[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301138
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT FRI AUG 30 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.

...SPECIAL FEATURES...

A TROPICAL WAVE STILL IS MOVING THROUGH AFRICA...FROM MAURITANIA
TO SENEGAL AND GUINEA-BISSAU. THE 30/0600 UTC POSITION REMAINS
ALONG 15W/16W BASED ON THE LONG-TERM SATELLITE IMAGERY AND A LOW
PRESSURE CENTER THAT IS NEAR 14N ALONG THE TROPICAL WAVE.
CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 9N TO 11N
BETWEEN 14W AND 17W.  ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE
FOR DEVELOPMENT...AND THIS SYSTEM HAS THE POTENTIAL TO BECOME A
TROPICAL DEPRESSION DURING THE NEXT COUPLE OF DAYS WHEN THE LOW
MOVES BETWEEN THE WEST COAST OF AFRICA AND THE CAPE VERDE
ISLANDS. AFTER THAT TIME...CONDITIONS ARE EXPECTED TO BECOME A
LESS CONDUCIVE FOR DEVELOPMENT AS THE DISTURBANCE MOVES TOWARD
THE WEST-NORTHWEST OVER THE EASTERN ATLANTIC. THE SYSTEM HAS A
MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48
HOURS AND HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 5 DAYS. WHETHER THIS SYSTEM BECOMES A TROPICAL CYCLONE OR
NOT...IT WILL LIKELY BRING CLOUDINESS AND THUNDERSTORMS TO
PORTIONS OF THE CAPE VERDE ISLANDS IN THE NEXT 2 OR 3 DAYS.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 48W/49W TO THE SOUTH OF
20N MOVING WESTWARD 10 TO 15 KNOTS. CONVECTIVE PRECIPITATION...
SCATTERED MODERATE TO ISOLATED STRONG FROM 14N TO 20N BETWEEN
42W AND 50W. RAINSHOWERS ARE POSSIBLE ELSEWHERE FROM 4N TO 22N
BETWEEN 40W AND 55W.   THIS WAVE IS FORECAST TO MOVE WESTWARD...
INTO A REGION WHERE THE UPPER LEVEL WINDS ARE NOT FAVORABLE FOR
DEVELOPMENT. THIS SYSTEM HAS A LOW CHANCE OF BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS...AND A LOW CHANCE OF BECOMING
A TROPICAL CYCLONE DURING THE NEXT 5 DAYS.

AN ATLANTIC OCEAN SURFACE TROUGH IS ALONG 61W TO THE SOUTH OF
19N. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 10N TO
20N BETWEEN 59W AND 63W...FROM THE ATLANTIC OCEAN INTO THE
CARIBBEAN SEA.

AN ATLANTIC OCEAN-TO-CARIBBEAN SEA TROPICAL WAVE CURVES ALONG
25N62W...TO 20N66W...CUTTING ACROSS CENTRAL PUERTO RICO...TO THE
COAST OF VENEZUELA ALONG 67W. IT IS MOVING WESTWARD 15 TO 20
KNOTS. THE WAVE IS MOVING THROUGH THE AREA OF AN ALREADY-
EXISTING MIDDLE LEVEL TO UPPER LEVEL TROUGH. THE TROUGH EXTENDS
FROM A 27N57W CYCLONIC CIRCULATION CENTER...TO 24N60W 22N66W...
ACROSS PUERTO RICO...TO 16N65W IN THE CARIBBEAN SEA. A SECONDARY
SURGE OF ENERGY INTO AN ALREADY-EXISTING TROUGH IS ALONG 32N66W
30N70W 27N72W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO
ISOLATED STRONG FROM 20N TO 25N BETWEEN 57W AND 68W...AND TO THE
NORTH OF 27N BETWEEN 60W AND 80W. RAINSHOWERS ARE POSSIBLE
ELSEWHERE TO THE WEST AND NORTHWEST OF THE LINE THAT PASSES
THROUGH 32N52W TO 25N55W TO 18N62W IN THE ATLANTIC OCEAN.
RAINSHOWERS ARE POSSIBLE IN THE CARIBBEAN SEA TO THE NORTH OF
16N BETWEEN 64W AND 80W.

AN INLAND TROPICAL WAVE HAS MOVED AWAY FROM THE ISTHMUS OF
TEHUANTEPEC OF SOUTHERN MEXICO. IT IS NOW AN EASTERN PACIFIC
OCEAN FEATURE. CONVECTIVE PRECIPITATION...ISOLATED MODERATE IN
THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO TO THE SOUTH OF
20N AND IN THE ISTHMUS OF TEHUANTEPEC.

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

THE MONSOON TROUGH PASSES THROUGH THE COASTAL SENEGAL NEAR
12N17W TO 9N30W 7N40W AND 7N48W. CONVECTIVE PRECIPITATION...
NUMEROUS STRONG FROM 10N TO 11N BETWEEN 26W AND 28W. SCATTERED
MODERATE TO ISOLATED STRONG FROM 11N TO 15N BETWEEN 32W AND
40W...AND FROM 3N TO 6N BETWEEN 28W AND 40W. ISOLATED MODERATE
FROM 4N TO 13N BETWEEN 43W AND 60W.

...DISCUSSION...

THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS IN
THE SOUTHERNMOST PART OF FLORIDA/THE FLORIDA KEYS/THE FLORIDA
STRAITS. THIS CYCLONIC CENTER HAS BEEN IN THIS GENERAL AREA FOR
THE LAST FEW DAYS. CYCLONIC WIND FLOW COVERS THE GULF OF
MEXICO...FLORIDA...THE FLORIDA STRAITS...THE BAHAMAS...THE
ATLANTIC OCEAN...CUBA...AND THE NORTHWESTERN PART OF THE
CARIBBEAN SEA FROM 21N TO 29N BETWEEN 76W AND 90W. CONVECTIVE
PRECIPITATION...SCATTERED TO NUMEROUS STRONG IN THE FLORIDA
STRAITS ALONG THE COAST OF CUBA BETWEEN 78W AND 81W. RAINSHOWERS
ARE POSSIBLE ELSEWHERE IN THE GULF OF MEXICO TO THE SOUTH OF 28N
TO THE EAST OF 84W TOWARD THE BAHAMAS.

A SECOND MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER
IS INLAND IN THE SOUTHWESTERN SECTIONS OF MEXICO NEAR 21N105W.
CYCLONIC WIND FLOW COVERS MEXICO AND THE GULF OF MEXICO TO THE
SOUTH OF 28N TO THE WEST OF 93W.

WEAK SURFACE TO LOW LEVEL CYCLONIC WIND FLOW COVERS THE AREA
FROM 22N TO 28N BETWEEN 87W AND 96W. A SURFACE TROUGH CURVES
ALONG 28N93W 25N93W 24N95W. RAINSHOWERS ARE POSSIBLE IN THIS
AREA ALSO.

COMPARATIVELY DRIER AIR IN SUBSIDENCE SHOWS UP IN WATER VAPOR
IMAGERY TO THE NORTH OF 22N TO THE WEST OF 84W.

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

LOW LEVEL CLOUD CEILINGS ARE AT THE FOLLOWING ICAO STATIONS...
KMZG...KBBF...LOW TO MIDDLE LEVEL AT KBQX AND AT KGVX...KCRH.
ICAO STATION KEMK IS REPORTING A VISIBILITY OF LESS THAN ONE
MILE WITH HAZE. FAIR SKIES/CLEAR SKIES AT OR LOWER THAN 12000
FEET ARE BEING REPORTED ELSEWHERE ACROSS THE AREA.

BROKEN LOW LEVEL TO MIDDLE LEVEL CLOUDS COVER TEXAS FROM THE
HOUSTON METROPOLITAN AREA SOUTHWARD TO THE COAST. BROKEN MIDDLE
LEVEL CLOUDS ARE IN TALLAHASSEE FLORIDA...AND IN PUNTA GORDA.
FAIR SKIES/CLEAR SKIES AT OR LOWER THAN 12000 FEET ARE BEING
REPORTED ELSEWHERE IN THE COASTAL STATIONS OF THE U.S.A. GULF
COAST STATES.

THE CARIBBEAN SEA...

A MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH IS ALONG 16N76W TO
13N78W TO 11N78W. CYCLONIC WIND FLOW IS TO THE SOUTH OF 17N
BETWEEN 73W AND 82W. THE TROUGH IS SURROUNDED BY COMPARATIVELY
DRIER AIR IN SUBSIDENCE AS SEEN ON WATER VAPOR IMAGERY. A MIDDLE
LEVEL TO UPPER LEVEL TROUGH CUTS ACROSS THE AREA THAT RUNS FROM
FROM PUERTO RICO TO HISPANIOLA.

BROAD MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS
THE CARIBBEAN SEA TO THE WEST OF THE WINDWARD PASSAGE.
CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG
IN THE CARIBBEAN SEA TO THE NORTH OF 16N TO THE WEST OF THE
WINDWARD PASSAGE.

THE MONSOON TROUGH IS ALONG 9N74W IN COLOMBIA...BEYOND 8N84W IN
THE EASTERN PACIFIC OCEAN. CONVECTIVE PRECIPITATION...SCATTERED
TO NUMEROUS STRONG IN COLOMBIA AND IN THE SOUTHWESTERN CORNER OF
THE CARIBBEAN SEA TO THE SOUTH OF 11N TO THE WEST OF 75W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE
OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT THE
NORTHEAST TO EAST WINDS 20 TO 25 KNOTS AND SEA HEIGHTS LOWER
THAN 8 FEET TO THE SOUTH OF 13N BETWEEN 67W AND 73W.

HISPANIOLA...

AN ATLANTIC OCEAN-TO-CARIBBEAN SEA TROPICAL WAVE CURVES ALONG
25N62W...TO 20N66W...CUTTING ACROSS CENTRAL PUERTO RICO...TO THE
COAST OF VENEZUELA ALONG 67W. IT IS MOVING WESTWARD 15 TO 20
KNOTS. THE WAVE IS MOVING THROUGH THE AREA OF AN ALREADY-
EXISTING MIDDLE LEVEL TO UPPER LEVEL TROUGH. THE TROUGH EXTENDS
FROM A 27N57W CYCLONIC CIRCULATION CENTER...TO 24N60W 22N66W...
ACROSS PUERTO RICO...TO 16N65W IN THE CARIBBEAN SEA. RAINSHOWERS
ARE POSSIBLE IN THE CARIBBEAN SEA TO THE NORTH OF 16N BETWEEN
64W AND 80W.

THE GFS FORECASTS FOR 700 MB AND 500 MB...SHOW THAT ANTICYCLONIC
WIND FLOW WILL BE MOVING ACROSS HISPANIOLA FOR THE NEXT 48
HOURS...WITH AN EAST-TO-WEST ORIENTED RIDGE. THE GFS FORECAST
FOR 250 MB SHOWS THAT A RIDGE WILL COVER HISPANIOLA FOR THE
FIRST 24 HOURS OF THE FORECAST PERIOD. A TROUGH WILL REPLACE THE
RIDGE FOR THE REST OF THE FORECAST PERIOD.

THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR 28N35W. CYCLONIC WIND FLOW COVERS THE AREA FROM 23N TO 33N
BETWEEN 28W AND 44W. A SURFACE TROUGH IS ALONG 33N38W 29N39W
26N41W. RAINSHOWERS ARE POSSIBLE TO THE NORTH OF 26N BETWEEN 34W
AND 42W.

A 1023 MB HIGH PRESSURE CENTER IS NEAR 33N45W. SURFACE
ANTICYCLONIC WIND FLOW IS TO THE NORTH OF 25N BETWEEN THE 33N38W
26N41W SURFACE TROUGH AND 60W.

PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR DETAILS
ABOUT THE TROPICAL WAVE THAT IS ALONG 48W FROM 12N TO 21N.
EXPECT WINDS 20 KNOTS OR LESS AND SEA HEIGHTS TO 8 FEET FROM 16N
TO 19N BETWEEN 45W AND 50W.

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

$$
MT


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