Tropical Weather Discussion
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000
AXNT20 KNHC 260721 AAA
TWDAT

TROPICAL WEATHER DISCUSSION...UPDATED
NWS NATIONAL HURRICANE CENTER
MIAMI FL 205 AM EDT TUE APR 26 2016

UPDATED FOR CLOUD CONDITIONS IN THE GULF OF MEXICO COASTAL
PLAINS...AND THE HISPANIOLA SECTION...

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

...GALE-FORCE WINDS ARE IN THE ATLANTIC OCEAN...

A 1002 MB ATLANTIC OCEAN LOW PRESSURE CENTER IS NEAR 30N50W.
A COLD FRONT EXTENDS FROM THE 1002 MB LOW CENTER TO 25N50W TO
20N60W...THEN A STATIONARY FRONT TO 20N71W. EXPECT GALE-FORCE
SOUTHWEST-TO-SOUTH WINDS AND SEA HEIGHTS RANGING FROM 8 FEET TO
16 FEET WITHIN THE AREA THAT IS BOUNDED BY A LINE FROM 31N46W TO
26N45W TO 23N53W TO 31N49W TO 31N46W.

A CENTRAL ATLANTIC OCEAN UPPER LEVEL TROUGH SUPPORTS THE 1002 MB
LOW PRESSURE CENTER THAT IS NEAR 30N50W...AND THE RELATED
FRONTAL SYSTEM. THE GALE-FORCE WINDS ARE OCCURRING AROUND THE
LOW PRESSURE CENTER AND FRONTS. A SEPARATE 1007 MB LOW PRESSURE
CENTER IS NEAR 28N58W. A SURFACE TROUGH EXTENDS FROM THE LOW
CENTER TO 26N59W AND 25N62W. CONVECTIVE PRECIPITATION...
SCATTERED STRONG FROM 29N TO 31N BETWEEN 43W AND 46W...AND FROM
26N TO 27N BETWEEN 47W AND 48W. RAINSHOWERS ARE POSSIBLE
ELSEWHERE FROM 25N NORTHWARD BETWEEN 40W AND 50W. THE 24-HOUR
RAINFALL TOTAL IN INCHES FOR THE PERIOD ENDING AT 26/0000
UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...IS 0.05 IN
BERMUDA.

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

THE MONSOON TROUGH PASSES THROUGH THE COASTAL AREAS OF GUINEA
NEAR 09N13W TO 06N15W AND 05N19W. THE ITCZ IS ALONG 05N19W TO
05N34W TO 05N44W AND 04N51W. CONVECTIVE PRECIPITATION...
SCATTERED STRONG FROM 01N TO 04N BETWEEN 06W AND 12W. WIDELY
SCATTERED MODERATE TO ISOLATED STRONG WITHIN 60 NM ON EITHER
SIDE OF 05N20W 05N33W...AND FROM 05N TO 07N BETWEEN 47W AND 49W.
RAINSHOWERS ARE POSSIBLE ELSEWHERE FROM 10N SOUTHWARD BETWEEN
AFRICA AND 60W.

...DISCUSSION...

...THE GULF OF MEXICO...

UPPER LEVEL NORTHWEST WIND FLOW IS MOVING ACROSS THE GULF OF
MEXICO. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS APPARENT IN
WATER VAPOR IMAGERY...EVERYWHERE IN THE GULF OF MEXICO.
UPPER LEVEL ANTICYCLONIC WIND FLOW IS MOVING ACROSS MEXICO AND
INTO THE WESTERN HALF OF THE GULF OF MEXICO.

A SURFACE RIDGE EXTENDS FROM AN ATLANTIC OCEAN 1019 MB HIGH
PRESSURE CENTER THAT IS NEAR 33N75W...ACROSS FLORIDA...INTO THE
NORTHWESTERN CORNER OF THE GULF OF MEXICO...TO THE COAST OF
TEXAS...BETWEEN THE MIDDLE TEXAS GULF COAST AND THE DEEP SOUTH
OF TEXAS.

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

IFR CONDITIONS...KHHV.

MVFR CONDITIONS...KMZG...KBBF...KBQX...KXIH...KGLS...
KVAF...KEMK...KGUL...KVQT...AND KGHB.

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 ALONG THE TEXAS COAST. LOUISIANA...MVFR IN THE
SOUTHWESTERN CORNER IN THE AREA OF LAKE CHARLES. VFR/NO CEILINGS
ELSEWHERE FOR THE REST OF LOUISIANA AND MISSISSIPPI. ALABAMA...
MVFR IN GULF SHORES...ON THE VERGE OF RETURNING TO LIFR. THE
LAST SEVERAL OBSERVATIONS BEFORE THE MVFR OBSERVATION
WERE SHOWING LIFR CONDITIONS. FLORIDA...MVFR IN PENSACOLA.
LIFR IN CRESTVIEW. LIFR AT THE NORTHWEST FLORIDA BEACHES
INTERNATIONAL AIRPORT NEAR PANAMA CITY...AND IN MARIANNA.

...THE CARIBBEAN SEA...

UPPER LEVEL NORTHWEST WIND FLOW COVERS THE CARIBBEAN SEA FROM
15N NORTHWARD FROM 80W WESTWARD...AND FROM 15N SOUTHWARD FROM
73W WESTWARD. UPPER LEVEL SOUTHWEST WIND FLOW IS MOVING ACROSS
SOUTHEASTERN CUBA...JAMAICA...AND HISPANIOLA. UPPER LEVEL
SOUTHWEST WIND FLOW IS FROM 15N SOUTHWARD FROM 73W EASTWARD.
BROAD UPPER LEVEL ANTICYCLONIC WIND FLOW ALSO IS FROM 17N
SOUTHWARD FROM 70W EASTWARD.

MOISTURE...RAIN...AND FLOODING HAVE BEEN PRESENT IN PUERTO RICO
DURING THE LAST 24 HOURS OR SO. PLEASE CONSULT FORECASTS AND
BULLETINS FROM THE SAN JUAN NWS OFFICE FOR MORE DETAILS. AN
ESTIMATE OF 0.11 INCHES HAS BEEN REPORTED AT THE SAN JUAN
INTERNATIONAL AIRPORT...BASED ON SURFACE OBSERVATIONS SINCE
25/1800 UTC.

A STATIONARY FRONT IS ALONG 20N BETWEEN 64W AND 72W NEAR THE
BORDER OF HAITI AND THE DOMINICAN REPUBLIC. EXPECT CONTINUED
MULTILAYERED CLOUDINESS AND CONVECTIVE PRECIPITATION FROM 17N TO
21N BETWEEN 65W AND THE WINDWARD PASSAGE...AT LEAST ON TUESDAY.

A SURFACE RIDGE PASSES THROUGH THE NORTHWESTERN BAHAMAS...
ACROSS CUBA...TO CENTRAL HONDURAS.

...HISPANIOLA...

UPPER LEVEL SOUTHWEST WIND FLOW IS MOVING ACROSS THE ISLAND.
MULTILAYERED CLOUDINESS IS PRESENT ACROSS THE AREA ALSO.

SURFACE OBSERVATIONS...FOR PORT-AU-PRINCE IN HAITI AT 25/2300
UTC...SCATTERED CUMULONIMBUS CLOUDS AND A CLOUD CEILING WHOSE
BASE IS AT 7000 FEET...VFR. FOR THE DOMINICAN REPUBLIC...
BARAHONA AT 26/0000 UTC...LIGHT RAIN. SANTO DOMINGO...SCATTERED
LOW LEVEL CLOUDS AND A CLOUD CEILING WHOSE BASE IS AT 7000
FEET...VFR. LA ROMANA AT 26/0300 UTC...FEW CUMULONIMBUS CLOUDS
AND A CLOUD CEILING WHOSE BASE IS AT 1600 FEET...MVFR. THUNDER
AND RAIN WERE BEING REPORTED DURING EARLIER OBSERVATIONS. PUNTA
CANA...SCATTERED LOW LEVEL CLOUDS AND A HIGH LEVEL CLOUD
CEILING...VFR. SANTIAGO...A LOW LEVEL CLOUD CEILING WHOSE BASE
IS AT 1600 FEET...MVFR...AND LIGHT RAIN DURING THE LAST FEW
EARLIER OBSERVATIONS. PUERTO PLATA...A LOW LEVEL CLOUD CEILING
WHOSE BASE IS AT 1600 FEET...MVFR...AND A CLOUD CEILING WHOSE
BASE IS AT 7000 FEET.

THE GFS MODEL FOR 250 MB SHOWS THAT DAY ONE WILL CONSIST OF A
TROUGH TO THE WEST OF HISPANIOLA...MOVING ON TOP OF HISPANIOLA
BY THE END OF DAY ONE. EXPECT CYCLONIC WIND FLOW IN HISPANIOLA
DURING DAY ONE. THE TROUGH WILL MOVE ACROSS HISPANIOLA DURING
DAY TWO AND IT WILL END UP ACROSS THE ISLANDS OF THE EASTERN
CARIBBEAN SEA AT THE END OF DAY TWO. EXPECT NORTHWEST WIND FLOW
DURING DAY TWO. THE GFS MODEL FOR 500 MB SHOWS THAT DAY ONE WILL
START WITH NORTHWEST WIND FLOW FOR THE FIRST HALF OF DAY
ONE...AND SOUTHWEST WIND FLOW FOR THE SECOND HALF OF DAY ONE. A
TROUGH WILL BE JUST TO THE WEST OF HISPANIOLA AT THE END OF DAY
ONE. EXPECT SOUTHWEST-TO-WEST WIND DURING DAY TWO. THE TROUGH
WILL REMAIN TO THE WEST OF THE AREA DURING DAY TWO. THE GFS
MODEL FOR 700 MB SHOWS THAT DAY ONE WILL START WITH WEST WIND
FLOW ACROSS MUCH OF THE AREA...AND AN ANTICYCLONIC CIRCULATION
CENTER IN THE SOUTHEASTERN CORNER OF HISPANIOLA. SOUTHWEST WIND
EVENTUALLY WILL CROSS HISPANIOLA DURING DAY ONE. AN EAST-TO-WEST
RIDGE WILL BE TO THE SOUTH OF HISPANIOLA ON DAY ONE...AND ON DAY
TWO ALSO. EXPECT SOUTHWEST WIND FLOW DURING PRACTICALLY ALL OF
DAY TWO. SOUTHWEST-TO-SOUTH WIND FLOW WILL CROSS HISPANIOLA AT
THE END OF DAY TWO.

...THE ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH PASSES THROUGH 32N21W TO 22N26W 13N25W AND
10N27W. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION IS APPARENT.

SURFACE ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN FROM
10N TO 30N BETWEEN AFRICA AND 40W. A 1018 MB HIGH PRESSURE
CENTER IS NEAR 26N32W. A 1017 MB HIGH PRESSURE CENTER IS NEAR
27N23W.

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

$$
MT



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