[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED JUL 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

TROPICAL STORM BRET IS CENTERED NEAR 31.9N 73.0W AT 20/2100 UTC
OR 235 NM SSE OF CAPE HATTERAS NORTH CAROLINA AND ABOUT 415 NM W
OF BERMUDA MOVING NE AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO
50 KT. SCATTERED MODERATE CONVECTION IS OCCURRING MOSTLY IN THE
SOUTHERN SEMICIRCLE FROM 27N-31N BETWEEN 71W-74W. BRET IS
FORECAST TO TRACK NE OVER THE NEXT 2 DAYS AND CONTINUE WEAKENING
GRADUALLY AS NORTH AND NORTHWESTERLY MIDDLE TO UPPER LEVEL SHEAR
TAKES ITS TOLL THROUGH LATE FRIDAY. SEE LATEST NHC FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE
DETAILS.

TROPICAL STORM CINDY IS CENTERED NEAR 35.2N 53.8W AT 20/2100 UTC
OR 575 NM ENE OF BERMUDA AND ABOUT 1300 NM W OF THE AZORES
MOVING NE AT 21KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009
MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT.
SCATTERED MODERATE CONVECTION IS LOCATED MAINLY WITHIN 180 NM
FROM CENTER IN THE NE QUADRANT. CINDY IS FORECAST TO TRACK NE
OVER THE NEXT 2 TO 3 DAYS AND HAS A 48 HOUR WINDOW FOR MODEST
STRENGTHENING BEFORE COOLER SEA SURFACE TEMPERATURES AND
WESTERLY UPPER LEVEL SHEAR DISSIPATE THE SYSTEM ALTOGETHER BY
LATE SATURDAY. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 07N46W TO 16N40W MOVING W AT 20
KT. THE WAVE IS LOCATED ON THE LEADING EDGE OF A RATHER LARGE
AND BROAD AREA OF LOW-LEVEL MOISTURE TO THE EAST OF THE WAVE
AXIS AS NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. THIS ALONG
WITH OVERALL BROAD CYCLONIC FLOW S OF 15N BETWEEN 35W-48W
ACCOMPANY THE WAVE WHICH CONTINUES TO PERTURB THE ITCZ AXIS.
ISOLATED MODERATE CONVECTION IS WITHIN 90 NM WEST OF THE WAVE N
OF 12N.

TROPICAL WAVE IS ANALYZED FROM 13N77W TO 22N75W MOVING W AT 20
KT. THE WAVE APPEARS VERY BROAD ON SATELLITE IMAGERY AND
CONTINUES TO INTERACT ALOFT WITH AN UPPER LEVEL LOW CENTERED
NEAR 19N72W. BOTH THE LOW-LEVEL CONVERGENCE AND UPPER LEVEL
DIFFLUENCE ARE GENERATING AN AREA OF ISOLATED MODERATE
CONVECTION FROM 17N-21N BETWEEN 69W-76W. IT IS VERY POSSIBLE
THIS CONVECTION IS ASSOCIATED MORE WITH THE UPPER LEVEL LOW THAN
THE LOWER-LEVEL WAVE DYNAMICS.

TROPICAL WAVE IS ANALYZED FROM 17N TO 22N ALONG 94W MOVING W AT
15 KT. THE WAVE EXHIBITS CYCLONIC TURNING OF THE LOW-LEVEL CLOUD
FIELD IN THE VICINITY OF THE WAVE AXIS HOWEVER IS QUICKLY
BECOMING EMBEDDED WITHIN ANTICYCLONIC FLOW ACROSS THE WESTERN
GULF OF MEXICO. NO ACTIVE CONVECTION IS NOTED WITH THE WAVE AT
THIS TIME.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
07N23W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N23W TO 11N42W...THEN RESUMES NEAR 07N48W TO 06N54W. ISOLATED
MODERATE CONVECTION IS FROM 04N-07N BETWEEN 23W-34W...AND FROM
02N-07N BETWEEN 38W-46W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES A BROAD UPPER LEVEL LOW IS
CENTERED OVER THE WESTERN GULF NEAR 24N94W WHICH IS PROVIDING
FOR MARGINAL MIDDLE TO UPPER LEVEL LIFT ACROSS MUCH OF THE
NORTH-CENTRAL GULF BASIN THIS EVENING. WHILE A RELATIVELY WEAK
SURFACE RIDGE EXTENDS ACROSS THE EASTERN GULF ANCHORED BY A 1017
MB HIGH CENTERED NEAR 28N87W...SOUTHERLY LOW-LEVEL MOISTURE
TRANSPORT AND INSTABILITY ACROSS PORTIONS OF THE WESTERN GULF
ARE GENERATING ISOLATED SHOWERS FROM 26N-29N BETWEEN 88W-95W.
THE SURFACE HIGH IS EXPECTED TO REMAIN NEARLY STATIONARY OVER
THE EASTERN GULF THROUGH THE WEEKEND AS AN AREA OF LOW PRESSURE
DEVELOPS ACROSS THE WESTERN HIGH PLAINS OF THE U.S.

CARIBBEAN SEA...
AS MENTIONED ABOVE...A TROPICAL WAVE IS ALONG 76W IN THE CENTRAL
CARIBBEAN AND CONTINUES TO INTERACT WITH AN UPPER LEVEL LOW
CENTERED NEAR 19N72W. WHILE MOST OF THE ISOLATED SHOWERS ARE
LOCATED OVER INTERIOR PORTIONS OF HISPANIOLA...THIS ISOLATED
SHOWER ACTIVITY EXTENDS TO THE EAST OF THE WAVE AXIS ALONG 18N
OVER PUERTO RICO AND THE US/UK VIRGIN ISLANDS. THE REMAINDER OF
THE EASTERN CARIBBEAN IS OVERALL TRANQUIL THIS EVENING WITH
MOSTLY CLEAR SKIES AND FAIR CONDITIONS. TO THE WEST OF THE WAVE
AXIS...AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE NW
CARIBBEAN NEAR 18N84W AND EXTENDS AN UPPER LEVEL RIDGE AXIS
SOUTHWARD TO COSTA RICA NEAR 11N83W. MOSTLY FAIR CONDITIONS ARE
NOTED OVER MUCH OF THE WESTERN CARIBBEAN THIS EVENING...HOWEVER
WITH AMPLE UPPER LEVEL DIFFLUENCE IN PLACE AND PEAK DAYTIME
HEATING ACROSS CUBA AND INTERIOR NICARAGUA AND HONDURAS...
SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER INTERIOR CUBA
BETWEEN 78W-84W...AND FROM 11N-16N BETWEEN 84W-87W ACROSS
CENTRAL AMERICA.

ATLANTIC OCEAN...
TROPICAL STORM BRET CONTINUES TO RESIDE ON THE NORTHERN
PERIPHERY OF THE SUBTROPICAL RIDGE ACROSS THE W ATLC THIS
EVENING. AS BRET TRACKS NE OVER THE NEXT FEW DAYS THE SURFACE
RIDGE AXIS IS EXPECTED TO RE-ESTABLISH ITSELF ALONG 26N THROUGH
THE REMAINDER OF THE WEEK AND GRADUALLY SHIFT NORTHWARD TO 29N
BY SATURDAY. FARTHER TO THE E-NE OF BRET THIS EVENING WATER
VAPOR IMAGERY SHOWS AN UPPER LEVEL TROUGH EAST OF BERMUDA ALONG
63W THAT IS EXPECTED TO MOVE TROPICAL STORM CINDY NE THROUGH
SATURDAY. ELSEWHERE...A STRONG 1034 MB AZORES HIGH IS CENTERED
NEAR 40N31W AND CARRIES INFLUENCE ACROSS THE REMAINDER OF THE
CENTRAL AND EASTERN TROPICAL ATLC N OF 18N WITH MOSTLY FAIR
CONDITIONS AND A LARGE AREA OF NE TO E WINDS OF 15 TO 20 KT.

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

$$
HUFFMAN




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