[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 061734
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED JUL 06 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1530 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE WAS FOUND THIS MORNING...EMBEDDED IN THE ITCZ
WITH AXIS ANALYZED FROM 11N39W TO 4N42W MOVING W AT ABOUT 12 KT.
A DEEP LAYER MOISTURE SURROUNDS THIS WAVE ON TOTAL PRECIPITABLE
WATER IMAGERY. THE AREA OF CONVECTION ASSOCIATED TO THE WAVE IS
EMBEDDED IN THE ITCZ DISCUSSED BELOW.

TROPICAL WAVE EXTENDS FROM 19N53W TO 12N57W MOVING W 15-20 KT.
WAVE IS WELL DEFINED IN THE LOW LEVEL SATELLITE DERIVED WINDS.
WAVE IS PRECEDING A BROAD AMPLITUDE MOISTURE SURGE INDICATED ON
THE TOTAL PRECIPITABLE WATER IMAGERY. NO CONVECTION IS OBSERVED
OVER THE NORTHERN HALF OF THE WAVE AXIS DUE TO A DRY SLOT
WRAPPING AROUND THIS REGION...LEAVING AN AREA OF SCATTERED
MODERATE TO ISOLATED CONVECTION FROM 12N-17N BETWEEN 52W-60W.

TROPICAL WAVE IS MOVING ACROSS THE YUCATAN PENINSULA FROM 23N86W
TO 17N90W MOVING WNW AT ABOUT 10-15 KT. WAVE REMAINS EMBEDDED
WITHIN A BROAD AREA OF DEEP LAYERED MOISTURE THAT COVERS MOST OF
THE NW CARIBBEAN AND SE GULF OF MEXICO BASINS. THE WAVE LIES
UNDERNEATH AN AREA OF DIFFLUENCE ALOFT WHICH IS HELPING SUPPORT
CONVECTION NEAR THE WAVE. SCATTERED MODERATE TO STRONG
CONVECTION IS S OF 27N E OF 88W AS WELL AS INLAND OVER THE
YUCATAN PENINSULA.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS INLAND OVER AFRICA AND ENTERS THE
EAST TROPICAL ATLC THROUGH GUINEA-BISSAU FROM 12N16W TO 10N19W.
THE ITCZ AXIS STARTS FROM 10N19W CONTINUING WSW ALONG 10N25W
9N30W 7N40W RESUMING WEST OF A TROPICAL WAVE NEAR 6N42W TO THE
COAST OF BRAZIL NEAR 4N51W. SCATTERED MODERATE TO ISOLATED
STRONG CONVECTION IS WITHIN 130/160 NM ON EITHER SIDE OF THE
ITCZ BETWEEN 30W-50W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER LEVEL CYCLONIC FLOW CONTINUES TO COVER THE
DISCUSSION AREA THIS AFTERNOON CENTERED NEAR 26N90W. THIS
FEATURE SUPPORTS AN AREA OF SCATTERED WEAK SHOWERS N OF 24N W OF
91W. THE ACTIVITY BECOMES FURTHER ENHANCED OVER THE EASTERN HALF
OF THE BASIN E OF 89W. SCATTERED HEAVY SHOWERS AND ISOLATED
THUNDERSTORMS ARE OVER THIS AREA...ASSOCIATED TO A TROPICAL WAVE
CURRENTLY MOVING ACROSS THE YUCATAN PENINSULA. DIFLUENT FLOW
ALOFT IS ALSO NOTICED OVER THE SE GULF AND NW CARIBBEAN BASINS.
THE REMAINDER OF THE BASIN IS UNDER DRY AIR ALOFT AND A VERY
WEAK SURFACE PRESSURE GRADIENT YIELDING LIGHT AND VARIABLE
WINDS. EXPECT THE SURFACE TROUGH TO CONTINUE TO DRIFT W WITH
LIMITED CONVECTION OVER THE NEXT 24 HOURS...AND THE TROPICAL
WAVE AXIS TO START MOVING INTO THE SE GULF DURING THE TIME
PERIOD.

CARIBBEAN SEA...
THE UPPER LEVELS OF THE ATMOSPHERE ACROSS THE CARIBBEAN SEA ARE
DOMINATED BY ANTICYCLONIC FLOW CENTERED NEAR 17N80W. THIS FLOW
BECOMES DIFFLUENT OVER THE FAR NW BASIN...BETWEEN THE UPPER LOW
OVER THE GULF AND THE UPPER HIGH OVER THE CARIBBEAN. DESPITE THE
UPPER LEVEL ENVIRONMENT...SCATTERED HEAVY SHOWERS AND
THUNDERSTORMS ARE OVER THE WEST AND NW CARIBBEAN...INCLUDING
INLAND PORTIONS OVER THE GREATER ANTILLES AND CENTRAL AMERICA N
OF 16N W OF 70W...DUE TO A TROPICAL WAVE MOVING ACROSS THE NW
BASIN...AND A BROAD AREA OF DEEP LAYER MOISTURE OVER THE N
CENTRAL BASIN. THE NATIONAL METEOROLOGICAL OFFICE IN DOMINICAN
REPUBLIC HAS REGISTERED RAINFALL TOTALS ABOVE 6 AND 7 INCHES IN
THE PAST 24-36 HOURS. SIMILAR ACTIVITY IS FOUND OVER THE FAR SW
BASIN S OF 12N W OF 75W...ASSOCIATED TO THE MONSOON TROUGH
EXTENDING ACROSS COSTA RICA INTO NORTHERN COLOMBIA. A SURFACE
TROUGH MOVING OVER THE LESSER ANTILLES ANALYZED FROM 14N61W TO
10N64W PRODUCING MODERATE TO STRONG CONVECTION TO THE FAR SE
BASIN S OF 15N E OF 65W. THIS SYSTEM IS EXPECTED TO TRACK NW
OVER THE NEXT FEW DAYS. FAIR WEATHER CONDITIONS ARE ELSEWHERE
ACROSS THE CARIBBEAN INFLUENCED BY DRY AIR ALOFT ASSOCIATED TO
THE SUBSIDENCE GENERATED BY THE UPPER HIGH.

ATLANTIC OCEAN...
THE MAIN FEATURE ACROSS THE ATLC DISCUSSION AREA IS A SURFACE
TROUGH MOVING ACROSS THE NORTHERN BAHAMAS...ANALYZED FROM 28N78W
TO 23N78W. THIS SYSTEM IS GENERATING CLUSTERS OF SCATTERED HEAVY
SHOWERS AND THUNDERSTORMS S OF 28N W OF 72W. THIS SURFACE
FEATURE LIES UNDER AN UPPER LEVEL RIDGE THAT COVERS THE WEST
ATLC W OF 70W. THE SURFACE TROUGH IS EXPECTED TO CONTINUE TO
TRACK NNW BRINGING CONVECTION TO THE COASTAL WATERS OF THE
FLORIDA PENINSULA OVER THE NEXT 24-48 HOURS. THE REMAINDER OF
THE ATLC IS DOMINATED BY A BROAD RIDGE ANCHORED BY A 1032 MB
HIGH NEAR 41N33W. THIS BROAD SYSTEM IS PROVIDING MOSTLY FAIR
WEATHER ACROSS THE CENTRAL AND EAST ATLC. AN UPPER LOW IS
EMBEDDED IN THE BROAD RIDGE SPINNING NEAR 27N55W SUPPORTING AN
AREA OF WEAK ISOLATED SHOWERS FROM 25N-29N BETWEEN 50W-58W.

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

$$

GARCIA




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