[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110549
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON JUL 11 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
0500 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IN THE CENTRAL TRPCL ATLC EXTENDS FROM NEAR 14N47W
TO 6N53W MOVING W 15-20 KT. WAVE CONTINUES TO PRECEDE A SURGE OF
DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY.
SATELLITE IMAGERY ALSO INDICATES LOW LEVEL CYCLONIC FLOW IS
AROUND THE WAVE AXIS CONFIRMED BY AN ASCAT SCATTEROMETER PASS
FROM 0100 UTC. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
WITHIN 120 NM W OF THE AXIS.

TROPICAL WAVE IN THE CENTRAL/WRN CARIBBEAN EXTENDS ACROSS THE
FAR WRN SIDE OF JAMAICA FROM 19N78W TO 11N79W MOVING W NEAR 15
KT. WAVE LIES WITHIN A BROAD AREA OF ENHANCED MOISTURE ACROSS
THE WRN CARIBBEAN...AND JUST W OF THE HIGHEST MOISTURE VALUES IN
THE AREA. THE WAVE LIES UNDER MOIST SWLY AND DIFFLUENT FLOW
ALOFT WHICH IS HELPING ENHANCE SCATTERED MODERATE/ISOLATED
STRONG CONVECTION W OF THE WAVE AXIS FROM 12N-19N BETWEEN
77W-84W.

TROPICAL WAVE IN THE BAY OF CAMPECHE EXTENDS FROM 23N94W TO
14N95W MOVING W NEAR 10 KT. WAVE IS EMBEDDED WITHIN AN AREA OF
ENHANCED MOISTURE PRESENT ACROSS THE WRN GULF OF MEXICO. WATER
VAPOR IMAGERY INDICATES DRY AIR IN THE MID AND UPPER LEVELS IS
BEING DRAWN AROUND THE SRN EXTENT OF AN UPPER LEVEL RIDGE OVER
THE ERN GULF WHICH IS INHIBITING CONVECTION NEAR THE WAVE AXIS
BESIDES AN AREA OF STRONG CONVECTION OVER MEXICO FROM 15N-18N
BETWEEN 92W-97W.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN
AT 23N ALONG 21N8W 18N17W 12N20W 10N28W. THE ITCZ CONTINUES FROM
10N28W ALONG 10N47W 8N63W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 7N-10N BETWEEN 15W-23W. SIMILAR ACTIVITY IS
FROM 8N-10N BETWEEN 41W-43W...AND FROM 7N-9N BETWEEN 54W-56W.

...DISCUSSION...

GULF OF MEXICO...
A TROPICAL WAVE IN THE SRN BAY OF CAMPECHE IS CAUSING AN AREA OF
CONVECTION OVER SRN MEXICO. SEE TROPICAL WAVE SECTION ABOVE FOR
MORE DETAILS. THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE
RIDGING AROUND A 1017 MB HIGH OFF THE NW COAST OF FLORIDA NEAR
28N85W. THIS RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED
OVER CENTRAL ALABAMA. AN UPPER LEVEL TROUGH COVERS THE FAR WRN
GULF CENTERED OVER NRN TEXAS. DRY AIR IS WRAPPING AROUND THE SRN
EXTENT OF THE UPPER RIDGE ACROSS THE FLORIDA STRAITS AND INTO
THE CENTRAL GULF WHICH IS SUPPORTING FAIR WEATHER ACROSS MUCH OF
THE BASIN. HOWEVER...A SHORTWAVE UPPER LEVEL TROUGH PERTURBS
INTO THE UPPER RIDGE FROM THE W ATLC AND ACROSS NRN FLORIDA.
THIS TROUGH COMBINED WITH THE EFFECTS OF ENHANCED MOISTURE IS
CURRENTLY ENHANCING AN AREA OF STRONG SHOWERS AND THUNDERSTORMS
ACROSS SW FLORIDA FROM LAKE OKEECHOBEE TO BETWEEN SARASOTA AND
FORT MYERS. A FEW ISOLATED SHOWERS ARE ELSEWHERE WITHIN 120 NM
OF THE W FLORIDA COAST N OF 25N. EXPECT THE TROPICAL WAVE TO
MOVE WWD TOWARDS MEXICO AS WEAK SURFACE RIDGING CONTINUES ACROSS
THE REMAINDER OF THE BASIN.

CARIBBEAN SEA...
A WEAK SURFACE TROUGH EXTENDS ACROSS WRN CUBA...BUT CURRENTLY
NOT CAUSING ANY ACTIVE WEATHER DUE TO DRY AIR WRAPPING AROUND
THE SRN END OF AN UPPER LEVEL RIDGE OVER THE ERN GULF. AN UPPER
LEVEL TROUGH COVERS THE NW CARIBBEAN CENTERED NEAR 18N82W. AN
UPPER LEVEL RIDGE COVERS THE CENTRAL CARIBBEAN CENTERED N OF
VENEZUELA. THIS PATTERN IS CREATING MOIST SWLY FLOW ALOFT FROM
COSTA RICA TO THE WINDWARD PASSAGE. THIS AREA OF DIFFLUENCE IS
ALSO ABOVE A TROPICAL WAVE ACROSS WRN JAMAICA. THIS COMBINATION
IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 11N-20N
BETWEEN 76W-86W. SIMILAR ACTIVITY IS S OF 11N ACROSS COSTA RICA
AND PANAMA INFLUENCED BY THE MONSOON TROUGH THAT EXTENDS FROM
THE E PACIFIC ACROSS COSTA RICA TO NRN COLOMBIA. MODEL GUIDANCE
STILL INDICATES THAT THE MONSOON TROUGH WILL BEGIN TO LIFT N
LATER IN THE WEEK ACROSS SRN MEXICO AND THE NRN CENTRAL
CARIBBEAN WHICH WILL CONCENTRATE SHOWER ACTIVITY OVER THESE
AREAS. THE ERN CARIBBEAN IS UNDER MOSTLY FAIR CONDITIONS IN ELY
20-25 KT TRADEWINDS. A FEW EMBEDDED SHOWERS ARE EMBEDDED IN THE
ELY FLOW ACROSS THE NE CARIBBEAN WITH A CLUSTER OF THUNDERSTORMS
CURRENTLY OVER THE MONA PASSAGE. A TROPICAL WAVE E OF THE LESSER
ANTILLES IS EXPECTED TO IMPACT THE BASIN LATER IN THE WEEK.

ATLANTIC OCEAN...
WEAK SURFACE RIDGING DOMINATES THE WRN ATLC MAINTAINING MOSTLY
FAIR CONDITIONS. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE
CENTERED OVER CENTRAL ALABAMA WITH ANTICYCLONIC CIRCULATION
EXTENDING TO 60W. HOWEVER...A SHORTWAVE UPPER TROUGH EXTENDS
INTO THE UPPER RIDGE ALONG 37N58W 31N72W 29N82W. THIS UPPER
TROUGH IS SUPPORTING AN AREA OF ISOLATED SHOWERS/POSSIBLE
THUNDERSTORMS N OF 29N BETWEEN 60W-78W. AN UPPER LEVEL LOW IS
SPINNING IN THE CENTRAL ATLC NEAR 30N55W SUPPORTING A SURFACE
TROUGH ALONG 31N55W TO 25N58W. SCATTERED SHOWERS ARE WITHIN 120
NM E OF THE AXIS. THE REMAINDER OF THE BASIN IS DOMINATED BY
SURFACE RIDGING AROUND A 1029 MB HIGH NEAR 35N36W PROVIDING FAIR
WEATHER. ALOFT...AN UPPER LEVEL RIDGE COVERS THE MAJORITY OF THE
ERN ATLC CENTERED SW OF THE AZORES ISLANDS. A NARROW UPPER LEVEL
TROUGH EXTENDS FROM THE CANARY ISLANDS TO JUST N OF THE CAPE
VERDE ISLANDS CAUSING NO ACTIVITY WEATHER IN THE DISCUSSION
AREA.

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

$$
WALTON





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