[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 011758
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU OCT 01 2015

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...
HURRICANE JOAQUIN IS CENTERED NEAR 23.0N 74.2W AT 01/1800 UTC OR
ABOUT 60 NM SSE OF SAN SALVADOR BAHAMAS MOVING SW AT 5 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 936 MB. MAXIMUM SUSTAINED
WIND SPEED IS 115 KT WITH GUSTS TO 140 KT. NUMEROUS STRONG
CONVECTION IS FROM 21N-25N BETWEEN 71W-75W. NUMEROUS MODERATE
AND STRONG CONVECTION IS FROM 20N-25N BETWEEN 71W-76W. SCATTERED
MODERATE CONVECTION IS ELSEWHERE FROM 18N-24N BETWEEN 70W-78W.
SEE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS.

A 1007 MB LOW IS CENTERED NEAR 26N56W WITH A REMNANT FRONTAL
BOUNDARY ANALYZED AS A SURFACE TROUGH EXTENDING FROM 26N50W INTO
THE LOW CENTER THEN TO 25N60W TO 27N64W. THE LOW CURRENTLY IS
SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH WITH AXIS EXTENDING
FROM 30N58W TO A BASE NEAR 22N63W. SCATTERED MODERATE CONVECTION
IS OCCURRING FROM 21N-28N BETWEEN 50W-58W...AND FROM 23N-26N
BETWEEN 58W-64W. THE SYSTEM IS EXPECTED TO CONTINUE GRADUALLY
ORGANIZING WITH NEAR GALE TO GALE FORCE WINDS MATERIALIZING
WITHIN THE NORTHERN SEMICIRCLE BY 02/0600 UTC. IN ADDITION...A
MEDIUM CHANCE EXISTS OF THE LOW DEVELOPING INTO A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 12N26W TO 17N25W MOVING W AT 5-10 KT.
THE WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 23W-30W AND A
MAXIMUM IN 850 MB RELATIVE VORTICITY FOCUSED AROUND A 1009 MB
LOW CENTERED AT THE SOUTHERN EXTENT OF THE WAVE AXIS NEAR
12N26W. SCATTERED MODERATE CONVECTION IS FROM 06N-08N BETWEEN
21W-25W...FROM 09N-13N BETWEEN 21W-25W...AND FROM 12N-18N
BETWEEN 21W-30W.

TROPICAL WAVE EXTENDS FROM 10N44W TO 16N38W MOVING W AT 5-10 KT.
THE WAVE COINCIDES WITH A RELATIVELY SHARP 700 MB TROUGH AXIS
WITH MAXIMUM 850 MB RELATIVE VORTICITY ELONGATED ALONG THE WAVE
AXIS. NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THE
WAVE AT THIS TIME.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO
11N30W TO 12N35W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 11N44W TO 10N54W. ISOLATED MODERATE CONVECTION IS
FROM 11N-13N BETWEEN 50W-53W.

...DISCUSSION...

GULF OF MEXICO...
A RELATIVELY SHARP MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON
WATER VAPOR IMAGERY EXTENDING FROM OVER THE OHIO RIVER VALLEY
SOUTH-SOUTHWESTWARD TO A BASE OVER THE SW GULF NEAR 21N95W. THE
TROUGHING SUPPORTS A COLD FRONT EXTENDING FROM THE FLORIDA BIG
BEND REGION SW TO 28N90W THEN TO THE TEXAS COAST NEAR 28N97W.
WHILE THE TROUGH AXIS LIES MOSTLY TO THE SOUTH OF THE FRONT...
THE FRONT REMAINS PRECIPITATION-FREE OVERALL. MOST OF THE LOW-
LEVEL MOISTURE IS NOTED ON VISIBLE SATELLITE IMAGERY ACROSS THE
SOUTHERN HALF OF THE BASIN FOCUSED AROUND A WEAK 1009 MB LOW
CENTERED NEAR 23N91W. A SURFACE TROUGH EXTENDS NE FROM THE LOW
TO 25N87W AND SW FROM THE LOW TO 21N95W. ISOLATED SHOWERS ARE
OCCURRING S OF 25N BETWEEN 86W-97W. THE COLD FRONT IS EXPECTED
TO CONTINUE MOVING ACROSS THE GULF THROUGH THE UPCOMING WEEKEND
PROVIDING FRESH TO STRONG NORTHERLY FLOW THROUGH LATE FRIDAY
NIGHT THEN MOSTLY MODERATE TO FRESH NORTH-NORTHWEST WINDS
THEREAFTER THROUGH THE REMAINDER OF THE WEEKEND INTO MONDAY.

CARIBBEAN SEA...
DUE TO THE PRESENCE OF HURRICANE JOAQUIN EAST OF THE CENTRAL
BAHAMAS...NORMAL TRADE WIND FLOW HAS BEEN DISRUPTED WITH GENTLE
TO MODERATE SOUTHERLY WINDS GENERALLY E OF 75W AND GENTLE TO
MODERATE WEST-SOUTHWEST WINDS W OF 75W. RECENT SCATTEROMETER
PASSES CONFIRM THIS FLOW WITH A SURFACE TROUGH ANALYZED FROM
COASTAL BELIZE NEAR 18N88W TO 21N85W. SCATTERED SHOWERS AND
TSTMS ARE OCCURRING WITHIN 90 NM TO THE EAST OF THE BOUNDARY...
AS WELL AS WITHIN 90 NM EITHER SIDE OF A LINE FROM 21N84W TO
19N72W IN ASSOCIATION WITH A SOUTHERN CONVECTIVE BAND OF
JOAQUIN. OTHERWISE...ONLY ISOLATED SHOWERS AND TSTMS ARE
OCCURRING WITHIN CLOSE PROXIMITY TO THE MONSOON TROUGH ANALYZED
ALONG 10N BETWEEN NORTHERN COLOMBIA AND COSTA RICA. ELSEWHERE...
SKIES REMAIN MOSTLY CLEAR WITH FAIR CONDITIONS. AREAS OF
CONVECTIVE PRECIPITATION ARE EXPECTED TO CONTINUE IMPACTING CUBA
AND PORTIONS OF HISPANIOLA THROUGH LATE SATURDAY AS JOAQUIN
TRACKS GENERALLY NORTHWARD.

...HISPANIOLA...
CURRENTLY...THE OUTER CONVECTIVE PRECIPITATION BANDS OF
HURRICANE JOAQUIN EXTEND ACROSS THE ISLAND AS SCATTERED SHOWERS
AND TSTMS GENERALLY N OF 18N BETWEEN 69W-76W. THE CONVECTION IS
EXPECTED TO PERSIST DURING THE NEXT 24 HOURS AS HURRICANE
LINGERS NORTH OF THE ISLAND BEFORE TRACKING NORTHWARD.

ATLANTIC OCEAN...
THE MAIN FEATURE ACROSS THE SW NORTH ATLC IS HURRICANE JOAQUIN.
WHILE JOAQUIN REMAINS THE FOCUS...THE AREA OF LOWER PRESSURE
VALUES EXTENDS NORTHWESTWARD TO THE SE CONUS COAST AS AN UPPER
LEVEL TROUGH CURRENTLY ACROSS THE OHIO RIVER VALLEY AND SE CONUS
SUPPORTS A STATIONARY FRONT EXTENDING FROM 34N76W TO THE SE
GEORGIA COAST NEAR 31N81W. THE FRONT CONTINUES SW INTO THE GULF
OF MEXICO AS A COLD FRONT. A PRE-FRONTAL SURFACE TROUGH EXTENDS
FROM THE FRONT NEAR 33N78W INTO A 1004 MB LOW CENTERED OFF THE
COAST OF CAPE CANAVERAL FLORIDA NEAR 28N80W. THE FRONT AND
TROUGH BOUNDARY IS PROVIDING FOCUS FOR SCATTERED SHOWERS AND
TSTMS OCCURRING N OF 28N BETWEEN 76W-81W. FARTHER EAST...THE
OTHER SPECIAL FEATURE...A 1007 MB LOW CENTERED NEAR 26N56W...
CONTINUES TO DEVELOP TROPICAL CHARACTERISTICS. HOWEVER...
REGARDLESS OF POTENTIAL TROPICAL CYCLONE DEVELOPMENT...NEAR GALE
TO GALE FORCE WINDS ARE FORECAST WITHIN THE NORTHERN SEMICIRCLE
BEGINNING 02/0600 UTC. OTHERWISE...THE EASTERN ATLC IS UNDER THE
INFLUENCE OF A DISSIPATING STATIONARY FRONT EXTENDING FROM
32N28W SW INTO A 1010 MB LOW CENTERED NEAR 24N44W. ISOLATED
SHOWERS AND TSTMS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE
BOUNDARY.

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

$$
HUFFMAN
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