[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 071802 CCA
TWDAT

TROPICAL WEATHER DISCUSSION...CORRECTED
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN AUG 07 2011

CORRECTED FOR TRACK OF EMILY

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 1745 UTC.

...SPECIAL FEATURE...

THE CENTER OF TROPICAL DEPRESSION EMILY WAS NEAR 30.1N 76.0W AT
07/1500 UTC. EMILY IS MOVING NE 15 KT. THE ESTIMATED MINIMUM
CENTRAL PRESSURE IS 1011 MB. THE MAXIMUM SUSTAINED WIND SPEEDS
ARE 30 KT WITH GUSTS TO 40 KT. EMILY WILL CONTINUE TO MOVE OVER
COOLER WATERS UNTIL IT IS ABSORBED INTO A FRONTAL SYSTEM IN 36
TO 48 HOURS. SCATTERED SHOWERS AND THUNDERSTORMS REMAIN OVER THE
FAR W ATLC AFFECTING THE COASTAL WATERS OF NORTHERN BAHAMAS AND
SOUTHERN FLORIDA N OF 25N BETWEEN 76W AND THE COAST OF FLORIDA.
THIS AREA OF CONVECTION WILL FOLLOW EMILYS TRACK DURING THE NEXT
24 HOURS...WITH A FEW ISOLATED SHOWERS LINGERING OVER THE AREA
AFTER THE FORECAST PERIOD. FOR MORE DETAILS....THE LATEST NHC
INTERMEDIATE PUBLIC ADVISORY IS TRANSMITTED UNDER AWIPS/WMO
HEADERS MIATCPAT5/WTNT35 AND THE FULL FORECAST ADVISORY IS UNDER
AWIPS/WMO HEADERS MIATCMAT5/WTNT25.

...TROPICAL WAVES...

A TROPICAL WAVE IS MOVING ACROSS THE FAR EAST ATLC ANALYZED FROM
17N19W TO 11N21W...MOVING W 10-15 KT. VISIBLE SATELLITE IMAGERY
REVEALED A SHARP LOW LEVEL CYCLONIC CIRCULATION IN THE SOUTHERN
EXTENSION OF THE WAVE AXIS. THE WAVE IS EMBEDDED IN A SURGE OF
DEEP MOISTURE ON THE TOTAL PRECIPITABLE WATER PRODUCT. ISOLATED
MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ARE WITHIN 70 NM ON
EITHER SIDE OF THE WAVE AXIS.

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC IS ANALYZED FROM
17N46W TO 10N49W...MOVING W 15-20 KT. WAVE REMAINS EMBEDDED IN A
REGION OF ELEVATED VALUES OF MOISTURE ON THE TOTAL PRECIPITABLE
WATER PRODUCT WITH A LOW LEVEL CYCLONIC CURVATURE OBSERVED IN
THE LOW LEVEL CLOUD FIELD. SCATTERED WEAK SHOWERS AND ISOLATED
THUNDERSTORMS ARE WITHIN 70 NM ON EITHER SIDE OF THE AXIS S OF
15N.

A TROPICAL WAVE IS MOVING ACROSS THE NE CARIBBEAN WITH AXIS
ANALYZED FROM 18N29W TO 13N31W...MOVING WNW AT 10-15 KT. A
SLIGHT CURVATURE OBSERVED IN THE LOW/MID LEVEL CLOUDS. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS COVER A GREAT AREA FROM
15N-19N BETWEEN 57W-70W. THIS AREA OF CONVECTION IS ENHANCED BY
AN UPPER LEVEL SHORTWAVE...NOTICED ON WATER VAPOR IMAGERY...
QUICKLY MOVING ACROSS THE N CENTRAL BASIN.

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

THE MONSOON TROUGH EXTENDS SW FROM THE AFRICAN COAST OF
MAURITANIA NEAR 18N16W TO 10N21W...THEN WNW TO 12N38W. THE ITCZ
IS ANALYZED WEST OF THE CENTRAL ATLC TROPICAL WAVE NEAR 14N47W
TO JUST E OF THE LESSER ANTILLES NEAR 15N60W. ISOLATED MODERATE
TO HEAVY SHOWERS AND THUNDERSTORMS ARE WITHIN 80-180 NM S OF THE
MONSOON TROUGH E OF 35W. ISOLATED WEAK SHOWERS ARE IN THE
VICINITY OF THE ITCZ.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL DRY AIRMASS MOVING
ACROSS THE GULF THIS AFTERNOON. THIS AIRMASS IS EMBEDDED IN
UPPER LEVEL CYCLONIC FLOW CENTERED IN SOUTHERN MEXICO. DESPITE
THIS UPPER LEVEL CYCLONIC FLOW...MID LEVEL ANTICYCLONIC FLOW
DOMINATES THE REGION CENTERED OVER NORTHERN FLORIDA. THIS
FEATURE HAS A STRONG INFLUENCE AT LOW/SURFACE LEVELS...WHERE A
VERY BROAD PRESSURE GRADIENT AND LIGHT ANTICYCLONIC FLOW ARE
OBSERVED ACROSS THE AREA. SCATTERED LOW TOP SHOWERS ARE OVER THE
NORTHERN GULF WATERS N OF 27N E OF 93W. SIMILAR BUT ISOLATED
CONVECTION IS FOUND ELSEWHERE DOTTING THE BASIN. SURFACE RIDGING
WILL BE THE DOMINANT FACTOR OVER THE NEXT 24 HOURS.

CARIBBEAN SEA...
DOPPLER RADAR IMAGERY INDICATES SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS OVER THE NE CARIBBEAN N OF 15N E OF 70W AFFECTING
THE SOUTHERN COASTAL WATERS OF PUERTO RICO WITHIN 30-50 NM. THIS
AREA OF CONVECTION IS ASSOCIATED TO A TROPICAL WAVE MOVING
ACROSS THIS AREA. THE ACTIVITY IS ENHANCED BY AN UPPER LEVEL
SHORTWAVE...NOTICED ON WATER VAPOR IMAGERY...QUICKLY MOVING
ACROSS THE N CENTRAL BASIN. SIMILAR CONVECTION IS OVER THE FAR
SW BASIN...WITHIN 50/80 NM OFF THE COASTS OF COLOMBIA...PANAMA
...AND COSTA RICA W OF 75W DUE TO CLOSE PROXIMITY TO THE MONSOON
TROUGH EXTENDING FROM SOUTHERN COSTA RICA TO NORTHERN COLOMBIA.
ISOLATED SHOWERS ARE ELSEWHERE ACROSS THE DISCUSSION AREA...
EMBEDDED IN THE MODERATE TO FRESH EASTERLY TRADE WINDS.

ATLANTIC OCEAN...
AS T.D. EMILY CONTINUES TO TRACK NE OUT OF OUR DISCUSSION
AREA...SCATTERED SHOWERS AND THUNDERSTORMS REMAIN OVER THE FAR W
ATLC AFFECTING THE COASTAL WATERS OF NORTHERN BAHAMAS AND
SOUTHERN FLORIDA N OF 25N BETWEEN 76W AND THE COAST OF FLORIDA.
THE ACTIVITY WILL FOLLOW EMILYS TRACK DURING THE NEXT 24 HOURS
WITH A FEW ISOLATED SHOWERS LINGERING OVER THE AREA AFTER THE
FORECAST PERIOD. AN UPPER LEVEL RIDGE COVERS THE REMAINDER OF
THE WEST ATLC ANCHORED BY A 1020 MB HIGH NEAR 25N62W. HOWEVER...
A BROAD UPPER LEVEL LONG WAVE TROUGH/CUT-OFF LOW MOVES ACROSS
THE N CENTRAL ATLC SUPPORTING A FRONTAL SYSTEM THAT BARELY
ENTERS OUR DISCUSSION AREA ALONG 32N45W 31N54W 32N62W. SCATTERED
HEAVY SHOWERS AND THUNDERSTORMS ARE WITHIN 150-200 NM S OF THE
FRONTAL BOUNDARY. THIS SYSTEM WILL CONTINUE TO ENTER OUR REGION
WITH STRONG CONVECTION OVER THE NEXT 24 HOURS. A LARGE SURFACE
RIDGE CONTINUES TO DOMINATE THE REMAINDER OF THE ATLC
BASIN...ANCHORED BY A 1023 MB HIGH NEAR 32N30W. THE CIMSS
SAHARAN AIR LAYER TRACKING PRODUCT AND LAST VISIBLE METEOSAT-9
SATELLITE IMAGERY OF THE DAY SHOWED A LARGE AREA OF AFRICAN DUST
FROM 10N-30N  E OF 45W.

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

$$

GARCIA





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