[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 111154
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU AUG 11 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
1015 UTC.

...SPECIAL FEATURES...

A 1010 MB LOW CENTERED NEAR 13N33W IS WELL EMBEDDED WITHIN THE
MONSOON TROUGH ACROSS THE TROPICAL ATLC MOVING W AT 10 KT.
ENERGY ASSOCIATED WITH THE LOW-LEVEL CYCLONIC MONSOON GYRE
CONTINUES TO CONSOLIDATE AND COVERS A SMALL AREA FROM 08N-18N
BETWEEN 28W-41W...OF WHICH ENCOMPASSES A TROPICAL WAVE ANALYZED
ALONG 12N36W TO 22N39W AND IS FORECAST TO CONTINUE WESTWARD OVER
THE NEXT 24-48 HOURS. THE LOW CONTINUES TO POSITION ITSELF ON
THE SOUTHWESTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONE
CENTERED NEAR 20N31W. LOW-LEVEL CONVERGENCE ALONG WITH A
FAVORABLE MIDDLE TO UPPER LEVEL DIFFLUENT ENVIRONMENT IS
SUSTAINING SCATTERED MODERATE CONVECTION S OF THE LOW CENTERED
FROM 07N-14N BETWEEN 30W-37W. NO SIGNIFICANT DEEP CONVECTION IS
NORTH OF THE LOW CENTER OR ASSOCIATED WITH THE TROPICAL WAVE.
ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR SOME SLOW
DEVELOPMENT INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS
AS IT MOVES WESTWARD 10 TO 15 MPH.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 10N20W TO 17N20W MOVING W AT
10-15 KT. A 1010 MB LOW IS CENTERED NEAR THE SOUTHERN EXTENT
OF THE WAVE AXIS NEAR 10N20W. EXAMINING UPPER AIR TIME-SECTION
ANALYSES FROM DAKAR SENEGAL SHOWS THIS WAVE PASSED AFTER
11/0000 UTC. FURTHERMORE...GLOBAL MODEL ANALYSIS AND FORECAST
STREAMLINES AT 850 MB AND 700 MB INDICATE THE WAVE IS LARGELY
LOCATED ALOFT AND THAT IT IS ANTICIPATED TO CONTINUE PROPAGATING
WESTWARD OVER THE NEXT FEW DAYS. SCATTERED MODERATE AND ISOLATED
STRONG CONVECTION IS FROM 09N-14N BETWEEN 19W-25W. SLOW
DEVELOPMENT INTO A TROPICAL CYCLONE IS POSSIBLE DURING THE
NEXT 48 HOURS.

TROPICAL WAVE IS ANALYZED FROM 12N71W TO 20N66W MOVING W AT 15
KT. THE WAVE REMAINS WITHIN AN AREA OF HIGHER TOTAL PRECIPITABLE
WATER VALUES ADVECTING ACROSS THE EASTERN CARIBBEAN SEA FROM
14N-21N BETWEEN 62W-70W. WHILE AN UNFAVORABLE UPPER LEVEL
ENVIRONMENT IS IN THE VICINITY OF THE WAVE...THUS INHIBITING ANY
SIGNIFICANT DEEP CONVECTION...LOW-LEVEL MOISTURE CONVERGENCE IS
GENERATING A FEW LOW-TOPPED ISOLATED SHOWERS FROM 15N-19N
BETWEEN 66W-71W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 19N16W
ALONG 12N17W TO 10N19W TO 14N28W TO 05N45W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 05N45W TO 03N51W. ASIDE FROM
CONVECTION ASSOCIATED WITH THE TWO TROPICAL WAVES NOTED
ABOVE...NO SIGNIFICANT DEEP CONVECTION IS NOTED ON SATELLITE
IMAGERY.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE CENTRAL GULF
NEAR 26N91W AND CONTINUES TO SUPPORT A SURFACE RIDGE AXIS
EXTENDING FROM THE SW NORTH ATLC THROUGH THE FLORIDA STRAITS TO
A 1014 MB HIGH CENTERED NEAR 25N83W THEN NW OF THE TEXAS COAST
NEAR 30N94W. SHORTWAVE INFRARED SATELLITE IMAGERY INDICATES MUCH
OF THE GULF IS UNDER CLEAR SKIES AND FAIR CONDITIONS THIS
MORNING...AS MUCH OF THE CONVECTION INITIATED LAST
AFTERNOON/EVENING HAS DISSIPATED OVER THE EASTERN GULF WATERS
AND THE FLORIDA PENINSULA. A SURFACE TROUGH REMAINS ANALYZED
OVER CENTRAL FLORIDA FROM DAYTONA BEACH TO THE TAMPA BAY REGION
WITH ONLY A FEW ISOLATED SHOWERS NOTED ON MOSAIC DOPPLER RADAR
IMAGERY OVER THE FLORIDA STRAITS SOUTH OF THE FLORIDA KEYS. THE
SURFACE RIDGE IS FORECAST TO REMAIN ACROSS THE GULF ALONG 24N
THROUGH FRIDAY AND GRADUALLY SHIFT NORTHWARD TO 26N/27N BY
SATURDAY INTO SUNDAY.

CARIBBEAN SEA...
WATER VAPOR IMAGERY SHOWS A WEAK UPPER LEVEL TROUGH AXIS
EXTENDING FROM THE SW NORTH ATLC ACROSS EASTERN CUBA NEAR 21N77W
TO THE YUCATAN PENINSULA NEAR 19N89W. AT THE SURFACE...MOSTLY
FRESH TO MODERATE EASTERLY TRADES CONTINUE WITH ONLY A FEW
ISOLATED SHOWERS DUE TO LOW-LEVEL MOISTURE CONVERGENCE OCCURRING
OVER WESTERN PORTIONS OF THE CARIBBEAN FROM 13N-17N BETWEEN
73W-85W. THE MONSOON TROUGH EXTENDS NORTH OF PANAMA ALONG 10N
WITH ISOLATED SHOWERS AND TSTMS OCCURRING S OF 12N. FARTHER
EAST...A TROPICAL WAVE CONTINUES TO MOVE WESTWARD INTO THE
CENTRAL CARIBBEAN WITH ISOLATED SHOWERS OCCURRING FROM 15N-19N
BETWEEN 66W-71W. THE EASTERLY TRADES ACROSS CENTRAL PORTIONS OF
THE CARIBBEAN ARE EXPECTED TO REMAIN STRONG THROUGH FRIDAY DUE
TO A HIGH PRESSURE RIDGE ALONG 24N IN THE W ATLC.

ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL TROUGHING IS NOTED ON WATER VAPOR IMAGERY
ACROSS THE SE CONUS THAT EXTENDS EASTWARD INTO ATLC OFFSHORE
ZONES N OF 30N W OF 70W. WHILE A COLD FRONT IS SUPPORTED BY THIS
UPPER LEVEL TROUGHING NORTH OF THE DISCUSSION AREA...A PAIR OF
SURFACE TROUGHS ARE OVER THE W ATLC WATERS AND FLORIDA PENINSULA
THIS MORNING. ONE SURFACE TROUGH IS ANALYZED FROM 29N78W TO
24N79W AND THE OTHER IS ANALYZED FROM 31N81W ACROSS THE NORTHERN
FLORIDA PENINSULA TO THE TAMPA BAY REGION. LOW-LEVEL MOISTURE
CONVERGENCE IS GENERATING ISOLATED SHOWERS AND TSTMS OVER THE W
ATLC WATERS W OF A LINE FROM 32N70W TO 22N78W. FARTHER EAST...AN
UPPER LEVEL LOW IS CENTERED NEAR 38N46W WITH THE ASSOCIATED
UPPER LEVEL TROUGH AXIS EXTENDING SOUTHWARD TO 29N51W. THIS
UPPER LEVEL FEATURE SUPPORTS A SURFACE TROUGH ANALYZED FROM
32N47W TO 24N56W. ISOLATED SHOWERS AND TSTMS COVER THE AREA FROM
21N-28N BETWEEN 45W-56W. THE REMAINDER OF THE EASTERN ATLC IS
UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1028 MB
HIGH CENTERED OVER THE AZORES NEAR 38N26W. THE RIDGE AXIS
EXTENDS FROM THE HIGH ALONG 32N33W TO 20N50W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
HUFFMAN



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