[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091040
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN AUG 09 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 20W/21W S OF 18N MOVING W 15-20 KT.
LATEST VISIBLE SATELLITE IMAGERY INDICATES THE WELL DEFINED
LOW/MID LEVEL CYCLONIC CIRCULATION CENTER MOVING JUST E OF THE
WAVE AXIS. THE WAVE AXIS IS EMBEDDED WITHIN THE MOISTURE MAXIMUM
OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE ASSOCIATED
WITH THE LOW/MID LEVEL CIRCULATION COVERING THE AREA FROM
9N-16N BETWEEN 19W-24W.

TROPICAL WAVE IS ALONG 36W S OF 19N MOVING W NEAR 15 KT. WAVE
REMAINS EMBEDDED WITH A MOISTURE MAXIMUM OBSERVED IN TOTAL
PRECIPITABLE WATER IMAGERY AND A BROAD AREA OF CYCLONIC
CIRCULATION. THERE IS NO DEEP CONVECTION ASSOCIATED WITH THE
WAVE.

TROPICAL WAVE IS ALONG 46W/47W S OF 16N MOVING W NEAR 15 KT.
WAVE IS ALONG THE TRAILING EDGE OF A MOISTURE MAXIMUM OBSERVED
IN TOTAL PRECIPITABLE WATER IMAGERY WITH NO ASSOCIATED DEEP
CONVECTION.

TROPICAL WAVE IS ALONG 63W S OF 18N MOVING WNW NEAR 15 KT. WAVE
REMAINS IN AN AREA BENEATH AN UPPER RIDGE PARTIALLY MASKING THE
WAVE SIGNATURE AND ANY SHOWERS/CONVECTION IS MORE ASSOCIATED
WITH THE UPPER LEVEL FEATURE THAN THE WAVE ITSELF.

TROPICAL WAVE IS ALONG 84W/85W S OF 20N MOVING W NEAR 20 KT.
WAVE REMAINS ALONG THE TRAILING EDGE OF A MOISTURE MAXIMUM
OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY AND IS EMBEDDED IN
RATHER DRY STABLE AIR WITH NO ASSOCIATED DEEP CONVECTION.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 15N15W 9N38W 12N55W 11N62W. A
SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ EXTENDING FROM 17N52W
TO 10N55W WITH CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION W OF THE TROUGH AXIS WITHIN 60/75 NM OF LINE FROM
16N523 ACROSS THE WINDWARD ISLANDS NEAR 12N62W. CLUSTERS OF
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE WITHIN 90
NM OF THE ITCZ BETWEEN 32W-50W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE ANCHORED OVER SOUTH CAROLINA CONTINUES TO DIG S
OVER THE FAR W ATLC ACROSS THE FLORIDA PENINSULA INTO THE E GULF
PUSHING ANY ISOLATED SHOWERS/THUNDERSTORMS OVER THE E GULF OF
MEXICO WITHIN 75 NM OF LINE FROM THE MISSISSIPPI GULF COAST TO
THE STRAITS OF FLORIDA NEAR 24N82W INCLUDING THE LOWER FLORIDA
KEYS. ISOLATED SHOWERS WITH POSSIBLE STRAY THUNDERSTORMS ARE
STREAMING NORTHWARD ACROSS THE REMAINDER OF THE N GULF N OF 26N
W OF 84W. AN UPPER LEVEL TROUGH ANCHORED OVER CENTRAL MEXICO
COVERS THE W GULF. A WEAKENING SURFACE TROUGH IS OVER THE E BAY
OF CAMPECHE FROM 22N91W TO 18N93W AND COUPLED WITH THE UPPER
RIDGE ARE GENERATING SCATTERED SHOWERS/THUNDERSTORMS SW OF A
LINE FROM THE BAY OF CAMPECHE COAST NEAR 18N94W TO NE MEXICO
NEAR 25N98W. THE REMAINDER OF THE GULF IS TRANQUIL AGAIN THIS
MORNING.

CARIBBEAN SEA...
AN UPPER RIDGE OVER THE W ATLC/E GULF OF MEXICO COVERS THE NW
CARIBBEAN WITH AN UPPER TROUGH OVER THE CENTRAL CARIBBEAN AND A
SECOND UPPER RIDGE OVER THE E CARIBBEAN. THE UPPER LEVEL
DIFFLUENCE OVER THE W CARIBBEAN CONTINUES TO GENERATE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS S OF 21N W OF 85W TO THE COAST OF
CENTRAL AMERICA AND INLAND OVER THE YUCATAN PENINSULA. THE ITCZ
EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA TO W PANAMA
GENERATING SCATTERED SHOWERS/THUNDERSTORMS FROM 12N TO INLAND
OVER PANAMA AND COSTA RICA BETWEEN 77W-84W. FRESH TO STRONG
TRADE WINDS CONTINUE ACROSS MOST OF THE CARIBBEAN USHERING IN
FAST MOVING ISOLATED SHOWERS MAINLY ACROSS THE E CARIBBEAN E OF
70W WHILE THE REMAINDER OF THE AREA IS DOMINATED BY DRY STABLE
AIR LIMITING SHOWER ACTIVITY.

ATLANTIC OCEAN...
AN UPPER RIDGE ANCHORED OVER SOUTH CAROLINA COVERS THE W ATLC
WITH A NARROW UPPER TROUGH TO THE E EXTENDING FROM 27N65W ACROSS
THE WINDWARD PASSAGE/E CUBA AND OVER THE CENTRAL CARIBBEAN. THIS
COMBINATION IS PROVIDING UPPER LEVEL DIFFLUENCE TO GENERATE
CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 150
NM OF S OF A SURFACE TROUGH THAT EXTENDS FROM 30N70W 28N74W TO
26N78W. THE LARGE UPPER LOW OVER THE CENTRAL ATLC IS BECOMING
ELONGATED N/S AND CENTERED NEAR 32N47W WITH ANY SHOWER ACTIVITY
N OF THE REGION AND A WEAKENING SURFACE TROUGH TO THE SW OF THE
UPPER LOW EXTENDING FROM 30N53W TO 22N57W. THE REMAINDER OF THE
ATLC REMAINS TRANQUIL AGAIN THIS MORNING WITH A BROAD AREA OF
SAHARAN DUST COVERING MOST OF THE AREA E OF 75W.

$$
WALLACE






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