[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 052357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT DEC 05 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...

A COLD FRONT EXTENDS FROM 32N48W TO 29N60W WHERE IT BECOMES
STATIONARY AND CONTINUES THROUGH 29N73W TO 27N76W TO THE STRAITS
OF FLORIDA. NORTH OF THE FRONT...A STRONG PRESSURE GRADIENT
PERSISTS BETWEEN LOWER PRESSURE ACROSS THE GREATER ANTILLES AND
BAHAMAS...AND A STRONG HIGH PRESSURE SYSTEM AT 1040 MB CENTERED
OVER CENTRAL PENNSYLVANIA. LATE MORNING SCATTEROMETER DATA
CONTINUED TO INDICATE A 120 NM WIDE SWATH OF GALE FORCE WINDS
DIRECTLY NORTH OF THE FRONT. THESE CONDITIONS ARE EXPECTED TO
PERSIST THROUGH 06/0600 UTC. SEE LATEST NWS HIGH SEAS FORECAST
UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

A STRENGTHENED PRESSURE GRADIENT IS EXPECTED TO MATERIALIZE
ACROSS THE SW CARIBBEAN SEA WITHIN CLOSE PROXIMITY TO THE COAST
OF COLOMBIA BY 06/0600 UTC. THESE NEAR GALE TO GALE FORCE WINDS
ARE EXPECTED TO PERSIST FOR 6-12 HOURS AND THEN DECREASE TO A
RANGE OF 20 TO 30 KT. SEE LATEST NWS HIGH SEAS FORECAST UNDER
AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 02N AND THE
PRIME MERIDIAN TO 03N10W TO LOW PRES NEAR 05N25W 1011 MB TO
05N35W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 03N
BETWEEN 06W-20W.

...DISCUSSION...

GULF OF MEXICO...

BROAD UPPER LEVEL TROUGHING OVER THE SE CONUS IS SUPPORTING A
STATIONARY FRONT WHICH EXTENDS FROM THE STRAITS OF FLORIDA TO
JUST N OF THE WESTERN COAST OF CUBA TO THE YUCATAN CHANNEL.
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING GENERALLY
WITHIN 60-90 NM EITHER SIDE OF THE FRONT INCLUDING THE APPROACH
TO THE YUCATAN CHANNEL. OTHERWISE...THE REMAINDER OF THE BASIN
IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1040 MB
HIGH CENTERED ACROSS CENTRAL PENNSYLVANIA EXTENDING AN AXIS S-SW
TO THE TEXAS COASTAL PLAIN THEN SOUTHWARD TO A 1028 MB HIGH
CENTERED NEAR TAMPICO MEXICO. UPPER LEVEL DRYING AND MANY STABLE
CONDITIONS DOMINATE THE BASIN AWAY FROM THE STATIONARY FRONT.
PRIMARY CLOUD COVER IS CONTINUING TO BE A BROKEN TO OVERCAST
STRATOCUMULUS DECK UNDER THE RELATIVELY STABLE CONDITIONS. FRESH
TO STRONG NE WINDS PREVAIL E OF 90W WHILE MAINLY MODERATE NE-E
WINDS CONTINUE W OF 90W. THIS OVERALL WIND REGIME IS EXPECTED TO
PERSIST THROUGH EARLY SUNDAY. EXPECT MODERATE TO FRESH N-NE
WINDS ACROSS THE BASIN BY SUN NIGHT THROUGH MONDAY AFTERNOON...
EXCEPT NEAR GALE FORCE ALONG AND OFFSHORE OF THE COAST OF
VERACRUZ SUNDAY AFTERNOON THROUGH MONDAY AFTERNOON.

CARIBBEAN SEA...

UPPER LEVEL RIDGING IS NOTED ON WATER VAPOR IMAGERY OVER THE
WESTERN CARIBBEAN WITH AXIS ANCHORED NEAR 13N84W EXTENDING N-NE
TO BEYOND EASTERN CUBA NEAR 22N78W. UPPER LEVEL DIFFLUENCE
ASSOCIATED WITH THE RIDGING ALOFT IN TANDEM WITH A STATIONARY
FRONT ANALYZED FROM THE YUCATAN CHANNEL NEAR 22N85.5W TO THE
GULF OF HONDURAS NEAR 16N87W IS PROVIDING FOCUS FOR SCATTERED
SHOWERS AND TSTMS ACROSS THE NW CARIBBEAN N OF 15N W OF 81W.
SCATTERED SHOWERS AND TSTMS CONTINUE TO THE SE ALONG THE EASTERN
HONDURAS...NICARAGUA AND WESTERN PANAMA COASTS FROM 09N-16N
WHERE A SURFACE TROUGH STRETCHES. ELSEWHERE...A NORTH-SOUTH
ELONGATED UPPER LEVEL LOW IS CENTERED NEAR 15.5N70W WITH MIDDLE
TO UPPER LEVEL MOISTURE NOTED ON WATER VAPOR IMAGERY ACROSS THE
EASTERN CARIBBEAN E OF 72W. ISOLATED SHOWERS ARE OCCURRING FROM
11N-19N E OF 72W. OTHERWISE...FRESH TO STRONG TRADES PREVAIL
ACROSS MOST OF THE BASIN...EXCEPT W OF 82W WHERE THE STATIONARY
FRONT IS GENERATING BROAD MODERATE TO FRESH CYCLONIC FLOW. THE
STRONGEST TRADES ARE NOTED WITHIN CLOSE PROXIMITY OF THE COAST
OF COLOMBIA WITH WINDS INCREASING TO GALE FORCE AS IS DISCUSSED
IN THE SPECIAL FEATURES SECTION.

...HISPANIOLA...

AN UPPER LEVEL LOW IS CENTERED NEAR 15.5N70W. SATELLITE AND
LIGHTNING DATA INDICATE SCATTERED SHOWERS AND ISOLATED TSTMS
ACROSS THE ISLAND WITH E-SE FLOW ALOFT AROUND THE UPPER LOW
COMBINING WITH OROGRAPHIC LIFTING. THIS ACTIVITY IS LIKELY TO
DIMINISH LATER THIS EVENING WITH THE LOSS OF DAYTIME HEATING.
THE UPPER LEVEL FEATURE WILL SLOWLY DRIFT EASTWARD BY LATE
SUNDAY AND WEAKEN E OF 68W AS UPPER LEVEL RIDGING SETTLES IN
WITH AN OVERALL DRYING TREND EXPECTED.

ATLANTIC OCEAN...

UPPER LEVEL TROUGHING EXTENDS FROM WELL N OF THE AREA NEAR
40N40W TO THE W-SW THROUGH 36N65W THEN TO THE SW TO CENTRAL
FLORIDA. THIS TROUGHING SUPPORTS A COLD FRONT ANALYZED FROM
32N48W TO 29N60W WHERE IT BECOMES STATIONARY AND CONTINUES
THROUGH 29N73W TO 27N76W TO THE STRAITS OF FLORIDA. SCATTERED
SHOWERS AND ISOLATED TSTMS ARE OCCURRING GENERALLY WITHIN 60-120
NM EITHER SIDE OF THE FRONT. STRONG TO GALE NE-E WINDS PERSIST N
OF THE FRONT AS IS DESCRIBED IN THE SPECIAL FEATURES SECTION.
OTHERWISE...SURFACE RIDGING PREVAILS ACROSS THE CENTRAL ATLC
ANCHORED BY A 1024 MB HIGH CENTERED S OF THE AZORES NEAR 32N28W.
ACROSS THE EASTERN ATLC...A MIDDLE TO UPPER LEVEL LOW IS
CENTERED NEAR 22N31W SUPPORTING A SURFACE TROUGH FROM 24N30W TO
19N35W. EXTENSIVE CLOUDINESS COVERS THE EASTERN ATLC FROM 14N-
32N E OF 28W DUE TO DIFFLUENT SOUTHWESTERLY FLOW ALOFT. ISOLATED
SHOWERS AND TSTMS ARE POSSIBLE ACROSS THIS AREA THROUGH AT LEAST
EARLY SUNDAY.

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

$$
LEWITSKY
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