[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 252344
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON JUL 25 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2300 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ABOUT TO MOVE OFF THE W AFRICAN COAST AND WILL
LIKELY BE ADDED ON THE NEXT ANALYSIS.

TROPICAL WAVE PREVIOUSLY NEAR 29W HAS BEEN DROPPED ON THE
SURFACE ANALYSIS AS OF 1800 UTC. THIS WAS BASED ON VARIED
SOURCES OF DATA INCLUDED SAL ANALYSIS...SATELLITE IMAGERY...AND
MODEL DATA THAT ALL POINT TO THE CONCLUSION THAT THE AREA OF
CONVECTION SEEN ALONG THE ITCZ IN THIS LOCATION IS NOT
INFLUENCED BY A TROPICAL WAVE...BUT LIKELY A WIND SURGE ALONG
THE ITCZ AREA.

TROPICAL WAVE IS ACROSS THE CENTRAL TRPCL ATLC ALONG 18N41W TO
10N43W MOVING W 10-15 KT. SATELLITE IMAGERY INDICATES BROAD
LOW-LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS...WHICH IS ALSO
INDICATED BY AN ASCAT SCATTEROMETER PASS FROM EARLIER TODAY.
TOTAL PRECIPITABLE WATER IMAGERY SHOWS THAT THE WAVE LIES WITHIN
A SURGE OF DEEP LAYER MOISTURE. ISOLATED MODERATE CONVECTION IS
FROM 14N-17N BETWEEN 41W-43W.

TROPICAL WAVE CONTINUES TO PUSH ACROSS CENTRAL CUBA ALONG 24N78W
TO 17N80W MOVING W NEAR 20 KT. BROAD CYCLONIC FLOW IS AROUND THE
WAVE AXIS. TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATES THAT
AN AREA OF ENHANCED MOISTURE COVERS THE NW CARIBBEAN AND ACROSS
THE WATERS N OF CUBA. CURRENTLY SCATTERED MODERATE/STRONG
CONVECTION IS FROM 17N-23N BETWEEN 74W-85W AFFECTING JAMAICA AND
MUCH OF CUBA. A CLUSTER OF SIMILAR ACTIVITY IS ALSO ACROSS
HAITI. EXPECT CONTINUED HEAVY SHOWERS/THUNDERSTORMS TO CONTINUE
OVER CUBA AND SPREAD ACROSS THE STRAITS OF FLORIDA AND POSSIBLY
S FLORIDA AS THE WAVE MOVES WWD.

...ITCZ/MONSOON TROUGH...

MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN AT
19N ALONG 18N15W 12N19W 8N27W. THE ITCZ CONTINUES FROM 8N27W TO
7N46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN
100 NM S OF THE AXIS BETWEEN 17W-26W. SIMILAR ACTIVITY IS FROM
7N-11N BETWEEN 35W-40W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGING CONTINUES TO COVER THE GULF OF MEXICO THIS
EVENING AROUND A PAIR OF 1018 MB HIGHS NEAR 21N97W AND 27N91W
PROVIDING MOSTLY FAIR WEATHER ACROSS THE CENTRAL PORTIONS OF THE
BASIN. THE RIDGE IS SUPPORTED BY A LARGE UPPER LEVEL RIDGE
CENTERED OVER NRN TEXAS WHICH IS PROVIDING MAINLY NE FLOW ALOFT
ACROSS THE BASIN. TOTAL PRECIPITABLE WATER IMAGERY CONTINUES TO
SHOW HIGHER MOISTURE VALUES ACROSS THE NRN GULF WHICH COINCIDES
WITH AN AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF
28N BETWEEN 86W-95W. AN AREA OF STRONG SHOWERS/THUNDERSTORMS IS
ALSO ACROSS SW FLORIDA WITH AN AREA OF LIGHTER ACTIVITY ACROSS
NE FLORIDA. NUMEROUS SHOWERS/THUNDERSTORMS ARE ALSO NOTED ACROSS
THE YUCATAN PENINSULA FROM 18N-22N BETWEEN 88W-90W. THIS
ACTIVITY MAY BE ASSOCIATED WITH AN UPPER LEVEL TROUGH EXTENDING
FROM N OF THE NW BAHAMAS NEAR 29N78W TO THE BAY OF CAMPECHE NEAR
20N92W. SHOWER ACTIVITY WILL BEGIN TO INCREASE OVER THE SE GULF
AS MOISTURE ASSOCIATED WITH A TROPICAL WAVE ACROSS CUBA MOVES
WWD TOWARDS THE AREA. SURFACE RIDGING WILL REMAIN ACROSS THE
REMAINDER OF THE BASIN WITH HIGH MOISTURE VALUES ALSO REMAINING
OVER THE NRN GULF INCREASING THE CHANCE OF PRECIPITATION.

CARIBBEAN SEA...
MOIST CONDITIONS ARE ACROSS THE NW CARIBBEAN AS A TROPICAL WAVE
CURRENTLY ACROSS CENTRAL CUBA MOVES WWD. SEE TROPICAL WAVE
SECTION FOR MORE DETAILS. CURRENTLY...SCATTERED
SHOWERS/THUNDERSTORMS COVER THE AREA FROM 17N-23N BETWEEN
74W-85W INCLUDING JAMAICA AND MUCH OF CUBA. AN UPPER LEVEL
TROUGH EXTENDING FROM N OF THE NW BAHAMAS TO THE BAY OF CAMPECHE
MAY BE ENHANCING SOME OF THIS ACTIVITY NEAR THE WAVE. THE
REMAINDER OF THE BASIN IS UNDER MOSTLY FAIR CONDITIONS UNDER THE
INFLUENCE OF DRY AIR ALOFT AROUND A WEAK UPPER LEVEL RIDGE
EXTENDING FROM N OF HISPANIOLA NEAR 24N71W TO THE SRN WINDWARD
ISLANDS NEAR 11N62W. A FEW ISOLATED SHOWERS ARE MOVING ACROSS
THE WINDWARD ISLANDS FROM 13N-16N E OF 68W EMBEDDED WITHIN 15-20
KT ELY FLOW ACROSS THE ERN CARIBBEAN. TOTAL PRECIPITABLE WATER
IMAGERY INDICATES SOME HIGHER MOISTURE VALUES IN THE AREA OF THE
ISOLATED SHOWERS THAT SPREADS EWD INTO THE TROPICAL ATLC. EXPECT
SHOWERS/THUNDERSTORMS TO CONTINUE ACROSS THE NW CARIBBEAN AS THE
WAVE ACROSS CUBA MOVES WWD. THE ERN CARIBBEAN MAY SEE CONTINUE
TO SEE ISOLATED SHOWERS DUE TO THE HIGHER MOISTURE VALUES ACROSS
THE AREA.

ATLANTIC OCEAN...
SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE FAR SW ATLC S OF
28N W OF 75W ASSOCIATED WITH A TROPICAL WAVE ACROSS CUBA. BROAD
SURFACE RIDGING CONTINUES TO DOMINATE THE REMAINDER OF THE ATLC
ANCHORED BY A 1028 MB AZORES HIGH PROVIDING MOSTLY FAIR WEATHER
BASIN-WIDE. ALOFT...AN UPPER LEVEL LOW COVERS THE FAR WRN ATLC
CENTERED NEAR 29N78W WITH TROUGH AXIS EXTENDING TO THE BAY OF
CAMPECHE. AN UPPER LEVEL RIDGE IS TO THE SE WITH AXIS ALONG
24N71W TO 11N62W. ANOTHER UPPER LEVEL LOW IS SPINNING IN THE
CENTRAL ATLC NEAR 27N50W WITH AXIS EXTENDING TO E OF THE
WINDWARD ISLANDS. THIS UPPER TROUGH SUPPORTS A SURFACE TROUGH
JUST E OF THE WINDWARD ISLANDS ALONG 59W FROM 12N-18N WITH
ISOLATED SHOWERS WITHIN 150 NM EITHER SIDE OF THE AXIS. AN UPPER
LEVEL RIDGE COVERS THE ERN ATLC WITH TWO CENTERS NEAR 19N36W AND
26N12W.

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

$$
WALTON



WWWW
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