000
AXNT20 KNHC 170558
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI MAY 17 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 0000 UTC SURFACE ANALYSIS AND SATELLITE
IMAGERY THROUGH 0515 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 46W/47W TO THE SOUTH OF 9N
MOVING WEST 10 TO 15 KNOTS. SCATTERED MODERATE TO ISOLATED
STRONG CONVECTIVE PRECIPITATION IS FROM 3N TO 11N BETWEEN
40W AND 50W. THE WAVE REMAINS LOW-AMPLITUDE AND EMBEDDED
WITHIN THE ITCZ. THIS POSITION COINCIDES WITH A GLOBAL-
MODEL-INDICATED AREA OF MAXIMUM POTENTIAL VORTICITY AT
315K. TOTAL PRECIPITATABLE WATER AND SATELLITE IMAGERY
ALSO INDICATE A MAXIMUM IN LOW-LEVEL MOISTURE CONVERGENCE.

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

THE MONSOON TROUGH PASSES THROUGH COASTAL GUINEA-
BISSAU NEAR 11N15W TO 5N21W. THE ITCZ CONTINUES FROM
5N21W TO 3N32W 4N45W...INTO NORTHEASTERN BRAZIL NEAR
3N52W. CONVECTIVE PRECIPITATION...NUMEROUS STRONG
FROM 6N TO 8N BETWEEN 18W AND 21W. SCATTERED STRONG
IS FROM LAND TO 9N BETWEEN 50W AND 57W. SCATTERED
MODERATE TO ISOLATED STRONG FROM 3N TO 4N BETWEEN
1W AND 11W...TO THE SOUTH OF 5N BETWEEN 25W AND 40W.

...DISCUSSION...

THE GULF OF MEXICO...

BROAD MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND
FLOW SPANS THE AREA THAT IS TO THE SOUTH OF 26N.
MULTILAYERED MOISTURE IS MOVING ACROSS THE GULF OF MEXICO
TO THE SOUTH OF 26N WITH THE ANTICYCLONIC WIND FLOW.

COMPARATIVELY DRIER AIR IS TO THE NORTH OF 26N. MIDDLE
LEVEL TO UPPER LEVEL WESTERLY WIND FLOW IS TO THE NORTH
OF 26N. A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION
CENTER IS MOVING THROUGH THE AREA OF SOUTHEASTERN MISSOURI
AND NORTHEASTERN ARKANSAS.

A SURFACE RIDGE PASSES THROUGH THE ATLANTIC OCEAN NEAR
30N68W TO 29N77W...ACROSS FLORIDA ALONG 29N/30N...INTO
THE GULF OF MEXICO NEAR 29N87W...TO 24N96W IN THE GULF
OF MEXICO.

LIGHT RAIN WAS REPORTED AT MCALLEN TEXAS IN THE LAST
OBSERVATION. LOW CLOUD CEILINGS WERE REPORTED AT
BROWNSVILLE AND WESLACO. FAIR SKIES AT OR LOWER THAN
12000 FEET ARE ELSEWHERE IN THE LOWER VALLEY OF TEXAS.
LOW CLOUD CEILINGS ARE REPORTED IN THE CORPUS CHRISTI
METROPOLITAN AREA. LOW CLOUD CEILINGS COVER THE REST OF
THE TEXAS GULF COAST PLAINS...INTO THE WESTERN HALF OF
THE LOUISIANA COASTAL PLAINS. THE EASTERN HALF OF THE
LOUISIANA COASTAL PLAINS CONSISTS OF SCATTERED TO BROKEN
LOW CLOUDS. SCATTERED TO BROKEN LOW CLOUDS AND MIDDLE
LEVEL CLOUD CEILINGS ARE IN COASTAL MISSISSIPPI. SCATTERED
TO BROKEN LOW CLOUDS ARE OBSERVED IN THE FLORIDA PANHANDLE.
LOW CLOUD CEILINGS ARE OBSERVED ELSEWHERE IN FLORIDA...IN
FORT MYERS AND NAPLES. A HIGH CLOUD CEILING IS OBSERVED
AT THE TAMPA INTERNATIONAL AIRPORT. A VISIBILITY OF 1 MILE
AND FOG IS REPORTED IN PERRY 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...KGVX...KMZG...KVBS...KHQI...KCRH.
FAIR SKIES/CLEAR SKIES AT OR LOWER THAN 12000 FEET
ARE REPORTED ELSEWHERE.

THE CARIBBEAN SEA...

A 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 15N81W...ACROSS THE NORTHEASTERN CORNER OF
NICARAGUA AND ACROSS THE NORTHERN HALF OF HONDURAS...
INTO THE YUCATAN PENINSULA.

THE MONSOON TROUGH IS ALONG 6N77W ALONG THE COLOMBIA COAST
TO 6N81W...9N85W...AND BEYOND 9N89W IN THE EASTERN PACIFIC
OCEAN. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS
STRONG IN THE SOUTHWESTERN CARIBBEAN SEA TO THE SOUTH OF
10N BETWEEN 77W AND 81W...AND IN COLOMBIA FROM 5N TO 6N
BETWEEN 75W AND 76W.

RAINSHOWERS ALSO ARE POSSIBLE TO THE NORTH OF 16N
BETWEEN 75W AND 81W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...
AND THE OFFSHORE FORECAST...MIAOFFNT3...FOR MORE
DETAILS ABOUT THE 20 KNOTS OR LESS WINDS AND SEA HEIGHTS
REACHING 8 FEET FROM 11N TO 13N BETWEEN 75W AND 80W
FOR THE NEXT 48 HOURS OR SO.

HISPANIOLA...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH THE ATLANTIC
OCEAN NEAR 26N51W...TO 21N59W...TO 19N68W NEAR THE NORTHERN PART
OF THE MONA PASSAGE...ACROSS THE NORTHERN COAST OF HISPANIOLA...
INTO THE NORTHERN PART OF THE WINDWARD PASSAGE. MIDDLE LEVEL TO
UPPER LEVEL CYCLONIC WIND FLOW SPANS THE ATLANTIC OCEAN AND THE
CARIBBEAN SEA TO THE NORTH OF 15N TO THE EAST OF 74W. THIS AREA
INCLUDES HISPANIOLA AND PUERTO RICO. SCATTERED MULTILAYERED
CLOUDS AND POSSIBLE RAINSHOWERS COVER THE AREA. RAINSHOWERS ALSO
ARE POSSIBLE TO THE NORTH OF 16N BETWEEN 75W AND 81W.

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 AT 700 MB DURING
THE SAME TIME PERIOD. A WEAK SURFACE TROUGH MAY PERSIST FOR THE
NEXT FEW DAYS. ENOUGH MOISTURE MAY CONTINUE TO BE PRESENT IN
ORDER TO HELP TO GIVE SOME PRECIPITATION TO THE AREA.

THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N47W
TO 26N51W...TO 21N59W...TO 19N68W NEAR THE NORTHERN PART OF THE
MONA PASSAGE...ACROSS THE NORTHERN COAST OF HISPANIOLA...INTO
THE NORTHERN PART OF THE WINDWARD PASSAGE. MIDDLE LEVEL TO UPPER
LEVEL CYCLONIC WIND FLOW SPANS THE ATLANTIC OCEAN AND THE
CARIBBEAN SEA TO THE NORTH OF 15N TO THE EAST OF 74W. THIS AREA
INCLUDES HISPANIOLA AND PUERTO RICO. A STATIONARY FRONT PASSES
THROUGH 32N56W TO 28N58W AND 24N62W. A SHEAR AXIS CONTINUES FROM
24N62W TO 22N67W...ACROSS THE SOUTHERN BAHAMAS TO 21N73W.
RAINSHOWERS ARE POSSIBLE TO THE NORTH OF 27N BETWEEN 53W AND
60W...TO THE NORTH OF 20N BETWEEN 60W AND 70W...AND FROM 20N
TO 22N BETWEEN 70W AND 74W. A SURFACE TROUGH IS ALONG 31N48W...
TO A 1020 MB LOW PRESSURE CENTER THAT IS NEAR 29N45W...
CONTINUING TO 27N43W. RAINSHOWERS ARE POSSIBLE FROM 17N TO 22N
BETWEEN 48W AND 54W...AND TO THE NORTH OF 23N BETWEEN 40W AND
50W.

A SURFACE RIDGE EXTENDS FROM A 1023 MB HIGH PRESSURE CENTER
THAT IS NEAR 34N58W...TO A SECOND 1023 MB HIGH PRESSURE
CENTER THAT IS NEAR 30N68W. THE RIDGE CONTINUES FROM 30N68W
TO 29N77W...ACROSS FLORIDA ALONG 29N/30N...INTO THE GULF OF
MEXICO NEAR 29N87W...TO 24N96W IN THE GULF OF MEXICO.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N18W
TO 22N23W AND 17N26W. NO SIGNIFICANT DEEP CONVECTIVE
PRECIPITATION APPEARS IN SATELLITE IMAGERY.

BROAD ATLANTIC OCEAN SURFACE ANTICYCLONIC WIND FLOW THAT IS
TO THE NORTH OF 12N TO THE EAST OF 54W IS INTERRUPTED BY
A 1020 MB LOW PRESSURE CENTER THAT IS NEAR 29N45W. A SURFACE
TROUGH IS ALONG 31N48W 29N45W 27N43W. AN EASTERN ATLANTIC
OCEAN SURFACE RIDGE PASSES THROUGH 32N36W TO 13N38W.

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

$$
MT