SPC Forecast Products Storm Prediction Center

  • SPC - No MDs are in effect as of Wed Jul 17 12:50:08 UTC 2019
    on July 17, 2019 at 12:50 pm

    No Mesoscale Discussions are in effect as of Wed Jul 17 12:50:08 UTC 2019. […]

  • SPC Severe Thunderstorm Watch 514 Status Reports
    on July 17, 2019 at 12:50 pm

    WW 0514 Status Updates STATUS REPORT ON WW 514 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 ENE OFK TO 40 NNE SUX TO 35 SE FSD. ..SMITH..07/17/19 ATTN...WFO...FSD...DMX...OAX... STATUS REPORT FOR WS 514 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS IAC021-025-027-035-041-047-093-119-133-141-149-151-161-167-193- 171330- IA . IOWA COUNTIES INCLUDED ARE BUENA VISTA CALHOUN CARROLL CHEROKEE CLAY CRAWFORD IDA LYON MONONA O'BRIEN PLYMOUTH POCAHONTAS SAC SIOUX WOODBURY NEC043-173-171330- NE . NEBRASKA COUNTIES INCLUDED ARE DAKOTA THURSTON THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read mor […]

  • SPC Severe Thunderstorm Watch 514
    on July 17, 2019 at 12:50 pm

    WW 514 SEVERE TSTM IA NE SD 170950Z - 171500Z URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 514 NWS Storm Prediction Center Norman OK 450 AM CDT Wed Jul 17 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northwest Iowa Northeast Nebraska Southeast South Dakota * Effective this Wednesday morning from 450 AM until 1000 AM CDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 75 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...A fast-moving bowing line of thunderstorms over southeast South Dakota will track across the watch area this morning, posing a risk of damaging winds and hail. The severe thunderstorm watch area is approximately along and 40 statute miles north and south of a line from 40 miles west of Yankton SD to 25 miles east southeast of Storm Lake IA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 28040. ...Hart Read mor […]

  • SPC Jul 17, 2019 1300 UTC Day 1 Convective Outlook
    on July 17, 2019 at 12:42 pm

    SPC 1300Z Day 1 Outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0738 AM CDT Wed Jul 17 2019 Valid 171300Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHERN PLAINS...UPPER MISSISSIPPI VALLEY...AND THE NORTHEAST STATES... ...SUMMARY... Severe thunderstorms capable of severe wind gusts and large hail are possible across portions of the northern High Plains and mid-to-upper Mississippi Valley through tonight. Storms capable of damaging wind gusts will be possible across portions of the Northeast this afternoon and evening. ...IA this morning... A mature bow echo is currently affecting northwest IA, and should maintain significant intensity for a few more hours, posing a risk of damaging wind across parts of IA. Please see WW514 for further information. ...Upper MS Valley this afternoon... A large cloud shield is associated with the IA convection. This will limit daytime heating and destabilization over much of southern/central MN today. Therefore have trimmed the SLGT risk in parts of this area. Redevelopment of strong/severe storms remains possible this afternoon in vicinity of the outflow associated with this morning's storms. However, that may be shunted southward into IA and adjacent parts of WI/IL/MO. ...Northern High Plains... Water vapor imagery shows a shortwave trough over eastern ID. This feature will move into MT/WY this afternoon, helping to develop scattered thunderstorms. A few severe storms capable of hail and damaging winds will affect parts of the western Dakotas, where the SLGT risk area was expanded slightly in this update. ...Northern MN... A shortwave trough is noted over eastern MT. This feature and its associated large scale forcing will overspread northern MN later today - with scattered thunderstorms expected. The effects of the ongoing convection farther south remains unclear, but it appears possible that clearing will move into this region by peak-heating, allowing pockets of moderate CAPE to develop. Hail and damaging winds would be possible in the strongest cells over this area. ...NY/PA/NJ into southern New England... A moist and potentially very unstable air mass is in place across this region today, with dewpoints in the upper 60s to lower 70s and early visible satellite imagery is showing the potential for strong heating. Afternoon SBCAPE values of 2000-3000 J/kg are expected, with scattered thunderstorms forming by mid-afternoon. Vertical shear profiles will not be particularly strong, but sufficient westerly steering flow will help organize outflows and pose a risk of locally damaging wind gusts in the strongest cells. Coverage and intensity of storms will decrease farther south across the Delmarva region, but isolated strong convection will be possible. ..Hart/Smith.. 07/17/2019 Read mor […]