[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 290552
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED JUN 29 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.

...SPECIAL FEATURE...

T.S. ARLENE IS CENTERED NEAR 21.6N 94.5...OR ABOUT 190 NM E OF
TAMPICO MEXICO...AS OF 0600 UTC. THE STORM IS MOVING WNW AT 6
KT. MINIMUM CENTRAL PRESSURE IS 1003 MB WHILE MAXIMUM SUSTAINED
WINDS ARE 35 KT WITH GUSTS TO 45 KT. ARLENE IS EXPECTED TO
SLOWLY DRIFT WNW BEFORE TURNING W. SOME STRENGTHENING IS
POSSIBLE. SEE NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO
HEADERS MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST/ ADVISORY
UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.
NUMEROUS STRONG CONVECTION IS IMPACTING GUATEMALA AND PORTIONS
OF SRN MEXICO FROM 15N-19N BETWEEN 90W-93W. NUMEROUS MODERATE
WITH LARGE CLUSTERS OF STRONG CONVECTION COVER SW PORTIONS OF
MEXICO FROM18N-23N BETWEEN 94W-98W...AND FROM 16N-20N BETWEEN
97W-102W. SIMILAR ACTIVITY IS WITHIN 75 NM OF THE CENTER.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NE OF THE
CENTER FROM 20N-25N BETWEEN 84W-93W.

...TROPICAL WAVES...

A TROPICAL WAVE IS ACROSS THE CENTRAL ATLC ALONG 14N44W TO 8N47W
MOVING W NEAR 15-20 KT. SATELLITE IMAGERY CONTINUES TO SHOW
CLEAR CUT LOW LEVEL CYCLONIC FLOW ABOUT THE WAVE AXIS. AN ASCAT
SCATTEROMETER PASS FROM 0006 UTC CONFIRMS THIS. THE WAVE IS ALSO
EMBEDDED WITHIN A SURGE OF DEEP LAYER MOISTURE EVIDENT IN TOTAL
PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS W OF THE WAVE AXIS FROM 11N-12N BETWEEN 46W-48W.

A TROPICAL WAVE IS S OF THE DOMINICAN REPUBLIC ALONG 71W FROM
14N-18N. THIS WAVE HAS LOST A LOT OF ITS ENERGY OVER THE PAST 24
HOURS...MOST LIKELY DUE TO THE INTERACTION WITH AN UPPER LEVEL
LOW NOW S OF HAITI NEAR 16N73W. MODERATELY HIGHER MOISTURE
VALUES STILL REMAIN IN THE VICINITY OF THE WAVE. A CLUSTER OF
MODERATE/STRONG CONVECTION IS E OF THE WAVE AXIS FROM 13N-15N
BETWEEN 66W-70W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN
AT 23N ALONG 16N10W 16N14W 10N23W. THE ITCZ CONTINUES FROM
10N23W ALONG 7N35W 2N52W. SCATTERED MODERATE/STRONG CONVECTION
IS FROM 7N-10N BETWEEN 13W-22W...FROM 4N-7N BETWEEN
32W-42W...FROM 9N-10N BETWEEN 32W-40W...AND FROM 1N-5N BETWEEN
47W-50W.

...DISCUSSION...

GULF OF MEXICO...
TROPICAL STORM ARLENE...LOCATED IN THE BAY OF CAMPECHE...IS
CURRENTLY AFFECTING MUCH OF THE SW GULF OF MEXICO. SEE SPECIAL
FEATURES SECTION ABOVE FOR MORE DETAILS. A WEAKENING SHORTWAVE
UPPER TROUGH STILL SITS OVER THE FAR NW GULF FROM SRN ALABAMA TO
NRN MEXICO NEAR 26N99W...WITH AN UPPER LEVEL RIDGE EXTENDING
FROM THE YUCATAN PENINSULA TO SRN FLORIDA. THIS PATTERN IS
KEEPING MOIST SWLY FLOW OVER MUCH OF THE CENTRAL AND ERN GULF OF
MEXICO...WHILE DRY AIR AND SUBSIDENCE COVERS THE FAR NW CORNER
MAINTAINING FAIR CONDITIONS. BESIDES THE CONVECTION ASSOCIATED
WITH ARLENE...ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS COVER MUCH
OF THE ERN GULF AND FLORIDA. A WEAK SURFACE TROUGH IS ANALYZED
IN THE NE GULF FROM 29N86W TO 27N90W. EXPECT CONTINUED MOISTURE
AND SHOWER ACTIVITY TO REMAIN ACROSS MUCH OF THE BASIN OVER THE
NEXT 24 HOURS.

CARIBBEAN SEA...
MUCH OF THE CENTRAL AND WRN CARIBBEAN IS UNDER FAIR CONDITIONS
AS DRY AIR ALOFT IS BEING DOWN SWD BETWEEN AN UPPER LEVEL RIDGE
EXTENDING FROM THE YUCATAN PENINSULA TO SRN FLORIDA...AND AN
UPPER LEVEL LOW CENTERED S OF HAITI NEAR 16N73W. A FEW AREAS OF
SHOWERS/THUNDERSTORMS REMAIN OVER PANAMA AND COAST RICA DUE TO
THE MONSOON TROUGH EXTENDING FROM COSTA RICA TO NRN
COLOMBIA...AND NICARAGUA...WRN HONDURAS..AND SRN BELIZE DUE TO
SOME OF THE MOISTURE THAT COVERS THE SW GULF OF MEXICO. A
TROPICAL WAVE IS S OF THE DOMINICAN REPUBLIC. THE ONLY AREA OF
ACTIVE WEATHER ASSOCIATED WITH IT IS E OF THE AXIS FROM 13N-15N
BETWEEN 66W-70W. AN AREA OF SCATTERED SHOWERS/POSSIBLE
THUNDERSTORMS IS ALSO MOVING ACROSS THE FAR SE CARIBBEAN FROM
11N-12N BETWEEN 62W-67W. EXPECT POSSIBLE SHOWERS/THUNDERSTORMS
TO CONTINUE OVER THE CENTRAL CARIBBEAN AS THE TROPICAL WAVE
MOVES WWD.

ATLANTIC OCEAN...
UPPER LEVEL RIDGING COVERS THE SW ATLC EXTENDING FROM THE
YUCATAN PENINSULA AND ACROSS FLORIDA TO NEAR 29N74W. HIGH
MOISTURE VALUES FROM THE SW GULF ARE BEING DRAWN INTO THE ATLC
IN MOIST SWLY FLOW ALOFT AROUND THE UPPER RIDGE SUPPORTING
ISOLATED SHOWERS FROM NEAR 28N80W TO 33N72W. A SURFACE
TROUGH...A SPLIT OFF PORTION OF A TROPICAL WAVE IN THE CENTRAL
CARIBBEAN...IS N OF THE DOMINICAN REPUBLIC EXTENDING FROM 25N67W
TO 21N70W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE W OF THE
TROUGH FROM 20N-25N BETWEEN 69W-73W. THE REMAINDER OF THE BASIN
IS DOMINATED BY SURFACE RIDGING AROUND A 1025 MB HIGH NEAR
31N50W MAINTAINING FAIR WEATHER ACROSS THE CENTRAL AND ERN ATLC.
ALOFT...AN UPPER LEVEL LOW IS CENTERED NEAR 27N50W WHICH WAS
SUPPORTING A FEW ISOLATED SHOWERS/THUNDERSTORMS THAT HAVE NOW
DIED OUT. AN UPPER LEVEL RIDGE IS ALONG 40W...WHILE AN UPPER
TROUGH COVER THE ERN ATLC WITH AXIS BETWEEN THE AZORES AND
CANARY ISLANDS. UPPER RIDGING COVERS THE TROPICAL ATLC.

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

$$
WALTON





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