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5-Day Uncertainty Track last updated Sun, 17 Aug 2025 05:31:50 GMT


Wind Speed Probabilities last updated Sun, 17 Aug 2025 03:22:28 GMT

Issued at 200 AM AST Sun Aug 17 2025 000 WTNT35 KNHC 170531 TCPAT5 BULLETIN Hurricane Erin Intermediate Advisory Number 23A NWS National Hurricane Center Miami FL AL052025 200 AM AST Sun Aug 17 2025 ...ERIN'S OUTER RAINBANDS PRODUCING GUSTY WINDS AND HEAVY RAINS ACROSS THE VIRGIN ISLANDS AND PUERTO RICO... SUMMARY OF 200 AM AST...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...20.4N 66.1W ABOUT 140 MI...220 KM N OF SAN JUAN PUERTO RICO ABOUT 330 MI...535 KM ESE OF GRAND TURK ISLAND MAXIMUM SUSTAINED WINDS...125 MPH...205 KM/H PRESENT MOVEMENT...WNW OR 290 DEGREES AT 14 MPH...22 KM/H MINIMUM CENTRAL PRESSURE...940 MB...27.76 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Watch is in effect for... * Turks and Caicos Islands A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, in this case in the next 24 hours. Interests elsewhere in the Virgin Islands, Puerto Rico, and the southeast and central Bahamas should monitor the progress of Erin. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 200 AM AST (0600 UTC), the center of Hurricane Erin was located near latitude 20.4 North, longitude 66.1 West. Erin is moving toward the west-northwest near 14 mph (22 km/h). This motion with a decrease in forward speed is expected today, followed by a turn to the north on Monday and Tuesday. On the forecast track, the core of Erin is expected to pass to the east of the Turks and Caicos Islands and the southeastern Bahamas tonight and Monday. Maximum sustained winds are near 125 mph (205 km/h) with higher gusts. Erin is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. Fluctuations in intensity are expected over the next day or two due to inner-core structural changes. Erin is becoming a larger system. Hurricane-force winds extend outward up to 25 miles (35 km) from the center and tropical-storm-force winds extend outward up to 205 miles (335 km). The minimum central pressure based on data from the Air Force Hurricane Hunters is 940 mb (27.76 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Erin can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT5 and WMO header WTNT45 KNHC. RAINFALL: The outer bands of Erin will continue to produce areas of heavy rainfall today across the northern Leeward Islands, the Virgin Islands, and Puerto Rico. Rainfall totals of 2 to 4 inches, with isolated totals of 8 inches, are expected. Locally considerable flash and urban flooding, along with landslides or mudslides, are possible. For a complete depiction of forecast rainfall and flash flooding associated with Erin, please see the National Weather Service Storm Total Rainfall Graphic, available at hurricanes.gov/graphics_at5.shtml?rainqpf WIND: Tropical storm conditions are possible within the watch area in the Turks and Caicos Islands beginning tonight. Squalls with wind gusts to tropical storm force could occur over portions of the Virgin Islands and Puerto Rico today and across the southeast and central Bahamas tonight through Tuesday. SURF: Swells generated by Erin will continue to affect portions of the northern Leeward Islands, the Virgin Islands, Puerto Rico, Hispaniola, and the Turks and Caicos Islands during the next couple of days. These swells will spread to the Bahamas, Bermuda, the east coast of the United States, and Atlantic Canada during the early and middle portions of the week. These rough ocean conditions will likely cause life-threatening surf and rip currents. Please consult products from your local weather forecast office for more information. A depiction of rip current risk for the United States can be found at: hurricanes.gov/graphics_at5.shtml?ripCurrents NEXT ADVISORY ------------- Next complete advisory at 500 AM AST. $$ Forecaster Cangialosi

...ERIN'S OUTER RAINBANDS PRODUCING GUSTY WINDS AND HEAVY RAINS ACROSS THE VIRGIN ISLANDS AND PUERTO RICO... As of 2:00 AM AST Sun Aug 17 the center of Erin was located near 20.4, -66.1 with movement WNW at 14 mph. The minimum central pressure was 940 mb with maximum sustained winds of about 125 mph.

360
ABPZ20 KNHC 170508
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Sat Aug 16 2025

For the eastern and central North Pacific east of 180 longitude:

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Cangialosi

146
ABNT20 KNHC 170508
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Sun Aug 17 2025

For the North Atlantic...Caribbean Sea and the Gulf of America:

Active Systems:
The National Hurricane Center is issuing advisories on Hurricane
Erin, located about 150 miles north of Puerto Rico.

Northwestern Atlantic:
The area of low pressure located a couple hundred miles off the
coast of North Carolina continues to produce disorganized shower
activity to the east of the center. Development, if any, of this
system should be slow to occur during the next day or so while it
moves little over the warm waters of the Gulf Stream. The
opportunity for development should end on Monday when environmental
conditions are expected to become unfavorable.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...low...10 percent.

Central Tropical Atlantic:
An area of low pressure could form over the central tropical
Atlantic during the middle to latter portion of the week. Some
subsequent development could occur as the system moves westward to
west-northwestward at 15 to 20 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...20 percent.

$$
Forecaster Cangialosi

MD 1970 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR FAR EASTERN WYOMING...WESTERN INTO CENTRAL SOUTH DAKOTA...EXTREME SOUTHEAST MONTANA...AND SOUTHERN NORTH DAKOTA
Mesoscale Discussion 1970 NWS Storm Prediction Center Norman OK 1023 PM CDT Sat Aug 16 2025 Areas affected...far eastern Wyoming...western into central South Dakota...extreme southeast Montana...and southern North Dakota Concerning...Severe potential...Watch likely Valid 170323Z - 170530Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms continue to gradually strengthen and increase in coverage. An increasing potential for damaging thunderstorm winds will likely warrant the need for a severe thunderstorm watch this evening/overnight. DISCUSSION...Thunderstorm organization and intensity continues to gradually increase this evening across northeast Wyoming and far western South Dakota. This is likely in response to increasing large-scale ascent as an upstream short-wave trough approaches the region. The airmass along and immediately ahead of the shortwave remains strongly unstable (MUCAPE up to 3000 J/kg) and sufficiently sheared (ESHR around 35 knots) to support severe thunderstorms. Current expectation is that these thunderstorms will continue to intensify and organize as they move into the more unstable environment and the nocturnal low-level jet strengthens. The primary severe threat should be damaging thunderstorm winds driven by internal MCS dynamics. That said, this evening's 00Z UNR (Rapid City, SD) sounding sampled sufficiently steep mid-level lapse rates to support at least some potential for large hail. Trends will continue to be monitored, but it is increasingly likely that a severe thunderstorm watch will be needed in the next 1-2 hours. ..Marsh/Smith.. 08/17/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...BIS...UNR...CYS...BYZ... LAT...LON 43650119 43030270 43170406 43910496 44810497 45790423 46750148 46680021 45889966 44979935 44219963 43650119 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

WW 0597 Status Updates
STATUS FOR WATCH 0597 HAS NOT BEEN ISSUED YET Read more

Issued at 0300 UTC SUN AUG 17 2025 000 FONT15 KNHC 170300 PWSAT5 HURRICANE ERIN WIND SPEED PROBABILITIES NUMBER 23 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052025 0300 UTC SUN AUG 17 2025 AT 0300Z THE CENTER OF HURRICANE ERIN WAS LOCATED NEAR LATITUDE 20.3 NORTH...LONGITUDE 65.1 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 120 KTS...140 MPH...220 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 00Z SUN 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 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 00Z SUN 12Z SUN 00Z MON 12Z MON 00Z TUE 00Z WED 00Z THU PERIODS TO TO TO TO TO TO TO 12Z SUN 00Z MON 12Z MON 00Z TUE 00Z WED 00Z THU 00Z FRI FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT EDDY POINT NS 34 X X( X) X( X) X( X) X( X) X( X) 3( 3) SABLE ISLAND 34 X X( X) X( X) X( X) X( X) X( X) 6( 6) YARMOUTH NS 34 X X( X) X( X) X( X) X( X) X( X) 6( 6) YARMOUTH NS 50 X X( X) X( X) X( X) X( X) X( X) 2( 2) YARMOUTH NS 64 X X( X) X( X) X( X) X( X) X( X) 1( 1) EASTPORT ME 34 X X( X) X( X) X( X) X( X) X( X) 3( 3) HYANNIS MA 34 X X( X) X( X) X( X) X( X) X( X) 4( 4) NANTUCKET MA 34 X X( X) X( X) X( X) X( X) X( X) 10(10) NANTUCKET MA 50 X X( X) X( X) X( X) X( X) X( X) 3( 3) NANTUCKET MA 64 X X( X) X( X) X( X) X( X) X( X) 1( 1) PROVIDENCE RI 34 X X( X) X( X) X( X) X( X) X( X) 5( 5) NEW LONDON CT 34 X X( X) X( X) X( X) X( X) X( X) 3( 3) MONTAUK POINT 34 X X( X) X( X) X( X) X( X) X( X) 6( 6) NYC JFK AIRPRT 34 X X( X) X( X) X( X) X( X) X( X) 3( 3) CAPE HENLOPEN 34 X X( X) X( X) X( X) X( X) 1( 1) 4( 5) OCEAN CITY MD 34 X X( X) X( X) X( X) X( X) 2( 2) 4( 6) WALLOPS CDA 34 X X( X) X( X) X( X) X( X) 2( 2) 4( 6) NORFOLK NAS 34 X X( X) X( X) X( X) X( X) 2( 2) 1( 3) NORFOLK VA 34 X X( X) X( X) X( X) X( X) 2( 2) 2( 4) OCEANA NAS VA 34 X X( X) X( X) X( X) X( X) 4( 4) 3( 7) ELIZABETH CTY 34 X X( X) X( X) X( X) X( X) 2( 2) 2( 4) CAPE HATTERAS 34 X X( X) X( X) X( X) X( X) 10(10) 6(16) CAPE HATTERAS 50 X X( X) X( X) X( X) X( X) 2( 2) 3( 5) CAPE HATTERAS 64 X X( X) X( X) X( X) X( X) 1( 1) 1( 2) CHERRY PT NC 34 X X( X) X( X) X( X) X( X) 4( 4) 1( 5) NEW RIVER NC 34 X X( X) X( X) X( X) X( X) 3( 3) 1( 4) MOREHEAD CITY 34 X X( X) X( X) X( X) X( X) 7( 7) 3(10) MOREHEAD CITY 50 X X( X) X( X) X( X) X( X) 2( 2) X( 2) MOREHEAD CITY 64 X X( X) X( X) X( X) X( X) 1( 1) X( 1) SURF CITY NC 34 X X( X) X( X) X( X) X( X) 6( 6) 1( 7) WILMINGTON NC 34 X X( X) X( X) X( X) X( X) 3( 3) X( 3) BALD HEAD ISL 34 X X( X) X( X) X( X) X( X) 5( 5) 2( 7) LITTLE RIVER 34 X X( X) X( X) X( X) X( X) 3( 3) 1( 4) MYRTLE BEACH 34 X X( X) X( X) X( X) X( X) 3( 3) X( 3) BERMUDA 34 X X( X) X( X) X( X) X( X) 6( 6) 16(22) BERMUDA 50 X X( X) X( X) X( X) X( X) X( X) 5( 5) BERMUDA 64 X X( X) X( X) X( X) X( X) X( X) 2( 2) GRAND BAHAMA 34 X X( X) X( X) X( X) 2( 2) 1( 3) X( 3) NEW PROVIDENCE 34 X X( X) X( X) X( X) 3( 3) 1( 4) X( 4) ANDROS 34 X X( X) X( X) X( X) 2( 2) X( 2) 1( 3) GREAT EXUMA 34 X X( X) 1( 1) 3( 4) 4( 8) X( 8) X( 8) SAN SALVADOR 34 X X( X) 4( 4) 8(12) 9(21) 1(22) X(22) SAN SALVADOR 50 X X( X) X( X) 1( 1) 3( 4) X( 4) X( 4) MAYAGUANA 34 X 2( 2) 8(10) 8(18) 5(23) X(23) X(23) MAYAGUANA 50 X X( X) 2( 2) 1( 3) 1( 4) 1( 5) X( 5) MAYAGUANA 64 X X( X) X( X) 1( 1) X( 1) X( 1) X( 1) GRAND TURK 34 2 7( 9) 17(26) 5(31) 2(33) 1(34) X(34) GRAND TURK 50 X 1( 1) 4( 5) 2( 7) X( 7) X( 7) X( 7) GRAND TURK 64 X X( X) 1( 1) 1( 2) X( 2) X( 2) X( 2) PUERTO PLATA 34 2 2( 4) 4( 8) 2(10) X(10) X(10) X(10) SANTO DOMINGO 34 1 2( 3) 3( 6) X( 6) X( 6) X( 6) X( 6) PONCE PR 34 2 2( 4) 1( 5) X( 5) X( 5) X( 5) X( 5) AGUADILLA PR 34 3 2( 5) 1( 6) X( 6) X( 6) X( 6) X( 6) SAN JUAN PR 34 2 1( 3) X( 3) X( 3) X( 3) X( 3) X( 3) VIEQUES PR 34 2 2( 4) X( 4) X( 4) X( 4) X( 4) X( 4) SAINT THOMAS 34 2 2( 4) X( 4) X( 4) X( 4) X( 4) X( 4) SAINT JOHN 34 2 2( 4) X( 4) X( 4) X( 4) X( 4) X( 4) SAINT CROIX 34 2 1( 3) X( 3) X( 3) X( 3) X( 3) X( 3) $$ FORECASTER PAPIN

Issued at 1100 PM AST Sat Aug 16 2025 239 WTNT45 KNHC 170259 TCDAT5 Hurricane Erin Discussion Number 23 NWS National Hurricane Center Miami FL AL052025 1100 PM AST Sat Aug 16 2025 After rapidly intensifying for the first part of the day, Erin now appears to be in the middle stages of an eyewall replacement cycle (ERC). Both the NOAA and Air Force Reserve reconnaissance have indicated concentric eyewalls on their missions this evening, and in response, the inner eyewall is starting to become more degraded with decreasing winds. With that said, there is not an especially well defined secondary wind maximum quite yet, primarily only observed in the NOAA-P3 Tail Doppler Radar data in the northeastern quadrant. The peak flight level winds reported by the NOAA and Air Force aircraft were both 130 kt at 700 mb. The initial intensity is therefore reduced to 120 kt for this advisory, and this could be generous. The inner eyewall of Erin has been wobbling around, likely due to some trochoidal motion as it interacts with the building secondary wind maximum, but the longer-term motion is around 290/12 kt. Erin has moved left of the NHC forecast track over the past day, and I suspect some of this left-of expected motion could be due to the small inner-core size of the hurricane, which was poorly resolved by all of the hurricane-regional forecast models. However, as the overall wind field of Erin grows in size, a more consistent west-northwestward motion is expected to resume tonight and persist over the next 12-24 hours. After that time, a series of shortwave troughs will move offshore of Atlantic Canada, helping to reinforce a longwave trough over the north-central portion of the Atlantic. This should create a growing weakness to the north of Erin, ultimately allowing the large hurricane to turn northward and then northeastward by the end of the forecast period. The track guidance this cycle made another westward adjustment, and the NHC track forecast was nudged in that direction. The current track remains to the east of both the HCCA and ECMWF track aids, so it would not be surprising to see some additional leftward adjustments in subsequent forecast cycles. The future intensity is probably the most challenging aspect of Erin's forecast. Erin's maximum sustained winds have been decreasing as a secondary eyewall gradually becomes better defined. A little more weakening could occur in the short term as these structural changes occur. However, none of the hurricane-regional models appears to have a good handle on Erin's current structure (they all have a much broader core). Given that the vertical wind shear is currently low, and the hurricane is well embedded in a moist environment, this ERC is expected to complete without much issue, though it will likely take a bit of time for the hurricane's maximum sustained winds to recover as its wind field broadens. Thus, the NHC intensity forecast shows some reintensification in the 24 h period after this ERC completes. Afterwards, it wouldn't be surprising to see another cycle begin, and at 36-48 h northwesterly shear is still anticipated to increase some. Their combination should begin a weakening trend with Erin as it continues to grow in size. The NHC intensity forecast is a little lower than the previous advisory, primarily due to the weaker initial intensity, but is still roughly in line with the intensity consensus aids. A recent scatterometer pass indicates that Erin's outer-core is growing in size, and the models remain in strong agreement that the system will grow further the next several days. In fact, by the middle of next week, Erin is forecast to at least double or triple in size, which will result in rough ocean conditions over the western Atlantic. KEY MESSAGES: 1. Heavy rainfall at times through Sunday across the northern Leeward Islands, the Virgin Islands, and Puerto Rico may lead to locally considerable flash and urban flooding, along with landslides or mudslides. 2. Tropical-storm conditions are possible in the Turks and Caicos Islands during the next 48 h, where a Tropical Storm Watch is in effect. Gusts to tropical storm force in Erin's outer rainbands are likely in portions of the Virgin Islands and Puerto Rico through Sunday. Tropical-storm force wind gusts are possible in the Southeast Bahamas beginning late Sunday. 3. Erin is expected to produce life-threatening surf and rip currents along the beaches of the Bahamas, much of the east coast of the U.S., and Atlantic Canada next week. 4. Interests in Bermuda should continue to monitor the progress of Erin since there is a risk of strong winds, heavy rainfall, and high surf by the middle part of next week. FORECAST POSITIONS AND MAX WINDS INIT 17/0300Z 20.3N 65.1W 120 KT 140 MPH 12H 17/1200Z 20.8N 66.7W 115 KT 130 MPH 24H 18/0000Z 22.0N 68.5W 130 KT 150 MPH 36H 18/1200Z 23.3N 69.9W 120 KT 140 MPH 48H 19/0000Z 24.5N 70.8W 115 KT 130 MPH 60H 19/1200Z 26.0N 71.5W 110 KT 125 MPH 72H 20/0000Z 28.0N 72.1W 105 KT 120 MPH 96H 21/0000Z 32.0N 71.5W 100 KT 115 MPH 120H 22/0000Z 37.5N 65.5W 90 KT 105 MPH $$ Forecaster Papin

Issued at 0300 UTC SUN AUG 17 2025 899 WTNT25 KNHC 170257 TCMAT5 HURRICANE ERIN FORECAST/ADVISORY NUMBER 23 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052025 0300 UTC SUN AUG 17 2025 HURRICANE CENTER LOCATED NEAR 20.3N 65.1W AT 17/0300Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 290 DEGREES AT 12 KT ESTIMATED MINIMUM CENTRAL PRESSURE 937 MB EYE DIAMETER 5 NM MAX SUSTAINED WINDS 120 KT WITH GUSTS TO 145 KT. 64 KT....... 20NE 20SE 15SW 20NW. 50 KT....... 70NE 30SE 20SW 50NW. 34 KT.......180NE 110SE 40SW 150NW. 4 M SEAS....270NE 180SE 120SW 240NW. 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 20.3N 65.1W AT 17/0300Z AT 17/0000Z CENTER WAS LOCATED NEAR 20.0N 64.5W FORECAST VALID 17/1200Z 20.8N 66.7W MAX WIND 115 KT...GUSTS 140 KT. 64 KT... 30NE 25SE 20SW 25NW. 50 KT... 70NE 45SE 30SW 50NW. 34 KT...170NE 130SE 60SW 150NW. FORECAST VALID 18/0000Z 22.0N 68.5W MAX WIND 130 KT...GUSTS 160 KT. 64 KT... 40NE 30SE 25SW 35NW. 50 KT... 80NE 70SE 40SW 60NW. 34 KT...160NE 140SE 105SW 150NW. FORECAST VALID 18/1200Z 23.3N 69.9W MAX WIND 120 KT...GUSTS 145 KT. 64 KT... 50NE 40SE 30SW 40NW. 50 KT... 90NE 80SE 50SW 70NW. 34 KT...160NE 150SE 120SW 150NW. FORECAST VALID 19/0000Z 24.5N 70.8W MAX WIND 115 KT...GUSTS 140 KT. 64 KT... 60NE 50SE 35SW 45NW. 50 KT...100NE 90SE 60SW 80NW. 34 KT...160NE 160SE 130SW 150NW. FORECAST VALID 19/1200Z 26.0N 71.5W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 65NE 65SE 40SW 50NW. 50 KT...110NE 100SE 70SW 80NW. 34 KT...180NE 180SE 140SW 160NW. FORECAST VALID 20/0000Z 28.0N 72.1W MAX WIND 105 KT...GUSTS 130 KT. 64 KT... 70NE 70SE 45SW 50NW. 50 KT...110NE 120SE 90SW 90NW. 34 KT...200NE 200SE 160SW 170NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 125 NM ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 21/0000Z 32.0N 71.5W MAX WIND 100 KT...GUSTS 120 KT. 50 KT...130NE 140SE 110SW 100NW. 34 KT...230NE 260SE 190SW 180NW. OUTLOOK VALID 22/0000Z 37.5N 65.5W MAX WIND 90 KT...GUSTS 110 KT. 50 KT...140NE 170SE 145SW 110NW. 34 KT...260NE 290SE 255SW 225NW. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.3N 65.1W INTERMEDIATE PUBLIC ADVISORY...WTNT35 KNHC/MIATCPAT5...AT 17/0600Z NEXT ADVISORY AT 17/0900Z $$ FORECASTER PAPIN

MD 1969 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHEASTERN IOWA SOUTHWEST WISCONSIN AND NORTHERN ILLINOIS
Mesoscale Discussion 1969 NWS Storm Prediction Center Norman OK 0806 PM CDT Sat Aug 16 2025 Areas affected...portions of northeastern Iowa southwest Wisconsin and northern Illinois Concerning...Severe potential...Watch unlikely Valid 170106Z - 170230Z Probability of Watch Issuance...20 percent SUMMARY...Storms forming along a trailing outflow boundary may remain capable of sporadic hail and occasional strong wind gusts for a few hours this evening. DISCUSSION...As of 01 UTC, regional radar imagery showed several clusters of storms had redeveloped along a trailing outflow boundary from prior convection across portions of northern IL, eastern IA and southwestern WI. Several of these storms have shown periods of higher intensity with reports of hail over the last hour. This threat should continue with occasional hail or damaging gusts as the air mass along and south of the outflow remains very unstable with 4000-5000 j/kg of MUCAPE. Vertical shear, while not overly strong (25-35 kt 0-6km agl), is sufficient for a mixed convective mode of multicell clusters and transient supercell structures near the boundary. The tendency for developing storms to move eastward toward weaker buoyancy suggests intensification of individual cells should be relatively brief. Additionally, the strongest vertical shear remains displaced farther north which should keep overall organization limited. A WW is unlikely given the lack of a more focused/sustained severe risk, but occasional hail and a damaging gust are possible. ..Lyons/Smith.. 08/17/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...MKX...DVN...ARX... LAT...LON 41308897 41728984 42259068 42849174 43259169 43279015 42868903 42028796 41488801 41278823 41308897 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

MD 1968 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR WESTERN SOUTH DAKOTA
Mesoscale Discussion 1968 NWS Storm Prediction Center Norman OK 0636 PM CDT Sat Aug 16 2025 Areas affected...western South Dakota Concerning...Severe potential...Watch possible Valid 162336Z - 170130Z Probability of Watch Issuance...40 percent SUMMARY...Severe thunderstorm potential will increase this afternoon into the evening. Large hail may be an initial concern, but the primary severe threat should be damaging winds. DISCUSSION...Strong heating of a moist airmass across western South Dakota has resulted in a strongly unstable environment with MUCAPE in excess of 3000 J/kg in areas. Within this environment, thunderstorms are gradually increasing in coverage in response to strengthening large-scale ascent ahead of another shortwave trough moving around the periphery of the southern Plains ridge. Continued southeast-to-east surface winds beneath westerly flow aloft will maintain a sheared (ESHR around 35-40 knots) environment across the region. The combination of a strongly unstable and sheared environment should result in a gradual increase in thunderstorm intensity late this afternoon into the evening. The primary threat will be strong, damaging thunderstorm winds as thunderstorm coverage increases later this evening and thunderstorm outflows congeal ahead of the aforementioned trough. Isolated large to perhaps significant hail may occur with the strongest, more discrete thunderstorms. The need for a severe thunderstorm watch this evening remains somewhat unclear, but may increase this evening into the overnight hours. The most likely onset of more widespread severe potential should be after 9 PM MDT. However, conditions will be monitored through the evening in the event coverage and intensity begins to increase. ..Marsh/Smith.. 08/16/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...BIS...LBF...UNR...BYZ... LAT...LON 42800197 43310375 44510434 45780402 46130352 45920163 45520078 44390047 43250061 42800197 MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Sat Aug 16 2025 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN AND CENTRAL SOUTH DAKOTA AND SOUTHERN NORTH DAKOTA... ...SUMMARY... A small organized cluster of thunderstorms with potential to produce a swath of strong to severe wind gusts still appears possible across parts of the central Dakotas later this evening into the overnight hours. More sporadic strong thunderstorms with potential to produce severe wind and hail are possible in a corridor across the Midwest into Great Lakes vicinity. ...01Z Update... In the wake of a weakening convective perturbation shifting east-southeastward through the Great Lakes region, modest mid-level height rises across eastern portions of the northern Great Plains will gradually overspread the Upper Midwest and adjacent Great Lakes region overnight. In the presence of weak and/or weakening deep-layer shear, and weak mid/upper support for convective development, the probabilities for the evolution of a sustained organized severe storm cluster appear to be lowering. However, weak low-level warm advection to the immediate cool side of convective outflow, and a quasi-stationary frontal zone extending roughly from west-northwest of the Dubuque IA vicinity into the middle Missouri Valley, is forecast to contribute to a corridor of increasing thunderstorm development overnight. Although mid-level profiles appear relatively warm, a plume of dry lower/mid-tropospheric air with steep lapse rates may contribute to a risk for localized strong wind gusts and some hail in sporadic stronger storms. Upstream, across the middle Missouri Valley, as a weak mid-level short wave trough slowly shifts eastward into the western Dakotas, models continue to suggest that associated scattered thunderstorm development may gradually consolidate into an organizing cluster, perhaps aided by lift associated with warm advection on the nose of a strengthening southerly low-level jet. As this occurs, although deep-layer mean wind fields will remain generally weak, modest shear and thermodynamic profiles with steep lower/mid-tropospheric lapse rates and sizable CAPE may contribute to potential for the development of strong to severe wind gusts overnight. ..Kerr.. 08/17/2025 Read more