[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231801
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED DEC 23 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...

THE SURFACE PRESSURE GRADIENT THAT IS BETWEEN AN ATLANTIC OCEAN
HIGH PRESSURE CENTER AND A NORTHERN COLOMBIA LOW PRESSURE CENTER
IS HELPING TO SUPPORT GALE-FORCE WINDS THAT ARE ALONG THE COAST
OF COLOMBIA...FROM 11N TO 14N BETWEEN 73W AND 78W. EXPECT ALSO
SEA HEIGHTS TO RANGE FROM 11 FEET TO 16 FEET. PLEASE READ THE
HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...AND THE OFFSHORE
FORECAST...MIAOFFNT3/FZNT23 KNHC...FOR MORE DETAILS.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 04N BETWEEN THE PRIME MERIDIAN AND
07W. THE ITCZ CONTINUES FROM 04N07W TO 04N20W 03N23W 04N26W AND
02N39W. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 02N TO
08N BETWEEN 22W AND 31W. RAINSHOWERS ARE POSSIBLE ELSEWHERE FROM
10N SOUTHWARD FROM 60W EASTWARD.

...DISCUSSION...

...THE GULF OF MEXICO...

BROAD UPPER LEVEL SOUTHWESTERLY WIND FLOW AND BROKEN TO OVERCAST
MULTILAYERED CLOUDS COVER THE GULF OF MEXICO. AN UPPER LEVEL
TROUGH PASSES THROUGH EAST TEXAS...TO THE COASTAL PLAINS OF THE
DEEP SOUTH OF TEXAS. A COLD FRONT PASSES THROUGH NORTH CENTRAL
TEXAS TO SOUTH CENTRAL TEXAS.

A BROAD SURFACE TROUGH EXTENDS FROM THE DEEP SOUTH OF TEXAS...
TO THE MEXICO COAST NEAR 21N97W TO THE ISTHMUS OF TEHUANTEPEC OF
SOUTHERN MEXICO NEAR 17N95W.

...FROM THE WESTERN SECTIONS OF THE ATLANTIC OCEAN...ACROSS THE
BAHAMAS AND CUBA...INTO THE WESTERN SECTIONS OF THE CARIBBEAN
SEA...INCLUDING CROSSING HISPANIOLA...AND THE REST OF THE
CARIBBEAN SEA...

AN UPPER LEVEL TROUGH EXTENDS FROM A CARIBBEAN SEA 17N70W
CYCLONIC CIRCULATION CENTER TO 12N74W TO THE NICARAGUA/COSTA
RICA BORDER. THE TROUGH ALSO EXTENDS FROM THE 17N70W CYCLONIC
CENTER TO 22N70W JUST OFF THE SOUTHEASTERN BAHAMAS. UPPER LEVEL
CYCLONIC WIND FLOW COVERS THE CARIBBEAN SEA BETWEEN A RIDGE THAT
IS ON TOP OF THE EASTERN CARIBBEAN SEA ISLANDS AND THE LINE THAT
RUNS FROM SOUTHEASTERN CUBA TO 18N83W TO NORTHWESTERN COASTAL
HONDURAS. CONVECTIVE PRECIPITATION...RAINSHOWERS ARE POSSIBLE
FROM 16N TO 18N BETWEEN 68W AND 71W. PRECIPITATION HAS BEEN
DISSIPATING/WEAKENING FROM 10N TO 11N BETWEEN NORTHWESTERN
COLOMBIA AND SOUTHEASTERN COASTAL NICARAGUA.

THE 24-HOUR RAINFALL TOTAL IN INCHES FOR THE PERIOD ENDING AT
23/1200 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...IS 0.20 IN
TRINIDAD...0.08 IN ST. THOMAS IN THE VIRGIN ISLANDS...AND 0.05
IN SAN JUAN IN PUERTO RICO.

CURRENT OBSERVATIONS...FOR PORT-AU-PRINCE IN HAITI...FEW LOW
LEVEL CLOUDS. FOR THE DOMINICAN REPUBLIC...FEW CUMULONIMBUS
CLOUDS ARE IN BARAHONA. SCATTERED LOW LEVEL CLOUDS ARE IN SANTO
DOMINGO...LA ROMANA...AND IN PUNTA CANA. SCATTERED LOW LEVEL
CLOUDS ARE IN SANTIAGO AND IN PUERTO PLATA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT THE CURRENT TROUGH
WILL MOVE SOUTHEASTWARD DURING DAY ONE...BRINGING FIRST CYCLONIC
WIND FLOW AND THEN NORTHERLY WIND FLOW TO HISPANIOLA DURING DAY
ONE. THE TROUGH WILL TAKE ON AN EAST-TO-WEST ORIENTATION DURING
DAY ONE INTO DAY TWO. EXPECT NORTHEASTERLY WIND FLOW DURING DAY
TWO. THE GFS MODEL FORECAST FOR 500 MB SHOWS THAT AN ATLANTIC
OCEAN ANTICYCLONIC CIRCULATION CENTER WILL BE FROM 600 NM TO 900
NM TO THE NORTHEAST OF HISPANIOLA. EASTERLY WIND FLOW WILL MOVE
ACROSS HISPANIOLA DURING THE NEXT 48 HOURS. THE GFS MODEL
FORECAST FOR 700 MB SHOWS THAT AN ATLANTIC OCEAN ANTICYCLONIC
CIRCULATION CENTER WILL BE FROM 800 NM TO 1000 NM TO THE
NORTHEAST OF HISPANIOLA. SOUTHEASTERLY WIND FLOW WILL MOVE
ACROSS HISPANIOLA DURING THE NEXT 48 HOURS.

...THE REST OF THE ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH PASSES THROUGH THE MADEIRA ARCHIPELAGO TO
29N29W AND 26N41W. A STATIONARY FRONT PASSES THROUGH 32N23W TO
31N26W. CONVECTIVE PRECIPITATION...RAINSHOWERS ARE POSSIBLE
WITHIN 120 NM TO THE NORTHWEST OF THE LINE THAT PASSES THROUGH
32N23W TO 30N27W.

MIDDLE LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW COVERS THE
ATLANTIC OCEAN FROM TO 32N BETWEEN 24W AND 55W. THIS FEATURE IS
SURROUNDED BY COMPARATIVELY DRIER AIR IN SUBSIDENCE THAT IS
APPARENT IN WATER VAPOR IMAGERY. NO SIGNIFICANT DEEP LAYER
CONVECTIVE PRECIPITATION IS APPARENT.

A RIDGE IS ALONG 35N23W TO A 1036 MB HIGH PRESSURE CENTER THAT
IS NEAR 34N43W...TO BERMUDA...26N75W...ACROSS THE WESTERN HALF
OF CUBA...TO 19N84W IN THE NORTHWESTERN CORNER OF THE CARIBBEAN
SEA.

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

$$
MT
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