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000
AXNT20 KNHC 181152
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT MAY 18 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...
A TROPICAL WAVE IS ALONG 52W/53W TO THE SOUTH OF 9N...INTO
FRENCH GUIANA. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS
STRONG FROM 7N TO 10N BETWEEN 51W AND 55W. SCATTERED MODERATE TO
ISOLATED STRONG FROM 6N TO 10N BETWEEN 46W AND 50W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH PASSES THROUGH COASTAL GUINEA NEAR 10N14W TO
6N21W. THE ITCZ CONTINUES FROM 6N21W TO 2N33W TO 2N38W.
CONVECTIVE PRECIPITATION...NUMEROUS STRONG ALONG THE COAST OF
LIBERIA AND SIERRA LEONE FROM 5N TO 7N BETWEEN 10W AND 13W.
SCATTERED STRONG FROM 1N TO 3N BETWEEN 8W AND 13W...FROM 5N TO
6N BETWEEN 15W AND 17W...AND FROM 2N TO 5N BETWEEN 33W AND 40W.
ISOLATED MODERATE FROM 3N TO 6N BETWEEN 20W AND 27W...AND TO THE
SOUTH OF 10N BETWEEN 56W AND 60W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE LEVEL TO UPPER LEVEL RIDGE IS ALONG 99W/100W FROM 20N
IN MEXICO INTO THE EASTERN HALF OF TEXAS. UPPER LEVEL
NORTHWESTERLY WIND FLOW MOVES ACROSS THE GULF OF MEXICO.
COMPARATIVELY DRIER AIR IS TO THE EAST OF 90W. MULTILAYERED
MOISTURE IS STREAMING FROM MEXICO INTO THE GULF OF MEXICO TO THE
WEST OF 90W.

A SURFACE RIDGE EXTENDS FROM AN ATLANTIC OCEAN 1022 MB HIGH
PRESSURE CENTER THAT IS NEAR 30N67W...INTO NORTHERN FLORIDA NEAR
30N82W...TO 28N92W IN THE GULF OF MEXICO...TO 21N98W IN THE
MEXICO COASTAL PLAINS...OFF THE SOUTHWESTERN CORNER OF THE GULF
OF MEXICO.

RAINSHOWERS ARE POSSIBLE TO THE SOUTH OF 27N BETWEEN 84W AND 88W.

LOW CLOUD CEILINGS COVER THE STATIONS THAT ARE IN THE COASTAL
PLAINS FROM THE DEEP SOUTH OF TEXAS TO THE WESTERN HALF OF
LOUISIANA. SCATTERED TO BROKEN LOW CLOUDS ARE IN THE EASTERN
HALF OF THE LOUISIANA COASTAL PLAINS AND IN COASTAL MISSISSIPPI
AND ALABAMA. CRESTVIEW FLORIDA IS REPORTING A VISIBILITY OF 1/4
OF A MILE WITH FOG. SCATTERED TO BROKEN LOW CLOUDS AND SCATTERED
TO BROKEN MULTILAYERED CLOUDS AND PATCHY FOG COVER THE FLORIDA
COASTAL PLAINS FROM APALACHEE BAY WESTWARD. PUNTA GORDA IS
REPORTING A VISIBILITY OF 1/4 OF A MILE WITH FOG. FOG AND
VISIBIILTIES OF 1 MILE OR SO ARE OBSERVED FROM TAMPA TO PERRY IN
FLORIDA. 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...KMZG...KGVX...KVBS...KCRH...KHQI...KSPR...AND KDLP.
FAIR SKIES/CLEAR SKIES AT OR LOWER THAN 12000 FEET ARE REPORTED
ELSEWHERE.

CARIBBEAN SEA...
MIDDLE LEVEL TO UPPER LEVEL RIDGE STARTS NEAR TRINIDAD AND
TOBAGO...CONTINUING ACROSS NORTHERN COASTAL SECTIONS OF
VENEZUELA AND COLOMBIA...TO 12N77W IN THE CARIBBEAN SEA...TO
15N80W AND 16N82W.

THE MONSOON TROUGH IS ALONG 7N74W IN COLOMBIA...TO 7N81W IN
PANAMA...BEYOND 8N85W IN THE EASTERN PACIFIC OCEAN. CONVECTIVE
PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 3N TO
10N IN THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA BETWEEN 78W
AT THE COLOMBIA COAST AND 85W IN THE EASTERN PACIFIC OCEAN.

RAINSHOWERS ALSO ARE POSSIBLE TO THE NORTH OF 17N BETWEEN THE
WINDWARD PASSAGE AND THE YUCATAN PENINSULA OF MEXICO.

HISPANIOLA...
MIDDLE LEVEL TO UPPER LEVEL NORTHWESTERLY WIND FLOW PASSES
THROUGH THE FLORIDA STRAITS...ACROSS CUBA AND HISPANIOLA...
MERGING WITH THE MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND
FLOW THAT IS RELATED TO THE TRINIDAD-TO-16N82W RIDGE.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH THE
ATLANTIC OCEAN NEAR 18N58W...TO 17N68W TO THE SOUTH OF THE MONA
PASSAGE. THE SOUTHERNMOST POINT OF AN ATLANTIC OCEAN STATIONARY
FRONT IS NEAR 21N71W IN THE ATLANTIC OCEAN. RAINSHOWERS ARE
POSSIBLE FROM 16N TO 20N BETWEEN 66W AND THE WINDWARD
PASSAGE...INCLUDING IN INTERIOR SECTIONS OF HISPANIOLA.

THE GFS MODEL GIVES A FORECAST OF A 250 MB TROUGH TO BE
ACROSS THE AREA DURING THE NEXT 48 HOURS OR SO. THE
GFS MODEL ALSO GIVES THE FORECAST OF A PERSISTENT RIDGE AT 500
MB AND 700 MB...WITH NORTHWESTERLY WIND FLOW ALSO AT 500
MB...DURING THE SAME TIME PERIOD. A WEAK SURFACE TROUGH AND
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 EXTENDS FROM A 32N43W
CYCLONIC CIRCULATION CENTER...TO 23N44W 18N58W...TO 17N68W TO
THE SOUTH OF THE MONA PASSAGE. THE SOUTHERNMOST POINT OF A
STATIONARY FRONT IS NEAR 21N71W IN THE ATLANTIC OCEAN.
RAINSHOWERS ARE POSSIBLE FROM 16N TO 20N BETWEEN 66W AND THE
WINDWARD PASSAGE...INCLUDING IN INTERIOR SECTIONS OF HISPANIOLA.
A STATIONARY FRONT PASSES THROUGH 32N55W TO 27N60W 22N65W AND
21N71W. A SURFACE TROUGH IS ALONG 31N50W TO 25N46W. RAINSHOWERS
ARE POSSIBLE TO THE NORTHWEST AND NORTH OF THE LINE THAT PASSES
THROUGH 32N52W 24N60W 20N67W... INCLUDING ACROSS THE BAHAMAS AND
THE ATLANTIC OCEAN TO THE EAST OF FLORIDA.

A SURFACE RIDGE EXTENDS FROM AN ATLANTIC OCEAN 1022 MB HIGH
PRESSURE CENTER THAT IS NEAR 30N67W...INTO NORTHERN FLORIDA NEAR
30N82W...TO 28N92W IN THE GULF OF MEXICO...TO 21N98W IN THE
MEXICO COASTAL PLAINS...OFF THE SOUTHWESTERN CORNER OF THE GULF
OF MEXICO.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N7W IN
MOROCCO...TO 23N15W IN THE WESTERN SAHARA...TO 16N19W. NO
SIGNIFICANT DEEP CONVECTIVE PRECIPITATION APPEARS IN SATELLITE
IMAGERY.

BROAD ATLANTIC OCEAN SURFACE ANTICYCLONIC WIND FLOW THAT IS TO
THE NORTH OF 14N TO THE EAST OF 52W IS INTERRUPTED BY THE 31N50W
25N46W SURFACE TROUGH.

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

$$
MT