[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI OCT 16 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...
STRONG RIDGING ACROSS INTERIOR EASTERN MEXICO AND AN INCREASED
PRESSURE GRADIENT ACROSS THE SW GULF OF MEXICO WATERS IS
FORECAST TO INITIATE NEAR GALE TO GALE FORCE NW TO N WINDS S OF
21N W OF 95W SATURDAY. THIS SMALL AREA OF GALE FORCE WINDS OFF
THE COAST OF VERACRUZ IS EXPECTED TO PERSIST THROUGH LATE SUNDAY.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 09N37W TO 13N37W MOVING W AT 10-15
KT. THE WAVE REMAINS LOW-AMPLITUDE AND COINCIDES WITH WEAK 700
MB TROUGHING BETWEEN 34W-40W. SCATTERED MODERATE CONVECTION IS
FROM 11N-15N BETWEEN 24W-27W.

TROPICAL WAVE EXTENDS FROM 09N47W TO 18N50W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH A 700 MB TROUGH BETWEEN 46W-51W AND
CONTINUES TO REMAIN EMBEDDED WITHIN THE SOUTHERN PERIPHERY OF A
LOW TO MID-LEVEL RIDGE ANCHORED OVER THE CENTRAL ATLC. NO
SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS
TIME.

TROPICAL WAVE EXTENDS FROM 13N87W TO 21N87W MOVING W AT 10-15
KT. THE WAVE COINCIDES WITH A FAIRLY BROAD AND ELONGATED 700 MB
TROUGH ANCHORED OVER THE EAST PACIFIC WATERS SOUTH OF GUATEMALA
AND SOUTHERN MEXICO. THE NORTHERN PORTION OF OVERALL LOW-LEVEL
WAVE ENERGY IS FOCUSED ON A 1008 MB LOW CENTERED ALONG THE WAVE
AXIS NEAR 16N. SCATTERED MODERATE TO STRONG CONVECTION IS
OCCURRING WITHIN 90 NM OF THE LOW. SCATTERED MODERATE CONVECTION
IS ELSEWHERE FROM 11N-23N BETWEEN 81W-90W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
12N16W INTO A 1010 MB LOW NEAR 10N19W. THE MONSOON TROUGH AXIS
CONTINUES FROM 15N23W INTO A 1011 MB NEAR 13N27W TO 07N42W.
WIDELY SCATTERED MODERATE CONVECTION IS FROM 05N-15N BETWEEN 22W-
28W. ISOLATED MODERATE CONVECTION IS FROM 02N-09N BETWEEN 30W-
42W.

...DISCUSSION...

GULF OF MEXICO...
BROAD LONGWAVE UPPER LEVEL TROUGHING IS NOTED ON WATER VAPOR
IMAGERY OVER THE EASTERN CONUS AND FAR WESTERN NORTH ATLC. THE
TROUGHING SUPPORTS A DISSIPATING STATIONARY FRONT EXTENDING FROM
LAKE OKEECHOBEE W-SW TO 24N88W. WHILE REMAINING RELATIVELY
WEAK...THE FRONT IS PROVIDING FOCUS ALONG WITH SOUTHWESTERLY
FLOW ALOFT A LARGE AREA OF SCATTERED TO NUMEROUS SHOWERS AND
SCATTERED TSTMS S OF 27N W OF 90W. MOST OF THE TROPICAL MOISTURE
IS BEING ADVECTED NORTHEASTWARD AWAY FROM A TROPICAL WAVE
CURRENTLY ANALYZED ALONG 87W IN THE NW CARIBBEAN SEA. ACROSS THE
SW GULF...AS SURFACE RIDGING MAINTAINS ITSELF ACROSS INLAND
PORTIONS OF MEXICO AND THE NORTHERN GULF WATERS...A SURFACE
TROUGH EXTENDS FROM 19N94W TO 22N97W. ISOLATED SHOWERS AND TSTMS
ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE BOUNDARY. THE
AREA TO THE WEST OF THE TROUGH AXIS IS THE LIKELY AREA FOR
DEVELOPING NEAR GALE TO GALE FORCE WINDS AS STATED IN THE
SPECIAL FEATURES SECTION ABOVE.

CARIBBEAN SEA...
A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION INFLUENCES MUCH OF
THE WESTERN CARIBBEAN AND CENTRAL AMERICA THIS EVENING ANCHORED
OVER THE NW CARIBBEAN NEAR 17N86W. WHILE PROVIDING AN OVERALL
DIFFLUENT ENVIRONMENT...THE MAIN SURFACE FEATURE IS A TROPICAL
WAVE ANALYZED ALONG 87W FROM THE NE TIP OF THE YUCATAN PENINSULA
SOUTHWARD TO FAR WESTERN NICARAGUA. A 1008 MB LOW IS CENTERED IN
THE GULF OF HONDURAS ALONG THE WAVE AXIS AND ALONG WITH THE
UPPER LEVEL DIFFLUENT ENVIRONMENT IN PLACE...IS GENERATING
NUMEROUS SHOWERS AND SCATTERED TSTMS GENERALLY W OF 80W...
INCLUDING INLAND PORTIONS OF CENTRAL AMERICA. SCATTERED SHOWERS
AND TSTMS ARE ALSO OCCURRING ACROSS JAMAICA AND CUBA...LIKELY
DUE TO THE INCREASED UPPER LEVEL DIFFLUENT PATTERN ALOFT AND
TYPICAL PEAK DAYTIME HEATING AND INSTABILITY. OTHERWISE...THE
REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF RELATIVELY DRY
NORTHERLY FLOW ALOFT E OF 76W WITH ONLY A FEW ISOLATED SHOWERS
NOTED ACROSS THE LEEWARD ISLANDS...PUERTO RICO...AND HISPANIOLA.
OUTSIDE THE INFLUENCE OF THE TROPICAL WAVE ALONG 87W...MODERATE
TO FRESH BREEZE TRADES ARE EXPECTED TO PERSIST THROUGH WEEKEND.

...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 ONLY ISOLATED...SHALLOW...AND
WESTWARD MOVING LOW-LEVEL SHOWERS INTO EARLY SATURDAY.

ATLANTIC OCEAN...
A LONGWAVE MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR
IMAGERY OVER THE EASTERN CONUS AND FAR WESTERN NORTH ATLC WATERS
SUPPORTING A STATIONARY FRONT EXTENDING FROM BERMUDA NEAR 32N65W
SW TO THE FLORIDA PENINSULA NEAR WEST PALM BEACH. ISOLATED
SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT E
OF 72W. NUMEROUS SHOWERS AND ISOLATED TSTMS HOWEVER ARE
OCCURRING S OF 29N W OF 72W ACROSS A LARGE PORTION OF THE SW
NORTH ATLC WATERS DUE TO NOT ONLY THE FRONT...BUT MAXIMUM MIDDLE
TO UPPER LEVEL DIFFLUENCE STEMMING FROM AN UPPER LEVEL RIDGE
ANCHORED OVER THE NW CARIBBEAN SEA. THE RIDGE AXIS EXTENDING NE
TO 30N70W. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR
23N57W AND REMAINS THE PRIMARY WEATHER GENERATOR ACROSS THE
CENTRAL ATLC. ISOLATED SHOWERS AND TSTMS ARE OCCURRING FROM 18N-
26N BETWEEN 47W-59W WITHIN THE EASTERN PERIPHERY OF THE UPPER
LEVEL LOW. OTHERWISE TO THE NORTH...A SUBTROPICAL RIDGE PREVAILS
ANCHORED BY A 1023 MB HIGH CENTERED NEAR 33N43W. FINALLY...
ACROSS THE EASTERN ATLC...A MIDDLE TO UPPER LEVEL SHORTWAVE
TROUGH AXIS EXTENDS FROM 37N15W SW TO 25N33W THAT SUPPORTS A
COLD FRONT FROM 32N14W TO 23N20W TO 19N30W TO 20N44W. POSSIBLE
ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE FRONT N OF
27N AND W OF 27W.

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

$$
HUFFMAN
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