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AXNT20 KNHC 010005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON AUG 31 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC.


...SPECIAL FEATURES...

THE CENTER OF HURRICANE FRED AT 01/0000 UTC IS NEAR 17.4N 25.0W... OR ABOUT 22 NM TO THE NORTH-NORTHEAST OF SANTO ANTAO IN THE CAPE VERDE ISLANDS. WIND...STORM SURGE...AND RAINFALL ARE THE MAIN THREATS TO THE CAPE VERDE ISLANDS. FRED IS MOVING TOWARD THE NORTHWEST...OR 310 DEGREES...10 KNOTS. THE MINIMUM CENTRAL PRESSURE IS 992 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 65 KNOTS WITH GUSTS TO 80 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 FROM 15N TO 19N BETWEEN 24W AND 25.5W.


...TROPICAL WAVES...

AN ATLANTIC OCEAN-TO-CARIBBEAN SEA TROPICAL WAVE CURVES FROM 20N59W TO 16N61W AND 11N61W. THE WAVE IS MOVING WESTWARD 15 KNOTS. THIS WAVE IS MOVING THROUGH THE AREA OF AN ATLANTIC OCEAN- TO-CARIBBEAN SEA MIDDLE LEVEL TO UPPER LEVEL TROUGH THAT REACHES 18N64W. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 10N TO 16N BETWEEN 55W AND 62W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 77W/78W FROM 20N SOUTHWARD...ACROSS JAMAICA. THE WAVE IS MOVING WESTWARD 20 KNOTS DURING THE LAST 24 HOURS...THROUGH THE AREA OF AN INVERTED MIDDLE LEVEL TO UPPER LEVEL TROUGH.


...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH IS ALONG 11N29W 09N36W...TO A 1012 MB LOW PRESSURE CENTER THAT IS NEAR 07N40W...TO 07N47W. THE ITCZ IS NOT PRESENT AT THIS TIME. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO LOCALLY STRONG IS WITHIN 60 NM ON EITHER SIDE OF THE LINE FROM 11N25W TO 09N32W TO 07N39W 06N45W 08N49W 08N52W 11N56W.


...DISCUSSION...

THE GULF OF MEXICO...

UPPER LEVEL SOUTHWESTERLY WIND FLOW SPANS THE GULF OF MEXICO. THIS WIND FLOW IS ASSOCIATED WITH BROAD UPPER LEVEL CYCLONIC WIND FLOW...THAT IS CONNECTED WITH A SOUTH TEXAS CYCLONIC CIRCULATION CENTER THAT IS NEAR 29N98W. CONVECTIVE PRECIPITATION...WIDELY SCATTERED TO SCATTERED MODERATE AND ISOLATED STRONG FROM NORTHEASTERN MEXICO NEAR 25N TO 31N BETWEEN 92W AND 100W. SIMILAR CONVECTIVE PRECIPITATION IS UNDER UPPER LEVEL ANTICYCLONIC WIND FLOW THAT COVERS THE EASTERN AND SOUTHEASTERN SECTIONS...TO THE EAST OF THE LINE THAT RUNS FROM 29N83W TO 24N89W TO 19N93W...INCLUDING IN THE YUCATAN PENINSULA.

A SURFACE TROUGH IS ALONG THE LINE FROM NORTHEASTERN FLORIDA...TO A 1015 MB LOW PRESSURE CENTER THAT IS NEAR 26N84W...TO THE NORTHWESTERN CORNER OF THE YUCATAN PENINSULA. THIS SURFACE TROUGH REPRESENTS THE REMNANTS OF ERIKA.

THE CARIBBEAN SEA...

A MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH EXTENDS FROM SOUTHEASTERN CUBA TO THE EASTERN HALF OF PANAMA. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG ALONG THE NORTHERN BORDER OF HAITI AND THE DOMINICAN REPUBLIC...IN CENTRAL CUBA ALONG THE CARIBBEAN SEA COAST. SCATTERED MODERATE TO ISOLATED FROM 17N TO 21N BETWEEN 80W AND 85W.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH REACHES THE NORTHEASTERN CORNER OF THE CARIBBEAN SEA NEAR 18N64W. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 16N TO 20N BETWEEN 60W AND 65W.

THE MONSOON TROUGH IS ALONG 10N BETWEEN 74W IN COLOMBIA AND 86W IN COSTA RICA. CONVECTIVE PRECIPITATION...SCATTERED STRONG IN PANAMA BETWEEN 80W AND 82W.

THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT 31/1200 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...ARE 0.20 IN NASSAU IN THE BAHAMAS...0.11 IN FREEPORT IN THE BAHAMAS...0.08 IN GUADELOUPE...0.07 IN TRINIDAD...AND 0.03 IN MONTEGO BAY IN JAMAICA.


...HISPANIOLA...

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 60W FROM 20N SOUTHWARD...TOWARD TRINIDAD. IT IS POSSIBLE THAT THIS WAVE MAY REACH HISPANIOLA DURING THE NEXT 48 HOURS ON WEDNESDAY.

A MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH EXTENDS FROM SOUTHEASTERN CUBA TO THE EASTERN HALF OF PANAMA. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG ALONG THE NORTHERN BORDER OF HAITI AND THE DOMINICAN REPUBLIC.

OBSERVATIONS...IN HAITI...FEW CUMULONIMBUS CLOUDS AND SCATTERED HIGH LEVEL CLOUDS ARE BEING OBSERVED IN PORT-AU-PRINCE. FOR THE DOMINICAN REPUBLIC...FEW CUMULONIMBUS CLOUDS AND SCATTERED HIGH LEVEL CLOUDS ARE IN BARAHONA. FEW LOW LEVEL CLOUDS AND SCATTERED HIGH LEVEL CLOUDS ARE IN SANTO DOMINGO. FEW LOW LEVEL CLOUDS ARE IN LA ROMANA. A LOW LEVEL CLOUD CEILING IS IN PUNTA CANA. FEW CUMULONIMBUS CLOUDS AND SCATTERED HIGH LEVEL CLOUDS ARE IN SANTIAGO. FEW CUMULONIMBUS CLOUDS AND A HIGH LEVEL CLOUD CEILING ARE BEING OBSERVED IN PUERTO PLATA.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT CYCLONIC WIND FLOW WILL CROSS HAITI AT THE START OF THE 48-HOUR FORECAST PERIOD... AND ANTICYCLONIC WIND FLOW WILL BE MOVING ACROSS THE DOMINICAN REPUBLIC. THE CYCLONIC CIRCULATION CENTER THAT IS RESPONSIBLE FOR THE CYCLONIC WIND FLOW IN HAITI EVENTUALLY WILL MOVE TOWARD SOUTHERN JAMAICA...AND ANTICYCLONIC WIND FLOW WILL COVER THE ENTIRE AREA FOR AT LEAST THE FIRST 24 HOURS. A NORTHEAST-TO- SOUTHWEST ORIENTED TROUGH WILL MOVE INTO THE AREA AFTER 24 HOURS...AND IT WILL CONTINUE UNTIL THE END OF THE PERIOD. THE GFS MODEL FORECAST FOR 500 MB AND FOR 700 MB SHOWS THAT AN ANTICYCLONIC CIRCULATION CENTER WILL BE IN THE ATLANTIC OCEAN NEAR 29N67W. LARGE-SCALE EAST-TO-NORTHEAST WIND FLOW WILL MOVE ACROSS THE AREA. AN INVERTED TROUGH WILL MOVE ACROSS THE AREA SLOWLY...CAUSING SOME SLIGHT WIND SHIFTS.

THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL INVERTED TROUGH EXTENDS FROM THE NORTHERN BAHAMAS TO SOUTHEASTERN CUBA. THE TROUGH EVENTUALLY CONTINUES SOUTHWARD TO PANAMA IN THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA. COMPARATIVELY DRIER AIR IN SUBSIDENCE SURROUNDS THE INVERTED TROUGH AT THIS MOMENT.

A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N45W TO 27N47W 24N55W 22N60W...INTO THE NORTHEASTERN CARIBBEAN SEA NEAR 18N64W. THIS TROUGH SUPPORTS A 1018 MB LOW PRESSURE CENTER THAT IS NEAR 33N56W...AND A TROUGH THAT TRAILS THE LOW CENTER TO 29N60W. CONVECTIVE PRECIPITATION...BROKEN MULTILAYERED DEBRIS CLOUDS AND ISOLATED MODERATE FROM 26N NORTHWARD BETWEEN 50W AND 60W. ISOLATED MODERATE FROM 16N TO 23N BETWEEN 52W AND 62W. RAINSHOWERS ARE POSSIBLE FROM 24N NORTHWARD BETWEEN 30W AND 50W.

LARGE-SCALE UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH AND NORTHWEST OF THE 32N45W 18N64W MIDDLE LEVEL TO UPPER LEVEL TROUGH. CONVECTIVE PRECIPITATION... ISOLATED MODERATE FROM 22N NORTHWARD BETWEEN 60W AND 77W. BROKEN TO OVERCAST MULTILAYERED DEBRIS CLOUDS AND WARMING CLOUD TOP TEMPERATURES FROM AREAS OF DISSIPATING PRECIPITATION ARE FROM 30N NORTHWARD BETWEEN 58W AND 66W.

A SURFACE RIDGE IS ALONG 31N14W 26N30W...TO A 1020 MB HIGH PRESSURE CENTER THAT IS NEAR 25N52W...TO A 1021 MB HIGH PRESSURE CENTER THAT IS NEAR 31N69W.

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

$$ MT

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