000 AXNT20 KNHC 071107 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM GRACE AT 07/0900 UTC IS NEAR 13.5N 33.9W. GRACE IS MOVING TOWARD THE WEST...OR 275 DEGREES...14 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 14N BETWEEN 33W AND 35W. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 18W/19W FROM 19N SOUTHWARD...MOVING WESTWARD 10 TO 15 KNOTS. A 1012 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 12N. CONVECTIVE PRECIPITATION...WIDELY SCATTERED TO SCATTERED MODERATE AND ISOLATED STRONG FROM 08N TO 12N BETWEEN 17W AND 24W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 42W/43W FROM 17N SOUTHWARD...MOVING WESTWARD 15 KNOTS. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 11N TO 15N BETWEEN 42W AND 47W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 56W FROM 17N SOUTHWARD...MOVING WESTWARD 15 KNOTS. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 11N TO 13N BETWEEN 56W AND 59W. ISOLATED MODERATE FROM 10N TO 12N BETWEEN 60W AND 62W. A CARIBBEAN SEA TROPICAL WAVE IS ALONG 73W/74W FROM HAITI TO NORTHERN 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 78W EASTWARD. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO LOCALLY STRONG FROM HAITI TO THE WINDWARD PASSAGE FROM 19N TO 20N BETWEEN 72W AND 76W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH REMAINS INLAND IN AFRICA. IT IS BROKEN UP BY TROPICAL STORM GRACE AND THE 42W/43W TROPICAL WAVE. THE ITCZ IS ALONG 10N34W 07N40W 07N43W 06N47W. CONVECTIVE PRECIPITATION... ISOLATED MODERATE ARE FROM 05N 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 LOW PRESSURE CENTER IS NEAR 27N87W. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 24N TO 29N BETWEEN FLORIDA AND 84W. ISOLATED MODERATE ELSEWHERE ACROSS THE OPEN WATERS OF THE GULF OF MEXICO FROM 22N NORTHWARD FROM 93W EASTWARD. A DIURNAL SURFACE TROUGH EXTENDS FROM 21N92W TO 15N93W...FROM JUST TO THE WEST OF 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 MODERATE TO ISOLATED STRONG AND ITS COASTAL WATERS FROM 15N TO 19N BETWEEN 92W AND 95W...MOSTLY IN 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 73W/74W FROM HAITI SOUTHWARD TO NORTHERN COLOMBIA. 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 10N74W IN COLOMBIA...TO 08N80W... BEYOND 08N83W IN COSTA RICA. CONVECTIVE PRECIPITATION...NUMEROUS STRONG IS IN COLOMBIA FROM 07N TO 10N BETWEEN 74W AND 76W...AND FROM 08N TO 09N BETWEEN 76W AND 78W INCLUDING IN THE GULF OF URABA OF COLOMBIA. RAINSHOWERS ARE POSSIBLE ELSEWHERE FROM 11N SOUTHWARD BETWEEN COLOMBIA AND NICARAGUA/COSTA RICA. 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 73W/74W FROM HAITI TO NORTHERN 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 78W EASTWARD. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO LOCALLY STRONG FROM HAITI TO THE WINDWARD PASSAGE FROM 19N TO 20N BETWEEN 72W AND 76W. CURRENT CONDITIONS...AT PORT-AU-PRINCE IN HAITI...FEW LOW LEVEL CLOUDS. IN THE DOMINICAN REPUBLIC...FEW LOW LEVEL CLOUDS IN BARAHONA. FEW LOW LEVEL CLOUDS ARE IN SANTO DOMINGO AND IN LA ROMANA. SCATTERED LOW LEVEL CLOUDS ARE IN PUNTA CANA. FEW LOW LEVEL CLOUDS AND SCATTERED HIGH 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 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 32N43W TO 26N48W. A COLD FRONT PASSES THROUGH 32N41W TO 31N43W. A STATIONARY FRONT CONTINUES FROM 31N43W TO 30N50W 30N60W AND 29N68W. A SURFACE TROUGH CONTINUES FROM 28N67W TO ANDROS ISLAND IN THE BAHAMAS. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 28N TO 31N BETWEEN 37W AND 40W. SCATTERED MODERATE TO ISOLATED STRONG WITHIN 150 NM TO THE NORTH OF THE LINE THAT RUNS FROM 30N56W 30N70W 32N79W. RAINSHOWERS ARE POSSIBLE ELSEWHERE TO THE NORTH OF THE LINE THAT RUNS FROM 30N35W TO 26N40W TO 24N50W TO 22N70W...TO THE COAST OF CUBA NEAR 22N79W...INCLUDING IN THE STRAITS OF FLORIDA. A 1017 MB HIGH PRESSURE CENTER IS NEAR 25N62W. SURFACE ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN FROM 20N TO 29N BETWEEN 46W AND 66W. A SURFACE RIDGE PASSES THROUGH 32N23W...TO A 1020 MB HIGH PRESSURE CENTER THAT IS NEAR 29N29W...TO 23N39W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT