[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251119
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS OFF THE W COAST OF AFRICA EXTENDING FROM
18N22W ACROSS THE CAPE VERDE ISLANDS TO 8N28W. THE WAVE IS
MOVING W AT 10-15 KT. CYCLONIC SURFACE WINDS ARE ABOUT THE WAVE
AXIS EVIDENT IN SATELLITE IMAGERY AND SATELLITE DERIVED WINDS.
THE WAVE ALSO LIES W OF A SURGE OF DEEP LAYER MOISTURE EVIDENT
IN TOTAL PRECIPITABLE WATER IMAGERY...AS WELL AS AN INTRUSION
INTO THE SAHARAN AIR LAYER. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS E OF THE WAVE AXIS FROM 5N-10N BETWEEN 19W-23W.

A TROPICAL WAVE EXTENDS FROM 17N47W TO 11N50W 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 85W
FROM 12N-20N NEAR 15 KT. THE WAVE LIES IN A LARGE AREA OF DEEP
LAYER MOISTURE PRESENT ACROSS THE CENTRAL AND WRN CARIBBEAN
BETWEEN 75W-87W. 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/STRONG FROM 10N-15N BETWEEN 78W-84W. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 15N-18N BETWEEN 78W-85W...
FROM 20N-22N BETWEEN 79W-84W JUST S OF CUBA...AND FROM 15N-17N
BETWEEN 86W-90W ACROSS NRN HONDURAS AND GUATEMALA. EXPECT
CONTINUED HEAVY SHOWER/THUNDERSTORM ACTIVITY TO IMPACT THE
CENTRAL/NW CARIBBEAN AS THE WAVE PROGRESSES WNW.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN
AT 22N ALONG 19N10W TO 20N16W. IT PICKS UP W OF A TROPICAL WAVE
CONTINUING ALONG 7N30W TO 5N34W. THE ITCZ AXIS CONTINUES FROM
5N34W ALONG 4N45W 3N57W. SCATTERED MODERATE/STRONG CONVECTION
WITHIN  90 NM S OF THE AXIS BETWEEN 30W-37W...AND WITHIN 90 NM
N...45 NM S OF THE AXIS BETWEEN 42W-47W.

...DISCUSSION...

GULF OF MEXICO...
ACTIVE WEATHER CONTINUES ACROSS THE GULF OF MEXICO DUE TO AN
UPPER LEVEL TROUGH EXTENDING ACROSS THE FAR ERN CONUS WITH THE
TAIL END CONTINUING FROM SRN GEORGIA TO JUST E OF THE SRN TIP OF
TEXAS. AN UPPER LEVEL RIDGE IS S OF THE TROUGH EXTENDING FROM
CENTRAL MEXICO ACROSS SRN FLORIDA. THIS PATTERN CREATES AN
AREA OF DIFFLUENCE ALOFT SUPPORTING SCATTERED
SHOWERS/THUNDERSTORMS FROM 21N-26N BETWEEN 94W-99W...AND FROM
26N-28N BETWEEN 83W-88W. ISOLATED SHOWER ACTIVITY IS BETWEEN
THESE TWO AREAS FROM 25N-30N BETWEEN 86W-94W. ISOLATED 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 THIS MORNING. 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 ERN 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
AND HAS ALMOST EMERGED OFF THE COAST SUPPORTING SCATTERED
SHOWERS/THUNDERSTORMS ALONG A LINE FROM THE NW BAHAMAS NEAR
26N77W ALONG 31N76W 34N72W. ISOLATED SHOWERS/THUNDERSTORMS ARE
WITHIN 90 NM EITHER SIDE OF THE LINE OF STRONG ACTIVITY. A FEW
ISOLATED SHOWERS ARE FROM 18N-28N BETWEEN 61W-70W DUE TO AN
UPPER LEVEL LOW NEAR 24N69W. A WEAK UPPER LEVEL RIDGE IS TO THE
E ALONG 59W SANDWICHED BETWEEN THE UPPER LEVEL LOW AND ANOTHER
WEAK UPPER LEVEL TROUGH IN THE CENTRAL ATLC ALONG 49W. THE ERN
ATLC IS DOMINATED BY A WEAK SURFACE RIDGE CENTERED AROUND A PAIR
OF 1021 MB HIGHS NEAR 28N51W AND 33N48W MAINTAINING FAIR
CONDITIONS ACROSS THIS AREA. ALOFT...AN UPPER LEVEL RIDGE IS
CENTERED NEAR 32N52W SUPPORTING THE SURFACE RIDGE. ANOTHER UPPER
LEVEL RIDGE DOMINATES THE TROPICAL ATLC CENTERED NEAR
14N34W...WHILE AN UPPER LEVEL TROUGH EXTENDS FROM THE AZORES
ISLANDS TO NEAR 24N36W 20N53W. A LARGE SAHARAN AIR LAYER
CONSISTING OF DRY AND DUSTY AIR IS ACROSS THE ERN TROPICAL ATLC
SURROUNDING THE TROPICAL WAVE THAT RECENTLY MOVED OFF THE COAST
OF AFRICA

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

$$
WALTON






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