[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 250546
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT JUN 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE EXTENDS FROM 17N46W TO 11N49W IN THE CENTRAL
TROPICAL ATLC MOVING W 10-15 KT. THE WAVE PRECEDES A SURGE OF
ENHANCED MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY.
NO DEEP CONVECTION IS ASSOCIATED WITH THE WAVE.

A TROPICAL WAVE IS MOVING WNW ACROSS THE NW CARIBBEAN ALONG
20N83W TO 13N84W NEAR 15 KT. THE WAVE LIES IN A LARGE AREA OF
DEEP LAYER MOISTURE PRESENT ACROSS THE CENTRAL AND WRN CARIBBEAN
BETWEEN 75W-85W. THE WAVE IS ALSO INTERACTING WITH THE MONSOON
TROUGH THAT EXTENDS FROM THE E PACIFIC ACROSS NICARAGUA TO NRN
COLOMBIA. THIS INTERACTION ALONG WITH UPPER LEVEL SUPPORT AROUND
AN UPPER TROUGH OVER THE FAR NW CARIBBEAN IS ENHANCING NUMEROUS
MODERATE CONVECTION FROM 16N-19N BETWEEN 76W-80W. SCATTERED
MODERATE/STRONG CONVECTION IS E OF NICARAGUA FROM 13N-16N
BETWEEN 80W-84W...AND ACROSS HONDURAS/GUATEMALA FROM 12N-16N W
OF 86W. EXPECT CONTINUED HEAVY SHOWER/THUNDERSTORM ACTIVITY TO
IMPACT THE CENTRAL/NW CARIBBEAN AS THE WAVE PROGRESSES WNW.

A TROPICAL WAVE IS CURRENTLY EMERGING OFF THE W AFRICA COAST AND
WILL LIKELY BE ADDED TO THE 0600 UTC SURFACE ANALYSIS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN
AT 21N ALONG 19N6W 21N17W CONTINUING OVER THE E ATLC WATERS
ALONG 15N24W 6N33W. THE ITCZ AXIS CONTINUES FROM 6N33W TO NEAR
4N45W. SCATTERED MODERATE/STRONG CONVECTION IS OFF THE W COAST
OF AFRICA FROM 5N-10N BETWEEN 18W-21W. SIMILAR ACTIVITY IS
WITHIN  90 NM S OF THE AXIS BETWEEN 29W-35W...AND WITHIN 100 NM
N...60 NM S OF THE AXIS BETWEEN 41W-47W.

...DISCUSSION...

GULF OF MEXICO...
ACTIVE WEATHER CONTINUES ACROSS THE GULF OF MEXICO DUE TO AN
UPPER LEVEL TROUGH EXTENDING ACROSS THE ERN CONUS WITH THE TAIL
END CONTINUING FROM SRN LOUISIANA TO THE SRN TIP OF TEXAS. AN
UPPER LEVEL RIDGE IS S OF THE TROUGH EXTENDING FROM CENTRAL
MEXICO ACROSS CENTRAL FLORIDA. THIS PATTERN CREATES AN AREA OF
DIFFLUENCE ALOFT SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM
23N-26N BETWEEN 93W-95W...AND FROM 27N-30N BETWEEN 83W-85W OFF
THE W COAST OF FLORIDA. ISOLATED SHOWER/THUNDERSTORM ACTIVITY IS
BETWEEN THESE TWO AREAS FROM 24N-29N BETWEEN 85W-93W...AND N OF
CUBA ACROSS THE FLORIDA STRAITS. SCATTERED SHOWERS ALSO REMAIN
ACROSS PORTIONS OF THE FLORIDA PENINSULA WHERE MOIST CONDITIONS
DOMINATE. THE REMAINDER OF THE BASIN...MAINLY THE FAR NW PORTION
AND SE PORTION...IS UNDER MOSTLY FAIR CONDITIONS DUE TO DRIER
AIR ALOFT. WHILE THE MAIN UPPER TROUGH IS EXPECTED TO MOVE
EWD...MODEL GUIDANCE INDICATES A SHORTWAVE UPPER TROUGH WILL
REMAIN ACROSS THE N CENTRAL GULF WHICH WILL LIKELY CONTINUE TO
SUPPORT SHOWER/THUNDERSTORM ACTIVITY ACROSS THE BASIN OVER THE
NEXT COUPLE OF DAYS.

CARIBBEAN SEA...
A TROPICAL WAVE MOVING ACROSS THE WRN CARIBBEAN IS FLARING UP
SHOWER/THUNDERSTORM ACTIVITY ACROSS MUCH OF THE CENTRAL/WRN
PORTIONS OF THE BASIN TONIGHT. SEE TROPICAL WAVE SECTION ABOVE
FOR MORE DETAILS. THE WAVE IS INTERACTING WITH BOTH THE MONSOON
TROUGH EXTENDING FROM THE E PACIFIC ACROSS NICARAGUA TO NRN
COLOMBIA...AND AN UPPER LEVEL TROUGH EXTENDING FROM CENTRAL CUBA
TO GUATEMALA. WEAK UPPER RIDGING IS ACROSS THE CENTRAL CARIBBEAN
WHILE BROAD UPPER TROUGHING IS OVER THE ERN CARIBBEAN EXTENDING
FROM AN UPPER LEVEL LOW IN THE ATLC N OF THE DOMINICAN REPUBLIC.
MOSTLY FAIR CONDITIONS ARE ACROSS THE ERN CARIBBEAN WITH ONLY A
FEW ISOLATED TRADEWIND SHOWERS IN 15 KT ELY WINDS. EXPECT
CONTINUED SHOWER ACTIVITY ACROSS THE CENTRAL/WRN CARIBBEAN AS
THE TROPICAL WAVE MOVES WNW OVER THE NEXT 24 HRS.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH OVER THE ERN CONUS CONTINUES TO MOVE EWD
WHICH HAS CAUSED THE AREA OF DIFFLUENCE ALOFT TO SHIFT OVER THE
FAR WRN ATLC SUPPORTING NUMEROUS SHOWERS/THUNDERSTORMS ALONG A
LINE FROM THE NW BAHAMAS NEAR 26N78W ALONG 31N79W 32N77W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 120 NM
EITHER SIDE OF THE LINE OF STRONG ACTIVITY. A FEW ISOLATED
SHOWERS/THUNDERSTORMS ARE FROM 24N-29N BETWEEN 67W-71W DUE TO AN
UPPER LEVEL LOW NEAR 25N69W. A WEAK UPPER LEVEL RIDGE IS TO THE
E ALONG 61W SANDWICHED BETWEEN THE UPPER LEVEL LOW AND ANOTHER
WEAK UPPER LEVEL TROUGH IN THE CENTRAL ATLC ALONG 50W. THE ERN
ATLC IS DOMINATED BY A WEAK SURFACE RIDGE CENTERED AROUND A 1022
MB HIGH NEAR 33N51W MAINTAINING FAIR CONDITIONS ACROSS THIS
AREA. ALOFT...AN UPPER LEVEL RIDGE DOMINATES THE TROPICAL ATLC
CENTERED NEAR 14N35W...WHILE AN UPPER LEVEL TROUGH EXTENDS FROM
THE AZORES ISLANDS TO NEAR 24N37W. A LARGE SAHARAN AIR LAYER
CONSISTING OF DRY AND DUSTY AIR IS ACROSS THE ERN TROPICAL ATLC
WHICH IS LIKELY PRECEDING THE NEXT TROPICAL WAVE TO MOVE OFF
THE COAST OF AFRICA.

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

$$
WALTON





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