TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL  
205 PM EDT FRI AUG 19 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION EIGHT HAS NOW BEEN UPGRADED TO TROPICAL 
STORM HARVERY AS OF 19/1800. HARVEY IS CENTERED NEAR 16.3N 84.2W 
OR ABOUT 135 NM E OF ISLA ROATAN HONDURAS. HARVEY IS MOVING W 
NEAR 9 KT. MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM 
SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. FOR MORE 
DETAILS REFER TO PUBLIC ADVISORIES ISSUED UNDER WMO HEADER 
WTNT33 KNHC AND UNDER AWIPS HEADER MIATCPAT3. 
FORECAST/ADVISORIES ARE ISSUED UNDER WMO HEADER WTNT22 KNHC AND 
UNDER AWIPS HEADER MIATCMAT3. NUMEROUS MODERATE/SCATTERED STRONG 
CONVECTION IS MAINLY N OF THE CENTER FROM 15N-18N BETWEEN 
81W-88W IMPACTING EXTREME NRN HONDURAS. THE HEAVY RAINFALL 
ACROSS NRN HONDURAS...GUATEMALA...AND BELIZE OVER THE NEXT 
COUPLE OF DAYS COULD CAUSE POTENTIAL FLOODING AND MUDSLIDES.

A WELL-DEFINED TROPICAL WAVE IS JUST OFF THE WRN COAST OF AFRICA 
ALONG 17N19W MOVING W AT 10-15 KT. LOW-LEVEL CYCLONIC FLOW IS 
AROUND THE WAVE AXIS CONCENTRATED NEAR 13N AROUND A 1006 MB 
SURFACE LOW. TOTAL PRECIPITABLE WATER IMAGERY INDICATES HIGH 
MOISTURE VALUES SURROUND THE WAVE. SCATTERED MODERATE/STRONG 
CONVECTION IS FROM 14N-16N BETWEEN 17W-23W....AND FROM 9N-12N 
BETWEEN 24W-30W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION 
IS FROM 8N-12N BETWEEN 17W-24W. WHILE THE CONVECTION IS 
DISORGANIZED AT THIS TIME...THE UPPER-LEVEL ENVIRONMENT IS 
FAVORABLE FOR FURTHER DEVELOPMENT.

ANOTHER WELL-DEFINED WAVE IS IN THE CENTRAL TRPCL ATLC ALONG 
17N48W TO 9N47W WITH CYCLONIC FLOW CONCENTRATED ALONG THE AXIS 
AROUND A 1006 MB LOW NEAR 13N. THIS SYSTEM IS MOVING W NEAR 20 
KT. CONVECTION NEAR THE WAVE HAS INCREASED OVER THE PAST 24 
HOURS. CURRENTLY NUMEROUS MODERATE/SCATTERED STRONG CONVECTION 
IS MAINLY W OF THE WAVE FROM 13N-17N BETWEEN 47W-53W...AND SE OF 
THE AXIS  FROM 6N-9N BETWEEN 42W-47W. UPPER LEVEL CONDITIONS ARE 
EXPECTED TO BECOME MORE CONDUCIVE FOR FURTHER DEVELOPMENT OVER 
THE NEXT COUPLE OF DAYS.

...TROPICAL WAVES...

SEE SPECIAL FEATURES SECTION FOR DETAILS ON THE TROPICAL WAVES. 

...THE ITCZ/THE MONSOON TROUGH...

THE ACTIVE TRPCL WAVE OVER THE FAR ERN TRPCL ATLC HAS SPLIT 
THE MONSOON TROUGH. ONE SECTION REMAINS INLAND OVER 
AFRICA...WHILE THE OTHER CONTINUES ON THE W SIDE OF THE TRPCL 
WAVE ALONG 13N22W 11N35W TO THE TRPCL WAVE IN THE CENTRAL TRPCL 
ATLC NEAR 13N48W. CONVECTION NEAR THE MONSOON TROUGH HAS BEEN 
ASSOCIATED WITH THE TROPICAL WAVES AND IS DISCUSSED IN THE 
SPECIAL FEATURES SECTION.

...DISCUSSION...

THE GULF OF MEXICO...
UPPER LEVEL RIDGING COVERS MUCH OF THE GULF OF MEXICO CENTERED 
OVER WRN TEXAS. WATER VAPOR IMAGERY ALSO INDICATES MOSTLY DRY 
AIR ALOFT COVERING THE AREA. THIS IS MAINTAINING MOSTLY FAIR 
WEATHER AND LIGHT SURFACE FLOW. WEAK HIGH PRESSURE IS CENTERED 
OVER ERN MEXICO NEAR 21N98W. A FEW ISOLATED 
SHOWERS/THUNDERSTORMS ARE NOTED OVER THE SE GULF S OF 27N E OF 
83W ASSOCIATED WITH AN AREA OF DEEP LAYER MOISTURE EVIDENT IN 
TOTAL PRECIPITABLE WATER IMAGERY. EXPECT WEAK RIDGING TO FORM 
OVER THE NE GULF WITH RELATIVELY LIGHT ANTI-CYCLONIC FLOW AROUND 
IT. 

THE CARIBBEAN SEA...
T.S. HARVERY IS CURRENTLY IMPACTING NRN HONDURAS AND HEADING WWD 
TOWARDS THE BAY ISLANDS OF HONDURAS AND BELIZE. SEE SPECIAL 
FEATURES SECTION FOR MORE DETAILS. SCATTERED 
SHOWERS/THUNDERSTORMS ARE ACROSS THE SW CARIBBEAN FROM 10N-12N 
BETWEEN 81W-83W...AND S OF 12N TO PANAMA BETWEEN 75W-80W 
ASSOCIATED WITH THE MONSOON TROUGH THAT EXTENDS FROM THE E 
PACIFIC ACROSS COSTA RICA AND PANAMA TO NRN COLOMBIA. ALOFT...AN 
UPPER LEVEL RIDGE IS CENTERED OVER THE FAR NW CARIBBEAN NEAR 
20N85W. UPPER LEVEL TROUGHING COVERS THE ERN ATLC EXTENDING FROM 
THE ATLC ACCOMPANIED BY MODERATE DRY AIR ALOFT. THIS IS 
MAINTAINING MOSTLY FAIR CONDITIONS ACROSS THE ERN CARIBBEAN WITH 
AREAS OF ISOLATED SHOWERS EMBEDDED WITHIN THE TRADEWIND FLOW. 
EXPECT T.S. HARVEY TO CONTINUE TO IMPACT PORTIONS OF THE NW 
CARIBBEAN. AN ACTIVE TROPICAL WAVE STILL E OF THE LESSER 
ANTILLES MAY BEGIN IMPACTING THE ERN ISLANDS WITHIN THE NEXT 
24-36 HOURS. SEE SPECIAL FEATURES FOR MORE DETAILS ON THIS WAVE. 

THE ATLANTIC OCEAN...
A LARGE AREA OF SCATTERED SHOWERS/THUNDERSTORMS IS OVER THE WRN 
ATLC W OF 73W ACROSS THE NW BAHAMAS AND REACHING S FLORIDA 
ASSOCIATED WITH A SHORTWAVE UPPER TROUGH EXTENDING FROM 35N74W 
TO 28N80W. A WEAK UPPER RIDGE IS TO THE E ACROSS THE CENTRAL 
BAHAMAS TO 31N65W. ANOTHER UPPER LEVEL TROUGH IS FROM 31N57W TO 
THE ERN CARIBBEAN. THIS UPPER TROUGH IS SUPPORTING A WEAK 
SURFACE TROUGH ALONG 32N54W TO 28N57W WITH ISOLATED SHOWERS 
WITHIN 90 NM EITHER SIDE THE AXIS. THE REMAINDER OF THE BASIN IS 
DOMINATED BY SURFACE RIDGING AROUND A 1026 MB HIGH NEAR 39N29W 
PROVIDING MOSTLY FAIR WEATHER. ALOFT...A PAIR OF UPPER RIDGES 
ARE CENTERED NEAR 25N48W...AND 34N33W SUPPORTING THE SURFACE 
RIDGE. AN UPPER LEVEL TROUGH IS TO THE E ALONG 15W N OF 25N. 
VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW AN AREA OF DUST E OF 
50W TO THE N OF THE TROPICAL WAVES.