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000
AXNT20 KNHC 201150
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON MAY 20 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 33W/34W TO THE SOUTH OF
9N. WIDELY SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE
PRECIPITATION IS FROM 2N TO 5N BETWEEN 30W AND 37W.

A TROPICAL WAVE IS ALONG 61W/62W TO THE SOUTH OF 13N...FROM THE
SOUTHEASTERN CARIBBEAN SEA ISLANDS INTO EASTERN VENEZUELA.
CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG
IN THE ATLANTIC OCEAN FROM 10N TO 13N BETWEEN 57W AND 61W NEAR
TRINIDAD. RAINSHOWERS ARE POSSIBLE FROM 15N TO 17N BETWEEN 55W
AND 65W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL GUINEA NEAR 11N15W TO
6N17W AND 4N21W. THE ITCZ CONTINUES FROM 4N21W TO 4N26W AND
3N30W. THE ITCZ STARTS AGAIN ALONG THE EQUATOR FROM 38W TO 46W.
CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 3N TO 5N TO THE
EAST OF 2W...AND FROM 3N TO 6N BETWEEN 19W AND 25W. ISOLATED TO
WIDELY SCATTERED MODERATE ELSEWHERE TO THE SOUTH OF 8N BETWEEN
AFRICA AND SOUTH AMERICA.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH EASTERN
ALABAMA/WESTERN GEORGIA...ACROSS THE FLORIDA PANHANDLE AND
APALACHEE BAY OF FLORIDA...INTO THE EAST CENTRAL GULF OF
MEXICO...AND INTO THE SOUTHEASTERN CORNER OF THE GULF OF MEXICO.
HIGH CLOUDS HAVE BEEN MOVING ACROSS THE GULF OF MEXICO...TO THE
SOUTHEAST AND SOUTH OF 31N87W 25N89W 23N91W 26N97W.
COMPARATIVELY DRIER AIR IN SUBSIDENCE IS TO THE NORTH OF THE
LINE FROM 30N86W 23N92W 26N87W TO 25N97W.

A SURFACE RIDGE PASSES THROUGH 31N73W IN THE ATLANTIC OCEAN...TO
29N78W...TO 28N89W IN THE NORTH CENTRAL GULF OF MEXICO...TOWARD
THE MIDDLE TEXAS GULF COAST.

LOW CLOUD CEILINGS COVER THE COASTAL PLAINS STATIONS FROM THE
DEEP SOUTH OF TEXAS INTO SOUTH CENTRAL COASTAL LOUISIANA. BILOXI
MISSISSIPPI AND MOBILE ALABAMA ARE REPORTING LOW CLOUD CEILINGS.
FAIR SKIES/CLEAR SKIES AT OR LOWER THAN 12000 FEET ARE ELSEWHERE
BETWEEN THE REST OF LOUISIANA AND THE FLORIDA PANHANDLE. FAIR
SKIES/CLEAR SKIES AT OR LOWER THAN 12000 FEET ARE ELSEWHERE IN
FLORIDA.

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

LOW CLOUD CEILINGS ARE BEING REPORTED AT THE FOLLOWING ICAO
STATIONS...KVBS...KCRH...KHQI...KGUL...KDLP... AND KSPR. FAIR
SKIES/CLEAR SKIES AT OR LOWER THAN 12000 FEET ARE REPORTED
ELSEWHERE.

CARIBBEAN SEA...
A MIDDLE LEVEL TO UPPER LEVEL SHORTWAVE TROUGH IS ALONG 26N68W
IN THE ATLANTIC OCEAN...THROUGH THE WINDWARD PASSAGE...TO 18N76W
IN THE CARIBBEAN SEA...TO 16N78W. UPPER LEVEL SOUTHWESTERLY WIND
FLOW IS TO THE SOUTH OF THE LINE THAT RUNS FROM THE NORTHEASTERN
CORNER OF THE AREA...TO THE CENTRAL SECTIONS OF THE CARIBBEAN
SEA...TO NORTHEASTERN NICARAGUA.

A MIDDLE LEVEL TO UPPER LEVEL RIDGE STARTS NEAR 7N66W IN
VENEZUELA...TO 9N74W IN COLOMBIA NEAR THE MONSOON TROUGH...TO
11N81W IN THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA...TO
13N86W IN NORTHWESTERN NICARAGUA.

THE MONSOON TROUGH IS ALONG 8N73W IN COLOMBIA...THROUGH 8N78W IN
EASTERN PANAMA...THROUGH THE WESTERN END OF PANAMA...FROM
SOUTHEAST TO NORTHWEST IN COSTA RICA...TO 11N87W IN THE EASTERN
PACIFIC OCEAN...AND BEYOND 9N90W IN THE EASTERN PACIFIC OCEAN.
CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 3N ALONG THE
COLOMBIA COAST IN THE EASTERN PACIFIC OCEAN TO 11N IN THE
SOUTHWESTERN CORNER OF THE CARIBBEAN SEA...BETWEEN 76W IN
COLOMBIA AND 85W IN THE COASTAL WATERS OF COSTA RICA. NUMEROUS
STRONG ALSO IS IN LAKE MARACAIBO OF NORTHWESTERN VENEZUELA.

HISPANIOLA...
A MIDDLE LEVEL TO UPPER LEVEL SHORTWAVE TROUGH IS ALONG 26N68W
IN THE ATLANTIC OCEAN...THROUGH THE WINDWARD PASSAGE...TO 18N76W
IN THE CARIBBEAN SEA...TO 16N78W. ISOLATED MODERATE CONVECTIVE
PRECIPITATION IS FROM 16N TO 20N BETWEEN THE EASTERN EDGE OF
PUERTO RICO AND 78W BETWEEN SOUTHEASTERN CUBA AND JAMAICA.

THE GFS MODEL GIVES A FORECAST OF ANTICYCLONIC WIND FLOW/ A
RIDGE ACROSS THE AREA AT 250 MB. A TROUGH IS PRESENT IN THE
FORECAST AT 500 MB AND AT 700 MB. THE SURFACE WIND FLOW FORECAST
IS MOSTLY EASTERLY. IT IS POSSIBLE THAT ENOUGH LOW LEVEL
MOISTURE MAY CONTINUE TO BE PRESENT IN ORDER TO HELP TO GIVE
PRECIPITATION TO THE AREA.

ATLANTIC OCEAN...
A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 33N55W TO
27N55W. THE REST OF THE MIDDLE LEVEL TO UPPER LEVEL WIND FLOW
THAT IS AROUND THAT AREA TO THE SOUTH IS NORTHWESTERLY-TO-
WESTERLY. THE TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH
32N53W TO 28N66W...CURVING BEYOND 32N71W. A REMNANT SURFACE
TROUGH IS ALONG 28N59W 21N66W. RAINSHOWERS ARE POSSIBLE TO THE
NORTHWEST AND NORTH OF THE LINE THAT PASSES THROUGH 32N48W TO
24N60W 20N66W...INCLUDING ACROSS THE BAHAMAS AND THE ATLANTIC
OCEAN TO THE EAST OF FLORIDA.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM A 32N32W
CYCLONIC CIRCULATION CENTER...TO 20N34W 16N37W. A SURFACE TROUGH
IS ALONG 28N48W 25N44W 22N42W. RAINSHOWERS ARE POSSIBLE IN
CLUSTERS OF LOW LEVEL AND MIDDLE LEVEL CLOUDS THAT COVER THE
ATLANTIC OCEAN FROM 16N BEYOND 32N BETWEEN 40W AND 50W.

BROAD SURFACE ANTICYCLONIC WIND FLOW IS TO THE NORTH OF 27N TO
THE EAST OF 40W.

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

$$
MT