[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 212342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUN 21 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
2330 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE MOVED OFF THE WEST COAST OF AFRICA THIS EARLY
AFTERNOON...NOW ANALYZED FROM 16N17W TO 10N18W MOVING W AT ABOUT
10-15 KT. THIS WAVE COINCIDES WITH A SURGE OF DEEP MOISTURE
EVIDENT ON TOTAL PRECIPITABLE WATER IMAGERY. A BROAD AREA OF
SCATTERED MODERATE CONVECTION SURROUNDS THE WAVE E OF 22W FROM
5N-15N.

TROPICAL WAVE IN THE TROPICAL ATLC IS ANALYZED FROM 15N46W TO
7N47W MOVING W NEAR 10 KT. THE WAVE IS EMBEDDED IN A SURGE OF
MOISTURE INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY. AN
INVERTED-V PATTERN SIGNATURE IS NOTICED ON THE LOW-MID LEVEL
CLOUD PATTERN. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION
IS WITHIN 150 NM ON EITHER SIDE OF THE WAVE AXIS. MOISTURE FROM
THIS TROPICAL WAVE WILL REACH THE N TROPICAL ATLC EARLY WED.
THIS WAVE WILL MOVE INTO THE E CARIBBEAN EARLY THU.

TROPICAL WAVE IS INLAND OVER WESTERN VENEZUELA ALONG 71W S OF
13N MOVING W NEAR 10 KT. THE CONVECTION ASSOCIATED TO THIS WAVE
REMAINS INLAND. THIS WAVE WILL BECOME ABSORBED INTO THE EASTERN
EXTENT OF THE MONSOON TROUGH OVER THE SW CARIBBEAN ONCE IT MOVES
OFF THE WESTERN COAST OF COLOMBIA IN THE NEXT 12 HOURS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH REMAINS INLAND ACROSS WEST AFRICA. THE ITCZ
STARTS W OF THE TROPICAL WAVE ALONG 10N20W 5N30W 7N40W TO THE
COAST OF SOUTH AMERICA NEAR 5N52W. SCATTERED MODERATE CONVECTION
IS WITHIN 80 NM ON EITHER SIDE OF THE ITCZ AXIS BETWEEN
23W-48W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE OF HIGH PRESSURE COVERS THE BASIN THIS
EVENING WITH VERY DRY AIR ALOFT AND STRONG SUBSIDENCE NOTICED ON
WATER VAPOR IMAGERY. THIS ENVIRONMENT IS KEEPING THE DISCUSSION
AREA UNDER FAIR WEATHER CONDITIONS. SURFACE RETURN FLOW UP TO 15
KT IS OBSERVED OVER THE ENTIRE BASIN...CARRYING A FEW ISOLATED
SHOWERS AND POSSIBLE THUNDERSTORMS MOVING N ACROSS THE CENTRAL
BASIN BETWEEN 87W-90W. COMPUTER MODELS SUGGEST CONDITIONS WILL
REMAIN SIMILAR OVER THE NEXT 24 HOURS WITH SOME WEAK CONVECTION
DEVELOPING IN THE SW-W BASIN DURING THE FORECAST PERIOD.

CARIBBEAN SEA...
LAST VISIBLE SATELLITE PICTURES OF THE DAY INDICATED SCATTERED
MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS OVER THE FAR SW
BASIN S OF 13N W OF 78W...DUE TO AN EXTENSION OF THE MONSOON
TROUGH ANALYZED ACROSS CENTRAL AMERICA OVER PANAMA TO THE
NORTHERN COAST OF COLOMBIA. OTHERWISE...FAIR WEATHER CONDITIONS
ARE OBSERVED ACROSS THE REMAINDER OF THE DISCUSSION AREA. MARINE
OBS INDICATE TRADE WIND FLOW 15-20 KT ACROSS THE AREA...GUSTING
TO 25 KT ALONG THE COAST OF COLOMBIA. THIS PATTERN IS EXPECTED
TO CONTINUE OVER THE NEXT 24 HOURS WITH SHALLOW MOISTURE
EMBEDDED IN THE TRADE WIND FLOW PRODUCING ISOLATED WEAK SHOWERS.
THE CONVECTION IN THE SW BASIN IS EXPECTED TO CONTINUE DURING
THE FORECAST PERIOD.

ATLANTIC OCEAN...
WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL SHORTWAVE/TROUGH
MOVING ACROSS THE W ATLC N OF THE DISCUSSION AREA...SUPPORTING A
LOW PRESSURE SYSTEM NEAR 34N66W. THE ASSOCIATED COLD FRONT
REMAINS N OF THE DISCUSSION AREA. HOWEVER...THIS BOUNDARY IS
EXPECTED TO ENTER THE AREA W OF 65W OVER THE NEXT 3-6 HOURS.
THIS SAME UPPER LEVEL FEATURE ALSO SUPPORTS AN AREA OF SCATTERED
SHOWERS AND POSSIBLE THUNDERSTORMS NE OF THE BAHAMAS FROM
22N-27N BETWEEN 69W-73W. AS THE UPPER TROUGH CONTINUES TO MOVE
E...AN UPPER LEVEL RIDGE WILL MOVE INTO THE WESTERN ATLC
PROMOTING FAIR WEATHER ACROSS THIS REGION. OTHERWISE...MOST OF
THE ATLC WITHIN THE DISCUSSION AREA IS DOMINATED BY A BROAD
UPPER LEVEL RIDGE...ANCHORED BY A PAIR OF SURFACE HIGHS IN THE
CENTRAL ATLC...A 1021 MB AROUND 26N51W...AND A 1024 MB NEAR
32N34W RESPECTIVELY. WHILE THE 1021 MB HIGH IS EXPECTED TO
REMAIN STATIONARY OVER THE NEXT 24 HOURS...TH LATTER WILL SHIFT
NE OUT OF THE AREA DURING THE FORECAST PERIOD.

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

$$

GARCIA




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