[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 251747
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU SEP 25 2014

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.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 15N33W TO 25N32W MOVING W-NW AT 5-10
KT. A 1012 MB LOW IS CENTERED ALONG THE WAVE AXIS NEAR 20N THAT
REMAINS NORTH OF THE MONSOON TROUGH REGION AND COINCIDES WITH A
RELATIVELY NARROW 700 MB TROUGH ZONE BETWEEN THE MID-LEVEL
RIDGING FROM 14N-28N BETWEEN 28W-38W. CONVECTION REMAINS NON-
EXISTENT WITH THE WAVE AT THIS TIME DUE TO STRONG WESTERLY WIND
SHEAR. A MIDDLE TO UPPER LEVEL LOW TO THE N-NE IS HOWEVER
GENERATING ISOLATED MODERATE CONVECTION FROM 23N-32N BETWEEN
19W-31W.

TROPICAL WAVE EXTENDS FROM 12N60W TO 21N59W MOVING W AT 10-15
KT. THE WAVE COINCIDES WITH BROAD LOW TO MIDDLE LEVEL TROUGHING
BETWEEN 55W-65W AND CONTINUES TO MOVE BENEATH THE INFLUENCE OF A
BROAD MIDDLE TO UPPER LEVEL LOW CENTERED NEAR 21N60W. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 19N-25N BETWEEN 55W-63W...
AND IS LIKELY ENHANCED BY DYNAMICS ASSOCIATED BY THE UPPER LEVEL
LOW.

TROPICAL WAVE EXTENDS FROM 10N80W TO 22N79W MOVING W AT 15 KT.
GENERALLY EAST-SOUTHEASTERLY FLOW ALOFT IS NOTED OVER THE REGION
OF THE WAVE WHICH CONTINUES TO STRETCH LOW TO MID-LEVEL ENERGY
NORTHWARD AROUND THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL RIDGE
CENTERED OVER THE SW NORTH ATLC NEAR 34N66W. A PORTION OF THIS
ENERGY IS ANALYZED AS A SURFACE TROUGH ACROSS THE NW BAHAMAS AND
PORTIONS OF THE FLORIDA STRAITS TO THE NORTH OF THE WAVE. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 15N-20N BETWEEN 75W-83W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 17N16W TO
15N23W TO 09N34W TO A 1012 MB LOW NEAR 13N44W TO 12N49W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 12N49W TO
12N60W. SCATTERED MODERATE CONVECTION IS FROM 12N-14N BETWEEN
40W-44W.

...DISCUSSION...

GULF OF MEXICO...
A PAIR OF MID-LEVEL SHORTWAVE TROUGHS ARE NOTED ON WATER VAPOR
IMAGERY OVER THE GULF THIS AFTERNOON. THE FIRST SHORTWAVE IS
FOCUSED IN THE VICINITY OF 27N87W AND THE OTHER IS CLOSER TO THE
PARENT UPPER LEVEL LOW IN THE VICINITY OF 27N98W. THE TROUGHING
IN BOTH CASES SUPPORT A STATIONARY FRONT EXTENDING ACROSS THE
CENTRAL FLORIDA PENINSULA THEN FROM THE TAMPA BAY REGION NEAR
27N83W TO 26N90W AND INTO A 1014 MB LOW CENTERED NEAR 27N95W. IN
ADDITION...A SURFACE TROUGH EXTENDS SOUTHWARD FROM THE LOW TO
20N96W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING
ACROSS THE EASTERN PORTION OF THE FRONT FROM 24N-27N BETWEEN 82W-
88W WITH STRONGER CONVECTION OCCURRING ACROSS THE WESTERN GULF
AS SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM 25N-29N
BETWEEN 91W-96W...AND WITHIN 90 NM EITHER SIDE OF THE SURFACE
TROUGH AXIS. OTHERWISE...THE APPROACH OF A TROPICAL WAVE
CURRENTLY BEGINNING TO IMPACT THE NW CARIBBEAN SEA AND A SURFACE
TROUGH ANALYZED ACROSS THE EASTERN YUCATAN PENINSULA AND BELIZE
IS PROVIDING SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE SE
GULF S OF 23N BETWEEN 83W-88W THAT IS FORECAST TO MOVE ACROSS
THE SOUTH-CENTRAL GULF AND YUCATAN PENINSULA THROUGH THE
OVERNIGHT HOURS INTO FRIDAY. THE WEAK LOW ACROSS THE WESTERN
GULF IS EXPECTED TO DRIFT WESTWARD DURING THE NEXT 6 TO 12 HOURS
AND MOVE INLAND ACROSS SOUTH TEXAS GRADUALLY DISSIPATING BY LATE
FRIDAY.

CARIBBEAN SEA...
A RELATIVELY DIFFLUENT ENVIRONMENT IS NOTED OVER THE NW
CARIBBEAN DUE TO AN UPPER LEVEL ANTICYCLONIC CIRCULATION
CENTERED NEAR 19N84W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING
ACROSS A FAIRLY BROAD AREA FROM 15N-22N BETWEEN 76W-89W...A
PORTION OF WHICH INCLUDES THE INFLUENCE OF A TROPICAL WAVE
ANALYZED ALONG 80W. TO THE EAST...ANOTHER TROPICAL WAVE LIES
EAST OF THE LESSER ANTILLES ALONG 60W AND IS LARGELY INFLUENCED
BY AN UPPER LEVEL LOW CENTERED NEAR 21N59W. SCATTERED SHOWERS
AND ISOLATED TSTMS ARE OCCURRING TO THE NE OF THE EASTERN
BASIN...HOWEVER A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING
SE OF PUERTO RICO WITH ISOLATED SHOWERS ELSEWHERE N OF 14N
BETWEEN 60W-71W.

...HISPANIOLA...
CURRENTLY...THE ISLAND LIES BETWEEN THE INFLUENCE OF TROPICAL
WAVES...RESULTING IN A RELATIVELY LESS CONVECTIVELY ACTIVE DAY.
ONLY A FEW ISOLATED SHOWERS ARE OCCURRING ACROSS HISPANIOLA THIS
AFTERNOON WITH MORE COVERAGE NOTED ON SATELLITE IMAGERY WITHIN
THE ADJACENT COASTAL CARIBBEAN SEA WATERS. AS A TROPICAL WAVE
ALONG 60W APPROACHES DURING THE NEXT 36 TO 48 HOURS...CLOUDINESS
AND AN INCREASED PROBABILITY OF CONVECTIVE PRECIPITATION IS
EXPECTED FRIDAY INTO SATURDAY.

ATLANTIC OCEAN...
MULTIPLE MIDDLE TO UPPER LEVEL SHORTWAVES CONTINUE TO MOVE N-NE
ACROSS THE EASTERN U.S. SEABOARD AS NOTED ON WATER VAPOR IMAGERY
ON THE WESTERN PERIPHERY OF AN ELONGATED UPPER LEVEL
ANTICYCLONIC CIRCULATION CENTERED OVER THE SW NORTH ATLC WATERS
NEAR 30N73W. THE UPPER LEVEL DIFFLUENT ENVIRONMENT ALONG WITH
LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF A STATIONARY
FRONT ANALYZED FROM A 1018 MB LOW CENTERED NEAR 32N79W S-SW TO
THE FLORIDA PENINSULA NEAR CAPE CANAVERAL. TO THE SE OF THE
FRONTAL AREA...ENERGY ASSOCIATED WITH THE TROPICAL WAVE ACROSS
THE WESTERN CARIBBEAN SEA HAS FRACTURED NORTH AND IS ANALYZED AS
A SURFACE TROUGH FROM 23N79W TO 31N78W. SCATTERED SHOWERS AND
TSTMS ARE OCCURRING FROM N OF 23N W OF 74W. TO THE EAST...A
BROAD ELONGATED UPPER LEVEL LOW IS CENTERED NEAR 21N59W THAT
SUPPORTS A BROAD AREA OF CLOUDINESS WITH EMBEDDED ISOLATED
SHOWERS AND TSTMS OCCURRING FROM 19N-26N BETWEEN 54W-63W.
OTHERWISE...SURFACE RIDGING INFLUENCES THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC GENERALLY N OF 25N WITH THE EXCEPTION
OF INCREASED CLOUDINESS...SCATTERED SHOWERS...AND ISOLATED TSTMS
OCCURRING ON THE EASTERN PERIPHERY OF A MIDDLE TO UPPER LEVEL
LOW CENTERED NEAR 31N31W. THE CONVECTION IS NOTED ON SATELLITE
IMAGERY FROM 23N-32N BETWEEN 17W-31W.

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

$$
HUFFMAN

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