[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 051108
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT SEP 05 2015

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
1045 UTC.

...SPECIAL FEATURES...

THE CENTER OF TROPICAL STORM FRED AT 05/0900 UTC IS NEAR 23.2N
41.0W. FRED IS MOVING TOWARD THE WEST-NORTHWEST...OR 290
DEGREES...10 KNOTS. THE MINIMUM CENTRAL PRESSURE IS 1007 MB. THE
MAXIMUM SUSTAINED WIND SPEEDS ARE 35 KNOTS WITH GUSTS TO 45
KNOTS. PUBLIC ADVISORIES ABOUT TROPICAL STORM FRED ARE BEING
ISSUED UNDER THE WMO HEADER WTNT31 KNHC...AND UNDER THE AWIPS
HEADER MIATCPAT1. FORECAST/ADVISORIES ABOUT TROPICAL STORM FRED
ARE BEING ISSUED UNDER THE WMO HEADER WTNT21 KNHC...AND UNDER
THE AWIPS HEADER MIATCMAT1. CONVECTIVE PRECIPITATION...SCATTERED
TO NUMEROUS STRONG WITHIN A RADIUS OF 90 NM OF THE CENTER IN THE
NORTHEASTERN QUADRANT.

A TROPICAL WAVE IS ALONG 22W/23W FROM 19N SOUTHWARD. A 1010 MB
LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 11.5N. THIS SYSTEM
GRADUALLY IS BECOMING BETTER ORGANIZED. IT IS LIKELY THAT A
TROPICAL DEPRESSION MAY FORM DURING THE NEXT COUPLE OF DAYS. THE
CHANCE FOR SUCH DEVELOPMENT IS HIGH...AS THE WAVE MOVES WESTWARD
15 TO 20 KNOTS. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO
STRONG FROM 11N TO 14N BETWEEN 23W AND 27W.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 31W/32W FROM 18N
SOUTHWARD...MOVING WESTWARD 15 KNOTS. A 1010 MB LOW PRESSURE
CENTER IS NEAR 11N ALONG THE WAVE. CONVECTIVE PRECIPITATION...
ISOLATED MODERATE TO LOCALLY STRONG FROM 08N TO 13N BETWEEN 29W
AND 37W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 18N57W 14N58W 09N59W...
MOVING WESTWARD 15 TO 20 KNOTS. TPW IMAGERY SHOWS THAT THIS WAVE
IS IN A DRY ENVIRONMENT. NO SIGNIFICANT DEEP CONVECTIVE
PRECIPITATION IS PRESENT AT THIS TIME.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 66W/67W FROM 20N
SOUTHWARD. THE WAVE IS MOVING WESTWARD 15 KNOTS. THIS WAVE IS
MOVING INTO THE EASTERN PART OF AN AREA OF PRE-EXISTING MIDDLE
LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW WITH A TROUGH. A MIDDLE
LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR
20N69W...WITHIN 60 NM TO 90 NM OFF THE COAST OF THE DOMINICAN
REPUBLIC. THE TROUGH EXTENDS FROM THE 20N69W CYCLONIC CENTER TO
NORTHEASTERN COLOMBIA/NORTHWESTERN VENEZUELA. UPPER LEVEL
NORTHEASTERLY WIND FLOW IS CROSSING HISPANIOLA. THE TROPICAL
WAVE SHOULD BE REACHING HISPANIOLA DURING THE NEXT 24 HOURS OR
LESS.

A SOUTHWESTERN GULF OF MEXICO TROPICAL WAVE IS 95W/96W FROM 18N
SOUTHWARD...ACROSS THE ISTHMUS OF TEHUANTEPEC...INTO THE EASTERN
PACIFIC OCEAN. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO
LOCALLY STRONG FROM 14N TO 20N BETWEEN 93W AND 97W IN THE
ISTHMUS OF TEHUANTEPEC OF SOUTHERN MEXICO...AND IN THE COASTAL
WATERS OF MEXICO IN THE EASTERN PACIFIC OCEAN.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES COASTAL SECTIONS OF SENEGAL NEAR
14N17W TO THE 1010 MB LOW PRESSURE CENTER THAT IS ALONG THE
22W/23W TROPICAL WAVE...TO THE 1010 MB LOW PRESSURE CENTER THAT
IS ALONG THE 31W/32W TROPICAL WAVE...TO 10N38W. THE ITCZ
CONTINUES FROM 10N38W TO 09N46W...AND TO 08N53W. CONVECTIVE
PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED STRONG ARE
IN THE COASTAL WATERS OF AFRICA FROM 06N TO 08N BETWEEN 11W AND
14W...AND FROM 13N TO 14N BETWEEN 46W AND 47W. BROKEN
MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE ELSEWHEREWITHIN 330 NM ON EITHER SIDE OF THE LINE 11N15W 09N30W 08N40W
08N50W AND 06N54W.

...DISCUSSION...

FROM THE WESTERN ATLANTIC OCEAN INTO THE GULF OF MEXICO...
INCLUDING THE REST OF THE GULF OF MEXICO...

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH THE ATLANTIC
OCEAN NEAR 32N70W TO 27N72W...INTO THE SOUTHEASTERN CORNER OF
THE GULF OF MEXICO NEAR 23N86W. A SURFACE TROUGH IS ALONG
31N69W...TO A 1012 MB LOW PRESSURE CENTER THAT IS NEAR 29N72W...
ACROSS THE NORTHERN BAHAMAS...TO 26N79W. CONVECTIVE
PRECIPITATION...IN THE GULF OF MEXICO...WIDELY SCATTERED
MODERATE TO ISOLATED STRONG FROM 27N NORTHWARD FROM 91W
EASTWARD. RAINSHOWERS ARE POSSIBLE ELSEWHERE FROM 23N NORTHWARD
FROM 93W EASTWARD IN THE GULF OF MEXICO. IN THE ATLANTIC
OCEAN...WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 25N
NORTHWARD FROM 69W WESTWARD.

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR 17N89W IN BELIZE. CYCLONIC WIND FLOW COVERS THE GULF OF
MEXICO AND THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA...THE
YUCATAN PENINSULA...AND PARTS OF CENTRAL AMERICA FROM 13N AND EL
SALVADOR TO 22N BETWEEN 85W AND 93W. CONVECTIVE PRECIPITATION...
ISOLATED MODERATE TO LOCALLY STRONG FROM 10N IN THE EASTERN
PACIFIC OCEAN TO 20N IN THE NORTHWESTERN CORNER OF THE CARIBBEAN
SEA...BETWEEN 84W AND 92W...INCLUDING ACROSS THE YUCATAN
PENINSULA AND PARTS OF CENTRAL AMERICA.

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR 18N103W ALONG THE EASTERN PACIFIC OCEAN COAST OF MEXICO.
CYCLONIC WIND FLOW COVERS MEXICO FROM 25N SOUTHWARD.

UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE REST OF THE
AREA...THAT IS FROM 24N NORTHWARD FROM 90W WESTWARD.

A WEAK SURFACE PRESSURE PATTERN IS IN THE GULF OF MEXICO.
A 1016 MB HIGH PRESSURE CENTER IS NEAR 27N87W.

THE CARIBBEAN SEA...

PLEASE REFER TO THE SECTION THAT IS ABOUT HISPANIOLA AND THE
SECTION THAT IS ABOUT TROPICAL WAVES...FOR MORE DETAILS ABOUT
THE CARIBBEAN SEA TROPICAL WAVE THAT IS ALONG 65W/66W FROM 20N
SOUTHWARD.

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR 17N89W IN BELIZE. CYCLONIC WIND FLOW COVERS THE GULF OF
MEXICO AND THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA...THE
YUCATAN PENINSULA...AND PARTS OF CENTRAL AMERICA FROM 13N AND EL
SALVADOR TO 22N BETWEEN 85W AND 93W. CONVECTIVE PRECIPITATION...
ISOLATED MODERATE TO LOCALLY STRONG FROM 10N IN THE EASTERN
PACIFIC OCEAN TO 20N IN THE NORTHWESTERN CORNER OF THE CARIBBEAN
SEA...BETWEEN 84W AND 92W...INCLUDING ACROSS THE YUCATAN
PENINSULA AND PARTS OF CENTRAL AMERICA.

UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA THAT IS
BETWEEN THE CYCLONIC WIND FLOW OF THE CENTRAL CARIBBEAN SEA
TROUGH AND THE CYCLONIC WIND FLOW THAT IS MOVING AROUND THE
BELIZE CYCLONIC CIRCULATION CENTER. CONVECTIVE PRECIPITATION...
SCATTERED MODERATE TO ISOLATED STRONG TO THE SOUTHWEST OF THE
LINE 15N82W 09N76W IN THE SOUTHWESTERN CORNER OF THE
CARIBBEAN SEA.

THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT
05/0000 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...ARE 0.69 IN
BERMUDA...0.51 IN TEGUCIGALPA IN HONDURAS...AND 0.11 IN
GUADELOUPE.

...HISPANIOLA...

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 66W/67W FROM 20N
SOUTHWARD. THE WAVE IS MOVING WESTWARD 15 KNOTS. THIS WAVE IS
MOVING INTO THE EASTERN PART OF AN AREA OF PRE-EXISTING MIDDLE
LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW WITH A TROUGH. A MIDDLE
LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR
20N69W...WITHIN 60 NM TO 90 NM OFF THE COAST OF THE DOMINICAN
REPUBLIC. THE TROUGH EXTENDS FROM THE 20N69W CYCLONIC CENTER TO
NORTHEASTERN COLOMBIA/NORTHWESTERN VENEZUELA. UPPER LEVEL
NORTHEASTERLY WIND FLOW IS CROSSING HISPANIOLA. THE TROPICAL
WAVE SHOULD BE REACHING HISPANIOLA DURING THE NEXT 24 HOURS OR
LESS.

CURRENT CONDITIONS...IN PORT-AU-PRINCE HAITI...THE LAST
OBSERVATION FOR 05/0000 UTC AND EARLIER OBSERVATIONS...SHOWED
SCATTERED CUMULONIMBUS CLOUDS AND SCATTERED HIGH LEVEL CLOUDS.
IN THE DOMINICAN REPUBLIC...FEW LOW LEVEL CLOUDS ARE IN SANTO
DOMINGO...IN SANTIAGO...AND IN PUERTO PLATA. SCATTERED LOW LEVEL
CLOUDS ARE IN PUNTA CANA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT CYCLONIC WIND FLOW
WILL CROSS HISPANIOLA FOR THE FIRST 24 HOURS. THE TROUGH WILL
MOVE EASTWARD AFTER 24 HOURS...BRINGING ANTICYCLONIC WIND FLOW
TO THE AREA FOR THE REST OF THE 48-HOUR FORECAST PERIOD. A RIDGE
WILL BE BUILDING ACROSS HISPANIOLA FROM THE SOUTHWESTERN CORNER
OF THE CARIBBEAN SEA. THE GFS MODEL FORECAST FOR 500 MB SHOWS
THAT CYCLONIC WIND FLOW WILL COVER THE AREA FOR THE FIRST 24
HOURS...THANKS TO THE 20N69W CYCLONIC CIRCULATION CENTER AND
TROUGH. THE CYCLONIC CENTER AND TROUGH WILL MOVE NORTHWARD...
BEING REPLACED BY AN INVERTED TROUGH FOR 6 TO 12 HOURS.
SOUTHERLY-TO-SOUTHWESTERLY WIND FLOW EVENTUALLY WILL COVER THE
AREA FOR THE REST OF THE 48-HOUR FORECAST PERIOD. THIS WIND FLOW
WILL BE RELATED TO A NORTHEAST-TO-SOUTHWEST ORIENTED ATLANTIC
OCEAN-TO-HISPANIOLA RIDGE. THE GFS MODEL FOR 700 MB STARTS WITH
NORTHERLY WIND FLOW THAT IS ASSOCIATED WITH A GULF OF MEXICO-TO-
CUBA-TO HISPANIOLA RIDGE. THE NORTHERLY WIND FLOW BECOMES
NORTHEASTERLY WITH A SHORTER-WAVELENGTH RIDGE THAT DEVELOPS FROM
THE BAHAMAS TO SOUTHEASTERN CUBA. THIS WIND REGIME LASTS FOR 12
HOURS OR SO. A SITUATION OF  DIFFLUENT WIND FLOW DEVELOPS AND
LASTS FOR 6 HOURS OR SO... GIVING WAY TO HISPANIOLA NEARLY BEING
IN A COL AT THE 24-HOUR POINT IN THE 48-HOUR FORECAST PERIOD. AN
INVERTED TROUGH MOVES THROUGH THE AREA FOR 6 HOURS OR SO.
SOUTHEAST-TO-EAST WIND FLOW EVENTUALLY CONTINUES FOR THE LAST 12
TO 18 HOURS OF THE FORECAST PERIOD...ASSOCIATED WITH AN ATLANTIC
OCEAN 25N RIDGE.

THE REST OF THE ATLANTIC OCEAN...

PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS
ABOUT TROPICAL STORM FRED.

UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN
FROM 22N SOUTHWARD BETWEEN 30W AND 60W. THIS ANTICYCLONIC WIND
FLOW COVERS THE ATLANTIC OCEAN TO THE SOUTHWEST OF THE WIND FLOW
THAT IS MOVING AROUND TROPICAL STORM FRED.

A SURFACE TROUGH EXTENDS FROM A 1010 MB LOW PRESSURE CENTER THAT
IS NEAR 33N61W TO 26N67W. CONVECTIVE PRECIPITATION...WIDELY
SCATTERED MODERATE TO ISOLATED STRONG FROM 26N NORTHWARD BETWEEN
50W AND 65W.

A SECOND SURFACE TROUGH EXTENDS FROM A 1015 MB LOW PRESSURE
CENTER THAT IS NEAR 31N49W...TO 26N50W. CONVECTIVE
PRECIPITATION...SCATTERED MODERATE TO STRONG FROM 29N NORTHWARD
BETWEEN 43W AND 46W.

A 1020 MB HIGH PRESSURE CENTER IS NEAR 30N30W. SURFACE
ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN FROM 22N
NORTHWARD BETWEEN AFRICA AND 40W...AWAY FROM T.S. FRED.

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

$$
MT
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