[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 141134
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU JUL 14 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
1100 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS NOW OFF THE COAST OF W AFRICA ACROSS THE CAPE
VERDE ISLANDS ALONG 18N24W 9N28W MOVING W NEAR 15 KT. THE WAVE
PRECEDES A LARGE SURGE OF MOISTURE EVIDENT IN TOTAL PRECIPITABLE
WATER IMAGERY. THERE IS ALSO A CLEARING IN THE SAHARAN AIR
LAYER. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE.

TROPICAL WAVE IN THE CENTRAL TRPCL ATLC IS ALONG 14N39W TO 7N40W
MOVING W 15-20 KT. THIS WAVE WAS RELOCATED FARTHER W DUE TO
TOTAL PRECIPITABLE WATER IMAGERY SHOWING A SURGE OF MOISTURE
WELL W OF THE PREVIOUS WAVE LOCATION. CONVECTION IS LIMITED TO
THE ITCZ REGION WHERE SCATTERED MODERATE/STRONG CONVECTION IS
FROM 7N-11N BETWEEN 35W-45W.

TROPICAL WAVE IN THE ERN CARIBBEAN EXTENDS ACROSS ERN DOMINICAN
REPUBLIC FROM 20N69W TO 13N72W MOVING W 15 KT. WAVE CONTINUES TO
PRECEDE A SURGE OF DEEP LAYER MOISTURE EVIDENT IN TOTAL
PRECIPITABLE WATER IMAGERY. HOWEVER...AN AREA OF MOISTURE IS
ALSO AHEAD OF IT ACROSS THE NRN CARIBBEAN. THIS AREA OF MOISTURE
IS NOT PREVIOUSLY ASSOCIATED WITH THE WAVE...BUT WILL LIKELY
BEGIN TO MERGE WITH THE MOISTURE BEHIND THE WAVE. CURRENTLY
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS E OF THE WAVE
AXIS ACROSS THE NRN LEEWARD ISLANDS FROM 16N-19N BETWEEN 58W-66W.

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

THE MONSOON TROUGH EXTENDS ACROSS AFRICA FROM THE PRIME MERIDIAN
AT 23N ALONG 16N11W 12N25W. THE ITCZ CONTINUES ALONG 11N29W
9N44W 6N58W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 5N-14N BETWEEN 13W-22W.

...DISCUSSION...

GULF OF MEXICO...
SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE BAY OF CAMPECHE
ASSOCIATED WITH A WEAK 1011 MB SURFACE LOW NEAR 20N97W THAT IS
MOVING INLAND OVER MEXICO. WEAK SURFACE RIDGING ALONG 25N COVERS
THE REMAINDER OF THE GULF OF MEXICO AROUND A 1015 MB HIGH NEAR
25N87W SUPPORTING FAIR WEATHER AND LIGHT ANTI-CYCLONIC FLOW
AROUND THE RIDGE. A FEW ISOLATED SHOWERS ARE NOTED ACROSS THE
NRN GULF N OF 27N BETWEEN 83W-93W. TOTAL PRECIPITABLE WATER
IMAGERY INDICATES ENHANCED MOISTURE ACROSS THIS AREA.
ALOFT...MAINLY NELY FLOW COVERS THE BASIN BETWEEN AN UPPER LEVEL
RIDGE CENTERED OVER NRN TEXAS AND AN UPPER LEVEL LOW OVER THE NW
CARIBBEAN. WATER VAPOR IMAGERY INDICATES DRY AIR IS BEING DRAWN
IN THE NELY FLOW ALOFT FROM THE W ATLC WHICH IS FURTHER
SUPPORTING THE FAIR WEATHER. WITH DAYTIME HEATING
SHOWERS/THUNDERSTORMS WILL LIKELY POP UP LATER IN THE AFTERNOON
ACROSS THE NRN GULF WHERE THE MOISTURE VALUES ARE HIGHER. WEAK
SURFACE RIDGING WILL CONTINUE OVER THE BASIN.

CARIBBEAN SEA...
THE NW CARIBBEAN IS CURRENTLY UNDER FAIR CONDITIONS AS DRY AIR
ALOFT IS BEING WRAPPED AROUND AN UPPER LEVEL LOW NEAR 20N83W.
SOME MOISTURE IS BEING DRAWN AROUND THE ERN SIDE OF THE UPPER
LOW WHICH IS SUPPORTING A FEW ISOLATED SHOWERS FROM 16N-21N
BETWEEN 77W-83W. THE SW CARIBBEAN REMAINS UNDER MOIST CONDITIONS
INFLUENCED BY THE MONSOON TROUGH THAT EXTENDS FROM THE E PACIFIC
JUST S OF MEXICO...ACROSS GUATEMALA...EL SALVADOR...AND ACROSS
NICARAGUA TO NRN COLOMBIA. LARGE CLUSTERS OF STRONG
SHOWERS/THUNDERSTORMS ARE CURRENTLY N OF COLOMBIA FROM 9N-13N
BETWEEN 74W-77W...AND N OF PANAMA FROM 10N-15N BETWEEN 77W-81W.
TOTAL PRECIPITABLE WATER IMAGERY INDICATES AN AREA OF ENHANCED
MOISTURE IS ACROSS THE N CENTRAL CARIBBEAN AHEAD OF A TROPICAL
WAVE EXTENDING ACROSS THE DOMINICAN REPUBLIC. ENHANCED MOISTURE
ALSO TRAILS THE WAVE ACROSS THE ERN CARIBBEAN. SEE TROPICAL WAVE
SECTION FOR MORE DETAILS. SIGNIFICANT RAINFALL HAS ALREADY
FALLEN ACROSS SOME OF THESE N CENTRAL CARIBBEAN ISLANDS WITH THE
FIRST BATCH OF MOISTURE...ESPECIALLY THE DOMINICAN REPUBLIC
WHICH HAS REPORTED OVER 7 INCHES IN SOME AREAS OF THE LAST 24
HOURS. WITH THE WAVE AND MOISTURE BEHIND IT APPROACHING...HEAVY
RAINFALL COULD CONTINUE OVER THE NEXT DAY OR SO INCREASING THE
CHANCE FOR LOCALIZED FLOODING AND MUDSLIDES. CURRENTLY...ONLY
ISOLATED SHOWERS ARE FROM 16N-19N E OF 66W. ALOFT...UPPER LEVEL
TROUGHING COVERS THE ERN CARIBBEAN EXTENDING FROM THE CENTRAL
ATLC ALONG 22N51W TO 13N67W. EXPECT SHOWER/THUNDERSTORM ACTIVITY
TO CONTINUE ACROSS MUCH OF THE NRN CARIBBEAN AND ERN CARIBBEAN
AS THE AREAS OF MOISTURE BOTH AHEAD AND BEHIND THE WAVE AXIS
MOVE WWD. ALSO...MUCH OF CENTRAL AMERICA AND SRN MEXICO HAS
ALREADY RECEIVED LARGE AMOUNTS OF RAINFALL OVER THE PAST COUPLE
OF DAYS WHICH COULD CONTINUE THROUGH THE END OF THE WEEK WHICH
WILL INCREASE THE CHANCE FOR DEADLY FLOODING AND MUDSLIDES.
MODEL GUIDANCE CONTINUES TO INDICATE THE MONSOON TROUGH WILL
REMAIN IN ITS NWD POSITION WITH POSSIBLE LOW LEVEL CIRCULATIONS
FORMING ALONG THE AXIS. THE W-SW FLOW ASSOCIATED WITH THE
MONSOON TROUGH WILL DRAW SIGNIFICANT TROPICAL MOISTURE ACROSS
THESE AREAS. COMBINED WITH OROGRAPHIC LIFT DUE TO MOUNTAINS THIS
CREATES A FORMULA TO EQUAL HEAVY PRECIPITATION. THESE AREAS
SHOULD MONITOR THE SITUATION OVER THE NEXT FEW DAYS AND STAY
TUNED FOR UPDATES ON THIS SCENARIO.

ATLANTIC OCEAN...
SURFACE RIDGING DOMINATES THE MAJORITY OF THE ATLC ANCHORED BY A
1032 MB AZORES HIGH NEAR 41N28W PROVIDING MOSTLY FAIR CONDITIONS
BASIN-WIDE. ALOFT...AN UPPER LEVEL RIDGE COVERS THE WRN ATLC
CENTERED OVER TEXAS. AN UPPER LEVEL TROUGH IS TO THE N OF THE
AREA ALONG 69W SUPPORTING AN AREA OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 28N-30N BETWEEN 61W-70W. AN UPPER LEVEL
TROUGH IS TO THE E OF THE RIDGE ALONG 53W. A SHORTWAVE UPPER
TROUGH EXTENDS OFF THE MAIN TROUGH EXTENDING TO THE ERN
CARIBBEAN. THIS IS SUPPORTING CLOUDINESS AND A FEW ISOLATED
SHOWERS FROM 22N-32N BETWEEN 52W-61W. UPPER LEVEL RIDGING COVERS
THE ERN ATLC CENTERED NEAR 38N37W. AN UPPER LEVEL TROUGH COVERS
THE FAR ERN ATLC EXTENDING FROM SPAIN TO THE CANARY ISLANDS.
ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE IS CENTERED OFF
THE W COAST OF AFRICA NEAR 18N24W.

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

$$
WALTON






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