Atlantic Hurricane and Tropical Storm Advisories
Active tropical cyclones in the Atlantic, Caribbean, and the Gulf of Mexico
Atlantic Tropical Weather Outlook-
ABNT20 KNHC 241750
TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED AUG 24 2016
For the North Atlantic...Caribbean Sea and the Gulf of Mexico:
The National Hurricane Center is issuing advisories on Tropical
Storm Gaston, located about 1000 miles west of the Cabo Verde
A strong tropical wave and associated broad area of low pressure is
moving westward across the northern Leeward Islands and Puerto Rico.
Reports from an Air Force Reconnaissance aircraft and surface
observations indicate that the system still lacks a well-defined
circulation, but it nevertheless is producing tropical-storm-force
winds in squalls over the northernmost Leeward Islands and adjacent
waters. Although upper-level winds are expected to be only
marginally conducive for additional development, this system could
become a tropical storm or tropical depression at any time during
the next couple of days. Environmental conditions could become more
conducive for development by the weekend when the system is near the
central or northwestern Bahamas.
Regardless of development, squalls to tropical storm force can be
expected over portions of the northern Leeward Islands and the
northern U.S. and British Virgin Islands this afternoon. Strong
winds, heavy rains, and possible flash floods and mudslides are
expected to occur over portions of the Leeward Islands, Puerto Rico,
Hispaniola, and the southeastern and central Bahamas during the next
couple of days. Please consult products issued by your local
meteorological offices and High Seas Forecasts from the National
Weather Service for further details.
Interests in the northwestern Bahamas and Florida should monitor the
progress of this disturbance. Because of the large uncertainties
regarding this system's development and future track, it is too
early to speculate on what specific impacts might occur in the
northwestern Bahamas, Florida or beyond.
* Formation chance through 48 hours...medium...60 percent
* Formation chance through 5 days...high...80 percent
High Seas Forecasts issued by the National Weather Service can be
found under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and
on the Web at http://www.opc.ncep.noaa.gov/shtml/NFDHSFAT1.shtml.
Summary for Tropical Storm GASTON (AT2/AL072016)- ...GASTON MAINTAINING ITS INTENSITY FOR NOW... As of 5:00 PM AST Wed Aug 24 the center of GASTON was located near 17.4, -40.6 with movement NW at 16 mph. The minimum central pressure was 990 mb with maximum sustained winds of about 70 mph.
Tropical Storm GASTON Public Advisory Number 9-Issued at 500 PM AST WED AUG 24 2016000 WTNT32 KNHC 242032 TCPAT2 BULLETIN TROPICAL STORM GASTON ADVISORY NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072016 500 PM AST WED AUG 24 2016 ...GASTON MAINTAINING ITS INTENSITY FOR NOW... SUMMARY OF 500 PM AST...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...17.4N 40.6W ABOUT 1100 MI...1775 KM W OF THE CABO VERDE ISLANDS MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...NW OR 315 DEGREES AT 16 MPH...26 KM/H MINIMUM CENTRAL PRESSURE...990 MB...29.24 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ At 500 PM AST (2100 UTC), the center of Tropical Storm Gaston was located near latitude 17.4 North, longitude 40.6 West. Gaston is moving toward the northwest near 16 mph (26 km/h). This general motion is expected to continue over the next couple of days. Maximum sustained winds remain near 70 mph (110 km/h) with higher gusts. Weakening is forecast during the next 48 hours. Tropical-storm-force winds extend outward up to 90 miles (150 km) from the center. The estimated minimum central pressure is 990 mb (29.24 inches). HAZARDS AFFECTING LAND ---------------------- None. NEXT ADVISORY ------------- Next complete advisory at 1100 PM AST. $$ Forecaster Kimberlain/Franklin
Tropical Storm GASTON Forecast Advisory Number 9-Issued at 2100 UTC WED AUG 24 2016000 WTNT22 KNHC 242032 TCMAT2 TROPICAL STORM GASTON FORECAST/ADVISORY NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072016 2100 UTC WED AUG 24 2016 THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. TROPICAL STORM CENTER LOCATED NEAR 17.4N 40.6W AT 24/2100Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTHWEST OR 315 DEGREES AT 14 KT ESTIMATED MINIMUM CENTRAL PRESSURE 990 MB MAX SUSTAINED WINDS 60 KT WITH GUSTS TO 75 KT. 50 KT....... 40NE 40SE 0SW 30NW. 34 KT....... 70NE 80SE 40SW 50NW. 12 FT SEAS..120NE 90SE 60SW 90NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 17.4N 40.6W AT 24/2100Z AT 24/1800Z CENTER WAS LOCATED NEAR 16.8N 39.9W FORECAST VALID 25/0600Z 18.8N 42.3W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 40NE 50SE 0SW 30NW. 34 KT... 80NE 70SE 30SW 60NW. FORECAST VALID 25/1800Z 21.0N 44.5W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 90NE 90SE 40SW 70NW. FORECAST VALID 26/0600Z 23.5N 46.6W MAX WIND 45 KT...GUSTS 55 KT. 34 KT...110NE 90SE 40SW 80NW. FORECAST VALID 26/1800Z 25.7N 49.2W MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 50NE 30SE 0SW 40NW. 34 KT...130NE 110SE 70SW 100NW. FORECAST VALID 27/1800Z 28.3N 54.6W MAX WIND 65 KT...GUSTS 80 KT. 50 KT... 70NE 70SE 30SW 50NW. 34 KT...150NE 130SE 80SW 110NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM ON DAY 4 AND 200 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 28/1800Z 30.1N 57.4W MAX WIND 80 KT...GUSTS 100 KT. OUTLOOK VALID 29/1800Z 31.6N 58.2W MAX WIND 85 KT...GUSTS 105 KT. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 17.4N 40.6W NEXT ADVISORY AT 25/0300Z $$ FORECASTER KIMBERLAIN/FRANKLIN
Tropical Storm GASTON Forecast Discussion Number 9-Issued at 500 PM AST WED AUG 24 2016000 WTNT42 KNHC 242034 TCDAT2 TROPICAL STORM GASTON DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072016 500 PM AST WED AUG 24 2016 Gaston is being affected by southwesterly vertical shear associated with a strong mid- to upper-level trough and cut-off low seen in water vapor imagery near 26n 51w. The shear has caused the low-level center to become partially exposed while much of the deep convection has been shunted to eastern half of the circulation. In spite of the degraded satellite presentation, dropsonde data from the unmanned NASA Global Hawk aircraft investigating Gaston support keeping the intensity at 60 kt. In fact, additional observations from the ongoing mission might reveal that the system is even a little stronger than this estimate. Gaston is in for a prolonged period of strong southwesterly shear for the next 36 to 48 hours, with the shear possibly peaking around 30 kt during that time. The considerable shear is expected to induce weakening, and it is possible that more weakening could occur than indicated in the forecast despite the cyclone's moving over warmer waters. Once Gaston's interaction with the trough lessens in about 2 days, the cyclone should reach 29 deg C water when the shear diminishes. This should give Gaston an opportunity to re-intensify for at least a couple of days before the models indicate an increase in shear at the end of the forecast period. The intensity forecast is reduced relative to the previous one and is a little below the multi-model consensus through 48 hours, but then reverses and is above the consensus aids from 72-120 hours. Gaston's heading is now definitively northwestward, and the initial motion estimate is 315/14. A continued northwestward motion is likely for the next few days as Gaston moves between one cell of the subtropical ridge centered over the eastern Atlantic and the cut-off low to the northwest. After 72 hours, Gaston should approach a more significant weakness in the Atlantic subtropical ridge around 60w and slow while turning north-northwestward to northward. There are substantial model differences again this cycle, with the ECMWF indicating a weaker subtropical ridge. The weaker ridge makes Gaston more vulnerable to the mid-latitude westerly flow over the North Atlantic, which results in an earlier recurvature. However, the bulk of the guidance has a stronger ridge, and thus have solutions that go much farther west. No major changes have been made to the previous forecast in the short term but the track has been adjusted much farther to the left after 72 hours, in the direction of but not as far left as the multi-model consensus. FORECAST POSITIONS AND MAX WINDS INIT 24/2100Z 17.4N 40.6W 60 KT 70 MPH 12H 25/0600Z 18.8N 42.3W 55 KT 65 MPH 24H 25/1800Z 21.0N 44.5W 45 KT 50 MPH 36H 26/0600Z 23.5N 46.6W 45 KT 50 MPH 48H 26/1800Z 25.7N 49.2W 50 KT 60 MPH 72H 27/1800Z 28.3N 54.6W 65 KT 75 MPH 96H 28/1800Z 30.1N 57.4W 80 KT 90 MPH 120H 29/1800Z 31.6N 58.2W 85 KT 100 MPH $$ Forecaster Kimberlain/Franklin
Tropical Storm GASTON Wind Speed Probabilities Number 9-Issued at 2100 UTC WED AUG 24 2016000 FONT12 KNHC 242033 PWSAT2 TROPICAL STORM GASTON WIND SPEED PROBABILITIES NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072016 2100 UTC WED AUG 24 2016 AT 2100Z THE CENTER OF TROPICAL STORM GASTON WAS LOCATED NEAR LATITUDE 17.4 NORTH...LONGITUDE 40.6 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 60 KTS...70 MPH...110 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 18Z WED AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 64 KT ARE SHOWN WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 18Z WED 06Z THU 18Z THU 06Z FRI 18Z FRI 18Z SAT 18Z SUN PERIODS TO TO TO TO TO TO TO 06Z THU 18Z THU 06Z FRI 18Z FRI 18Z SAT 18Z SUN 18Z MON FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT BERMUDA 34 X X( X) X( X) X( X) X( X) 4( 4) 8(12) BERMUDA 50 X X( X) X( X) X( X) X( X) 1( 1) 3( 4) BERMUDA 64 X X( X) X( X) X( X) X( X) 1( 1) 1( 2) $$ FORECASTER KIMBERLAIN
Tropical Storm GASTON Graphics-
5-Day Uncertainty Track last updated Wed, 24 Aug 2016 20:36:06 GMT
Wind Speed Probabilities last updated Wed, 24 Aug 2016 21:05:40 GMT