[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 291146
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU JUL 29 2010

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 APPROACHING THE W AFRICAN COAST ALONG 17W S OF
17N MOVING W NEAR 15 KT. UPPER AIR SOUNDINGS FROM DAKAR SENEGAL
INDICATE THE WAVE IS JUST ABOUT TO PASS THE STATION. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-10N BETWEEN
14W-18W. SIMILAR ACTIVITY IS FROM 12N-15N BETWEEN 15W-19W.

TROPICAL WAVE IS IN THE W TROPICAL ATLC ALONG 17N49W 11N53W
4N55W MOVING W NEAR 20 KT. SATELLITE IMAGERY AND SATELLITE
DERIVED WINDS INDICATE BROAD CYCLONIC FLOW ABOUT THE WAVE AXIS.
THE WAVE ALSO LIES EMBEDDED IN A DEEP LAYER MOISTURE MAXIMUM
EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. NUMEROUS STRONG
CONVECTION IS MOSTLY W OF THE AXIS FROM 10N-15N BETWEEN 50W-60W.

TROPICAL WAVE IS IN THE ERN CARIBBEAN EXTENDING FROM THE MONA
PASSAGE NEAR 18N68W TO INLAND VENEZUELA NEAR 5N67W MOVING W NEAR
15 KT. THE WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE
EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N-17N BETWEEN
67W-70W. SIMILAR ACTIVITY IS INLAND OVER VENEZUELA FROM 6N-10N
BETWEEN 66W-69W.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 13N18W 8N31W 9N44W 8N62W. A
SURFACE TROUGH LIES WITHIN THE ITCZ ALONG 11N29W TO 7N31W
ENHANCING NUMEROUS STRONG CONVECTION FROM 6N-10N BETWEEN
27W-36W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE TROUGH EXTENDS OFF THE NW COAST OF FLORIDA ALONG
30N84W TO 26N83W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 45
NM EITHER SIDE OF THE AXIS. A SECOND WEAK SURFACE TROUGH
LINES THE SE MEXICAN COASTLINE ALONG 23N98W TO 18N96W IN THE
SW GULF OF MEXICO ENHANCING ISOLATED
SHOWERS/THUNDERSTORMS NEAR THE COASTLINE. THE REMAINDER OF THE
BASIN IS DOMINATED BY SURFACE RIDGING ANCHORED BY A 1021 MB HIGH
S OF SE LOUISIANA NEAR 29N91W MAINTAINING FAIR CONDITIONS AND
MOSTLY CLEAR SKIES. ALOFT...AN UPPER LEVEL TROUGH COVERS THE WRN
GULF EXTENDING FROM THE W CARIBBEAN ACROSS THE YUCATAN PENINSULA
TO LOUISIANA. UPPER LEVEL RIDGING COVERS THE ERN GULF CENTERED
OVER NE FLORIDA NEAR 30N81W. EXPECT THE SURFACE RIDGE TO
GRADUALLY SHIFT WWD SUPPORTING GENERALLY FAIR WEATHER ACROSS THE
BASIN.

CARIBBEAN SEA...
THE PRESSURE GRADIENT BETWEEN SURFACE RIDING ACROSS THE ATLC AND
LOWER PRESSURES ACROSS NRN SOUTH AMERICA IS MAINTAINING MODERATE
TO FRESH TRADEWINDS ACROSS MUCH OF THE BASIN. DRY AIR ALOFT
AROUND AN UPPER LEVEL TROUGH CENTERED OVER NE NICARAGUA IS
PROVIDING CLEAR SKIES OVER THE NW CARIBBEAN.
HOWEVER...DIFFLUENCE ALOFT AROUND THE BASE AND ERN SIDE OF THE
UPPER TROUGH IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM
11N-14N BETWEEN 79W-85W. SIMILAR ACTIVITY HAS MOVED OFF THE
NRN COAST OF COLOMBIA FROM 11N-14N BETWEEN 72W-77W. ISOLATED
SHOWERS/THUNDERSTORMS ARE ALSO S OF CUBA FROM 18N-21N BETWEEN
80W-84W. A TROPICAL WAVE IS MOVING ACROSS THE ERN CARIBBEAN
SUPPORTING SCATTERED SHOWERS FROM 14N-17N BETWEEN
67W-70W AS WELL
AS INLAND OVER VENEZUELA. ELSEWHERE ALOFT...UPPER LEVEL RIDGING
COVERS THE ERN CARIBBEAN CENTERED OVER THE LESSER ANTILLES NEAR
15N61W. EXPECT CONVECTION TO INCREASE ACROSS THE FAR ERN
CARIBBEAN AS A TROPICAL WAVE E OF THE LESSER ANTILLES PROGRESSES
WWD. SOME ISOLATED SHOWERS/THUNDERSTORMS ARE ALREADY IMPACTING
THE WINDWARD ISLANDS.

ATLANTIC OCEAN...
SURFACE RIDGING ANCHORED BY A 1024 MB HIGH NEAR 30N46W IS
MAINTAINING FAIR CONDITIONS ACROSS THE ENTIRE ATLC BASIN. AN
UPPER LEVEL TROUGH TO THE N OF THE DISCUSSION AREA IS SUPPORTING
A STATIONARY FRONT LINING THE NRN BORDER ALONG 31N BETWEEN
57W-74W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 90 NM EITHER
SIDE OF THE FRONT BETWEEN 55W-70W. SIMILAR ACTIVITY IS ALSO FROM
29N-32N BETWEEN 75W-78W. ELSEWHERE ALOFT...AN UPPER LEVEL RIDGE
COVERS THE W ATLC CENTERED OVER NE FLORIDA NEAR 30N81W. A NARROW
UPPER LEVEL TROUGH EXTENDS FROM NEAR 31N54W TO N OF THE VIRGIN
ISLANDS NEAR 22N63W. AN UPPER LEVEL RIDGE IS CENTERED OVER THE
LESSER ANTILLES NEAR 15N61W WITH AN UPPER LEVEL TROUGH TO ITS E
ALONG 17N46W TO 5N49W. UPPER LEVEL RIDGING COVERS THE CENTRAL/E
ATLC CENTERED NEAR 23N38W. ANOTHER UPPER LEVEL TROUGH COVERS THE
FAR E ATLC EXTENDING FROM 21N26W ACROSS THE CAPE VERDE ISLANDS.

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

$$
WALTON






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