000 AXNT20 KNHC 070555 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON SEP 07 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM GRACE AT 07/0300 UTC IS NEAR 13.3N 32.5W. GRACE IS MOVING TOWARD THE WEST...OR 280 DEGREES...13 KNOTS. THE MINIMUM CENTRAL PRESSURE IS 1002 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 45 KNOTS WITH GUSTS TO 55 KNOTS. PUBLIC ADVISORIES ABOUT TROPICAL STORM GRACE ARE BEING ISSUED UNDER THE WMO HEADER WTNT32 KNHC...AND UNDER THE AWIPS HEADER MIATCPAT2. FORECAST/ADVISORIES ABOUT TROPICAL STORM GRACE ARE BEING ISSUED UNDER THE WMO HEADER WTNT22 KNHC...AND UNDER THE AWIPS HEADER MIATCMAT2. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG FROM 12N TO 14.5N BETWEEN 32W AND 33.5W. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 17W/18W FROM 19N SOUTHWARD...MOVING WESTWARD 10 TO 15 KNOTS. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 08N TO 14N BETWEEN AFRICA AND 20W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 41W/42W FROM 16N SOUTHWARD...MOVING WESTWARD 15 KNOTS. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 12N TO 14N BETWEEN 42W AND 44W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 54W/55W FROM 16N SOUTHWARD...MOVING WESTWARD 15 KNOTS. CONVECTIVE PRECIPITATION... ISOLATED MODERATE TO LOCALLY STRONG FROM 08N TO 14N BETWEEN 54W AND 61W. A CARIBBEAN SEA TROPICAL WAVE IS ALONG 71W/72W FROM 20N IN THE DOMINICAN REPUBLIC TO THE COAST OF COLOMBIA. THE WAVE IS MOVING WESTWARD 10 TO 15 KNOTS. THIS WAVE IS MOVING THROUGH THE AREA OF MIDDLE LEVEL TO UPPER LEVEL SOUTHEAST-TO-SOUTH WIND FLOW. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS APPARENT IN WATER VAPOR IMAGERY FROM 77W EASTWARD. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF SENEGAL NEAR 14N17W...THROUGH THE 1012 MB LOW PRESSURE CENTER THAT IS NEAR 14N AND THAT IS ALONG THE 17W/18W TROPICAL WAVE...TO 13N23W AND 14N26W. THE MONSOON TROUGH IS BEING BROKEN UP BY TROPICAL STORM GRACE AND THE 41W/42W TROPICAL WAVE. THE ITCZ IS ALONG 09N43W 09N50W 10N57W...TO THE COAST OF VENEZUELA NEAR 09N61W. CONVECTIVE PRECIPITATION...RAINSHOWERS ARE POSSIBLE FROM 04N TO 10N FROM 30W WESTWARD. ...DISCUSSION... THE GULF OF MEXICO... A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH THE FLORIDA PANHANDLE NEAR 31N85W...INTO THE SOUTHWESTERN CORNER OF THE AREA. A 1013 MB SURFACE LOW PRESSURE CENTER IS NEAR 28N86W. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 24N TO 28N BETWEEN FLORIDA AND 87W. ISOLATED MODERATE ELSEWHERE ACROSS THE OPEN WATERS OF THE GULF OF MEXICO FROM 22N NORTHWARD. A DIURNAL SURFACE TROUGH EXTENDS FROM THE NORTHWESTERN CORNER OF THE YUCATAN PENINSULA INTO SOUTHERN MEXICO THAT IS BETWEEN THE ISTHMUS OF TEHUANTEPEC AND THE GUATEMALA BORDER. CONVECTIVE PRECIPITATION...WIDELY SCATTERED TO SCATTERED MODERATE AND ISOLATED STRONG IN MEXICO BETWEEN 88W AND 95W FROM THE YUCATAN PENINSULA TO THE ISTHMUS OF TEHUANTEPEC OF SOUTHERN MEXICO. 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 72W/73W FROM 20N SOUTHWARD. UPPER LEVEL ANTICYCLONIC WIND FLOW AND BROKEN TO OVERCAST MULTILAYERED CLOUDS COVER THE CARIBBEAN SEA FROM 70W WESTWARD. A RIDGE EXTENDS FROM THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA...NORTHWESTWARD...TO THE YUCATAN CHANNEL AND WESTERN CUBA. THE MONSOON TROUGH IS ALONG 08N/09N BETWEEN 73W IN COLOMBIA AND THE PANAMA/COSTA RICA BORDER THAT IS ALONG 83W. CONVECTIVE PRECIPITATION...NUMEROUS STRONG IS IN NORTHWESTERN VENEZUELA... BETWEEN LAKE MARACAIBO AND THE COLOMBIA/VENEZUELA BORDER. WIDELY SCATTERED MODERATE TO ISOLATED STRONG ELSEWHERE FROM 06N TO 10N BETWEEN 74W AND 83W. THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT 07/0000 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...ARE 0.39 IN GUADELOUPE...0.06 IN TEGUCIGALPA IN HONDURAS...AND 0.02 IN BERMUDA. ...HISPANIOLA... A CARIBBEAN SEA TROPICAL WAVE IS ALONG 71W/72W FROM 20N IN THE DOMINICAN REPUBLIC TO THE COAST OF COLOMBIA. THE WAVE IS MOVING WESTWARD 10 TO 15 KNOTS. THIS WAVE IS MOVING THROUGH THE AREA OF MIDDLE LEVEL TO UPPER LEVEL SOUTHEAST-TO-SOUTH WIND FLOW. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS APPARENT IN WATER VAPOR IMAGERY FROM 77W EASTWARD. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG ALONG THE NORTHERN COAST WITHIN A 30 NM RADIUS OF 20N72W. ISOLATED TO WIDELY SCATTERED MODERATE FROM 18N TO 19N BETWEEN 72W AND 74W IN THE SOUTHERN HALF OF HAITI. CURRENT CONDITIONS...IN PORT-AU-PRINCE IN HAITI...A LOW LEVEL CLOUD CEILING WAS BEING REPORTED AS LATE AS 07/0000 UTC. IN THE DOMINICAN REPUBLIC...FEW CUMULONIMBUS CLOUDS ARE IN SANTO DOMINGO. FEW LOW LEVEL CLOUDS ARE IN LA ROMANA AND IN PUNTA CANA. SCATTERED LOW LEVEL CLOUDS ARE IN SANTIAGO. FEW LOW LEVEL CLOUDS ARE IN PUERTO PLATA. THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT A NORTH-TO-SOUTH ORIENTED RIDGE WILL COVER HISPANIOLA FOR THE FIRST 18 HOURS OR SO OF THE 48-HOUR FORECAST PERIOD. NORTHERLY WIND FLOW EVENTUALLY WILL CROSS HISPANIOLA...WITH A RIDGE THAT IS FORECAST TO EXTEND FROM THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA TO HISPANIOLA FIRST...AND THEN TO CENTRAL CUBA. THE GFS MODEL FORECAST FOR 500 MB SHOWS THAT SOUTH-TO-SOUTHEAST WIND FLOW WILL CROSS THE ISLAND...WITH AN ATLANTIC OCEAN-TO-HISPANIOLA NORTHEAST-TO-SOUTHWEST ORIENTED RIDGE. THE ANTICYCLONIC CIRCULATION CENTER THAT IS WITH THE RIDGE IS FORECAST TO MOVE INTO THE NORTHERN COASTAL WATERS OF HISPANIOLA...AND BRING EASTERLY WIND FLOW TO THE AREA. THE GFS MODEL FOR 700 MB SHOWS THAT TWO INVERTED TROUGHS WILL PASS ACROSS HISPANIOLA DURING THE NEXT 48 HOURS. THE REST OF THE ATLANTIC OCEAN... PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS ABOUT TROPICAL STORM GRACE. A SURFACE TROUGH IS ALONG 30N42W 26N43W 22N44W. THIS TROUGH IS THE REMNANT OF FRED. UPPER LEVEL NORTHWEST-TO-NORTH WIND FLOW IS ON TOP OF THE AREA OF THE SURFACE TROUGH. A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N46W TO 27N48W. A COLD FRONT PASSES THROUGH 32N43W TO 31N47W. A STATIONARY FRONT CONTINUES FROM 31N47W TO 30N55W AND 29N68W. A SURFACE TROUGH CONTINUES FROM 28N67W TO ANDROS ISLAND IN THE BAHAMAS. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG WITHIN 30 NM TO 60 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH 33N37W TO 30N39W TO 29N41W TO 26N42W. ISOLATED MODERATE ELSEWHERE WITHIN 120 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH 32N39W 27N44W 26N52W 24N58W. ISOLATED MODERATE ELSEWHERE ALSO TO THE NORTH OF THE LINE FROM 22N78W AT THE COAST OF CUBA... TO 25N67W 30N54W. A 1017 MB HIGH PRESSURE CENTER IS NEAR 24N62W. SURFACE ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN FROM 20N TO 29N BETWEEN 46W AND 66W. A SURFACE RIDGE PASSES THROUGH 32N26W...TO A 1021 MB HIGH PRESSURE CENTER THAT IS NEAR 29N29W...TO 22N39W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT