[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 252357
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUL 25 2013

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 FEATURE...

THE CENTER OF TROPICAL STORM DORIAN AT 25/2100 UTC IS NEAR
16.5N 37.8W. THE CENTER OF DORIAN IS ABOUT 1450 NM TO THE
EAST OF THE NORTHERN LEEWARD ISLANDS. DORIAN IS MOVING
WEST-NORTHWESTWARD 16 KNOTS. THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 999 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE
50 KNOTS WITH GUSTS TO 60 KNOTS. PLEASE READ THE FORECAST/
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND
THE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/
WTNT34 KNHC FOR MORE DETAILS. CONVECTIVE PRECIPITATION...
NUMEROUS STRONG FROM 16N TO 18N BETWEEN 36W AND 38W.

...TROPICAL WAVES...

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 87W/88W FROM THE
YUCATAN PENINSULA NEAR 21N SOUTHWARD...MOVING WESTWARD
15 KNOTS. CONVECTIVE PRECIPITATION...SCATTERED STRONG
IN THE NORTHERN HALF OF GUATEMALA.

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

THE MONSOON TROUGH PASSES THROUGH THE COASTAL BORDER AREAS
OF SENEGAL AND GUINEA-BISSAU NEAR 12N16W...TO 10N18W AND
8N24W. THE ITCZ CONTINUES FROM 8N24W TO 7N26W AND 13N32W.
THE ITCZ IS DISRUPTED BY THE WIND FLOW THAT IS MOVING AROUND
TROPICAL STORM DORIAN. THE ITCZ CONTINUES FROM 12N38W TO
10N41W 8N50W AND 6N56W. CONVECTIVE PRECIPITATION...NUMEROUS
STRONG FROM 8N TO 9N BETWEEN 18W AND 19W. SCATTERED MODERATE
TO ISOLATED STRONG FROM 7N TO 9N BETWEEN 32W AND 34W. ISOLATED
MODERATE ELSEWHERE FROM 5N TO 10N BETWEEN 12W AND 36W...FROM
4N TO 13N BETWEEN 38W AND 47W...AND TO THE SOUTH OF 10N TO
THE WEST OF 51W.

...DISCUSSION...

THE GULF OF MEXICO...

MIDDLE LEVEL TO UPPER LEVEL NORTHEASTERLY WIND FLOW CROSSES
INTO THE AREA FROM THE U.S.A. GULF COAST STATES...AND IT
SPANS THE ENTIRE AREA. THE U.S.A. EAST COAST TROUGH HAS
MOVED EASTWARD JUST ENOUGH NOT TO BE REACHING FLORIDA
ANYMORE. THE TROUGH ENDS NEAR 29N78W IN THE WESTERN ATLANTIC
OCEAN.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG 21N95W TO
16N94W...JUST INLAND OF THE GULF OF TEHUANTEPEC ON THE
EASTERN PACIFIC OCEAN SIDE OF SOUTHERN MEXICO.

A SURFACE RIDGE EXTENDS ALONG 24N73W...ACROSS THE BAHAMAS...
THROUGH THE FLORIDA STRAITS...TO A CENTRAL GULF OF MEXICO
1020 MB HIGH PRESSURE CENTER THAT IS NEAR 25N91W. BROAD
SURFACE ANTICYCLONIC WIND FLOW COVERS THE ENTIRE AREA.

A HIGH LEVEL CEILING IS REPORTED AT THE NAVAL AIR STATION
IN CORPUS CHRISTI. A LOW CLOUD CEILING IS OBSERVED AT
ELLINGTON FIELD IN HOUSTON...IN TEXAS. A LOW CLOUD CEILING
AND A MIDDLE LEVEL CLOUD CEILING ARE REPORTED IN LAKE
CHARLES LOUISIANA. HIGH CLOUD CEILINGS ARE OBSERVED IN THE
NEW ORLEANS LOUISIANA METROPOLITAN AREA. MULTILAYERED CLOUD
CEILINGS AND NEARBY RAINSHOWERS ARE IN THE FLORIDA PANHANDLE
FROM MARY ESTHER TO VALPARAISO TO DESTIN. LOW LEVEL TO
MIDDLE LEVEL CLOUD CEILINGS ARE REPORTED FROM BROOKSVILLE
TO THE TAMPA METROPOLITAN AREA. FAIR SKIES/CLEAR SKIES
AT OR LOWER THAN 12000 FEET ARE BEING REPORTED ELSEWHERE.

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

FAIR SKIES/CLEAR SKIES AT OR LOWER THAN 12000 FEET
ARE BEING REPORTED ACROSS THE AREA.

THE CARIBBEAN SEA...

MIDDLE LEVEL TO UPPER LEVEL EASTERLY WIND FLOW COVERS THE
AREA TO THE NORTH OF 17N TO THE WEST OF THE WINDWARD PASSAGE.
THIS WIND HAS MOVED FROM THE ATLANTIC OCEAN...BETWEEN THE
23N63W CYCLONIC CENTER AND FLORIDA...CROSSING CUBA...AND
INTO THE NORTHWESTERN CORNER OF THE AREA.

UPPER LEVEL SOUTHERLY TO SOUTHWESTERLY WIND FLOW COVERS THE
AREA THAT IS TO THE SOUTH OF 17N81W 16N72W 18N64W. SOME OF
THIS WIND FLOW MERGES WITH THE CYCLONIC WIND FLOW THAT IS
MOVING AROUND THE 23N63W-TO-17N71W TROUGH.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 87W/88W FROM THE
YUCATAN PENINSULA NEAR 21N SOUTHWARD...MOVING WESTWARD
15 KNOTS. CONVECTIVE PRECIPITATION...SCATTERED STRONG
IN THE NORTHERN HALF OF GUATEMALA.

THE MONSOON TROUGH IS ALONG 8N74W IN COLOMBIA...TO 9N79W
IN PANAMA...BEYOND 9N84W IN COSTA RICA...INTO THE EASTERN
PACIFIC OCEAN. CONVECTIVE PRECIPITATION...NUMEROUS STRONG
IN COLOMBIA FROM 6N TO 7N BETWEEN 76W AND 77W AND FROM 10N
TO 11N BETWEEN 74W AND 75W...IN PANAMA FROM 7N TO 9N BETWEEN
81W AND 82W. SCATTERED STRONG IN PANAMA AND COSTA RICA AND
COASTAL WATERS FROM 10N TO 12N BETWEEN 82W AND 86W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT THE
NORTHEAST TO EAST WINDS 25 TO 30 KNOTS AND 9 TO 11 FOOT SEA
HEIGHTS FROM 11N TO 13N BETWEEN 72W AND 75W. EXPECT
NORTHEAST TO EAST WINDS 20 TO 25 KNOTS AND SEA HEIGHTS
TO 10 FEET ELSEWHERE FROM 11N TO 16N BETWEEN 71W AND 82W.

HISPANIOLA...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM A 23N63W
CYCLONIC CIRCULATION CENTER...TO 20N68W...TO 17N71W IN THE
CARIBBEAN SEA ABOUT 90 NM TO THE SOUTH OF HISPANIOLA.
CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO
ISOLATED STRONG IN HISPANIOLA TO THE SOUTH OF 19N TO THE
EAST OF 72W IN HAITI. SCATTERED STRONG IN SOUTHERN CUBA TO
THE WEST OF 80W...IN SOUTHEASTERN CUBA.

THE GFS FORECAST FOR 700 MB AND FOR 500 MB SHOWS THAT
A RIDGE WILL SPAN THE AREA FOR THE FIRST HALF OF THE FIRST
24 HOURS OR SO. THE RIDGE WILL SHIFT NORTHWESTWARD AND IT
WILL BE REPLACED BY AN INVERTED TROUGH ACROSS THE AREA FOR
MOST OF THE REST OF THE 48 HOUR PERIOD. THE INVERTED TROUGH
EVENTUALLY WILL SHIFT WESTWARD ALSO...PUTTING HISPANIOLA ON
THE EASTERN SIDE OF THE TROUGH. THE GFS FORECAST FOR 250 MB
SHOWS THAT A TROUGH WITH A NORTHEAST-TO-SOUTHWEST ORIENTATION
WILL SPAN THE AREA FOR THE NEXT 48 HOURS. NO TROPICAL WAVE
IS APPARENT FOR AT LEAST THE NEXT FEW DAYS.

THE ATLANTIC OCEAN...

A WESTERN ATLANTIC OCEAN MIDDLE LEVEL TO UPPER LEVEL
TROUGH PASSES THROUGH 32N77W TO 29N78W. THE TROUGH SUPPORTS
A SURFACE FRONTAL BOUNDARY THAT IS ALONG 32N BETWEEN 78W
AND GEORGIA IN THE SOUTHEASTERN U.S.A. BROAD SURFACE
CYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN...FLORIDA...
AND THE GULF OF MEXICO TO THE NORTH OF 26N BETWEEN 73W AND
88W. CYCLONIC WIND FLOW MOVES AWAY FROM THE TROUGH AND
IT SHIFTS EASTWARD TOWARD THE 23N63W MIDDLE LEVEL TO
UPPER LEVEL CYCLONIC CIRCULATION CENTER AND TROUGH.
CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE
TO ISOLATED STRONG TO THE NORTH OF 26N BETWEEN 70W AND 80W.
THE 24-HOUR RAINFALL TOTAL...ACCORDING TO THE PAN AMERICAN
TEMPERATURE AND RAINFALL TABLE...FOR THE TIME PERIOD ENDING
AT 25/1200 UTC...WAS 0.42 INCHES FOR FREEPORT IN THE BAHAMAS.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM 32N57W
TO 28N60W TO A 23N63W CYCLONIC CIRCULATION CENTER...TO
20N68W...TO 17N71W IN THE CARIBBEAN SEA ABOUT 90 NM TO THE
SOUTH OF HISPANIOLA. CONVECTIVE PRECIPITATION...WIDELY
SCATTERED MODERATE TO ISOLATED STRONG IN HISPANIOLA TO THE
SOUTH OF 19N TO THE EAST OF 72W IN HAITI. SCATTERED STRONG
IN SOUTHERN CUBA TO THE WEST OF 80W...IN SOUTHEASTERN CUBA.
SCATTERED MODERATE TO STRONG IN THE ATLANTIC OCEAN FROM 26N
TO 30N BETWEEN 56W AND 60W. WIDELY SCATTERED TO SCATTERED
MODERATE ELSEWHERE TO THE NORTH OF 20N BETWEEN 55W AND 69W.

MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY WINDS...THAT ARE
ON THE EASTERN SIDE OF THE 32N57W 23N63W 17N71W TROUGH...
MEET AN AREA OF MIDDLE LEVEL SOUTHEASTERLY WIND FLOW...
ROUGHLY IN THE AREA FROM 20N TO 30N ALONG 50W. BROKEN TO
OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE
FROM 20N TO 31N BETWEEN 37W AND 51W.

A MIDDLE LEVEL INVERTED TROUGH IS ALONG 20N48W 11N50W.
IT IS SURROUNDED BY COMPARATIVELY DRIER AIR IN SUBSIDENCE
IN WATER VAPOR IMAGERY.

A SURFACE RIDGE EXTENDS FROM A 1033 MB HIGH PRESSURE CENTER
THAT IS NEAR 40N45W TO 36N43W 29N32W AND 22N26W. A SECOND
SURFACE RIDGE PASSES THROUGH 32N48W TO 24N60W. BROAD SURFACE
ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN TO THE EAST
OF 65W.

A SURFACE RIDGE EXTENDS ALONG 24N73W...ACROSS THE BAHAMAS...
THROUGH THE FLORIDA STRAITS...INTO THE CENTRAL GULF OF MEXICO.

PLEASE READ THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT4/WTNT24 KNHC...THE PUBLIC ADVISORY UNDER AWIPS/WMO
HEADERS MIATCPAT4/WTNT34 KNHC...AND THE HIGH SEAS FORECAST...
MIAHSFAT2...FOR MORE DETAILS ABOUT TROPICAL STORM DORIAN.

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

$$
MT


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