBEAN WITH AXIS ALONG 18N. AN UPPER RIDGE IS TO THE S OF THE UPPER TROUGH CENTERED OVER THE WINDWARD ISLANDS NEAR 13N62W. EXPECT SHOWER/THUNDERSTORM ACTIVITY TO PERSIST ACROSS THE WRN CARIBBEAN AS MOISTURE ASSOCIATED WITH THE TROPICAL WAVE REMAINS. ALSO...MUCH OF CENTRAL AMERICA AND SRN MEXICO IS AT THREAT FOR PROLONGED HEAVY RAINFALL THROUGHOUT THE END OF THE WEEK WHICH WILL INCREASE THE CHANCE FOR DEADLY FLOODING AND MUDSLIDES. MODEL GUIDANCE INDICATES THE MONSOON TROUGH WILL STRENGTHEN AND LIFT FARTHER N PLACING ABNORMALLY STRONG WLY FLOW AGAINST CENTRAL AMERICA AND SRN MEXICO. THIS W-SW FLOW WILL DRAW SIGNIFICANT TROPICAL MOISTURE ACROSS THESE AREAS. COMBINED WITH OROGRAPHIC LIFT DUE TO MOUNTAINS THIS CREATES A FORMULA TO EQUAL HEAVY PRECIPITATION. THESE AREAS SHOULD MONITOR THE SITUATION OVER THE NEXT FEW DAYS AND STAY TUNED FOR UPDATES ON THIS POSSIBLY DANGEROUS SCENARIO. ATLANTIC OCEAN... SURFACE RIDGING DOMINATES THE MAJORITY OF THE ATLC THIS MORNING ANCHORED BY A 1028 MB HIGH NEAR 33N47W PROVIDING FAIR CONDITIONS BASIN-WIDE. ALOFT...AN UPPER LEVEL RIDGE COVERS THE WRN ATLC CENTERED OVER NRN ALABAMA. AN UPPER LEVEL TROUGH IS TO THE E ALONG 52W. A SHORTWAVE UPPER TROUGH EXTENDS OFF THE MAIN TROUGH EXTENDING TO THE NW BAHAMAS ALONG 25N. THIS IS PRODUCING SOME UPPER LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS FROM 24N-32N BETWEEN 51W-74W. UPPER LEVEL RIDGING COVERS MUCH OF THE ERN ATLC CENTERED NEAR 36N33W. AN UPPER LEVEL TROUGH COVERS THE FAR ERN ATLC EXTENDING ACROSS SPAIN TO E OF THE CANARY ISLANDS. ACROSS THE TROPICAL ATLC S OF 26N...AN UPPER LEVEL RIDGE IS CENTERED OVER THE SRN WINDWARD ISLANDS NEAR 13N62W. AN UPPER LEVEL LOW IS CENTERED NEAR 23N35W...AND AN UPPER LEVEL RIDGE IS CENTERED OFF THE W COAST OF AFRICA NEAR 19N18W.\ FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON 000 AXNT20 KNHC 121133 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE JUL 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1100 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS INTRODUCED IN THE ERN TRPCL ATLC ALONG 13N25W TO 7N26W MOVING W 10-15 KT. WAVE IS LOW AMPLITUDE AND DIFFICULT TO DISCERN AT THE SURFACE. HOWEVER...SATELLITE HOVMOLLER DIAGRAMS INDICATE A TRACKABLE FEATURE BACK TO THE COAST OF AFRICA. UPPER AIR DATA FROM DAKAR SENEGAL ALSO INDICATES A CLEAR WAVE SIGNAL CROSSING THE STATION AROUND 10/1200 UTC. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE. TROPICAL WAVE IN THE WRN TRPCL ATLC EXTENDS FROM NEAR 17N54W TO 8N59W MOVING WNW 10-15 KT. WAVE CONTINUES TO PRECEDE A SURGE OF DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SATELLITE IMAGERY ALSO INDICATES LOW LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-14N BETWEEN 55W-60W. TROPICAL WAVE IN THE WRN CARIBBEAN EXTENDS ACROSS ERN NICARAGUA/HONDURAS ALONG 84W FROM 13N-17N MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF ENHANCED MOISTURE ACROSS THE WRN CARIBBEAN. THE WAVE LIES UNDER DIFFLUENT FLOW ALOFT WHICH IS HELPING ENHANCE CONVECTION. IT IS DIFFICULT TO DETERMINE WHAT CONVECTION IS CAUSED BY THE WAVE...THE UPPER LEVEL INFLUENCE...AND ALSO THE MONSOON TROUGH TO THE S OF THE WAVE. NUMEROUS STRONG CONVECTION IS FROM 11N-13N BETWEEN 82W-84W. SCATTERED MODERATE/STRONG CONVECTION IS E OF THE WAVE AXIS FROM 12N-17N BETWEEN 81W-83W. SIMILAR ACTIVITY IS ALSO MOVING INTO THE YUCATAN PENINSULA AND BELIZE FROM 15N-20N BETWEEN 87W-90W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN AT 23N ALONG 22N12W 11N23W. THE ITCZ AXIS CONTINUES ON THE OTHER SIDE OF A TROPICAL WAVE ALONG 8N31W 5N44W 6N55W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM N...AND 75 NM S OF THE AXIS BETWEEN 30W-37W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING COVERS THE GULF OF MEXICO THIS MORNING CENTERED AROUND A 1018 MB HIGH OFF THE W CENTRAL COAST OF FLORIDA NEAR 28N83W SUPPORTING FAIR WEATHER AND LIGHT ANTI-CYCLONIC FLOW AROUND THE RIDGE. ALOFT...AN UPPER LEVEL RIDGE COVERS THE NRN GULF CENTERED OVER NRN ALABAMA. AN UPPER LEVEL TROUGH COVERS THE SW GULF EXTENDING FROM SRN MEXICO NEAR 18N95W TO 25N93W. A SHORTWAVE UPPER TROUGH IS ALONG IN THE N CENTRAL GULF FROM SE LOUISIANA TO 25N89W SUPPORTING A FEW ISOLATED SHOWERS/THUNDERSTORMS ALONG THE NRN GULF COAST BETWEEN 83W-89W. WATER VAPOR IMAGERY INDICATES DRY AIR IS WRAPPING AROUND THE SRN EXTENT OF THE UPPER RIDGE WHICH IS FURTHER SUPPORTING THE FAIR WEATHER. TOTAL PRECIPITABLE WATER IMAGERY STILL INDICATES ENHANCED MOISTURE IS ACROSS THE NRN GULF. WITH DAYTIME HEATING THIS WILL LIKELY MEAN SHOWERS/THUNDERSTORMS WILL POP UP LATER IN THE AFTERNOON TODAY. SHOWER/THUNDERSTORM ACTIVITY WILL ALSO LIKELY INCREASE OVER THE SE GULF AS MOISTURE FROM A TROPICAL WAVE IN THE WRN CARIBBEAN FLOWS INTO THE BASIN AS THE WAVE MOVES WWD. WEAK SURFACE RIDGING WILL CONTINUE OVER THE NRN GULF. CARIBBEAN SEA... MOIST DIFFLUENT FLOW ALOFT COVERS THE NW CARIBBEAN AROUND THE ERN SIDE OF AN INVERTED UPPER TROUGH OVER THE SRN GULF OF MEXICO...AND A NARROW UPPER RIDGE EXTENDING FROM NRN COLOMBIA TO NEAR 19N83W. THIS AREA OF DIFFLUENCE LIES OVER A TROPICAL WAVE ALONG 84W. THIS COMBINATION IS PRODUCING SHOWERS/ THUNDERSTORMS ACROSS THE WRN CARIBBEAN S OF 20N BETWEEN 80W-90W WITH THE STRONGEST ACTIVITY E OF THE WAVE AXIS...AND ACROSS SRN NICARAGUA. STRONG SHOWERS/THUNDERSTORMS ARE ALSO FROM 9N-12N BETWEEN 74W-86W INFLUENCED BY THE MONSOON TROUGH EXTENDING FROM THE ERN PACIFIC ACROSS NRN COSTA RICA TO NRN COLOMBIA. THE REMAINDER OF THE BASIN IS UNDER MOSTLY FAIR CONDITIONS WITH 15-20 KT ELY TRADEWIND FLOW. A FEW ISOLATED SHOWERS ARE NOTED IN THE NE CARIBBEAN N OF 15N E OF 71W. THIS AREA IS ALSO IN AN AREA OF MODERATE MOISTURE INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. A FEW ISOLATED SHOWERS ARE ALSO MOVING ACROSS THE SRN WINDWARD ISLANDS DUE TO MOISTURE ASSOCIATED WITH A TROPICAL WAVE E OF THE ISLANDS. SHOWER ACTIVITY IN THIS AREA WILL INCREASE AS THE WAVE MOVES WWD TOWARDS THE BASIN. ALOFT...A HORIZONTALLY ALIGNED UPPER LEVEL TROUGH IS ACROSS THE NRN CARIBBEAN WITH AXIS ALONG 18N. AN UPPER RIDGE IS TO THE S OF THE UPPER TROUGH CENTERED OVER THE WINDWARD ISLANDS NEAR 13N62W. EXPECT SHOWER/THUNDERSTORM ACTIVITY TO PERSIST ACROSS THE WRN CARIBBEAN AS MOISTURE ASSOCIATED WITH THE TROPICAL WAVE REMAINS. ALSO...MUCH OF CENTRAL AMERICA AND SRN MEXICO IS AT THREAT FOR PROLONGED HEAVY RAINFALL THROUGHOUT THE END OF THE WEEK WHICH WILL INCREASE THE CHANCE FOR DEADLY FLOODING AND MUDSLIDES. MODEL GUIDANCE INDICATES THE MONSOON TROUGH WILL STRENGTHEN AND LIFT FARTHER N PLACING ABNORMALLY STRONG WLY FLOW AGAINST CENTRAL AMERICA AND SRN MEXICO. THIS W-SW FLOW WILL DRAW SIGNIFICANT TROPICAL MOISTURE ACROSS THESE AREAS. COMBINED WITH OROGRAPHIC LIFT DUE TO MOUNTAINS THIS CREATES A FORMULA TO EQUAL HEAVY PRECIPITATION. THESE AREAS SHOULD MONITOR THE SITUATION OVER THE NEXT FEW DAYS AND STAY TUNED FOR UPDATES ON THIS POSSIBLY DANGEROUS SCENARIO. ATLANTIC OCEAN... SURFACE RIDGING DOMINATES THE MAJORITY OF THE ATLC THIS MORNING ANCHORED BY A 1028 MB HIGH NEAR 33N47W PROVIDING FAIR CONDITIONS BASIN-WIDE. ALOFT...AN UPPER LEVEL RIDGE COVERS THE WRN ATLC CENTERED OVER NRN ALABAMA. AN UPPER LEVEL TROUGH IS TO THE E ALONG 52W. A SHORTWAVE UPPER TROUGH EXTENDS OFF THE MAIN TROUGH EXTENDING TO THE NW BAHAMAS ALONG 25N. THIS IS PRODUCING SOME UPPER LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS FROM 24N-32N BETWEEN 51W-74W. UPPER LEVEL RIDGING COVERS MUCH OF THE ERN ATLC CENTERED NEAR 36N33W. AN UPPER LEVEL TROUGH COVERS THE FAR ERN ATLC EXTENDING ACROSS SPAIN TO E OF THE CANARY ISLANDS. ACROSS THE TROPICAL ATLC S OF 26N...AN UPPER LEVEL RIDGE IS CENTERED OVER THE SRN WINDWARD ISLANDS NEAR 13N62W. AN UPPER LEVEL LOW IS CENTERED NEAR 23N35W...AND AN UPPER LEVEL RIDGE IS CENTERED OFF THE W COAST OF AFRICA NEAR 19N18W.\ FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON