000 AXNT20 KNHC 210559 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON SEP 21 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 0515 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM IDA AT 21/0300 UTC IS NEAR 18.9N 47.0W. IDA IS MOVING TOWARD THE NORTHWEST...OR 310 DEGREES...12 KNOTS. THE MINIMUM CENTRAL PRESSURE IS 1005 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 40 KNOTS WITH GUSTS TO 55 KNOTS. PUBLIC ADVISORIES ABOUT TROPICAL STORM IDA ARE BEING ISSUED UNDER THE WMO HEADER WTNT35 KNHC...AND UNDER THE AWIPS HEADER MIATCPAT5. FORECAST/ADVISORIES ABOUT TROPICAL STORM IDA ARE BEING ISSUED UNDER THE WMO HEADER WTNT25 KNHC...AND UNDER THE AWIPS HEADER MIATCMAT5. CONVECTIVE PRECIPITATION...NUMEROUS STRONG WITHIN A RADIUS OF 180 NM FROM THE CENTER IN THE EASTERN SEMICIRCLE. ISOLATED MODERATE TO LOCALLY STRONG ELSEWHERE FROM 12N TO 22N BETWEEN 39W AND 45W. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 17W/18W FROM 16N SOUTHWARD...JUST EMERGING FROM THE COAST OF AFRICA. CONVECTIVE PRECIPITATION...SCATTERED STRONG FROM 12N TO 13N BETWEEN 18W AND 20W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 10N20W 07N26W 06N30W 07N39W. NO ITCZ IS PRESENT AT THIS MOMENT. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 04N TO 07N BETWEEN 10W AND 15W. ISOLATED MODERATE TO LOCALLY STRONG FROM 05N TO 08N BETWEEN 26W AND 43W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 07N TO 11N BETWEEN 46W AND 52W. ...DISCUSSION... THE GULF OF MEXICO... BROAD UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE GULF OF MEXICO TO THE NORTH AND NORTHWEST OF THE ATLANTIC OCEAN-TO- STRAITS OF FLORIDA TROUGH...AND TO THE NORTH OF THE AREA OF CYCLONIC WIND FLOW THAT IS ASSOCIATED WITH THE EASTERN PACIFIC OCEAN 14N104W CYCLONIC CIRCULATION CENTER. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS APPARENT IN WATER VAPOR IMAGERY IN THE AREA OF ANTICYCLONIC WIND FLOW. A STATIONARY FRONT IS INLAND...BETWEEN GEORGIA AND EAST TEXAS. A SURFACE TROUGH IS ALONG THE FLORIDA WEST COAST. AN EASTERN PACIFIC OCEAN MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 14N104W. CYCLONIC WIND FLOW THAT IS MOVING AROUND THE CENTER COVERS MEXICO AND THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO FROM 23N SOUTHWARD...FROM 92W WESTWARD. A DIURNAL SURFACE TROUGH EXTENDS FROM THE WESTERN PART OF THE YUCATAN PENINSULA TO THE EASTERN PART OF THE ISTHMUS OF TEHUANTEPEC OF SOUTHERN MEXICO. CONVECTIVE PRECIPITATION... WIDELY SCATTERED MODERATE TO ISOLATED STRONG IS INLAND BETWEEN 87W IN HONDURAS AND 97W IN THE ISTHMUS OF TEHUANTEPEC OF SOUTHERN MEXICO. THE CARIBBEAN SEA... AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 14N78W. CYCLONIC WIND FLOW THAT IS MOVING AROUND THE 14N78W CENTER COVERS THE CARIBBEAN SEA BETWEEN 70W AND 84W. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO LOCALLY STRONG FROM 16N SOUTHWARD BETWEEN 74W AND CENTRAL AMERICA. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED STRONG COVERS THE NORTHWESTERN CORNER OF THE AREA...TO THE WEST AND NORTHWEST OF THE LINE THAT RUNS FROM 21N80W TO THE EASTERN COAST OF HONDURAS. UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE NORTHWESTERN CORNER OF THE AREA. AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 21N58W. CYCLONIC WIND FLOW THAT IS MOVING AROUND THE CENTER COVERS THE ATLANTIC OCEAN FROM 10N TO 32N BETWEEN 50W AND 70W...IN THE CARIBBEAN SEA. THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT 06/0000 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...ARE 0.11 IN TEGUCIGALPA IN HONDURAS...0.05 IN BERMUDA...AND 0.02 IN HAVANA CUBA. ...HISPANIOLA... UPPER LEVEL NORTHERLY WIND FLOW IS REACHING THE ISLAND...PARTLY WITH THE CYCLONIC FLOW THAT IS MOVING AROUND THE 21N58W ATLANTIC OCEAN CYCLONIC CIRCULATION CENTER. UPPER LEVEL SOUTHEASTERLY WIND FLOW ALSO IS REACHING THE ISLAND...WITH THE FLOW THAT IS MOVING AROUND THE 14N78W CYCLONIC CIRCULATION CENTER. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 18N TO 19N BETWEEN 73W AND 74W IN THE LAND AND WATER AREAS THAT ARE AROUND SOUTHERN HAITI. WARMING CLOUD TOP TEMPERATURES HAVE CAUSE INLAND PRECIPITATION TO APPEAR TO BE WEAKENING WITH TIME. CURRENT CONDITIONS...IN PORT-AU-PRINCE IN HAITI...THE LAST OBSERVATION AT 21/0100 UTC SHOWED RAINSHOWERS WITH THUNDER. IN THE DOMINICAN REPUBLIC...FEW LOW LEVEL CLOUDS WITH EARLIER CUMULONIMBUS CLOUDS IN SANTO DOMINGO. SCATTERED LOW LEVEL CLOUDS ARE IN LA ROMANA. FEW LOW LEVEL CLOUDS ARE IN PUNTA CANA. SCATTERED LOW LEVEL CLOUDS ARE IN SANTIAGO AND PUERTO PLATA. THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT THE EASTERN HALF OF THE ISLAND WILL RECEIVE NORTHERLY WIND FLOW AND THE WESTERN HALF WILL RECEIVE SOUTHERLY WIND FLOW...BECAUSE OF THE 21N58W CYCLONIC CENTER AND THE 14N78W CYCLONIC CENTER. ANTICYCLONIC WIND FLOW IS FORECAST TO BUILD FROM THE SOUTH AND A RIDGE WILL COVER HISPANIOLA FOR THE REST OF DAY ONE OF THE 48-HOUR FORECAST PERIOD. THE SAME RIDGE WILL CONTINUE ACROSS THE AREA FOR THE REST OF THE TIME. THE GFS MODEL FORECAST FOR 500 MB SHOWS THAT ANTICYCLONIC WIND FLOW WILL COVER THE AREA FOR FIRST 24 HOURS. NORTHERLY WIND FLOW WILL COVER HISPANIOLA FOR DAY TWO OF THE 48- HOUR FORECAST PERIOD. THE ATLANTIC OCEAN CYCLONIC CENTER IS FORECAST TO BE NEAR 23N65W. AN ANTICYCLONIC CIRCULATION CENTER IS FORECAST TO BE NEAR 22N75W. THE GFS MODEL FOR 700 MB STARTS WITH HISPANIOLA RECEIVING NORTHEAST-TO-EAST WIND FLOW...BEING ON THE WESTERN SIDE OF AN INVERTED TROUGH. THE WIND FLOW VARIES FROM EAST-SOUTHEAST...FROM THE NORTHEAST...AND FROM THE SOUTHEAST AGAIN...DURING DAY TWO...AS AN INVERTED TROUGH SPANS PUERTO RICO. THE ATLANTIC OCEAN... PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS ABOUT TROPICAL STORM IDA. AN UPPER LEVEL TROUGH PASSES THROUGH 32N72W TO 29N76W...INTO THE STRAITS OF FLORIDA...TO WESTERN CUBA...TOWARD THE NORTHEASTERN COAST OF THE YUCATAN PENINSULA OF MEXICO. A SURFACE TROUGH EXTENDS FROM A 1007 MB LOW PRESSURE CENTER THAT IS NEAR 33N71W...TO 29N74W...TO THE NORTHERN BAHAMAS NEAR 26N78W. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 20N NORTHWARD BETWEEN 64W AND 80W...AND FROM 20N TO 26N BETWEEN 76W AND THE STRAITS OF FLORIDA...AND FROM 20N NORTHWARD BETWEEN 80W AND THE YUCATAN PENINSULA IN THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA. AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 21N58W. CYCLONIC WIND FLOW THAT IS MOVING AROUND THE CENTER COVERS THE ATLANTIC OCEAN FROM 10N TO 32N BETWEEN 50W AND 70W...IN THE CARIBBEAN SEA. A SURFACE TROUGH IS ALONG 23N56W...TO A 1010 MB LOW PRESSURE CENTER THAT IS NEAR 19N54W...TO 17N52W. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG FROM 20N TO 23N BETWEEN 53W AND 55W. SCATTERED STRONG FROM 25N TO 28N BETWEEN 49W AND 53W. ISOLATED TO WIDELY SCATTERED MODERATE ELSEWHERE FROM 23N NORTHWARD BETWEEN 43W AND 57W...AND FROM 18N TO 23N BETWEEN 57W AND 62W. RAINSHOWERS ARE POSSIBLE ALSO FROM 14N TO 20N BETWEEN 57W AND 70W IN THE CARIBBEAN SEA. AN UPPER LEVEL TROUGH EXTENDS FROM A 32N18W CYCLONIC CIRCULATION CENTER...TOWARD THE CAPE VERDE ISLANDS. CONVECTIVE PRECIPITATION...ISOLATED MODERATE TO LOCALLY STRONG FROM 30N NORTHWARD BETWEEN 26W AND 35W. RAINSHOWERS ARE POSSIBLE IN SCATTERED TO BROKEN STRATIFORM CLOUDS THAT COVER THE AREA FROM 23N NORTHWARD BETWEEN 18W AND 40W. SURFACE ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH OF THE LINE THAT PASSES THROUGH 32N17W TO 25N39W AND BEYOND 32N54W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT