[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 262354
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT DEC 26 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 STRONG PRESSURE GRADIENT EXISTS BETWEEN LOWER PRESSURE ACROSS
NORTHWESTERN SOUTH AMERICA AND A 1029 MB HIGH CENTERED NEAR
BERMUDA INFLUENCING THE SW NORTH ATLC. NEAR GALE TO GALE FORCE
WINDS ACROSS THE SOUTH-CENTRAL AND SW CARIBBEAN ARE OCCURRING
FROM 11N-14N BETWEEN 73W-77W. THESE CONDITIONS ARE FORECAST TO
PERSIST THROUGH EARLY MONDAY. SEE LATEST NWS HIGH SEAS FORECAST
UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

AN AREA OF DEVELOPING LOW PRESSURE IS CURRENTLY ANALYZED ACROSS
WESTERN TEXAS AND NORTH-CENTRAL MEXICO FOCUSED ON A 1000 MB LOW
CENTERED NEAR 31N105W. THE ASSOCIATED COLD FRONT IS EXPECTED TO
EMERGE OFF THE TEXAS GULF OF MEXICO COAST LATE SUNDAY INTO EARLY
MONDAY WITH NEAR GALE TO GALE FORCE NORTHERLY WINDS FORECAST TO
MATERIALIZE BY 27/1800 UTC WEST OF THE FRONT. 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 THE EQUATOR
AT THE PRIME MERIDIAN TO 03N12W TO 01N27W TO THE EQUATOR NEAR
40W THEN ALONG THE EQUATOR TO 43W. ISOLATED MODERATE CONVECTION
IS FROM THE EQUATOR TO 09N BETWEEN 12W-41W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF BASIN REMAINS UNDER THE INFLUENCE OF GENERALLY
SOUTHWESTERLY FLOW ALOFT WITH AN EMBEDDED SHORTWAVE TROUGH AXIS
NOTED ON WATER VAPOR IMAGERY ALONG 90W. THIS SW FLOW REGIME
COMES ON THE HEELS OF AN APPROACHING VIGOROUS MIDDLE TO UPPER
LEVEL LOW CENTERED OVER THE NW MEXICO NEAR 31N109W. THE UPPER
LEVEL DYNAMICS ARE INDUCING A BROAD AREA OF LOW PRESSURE FOCUSED
ON A 1000 MB LOW CENTERED OVER FAR WESTERN TEXAS. AS THE LOW
CONTINUES TO DEVELOP ACROSS NORTHERN MEXICO AND SOUTHERN
TEXAS...SOUTHEASTERLY SURFACE WINDS PREVAIL ACROSS THE GULF
BASIN THIS EVENING WITH GENERALLY MODERATE TO FRESH BREEZE
CONDITIONS E OF 90W AND FRESH TO STRONG BREEZE CONDITIONS W OF
90W. AS THE LOW MOVES EASTWARD ACROSS EASTERN TEXAS BY SUNDAY
AFTERNOON...THE ASSOCIATED COLD FRONT IS EXPECTED TO SWEEP
ACROSS THE WESTERN GULF THROUGH EARLY MONDAY MORNING WITH NEAR
GALE TO GALE FORCE NW TO N WINDS OCCURRING IN WAKE OF THE FRONT.
THE FRONT IS FORECAST TO STALL FROM THE FLORIDA PANHANDLE S-SW
TO THE SW GULF BY TUESDAY WITH WINDS DECREASING AS THE FRONTAL
BOUNDARY BECOMES DIFFUSE.

CARIBBEAN SEA...
WATER VAPOR IMAGERY INDICATES MOSTLY DRY AIR AND SUBSIDENCE
ALOFT OVER A MAJORITY OF THE BASIN THIS EVENING RESULTING IN
MOSTLY CLEAR SKIES. THE ONLY AREA OF SIGNIFICANT CLOUDINESS AND
POSSIBLE ISOLATED SHOWERS ARE OCCURRING ACROSS THE SE
CARIBBEAN...INCLUDING THE WINDWARD ISLANDS. OTHER PASSING
ISOLATED SHOWERS ARE POSSIBLE ACROSS PUERTO RICO...THE US/UK
VIRGIN ISLANDS...AND PORTIONS OF HISPANIOLA. WHILE OVERALL
TRANQUIL SKIES PREVAILS...THE PRIMARY MARINE IMPACT TO THE BASIN
IS THE STRONG TO OCCASIONAL NEAR GALE TRADES OCCURRING DUE TO A
STRENGTHENED PRESSURE GRADIENT BETWEEN LOWER PRESSURE ACROSS NW
SOUTH AMERICA AND A STRONG SURFACE RIDGE ANCHORED IN THE
VICINITY OF BERMUDA. GALE FORCE CONDITIONS ARE EXPECTED TO
PERSIST THROUGH EARLY MONDAY WITHIN CLOSE PROXIMITY TO THE COAST
OF COLOMBIA AS MENTIONED ABOVE IN THE SPECIAL FEATURES SECTION.
OTHERWISE...BY EARLY NEXT WEEK...THE SW NORTH ATLC RIDGING IS
FORECAST TO WEAKEN SLIGHTLY ON MONDAY RELAXING THE PRESSURE
GRADIENT SOMEWHAT...HOWEVER RE-STRENGTHENING LATE TUESDAY INTO
WEDNESDAY INCREASING THE TRADES ONCE AGAIN.

...HISPANIOLA...
DRY AIR AND STABILITY ALOFT ARE PROVIDING FOR OVERALL FAIR
CONDITIONS ACROSS THE ISLAND THIS EVENING. A STRAY LOW-TOPPED
ISOLATED SHOWER WITHIN THE EASTERLIES CANNOT BE RULED OUT
HOWEVER.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL RIDGE IS NOTED ON WATER VAPOR IMAGERY
ANCHORED NEAR 28N70W. THE RIDGING ALOFT SUPPORTS A STRONG 1029
MB HIGH CENTERED NEAR BERMUDA PROVIDING OVERALL FAIR CONDITIONS
FOR MUCH OF THE SW NORTH AND CENTRAL ATLC WATERS THIS EVENING.
THE PRIMARY IMPACT FROM THE ANTICYCLONE IS STRONG WINDS WITHIN
THE SOUTHERN PERIPHERY DUE TO A STRENGTHENED PRESSURE GRADIENT
BETWEEN THE HIGH AND LOWER PRESSURE ASSOCIATED WITH THE
INTERTROPICAL CONVERGENCE ZONE REGION ACROSS NORTHERN SOUTH
AMERICA. FRESH TO STRONG EASTERLY WINDS ARE FOUND GENERALLY FROM
12N-24N BETWEEN 55W-77W. OTHERWISE...MODERATE TO FRESH ANTI-
CYCLONIC FLOW PREVAILS N OF 24N W OF 50W. ELSEWHERE...THE
EASTERN ATLC IS UNDER RELATIVELY QUIET CONDITIONS AS WELL...
HOWEVER A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM 34N20W
TO 18N30W THAT IS SUPPORTIVE OF A WEAKENING COLD FRONT EXTENDING
FROM 32N17W TO 22N30W TO 23N43W. ISOLATED SHOWERS ARE POSSIBLE
WITHIN 90 NM EITHER SIDE OF THE FRONT.

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

$$
HUFFMAN
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