Tropical Weather Discussion
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000
AXNT20 KNHC 190001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN JAN 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.

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

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF GUINEA
NEAR 9N13W...JUST TO THE NORTH OF ITS BORDER WITH SIERRA
LEONE...TO 6N15W AND 4N18W. THE ITCZ CONTINUES FROM 4N18W TO
1N30W AND 1N46W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE
TO ISOLATED STRONG WITHIN 15 NM ON EITHER SIDE OF 4N15W 4N19W
3.5N23W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM THE
EQUATOR TO 10N BETWEEN 23W AND 46W. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE ELSEWHERE FROM
10N TO 23N BETWEEN AFRICA AND 32W.

...DISCUSSION...

...THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH NORTH
CAROLINA...TO GEORGIA...ACROSS THE FLORIDA PANHANDLE...TO
SOUTHERN LOUISIANA AND THE MIDDLE TEXAS GULF COAST. DRY AIR IN
SUBSIDENCE IS APPARENT IN WATER VAPOR IMAGERY...ABOUT 300 NM TO
THE NORTHWEST AND NORTH OF THE LINE THAT PASSES THROUGH 32N77W
TO 29N85W...BEYOND 28N97W. BROKEN TO OVERCAST MULTILAYERED
CLOUDS ARE WITHIN 300 NM TO 360 NM TO THE SOUTHEAST AND SOUTH OF
THE SAME 32N77W 28N97W LINE. THE TROUGH SUPPORTS A COLD FRONT
THAT PASSES THROUGH 32N77W...TO FLORIDA NEAR 28N82W...INTO THE
CENTRAL GULF OF MEXICO NEAR 25N90W...TO THE DEEP SOUTH OF TEXAS.
A SURFACE TROUGH IS ALONG 76W/77W FROM 24N IN THE BAHAMAS TO
31N. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO STRONG
FROM 31N NORTHWARD BETWEEN 71W AND 73W. RAINSHOWERS ARE POSSIBLE
ELSEWHERE IN THE AREA OF MULTILAYERED CLOUDINESS THAT IS TO THE
SOUTHEAST AND SOUTH OF THE 32N77W 28N97W LINE.

A SURFACE RIDGE EXTENDS FROM A NORTHERN MEXICO 1029 MB HIGH
PRESSURE CENTER THAT IS NEAR 27N100W...ALONG THE MEXICO COAST...
INTO THE ISTHMUS OF TEHUANTEPEC OF SOUTHERN MEXICO. GALE-FORCE
WINDS ARE BLOWING IN THE GULF OF TEHUANTEPEC ON THE EASTERN
PACIFIC OCEAN SIDE OF SOUTHERN MEXICO. PLEASE READ THE EASTERN
PACIFIC OCEAN HIGH SEAS FORECAST...MIAHSFEP2/FZPN03 KNHC...AND
THE EASTERN PACIFIC OCEAN TROPICAL WEATHER DISCUSSION...
MIATWDEP/AXPZ20 KNHC...FOR MORE DETAILS.

FOR THE OFFSHORE OIL PLATFORM SITES THAT ARE TO THE NORTH OF 27N
TO THE WEST OF 88W...

LOW LEVEL CLOUD CEILINGS ARE BEING REPORTED AT THE FOLLOWING
ICAO PLATFORM SITES...KVOA.

LOW LEVEL CLOUD CEILINGS AND WEATHER...FOR THE COASTAL PLAINS OF
THE U.S.A. FROM THE DEEP SOUTH OF TEXAS TO FLORIDA...

NO LOW LEVEL CLOUD CEILINGS ARE BEING REPORTED.

...THE CARIBBEAN SEA...

AN UPPER LEVEL RIDGE EXTENDS FROM NORTH CENTRAL VENEZUELA TO
15N75W IN THE CARIBBEAN SEA...INTO CENTRAL GUATEMALA. LARGE-
SCALE ANTICYCLONIC WIND FLOW SPANS THE CARIBBEAN SEA.

RAINSHOWERS ARE POSSIBLE ACROSS MUCH OF THE OPEN WATERS OF THE
CARIBBEAN SEA...IN SCATTERED TO BROKEN LOW LEVEL CLOUDS AND
SURFACE-TO-LOW LEVEL TRADE WIND FLOW.

THE MONSOON TROUGH IS ALONG 7N74W IN COLOMBIA...TO 6N77W BEYOND
6N86W IN THE EASTERN PACIFIC OCEAN. CONVECTIVE PRECIPITATION...
ISOLATED TO WIDELY SCATTERED MODERATE FROM 87W EASTWARD FROM 10N
SOUTHWARD. HIGH LEVEL CLOUDS ARE MOVING ACROSS THE SOUTHWESTERN
CORNER OF THE CARIBBEAN SEA...ON TOP OF LOW LEVEL CLOUDS THAT
ARE CURVING ANTICYCLONICALLY THROUGH THE AREA.

...HISPANIOLA...

UPPER LEVEL WESTERLY WIND FLOW IS CROSSING HISPANIOLA. LARGE-
SCALE ANTICYCLONIC WIND FLOW SPANS THE CARIBBEAN SEA.

AN ATLANTIC OCEAN STATIONARY FRONT IS ALONG 23N56W TO 22N62W AND
19N68W...JUST OFF THE EASTERN COAST OF THE DOMINICAN REPUBLIC NO
SIGNIFICANT DEEP CONVECTIVE PRECIPITATION IS APPARENT.
RAINSHOWERS ARE POSSIBLE FROM 20N TO 30N BETWEEN 50W AND 60W.

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

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT A RIDGE WILL EXTEND
FROM NORTHEASTERN COLOMBIA INTO THE NORTHWESTERN CORNER OF THE
CARIBBEAN SEA. EXPECT SOUTHWEST-TO-WEST WIND FLOW ACROSS
HISPANIOLA. THE GFS MODEL FORECAST FOR 500 MB SHOWS THAT AN EAST-
TO-WEST ORIENTED RIDGE WILL BE IN THE CARIBBEAN SEA. EXPECT
NORTHWEST WIND FLOW ACROSS HISPANIOLA. THE GFS MODEL FORECAST
FOR 700 MB SHOWS THAT NORTHWEST-TO-NORTH-TO-NORTHEAST WIND FLOW
WILL CROSS HISPANIOLA WITH AN EAST-TO-WEST ORIENTED RIDGE THAT
STRETCHES FROM THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA TO
PUERTO RICO.

...THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM A 34N52W
CYCLONIC CIRCULATION CENTER...TO 30N52W AND TO 26N48W. THE
TROUGH SUPPORTS A COLD FRONT THAT EXTENDS FROM A 1016 MB LOW
PRESSURE CENTER THAT IS NEAR 32N50W TO 28N50W AND 23N56W. A
STATIONARY FRONT CONTINUES FROM 23N56W TO 22N62W AND 19N68W...
JUST OFF THE EASTERN COAST OF THE DOMINICAN REPUBLIC. A PRE-
FRONTAL SURFACE TROUGH IS ALONG 23N55W 21N59W 19N62W. CONVECTIVE
PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 26N
NORTHWARD BETWEEN 47W AND 50W. RAINSHOWERS ARE POSSIBLE
ELSEWHERE WITHIN 90 NM TO 150 NM ON EITHER SIDE OF THE LINE THAT
PASSES THROUGH 32N46W TO 25N48W TO 22N59W...AND FROM 20N TO 30N
BETWEEN 50W AND 60W.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM A 23N39W
CYCLONIC CIRCULATION CENTER...TO 18N30W AND 15N28W. A SEPARATE
MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM 20N36W TO 8N37W.
BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS
ARE FROM 10N TO 23N BETWEEN AFRICA AND 32W.

A SURFACE RIDGE PASSES THROUGH 32N65W NEAR BERMUDA TO 28N72W.

ONE SURFACE RIDGE EXTENDS FROM A 1036 MB HIGH PRESSURE CENTER
THAT IS NEAR 36N30W TO 19N40W. A SECOND RIDGE EXTENDS FROM
36N30W TO 29N22W AND 28N9W.

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

$$
MT



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