[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUL 25 2012

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.

...TROPICAL WAVES...

TROPICAL WAVE IS WEST OF CAPE VERDE ISLANDS ANALYZED FROM 18N17W
TO A 1012 MB LOW EMBEDDED IN THE MONSOON TROUGH NEAR 11N17W.
THIS SYSTEM IS EMBEDDED WITHIN A REGION OF DEEP LAYER OF
MOISTURE DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS
OF SCATTERED MODERATE TO STRONG CONVECTION COVER THE AREA FROM
10N-15N BETWEEN 20W-27W. THIS CONVECTION IS ALSO ASSOCIATED TO
THE MONSOON TROUGH DISCUSSED BELOW.

TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC WITH AXIS
ANALYZED FROM 23N39W TO THE MONSOON TROUGH AXIS NEAR 12N40W
MOVING W AT ABOUT 5-10 KT. THE WAVE REMAINS ALONG THE WRN EDGE
OF A SURGE OF DEEP LAYER MOISTURE AS DEPICTED ON TOTAL
PRECIPITABLE WATER IMAGERY. HOWEVER...THIS SYSTEM IS EMBEDDED IN
A DENSE REGION OF SAHARAN DUST LIMITING THE CONVECTIVE ACTIVITY
AROUND THE WAVE TO NEAR ZERO.

A TROPICAL WAVE MOVES ACROSS THE WESTERN CARIBBEAN WITH AXIS
ANALYZED FROM 20N75W TO 12N78W. WAVE REMAINS ON THE WRN EDGE OF
A SURGE OF DEEP MOISTURE NOTED ON TOTAL PRECIPITABLE WATER
IMAGERY. HOWEVER...THIS SYSTEM IS EMBEDDED IN REGION OF STRONG
SUBSIDENCE ALOFT AND SAHARAN DUST LIMITING THE CONVECTIVE
ACTIVITY AROUND THE WAVE TO JUST A FEW ISOLATED SHOWERS IN THE
VICINITY OF THE WAVE AXIS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE TROPICAL
ATLC THROUGH THE COAST OF MAURITANIA ALONG 18N16W TO THE
TROPICAL WAVES 1012 MB LOW NEAR 11N17W CONTINUING WESTWARD ALONG
10N27W 12N40W TO 7N50W...WHERE A SHORT SECTION OF THE ITCZ
CONTINUES TO THE COAST OF GUYANA NEAR 6N58W. CLUSTERS OF WEAK
SCATTERED CONVECTION ARE FROM 4N-10N BETWEEN 46W-55W. CLUSTERS
OF SCATTERED MODERATE TO STRONG CONVECTION ARE WITHIN 100-150 NM
ON EITHER SIDE OF THE MONSOON TROUGH BETWEEN 20W-33W.

...DISCUSSION...

GULF OF MEXICO...
WEAK UPPER LEVEL CYCLONIC FLOW FLOW REMAINS OVER THE SE CONUS
SUPPORTING A SURFACE TROUGH ANALYZED ALONG THE BIG BEND REGION
OF FLORIDA NEAR 30N84W TO 25N86W. DOPPLER RADAR IMAGERY SHOWS
SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS WITHIN 70
NM O NEITHER SIDE OF THE TROUGH AXIS FROM 26N-29N. THE ACTIVITY
IN THIS REGION IS EXPECTED TO DECREASE AND SHIFT TO THE WSW OVER
THE NEXT 24 HOURS. SIMILAR CONVECTION IS NOTED ON SATELLITE
IMAGERY ACROSS THE GOLF COAST OF MEXICO AFFECTING THE COASTAL
WATERS FROM VERACRUZ TO MATAMOROS. THE ACTIVITY IS SUPPORTED
ALOFT BY AN ELONGATED UPPER LEVEL LOW NOTED OVER NE MEXICO.
WHILE THE ACTIVITY IS EXPECTED TO DECREASE DURING THE NEXT 24
HOURS...THIS AREA OF SHOWERS IS EXPECTED TO REMAIN NEARLY
STATIONARY DURING THE FORECAST PERIOD.

CARIBBEAN SEA...
AN UPPER LEVEL INVERTED TROUGH MOVES ACROSS CENTRAL AMERICA ON
WATER VAPOR IMAGERY. ALTHOUGH THIS FEATURE IS EMBEDDED IN DRY
AIR ALOFT...ITS MID-UPPER LEVEL LIFTING COMBINED WITH LOW LEVEL
MOISTURE CONVERGENCE ALONG THE MONSOON TROUGH OVER THE FAR SW
BASIN IS GENERATING AN AREA OF SCATTERED SHOWERS AND
THUNDERSTORMS AFFECTING THE COASTAL WATERS OF NICARAGUA AND
COSTA RICA WITHIN 100 NM S OF BLUEFIELDS. THIS AREA OF
CONVECTION WILL CONTINUE TO MOVE INLAND DURING THE NEXT 24
HOURS. A TROPICAL WAVE MOVES ACROSS THE WESTERN CARIBBEAN BASIN
WITH NO ASSOCIATED ACTIVITY DUE TO STRONG SUBSIDENCE AND DRY AIR
ALOFT AROUND THIS SYSTEM. THE REMAINDER OF THE DISCUSSION AREA
IS UNDER FAIR WEATHER CONDITIONS WITH A FEW ISOLATED SHOWERS
EMBEDDED IN THE LIGHT TO MODERATE EASTERLY TRADEWIND FLOW. UPPER
AIR SOUNDINGS AND SATELLITE DATA CONTINUE TO SAHARAN DUST ALOFT
ACROSS MOST OF THE DISCUSSION AREA.

ATLANTIC OCEAN...
A BROAD UPPER LEVEL LONGWAVE TROUGH MOVES ACROSS THE WEST
ATLANTIC SUPPORTING TWO SURFACE TROUGHS EXTENDING INTO THE AREA.
THE LEADING SURFACE TROUGH EXTENDS FROM THE SAME LOW THROUGH
32N54W TO 28N59W. THE TRAILING SURFACE TROUGH EXTENDS THROUGH
32N63W TO 28N67W. THE COMBINATION OF THESE TWO FEATURES IS
GENERATING AN AREA OF SCATTERED SHOWERS AND THUNDERSTORMS N OF
28N BETWEEN 55W-65W. THIS AREA OF CONVECTION IS FORECAST TO
TRACK ESE DURING THE NEXT 24 HOURS. OTHERWISE...BROAD UPPER
LEVEL RIDGING COVERS THE REMAINDER OF THE ATLC DISCUSSION AREA.
THE FAIR WEATHER IS FURTHER ENHANCED BY SAHARAN DUST COVERING
THE ENTIRE ATLC DISCUSSION AREA.

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

$$

GARCIA




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