Tropical Weather Discussion
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000
AXNT20 KNHC 231120
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT APR 23 2016

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

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

THE MONSOON TROUGH PASSES THROUGH THE COASTAL AREAS OF GAMBIA
NEAR 13N17W...CURVING TO 10N20W AND 06N21W. THE ITCZ CONTINUES
FROM 06N21W TO 03N33W 02N42W AND 01N45W. CONVECTIVE
PRECIPITATION...SCATTERED STRONG FROM 07N TO 08N BETWEEN 15W AND
17W...WITHIN 30 NM ON EITHER SIDE OF 05N22W 04N27W 04N31W
04N36W...WITHIN 30 NM ON EITHER SIDE OF THE EQUATOR BETWEEN 46W
AND 49W...FROM 02N TO 03N BETWEEN 47W AND 48W...AND ALONG THE
BRAZIL COAST WITHIN A 30 NM RADIUS OF 03N51W. NUMEROUS STRONG
WITHIN 30 NM ON EITHER SIDE 01N ALONG THE PRIME MERIDIAN...TO THE
EQUATOR ALONG 06W...TO 01S08W.

...DISCUSSION...

...THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS MOVING THROUGH THE
SOUTHEASTERN CORNER OF THE U.S.A....INTO THE NORTHEASTERN CORNER
OF THE GULF OF MEXICO AND ACROSS FLORIDA. COMPARATIVELY DRIER
AIR IN SUBSIDENCE IS APPARENT IN WATER VAPOR SATELLITE IMAGERY
FROM 27N NORTHWARD. THE TROUGH SUPPORTS A WEAK COLD FRONT THAT
PASSES THROUGH THE FLORIDA BIG BEND...INTO THE CENTRAL GULF OF
MEXICO NEAR 26N90W...TO 25N95W. NO SIGNIFICANT DEEP CONVECTIVE
PRECIPITATION IS APPARENT.

MIDDLE LEVEL TO UPPER LEVEL WESTERLY WIND FLOW COVERS MUCH OF
THE GULF OF MEXICO. MIDDLE LEVEL TO UPPER LEVEL SOUTHWEST WIND
FLOW IS MOVING ACROSS FLORIDA...ASSOCIATED WITH THE TROUGH THAT
IS SUPPORTING THE COLD FRONT AND SURFACE TROUGH.

FOR THE OFFSHORE OIL PLATFORM SITES THAT ARE IN THE AREA WHOSE
BOUNDARIES ARE FROM 27N NORTHWARD AND FROM 88W WESTWARD...

VFR/NO CEILINGS.

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

TEXAS...MVFR IN HARLINGEN. LIFR IN ANGLETON/LAKE JACKSON. FROM
LOUISIANA TO ALABAMA...VFR/NO CEILINGS. FLORIDA...LIGHT RAIN IN
MILTON. LIFR AT THE NORTHWEST FLORIDA BEACHES INTERNATIONAL
AIRPORT TO THE NORTHWEST OF PANAMA CITY. IFR IN PANAMA CITY.
LIFR IN APALACHICOLA. IFR IN MARIANNA AND TALLAHASSEE. MVFR IN
PERRY AND BROOKSVILLE. MVFR AT THE MACDILL AIR FORCE BASE AND
IN PUNTA GORDA.

...THE CARIBBEAN SEA...

BROAD UPPER LEVEL WESTERLY WIND FLOW MOVES FROM THE GULF OF
MEXICO...AND ACROSS THE LAND MASS FROM THE YUCATAN PENINSULA-TO-
GUATEMALA...INTO THE CARIBBEAN SEA. THIS WEST WIND FLOW REACHES
83W. UPPER LEVEL SOUTHWEST WIND FLOW COVERS THE REST OF THE
CARIBBEAN SEA...TO THE SOUTHEAST OF THE LINE THAT RUNS FROM
NORTHERN NICARAGUA BEYOND HISPANIOLA.

A WEAK UPPER LEVEL TROUGH IS ALONG 80W/81W FROM 16N TO CUBA.
CONVECTIVE PRECIPITATION...BROKEN TO OVERCAST MULTILAYERED
CONVECTIVE DEBRIS CLOUDS...FROM EARLIER PRECIPITATION...AND
LINGERING RAINSHOWERS...ARE FROM 16N IN THE CARIBBEAN SEA TO 26N
IN THE ATLANTIC OCEAN BETWEEN 62W AND 82W.

THE 24-HOUR RAINFALL TOTAL IN INCHES FOR THE PERIOD ENDING AT
23/0000 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...IS 0.05 IN
GUADELOUPE.

...HISPANIOLA...

UPPER LEVEL WEST AND SOUTHWEST WIND FLOW IS MOVING ACROSS
HISPANIOLA AT THE MOMENT.

SURFACE OBSERVATIONS...FOR PORT-AU-PRINCE IN HAITI...FEW CLOUDS
AT 1800 FEET...AND A CLOUD CEILING AT 6000 FEET...VFR. FOR THE
DOMINICAN REPUBLIC...BARAHONA...SCATTERED LOW LEVEL CLOUDS AND
SCATTERED MIDDLE LEVEL CLOUDS. SANTO DOMINGO...SCATTERED CLOUDS
AT 1600 FEET...SCATTERED CLOUDS AT 7000 FEET...AND A HIGH LEVEL
CLOUD CEILING...VFR. LA ROMANA...FEW CLOUDS AT 1600 FEET AND
SCATTERED CLOUDS AT 8000 FEET...VFR. PUNTA CANA...SCATTERED LOW
LEVEL CLOUDS AND SCATTERED CLOUDS AT 8000 FEET...VFR.
SANTIAGO...A CLOUD CEILING AT 1700 FEET...MVFR...AND A CLOUD
CEILING AT 7000 FEET. PUERTO PLATA...SCATTERED CLOUDS AT 1700
FEET...AND A CLOUD CEILING AT 7000 FEET...VFR.

THE GFS MODEL FOR 250 MB SHOWS THAT THE FIRST 24 HOURS OF THE 48-
HOUR FORECAST PERIOD WILL CONSIST OF NORTHWEST WIND FLOW. DAY
TWO WILL START WITH NORTHWEST-TO-WEST WIND FLOW...FOLLOWED BY
NORTHWEST WIND FLOW FOR THE REST OF THE DAY. THE GFS MODEL FOR
500 MB SHOWS THAT THE FIRST 24 HOURS OF THE 48-HOUR FORECAST
PERIOD WILL CONSIST OF SOUTHWEST WIND FLOW. DAY TWO WILL START
WITH SOUTHWEST WIND FLOW...THAT WILL BECOME WESTERLY FOR MUCH OF
THE REST OF THE DAY...BECOMING NORTHWEST WIND FLOW RIGHT AT THE
END OF DAY TWO. THE GFS MODEL FOR 700 MB SHOWS THAT A RIDGE WILL
PASS THROUGH THE ATLANTIC OCEAN...AND DIRECTLY ACROSS PUERTO
RICO AND HISPANIOLA FOR MOST OF DAY ONE OF THE 48-HOUR FORECAST
PERIOD. THE RIDGE WILL MOVE TO THE SOUTH...AND STAY TO THE SOUTH
OF PUERTO RICO AND HISPANIOLA...DURING DAY TWO. EXPECT SOUTHWEST
WIND DURING THE NEXT 48 HOURS.

...THE ATLANTIC OCEAN...

AN EASTERN ATLANTIC OCEAN TROUGH PASSES THROUGH 32N27W TO 26N32W
TO 22N39W. THE TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH
32N30W TO 24N40W AND 21N50W. THE COLD FRONT IS DISSIPATING FROM
21N50W TO 21N60W. CONVECTIVE PRECIPITATION...HIGH CLOUDS ARE
WITHIN 120 NM TO 180 NM ON EITHER SIDE OF THE LINE THAT PASSES
THROUGH 32N22W TO 23N30W 20N57W. SCATTERED MODERATE FROM 23N TO
27N BETWEEN 34W AND 44W. RAINSHOWERS ARE POSSIBLE ELSEWHERE
WITHIN 120 NM ON EITHER SIDE OF 28N34W 22N50W 22N60W.

A SURFACE RIDGE EXTENDS FROM A 1021 MB HIGH PRESSURE CENTER THAT
IS NEAR 30N21W...TO 23N30W AND 19N47W. SURFACE ANTICYCLONIC WIND
FLOW COVERS THE AREA FROM 15N NORTHWARD BETWEEN AFRICA AND THE
32N30W 21N50W COLD FRONT.

A SURFACE RIDGE IS TO THE WEST OF THE 32N30W 21N50W COLD FRONT.
THE RIDGE PASSES THROUGH 32N68W...TO A 1021 MB HIGH PRESSURE
CENTER THAT IS NEAR 30N66W...TO 26N53W AND 26N42W.

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

$$
MT


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