[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN OCT 18 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
THE COMBINATION OF STRONG HIGH PRESSURE ACROSS EASTERN MEXICO...
LOWER PRESSURE ACROSS CENTRAL AMERICA AND SOUTHERN MEXICO...AND
A SURFACE TROUGH ANALYZED ACROSS THE SW GULF OF MEXICO WATERS IS
SUPPORTING NEAR GALE TO GALE FORCE NW WINDS ALONG THE COAST OF
VERACRUZ...MAINLY S OF 21N W OF 95W. SEE LATEST NWS HIGH SEAS
FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 FOR MORE
DETAILS.

...TROPICAL WAVES...
NONE.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
12N17W TO A 1011 MB LOW NEAR 09N22W TO 07N25W...THEN RESUMES IN
THE VICINITY OF A 1011 MB LOW NEAR 13N30W TO A 1012 MB LOW NEAR
10N39W TO 08N42W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS FROM 10N-14N BETWEEN 20W-25W. SCATTERED MODERATE
CONVECTION IS ELSEWHERE FROM 03N-18N BETWEEN 20W-26W. ISOLATED
MODERATE CONVECTION IS FROM 13N-17N BETWEEN 26W-30W...FROM 08N-
12N BETWEEN 33W-39W...AND FROM 07N-14N BETWEEN 42W-52W. TO THE
WEST OF THE MONSOON TROUGH AXIS...A 1012 MB LOW IS CENTERED NEAR
11N53W WITH A SURFACE TROUGH EXTENDING NORTHWARD TO 17N54W.
SCATTERED MODERATE CONVECTION IS FROM 11N-16N BETWEEN 48W-53W.

...DISCUSSION...

GULF OF MEXICO...
BROAD LONGWAVE TROUGHING IS NOTED ON WATER VAPOR IMAGERY OVER
THE EASTERN CONUS AND WESTERN NORTH ATLC WATERS THIS EVENING
SUPPORTING A COLD FRONT ANALYZED AT 18/2100 UTC FROM LAKE
OKEECHOBEE TO 25N90W TO 23N94W. WHILE A RELATIVELY COOLER AND
DRIER AIR MASS IS NOTED IN OBSERVATIONS TO THE NORTH OF THE
FRONT...STRONG NE WINDS COVER MOST OF THE BASIN AS INDICATED BY
EARLIER ASCAT PASSES. THIS WIND FIELD IS EXPECTED TO PERSIST
THROUGH WEDNESDAY WITH WINDS SHIFTING MORE EASTERLY BY MONDAY AS
HIGH PRESSURE TO THE NORTH ACROSS THE SE AND MID-ATLC SLIDES
EASTWARD. ACROSS THE SW GULF...AS NOTED IN THE SPECIAL FEATURES
SECTION...A 1008 MB LOW IS CENTERED ALONG THE MEXICO COAST NEAR
18N94W WITH A SURFACE TROUGH EXTENDING NW TO 22N97W. SCATTERED
SHOWERS AND TSTMS ARE OCCURRING MAINLY S OF 23N W OF 91W...WITH
THE NEAR GALE TO GALE FORCE NW WINDS WITHIN CLOSE PROXIMITY TO
THE COAST OF VERACRUZ.

CARIBBEAN SEA...
UPPER LEVEL RIDGING EXTENDS OVER CENTRAL AMERICA AND MUCH OF THE
WESTERN CARIBBEAN WITH AXIS EXTENDING FROM OVER HONDURAS NE TO
BEYOND 22N72W. GIVEN THE OVERALL DIFFLUENT ENVIRONMENT THE
RIDGING PROVIDES...SCATTERED SHOWERS AND TSTMS...A FEW LOCALLY
STRONG...ARE OCCURRING NW OF A LINE FROM THE WINDWARD PASSAGE
NEAR 20N74W TO COASTAL NICARAGUA NEAR 12N84W. OTHERWISE...THE
REMAINDER OF THE CENTRAL AND EASTERN CARIBBEAN ARE UNDER THE
INFLUENCE OF NORTH-NORTHEASTERLY FLOW ALOFT BETWEEN THE RIDGE
AND AN UPPER LEVEL TROUGH AXIS EXTENDING FROM 17N59W SW TO A
BASE OVER SOUTHERN VENEZUELA. WATER VAPOR IMAGERY INDICATES
MOSTLY DRY AIR AND SUBSIDENCE PREVAIL WITH CLEAR SKIES AND FAIR
CONDITIONS THIS EVENING. A FEW LINGERING ISOLATED SHOWERS AND
TSTMS ARE NOTED ACROSS HISPANIOLA AND THE LEEWARD ISLANDS BUT
CONTINUE TO TREND DOWNWARD IN INTENSITY. FINALLY...GENTLE TO
MODERATE TRADES CONTINUE WITH ONLY OCCASIONAL FRESH BREEZE
CONDITIONS EXPECTED WITHIN CLOSE PROXIMITY TO THE NW VENEZUELA
AND COLOMBIA COASTS THROUGH THE OVERNIGHT HOURS INTO MONDAY.

...HISPANIOLA...
CURRENTLY A FEW ISOLATED SHOWERS AND TSTMS LINGER ACROSS THE
ISLAND DUE TO A RELATIVELY DIFFLUENT ENVIRONMENT ALOFT AND PEAK
DAYTIME HEATING. THIS ACTIVITY SHOULD DIMINISH GRADUALLY THROUGH
THE OVERNIGHT HOURS LEAVING MOSTLY CLEAR SKIES AND FAIR
CONDITIONS FOR EARLY MONDAY.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE
WESTERN NORTH ATLC WATERS AND PORTIONS OF NEW ENGLAND THAT
SUPPORT A COLD FRONT EXTENDING FROM 32N70W SW TO THE FLORIDA
PENINSULA NEAR WEST PALM BEACH. IN ADDITION...A PRE-FRONTAL
SURFACE TROUGH EXTENDS FROM 32N61W SW TO 24N73W. BETWEEN THESE
TWO BOUNDARIES...ISOLATED SHOWERS ARE OCCURRING WITH MORE
INTENSE ACTIVITY OF SCATTERED SHOWERS AND TSTMS WITHIN 150 NM
EAST OF THE SURFACE TROUGH. OTHERWISE...BEHIND THE COLD FRONT
STRONG N-NE WINDS PREVAIL AND WILL CONTINUE TO SPREAD
SOUTHEASTWARD AS THE FRONT CONTINUE TO MARCH EASTWARD THROUGH
MONDAY. ACROSS THE CENTRAL ATLC...AN UPPER LEVEL LOW AND MID-
LEVEL ENERGY IS NOTED ON WATER VAPOR IMAGERY IN THE VICINITY OF
23N54W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING FROM 20N-25N
BETWEEN 49W-59W. THIS CONVECTION IS FOUND ON THE SOUTHWESTERN
PERIPHERY OF A SURFACE RIDGE ANCHORED BY A 1025 MB HIGH CENTERED
NEAR 35N42W. FINALLY...ACROSS THE NORTHEASTERN PORTION OF THE
DISCUSSION AREA...A COLD FRONT EXTENDS FROM 32N13W TO 27N21W TO
31N30W. OTHER THAN MODERATE TO FRESH NORTHERLY WINDS...ONLY A
FEW ISOLATED SHOWERS ARE OCCURRING NE OF THE CANARY ISLANDS N OF
30N E OF 14W.

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

$$
HUFFMAN
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