[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301759
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUL 30 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL WAVE IS ANALYZED FROM 10N48W TO 19N50W MOVING W AT
15-20 KT. A 1008 MB LOW IS CENTERED NEAR THE SOUTHERN EXTENT OF
THE WAVE NEAR 12N49W AND CONTINUES TO BE LOCATED BENEATH THE
SOUTHWESTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC
CIRCULATION OVER THE CENTRAL TROPICAL ATLC CENTERED NEAR 14N40W.
AN AREA OF INCREASED TOTAL PRECIPITABLE WATER VALUES ALSO
COINCIDES WITH THE WAVE AXIS FROM 10N-18N BETWEEN 46W-53W WITH
SCATTERED MODERATE CONVECTION OCCURRING FROM 10N-15N BETWEEN
43W-52W.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 13N32W TO 24N32W MOVING W AT
15-20 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOWS A MAXIMUM AREA
OF LOW-LEVEL MOISTURE TO THE NW OF THE CAPE VERDE ISLANDS IN THE
VICINITY OF 22N31W. WHILE NO SIGNIFICANT CONVECTION IS NOTED ON
SATELLITE IMAGERY...THE WAVE CONTINUES TO COINCIDE WITH A
RELATIVELY ROBUST 700 MB TROUGH ALONG 33W.

TROPICAL WAVE IS ANALYZED FROM 11N82W TO 21N82W MOVING W AT
15-20 KT. BOTH LOWER LEVEL STREAMLINE ANALYSIS AND NEAR 700 MB
MODEL EVALUATION INDICATES THE WAVE REMAINS BROAD AS IT MOVES
ACROSS THE WESTERN CARIBBEAN SEA. THIS IS CONFIRMED IN TOTAL
PRECIPITABLE WATER IMAGERY AS VALUES OF LOW-LEVEL MOISTURE ARE
MAXIMIZED S OF 22N BETWEEN 75W-87W. THE WAVE IS ALSO PARTIALLY
EMBEDDED WITHIN THE MONSOON TROUGH AND THE ASSOCIATED LOW-LEVEL
CYCLONIC GYRE CENTERED OVER THE SW CARIBBEAN NEAR 12N82W.
SCATTERED MODERATE CONVECTION IS FROM 10N-22N BETWEEN 76W-87W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
09N20W TO 11N30W THEN RESUMES NEAR 11N33W TO 11N47W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 10N49W TO
06N57W. ISOLATED MODERATE CONVECTION IS FROM 07N-10N BETWEEN
14W-18W...AND FROM 09N-13N BETWEEN 32W-37W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL EASTERLY ZONAL FLOW DOMINATES ACROSS MUCH OF THE
GULF BASIN THIS AFTERNOON ON THE SOUTHERN PERIPHERY OF AN UPPER
LEVEL ANTICYCLONE THAT ENCOMPASSES A VERY LARGE PORTION OF THE
CONTINENTAL UNITED STATES. AT THE SURFACE...THE OVERALL STABLE
AND SUBSIDENT ATMOSPHERIC CONDITIONS ARE ALSO EVIDENT AS A 1020
MB HIGH IS CENTERED OVER SW ALABAMA AND IS PROVIDING MUCH OF THE
GULF WITH EASTERLY FLOW. THIS PATTERN IS EXPECTED TO PERSIST
THROUGH SUNDAY. WITH THE APPROACH OF A TROPICAL WAVE LOCATED IN
THE WESTERN CARIBBEAN SEA...INCREASE CHANCES FOR PRECIPITATION
IS FORECAST ACROSS THE YUCATAN PENINSULA AND AREAS S OF 23N
THROUGH THE REMAINDER OF THE WEEKEND INTO MONDAY.

CARIBBEAN SEA...
AS THE TROPICAL WAVE ALONG 82W TRACKS WESTWARD...WATER VAPOR
IMAGERY INDICATES IT CONTINUES TO MOVE ON THE SOUTHERN PERIPHERY
OF A LARGE ANTICYCLONIC CIRCULATION ORIGINATING OVER THE CENTRAL
CONTINENTAL UNITED STATES. LOW-LEVEL CONVERGENCE IN THE VICINITY
OF THE WAVE AXIS AND UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE
RIDGING IS SUPPORTIVE OF A BROAD AREA OF SCATTERED MODERATE
CONVECTION S OF 22N W OF 75W. FARTHER EAST...AN UPPER LEVEL
TROUGH AXIS EXTENDS FROM HISPANIOLA S-SE TO NORTHEAST VENEZUELA.
LOW-LEVEL MOISTURE CONVERGENCE ALONG WITH MIDDLE TO UPPER LEVEL
ENHANCING DYNAMICS ARE GENERATING A FEW ISOLATED SHOWERS BETWEEN
64W-72W. OVER THE NEXT FEW DAYS...IT IS ANTICIPATED THAT THE
TROPICAL WAVE ALONG 50W IN THE TROPICAL ATLC WILL CONTINUE TO
GATHER GRADUAL ORGANIZATION AND MOVE W-NW TOWARD THE LESSER
ANTILLES AND NE CARIBBEAN.

ATLANTIC OCEAN...
AN UPPER LEVEL ANTICYCLONE IS CENTERED OFFSHORE OF THE CAROLINAS
NEAR 34N75W AND CONTINUES TO PROVIDE STABLE NE TO E FLOW ALOFT
OVER THE W ATLC W OF 60W. THIS UPPER LEVEL REGIME SUPPORTS A
PAIR OF 1019 MB HIGHS CENTERED NEAR 29N69W AND 29N75W. TWO
SURFACE TROUGHS DANGLE SOUTHWARD INTO THE RIDGE...ONE ANALYZED
FROM EAST OF BERMUDA NEAR 32N64W TO 29N67W...THE OTHER FROM
32N71W TO 30N73W. ISOLATED LOW-TOPPED SHOWERS ARE OCCURRING FROM
29N-32N BETWEEN 68W-75W...AND FROM 28N-34N BETWEEN 58W AND THE
EASTERNMOST SURFACE TROUGH. THE REMAINDER OF THE CENTRAL AND
EASTERN ATLC IS UNDER THE INFLUENCE OF A 1031 MB HIGH CENTERED
W-SW FROM THE AZORES NEAR 37N34W PROVIDING MOSTLY STABLE
CONDITIONS AND FAIR WEATHER N OF 24N E OF 58W. EXAMINING THE
CIMSS SAHARAN AIR LAYER TRACKING PRODUCT AND VISIBLE METEOSAT-9
SATELLITE IMAGERY...A LARGE AREA OF AFRICAN DUST IS PRIMARILY N
OF 15N E OF 30W.

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

$$
HUFFMAN



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