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AN ANALYSIS OF THURSDAY’S NORTHERN ILLINOIS/SOUTHERN WISCONSIN T-STORM AND LOCAL SEVERE WEATHER OUTBREAK FROM THE UNIVERSITY OF WISCONSIN-MADISON

  • An outbreak which included some tornadoes—one 125 miles southwest of Chicago in Henry, Illinois Thursday afternoon; several others in Wisconsin, including a first on record February tornado touchdown in the Badger State.

NOTE THIS FRIDAY MORNING POST FROM “CIMSS” AT UW-MADISON:

  • “The first February tornado ever recorded in Wisconsin weather history touched down Thursday evening. Plus 1-inch hail.”
  • Check out the excellent post on THURSDAY’S EARLY SEASON T-STORM OUTBREAK — which includes a thorough rundown of analyses and forecast products, most animated, which track the day’s afternoon and evening storm development Thursday.
  • The post comes from Scott Lindstrom of CIMSS (the Cooperative Institute for Meteorological Satellite Studies) at the University of Wisconsin-Madison and can be accessed here: https://cimss.ssec.wisc.edu/satellite-blog/archives/57036
  • The post referenced here is technical—so as I like to say, if that’s NOT your cup of tea—you may wish to pass on this. BUT FOR MY FELLOW WEATHER ENTHUSIASTS—it offers spectacular insights into the meteorological conditions backstopping late Thursday’s storm outbreak. It includes a series of fascinating satellite derived products developed within the University of Wisconsin-Madison’s Department of Atmospheric and Oceanic Sciences.

THE STORM WHICH PRODUCED THURSDAY’S MIDWEST T-STORMS

  • Here’s what the storm which produced Thursday’s Midwest thunderstorms, including the first recorded February tornado touchdown in Wisconsin and Chicago’s near record, April-level unseasonable warmth, looked like as it swept onto the West Coast this past Sunday (February 4).
  • Medium-range computer model forecasts suggest more weather troubles may lie ahead, beginning in a week for California and the West Coast East into Arizona, reports the NWS Climate Prediction Center (CPC).
  • NASA put out an interesting review/analysis of the recent California late winter storm which lambasted that state with record rains totals more than a foot in the Los Angeles area, 100 mph winds gusts last weekend in central California snows and up to 3 ft. of snow in the Sierra. READ THE REPORT HERE:
    https://earthobservatory.nasa.gov/images/152414/potent-storm-drenches-california?fbclid=IwAR2Un28NYbGbYs3VqV3O1rraMvhVHtpv0KUOHBMOxT3bX3rkaG4ffs8TZM8
  • CHECK OUT THIS FINAL LIST OF SOUTHERN CALIFORNIA RAINFALLS WITH THE STORM from the Oxnard CA National Weather Service Office: https://www.weather.gov/wrh/TextProduct?product=rrmlox
  • MORE WEATHER TROUBLES MAY LIE AHEAD FOR THE WEST STARTING AGAIN LATE NEXT WEEK—A powerhouse 175 mph jet stream, currently sweeping off the Eurasian continent and out over the western Pacific, slicing through the airspace above and just south of Japan, is the basis for concerns about Western U.S. weather beginning late next week. That jet is the basis for the potential development of a new series of storms, according to modeling, later next week into the weekend and week which follows (Feb 16-21).
  • In a Thursday release out of the National Weather Service’s Climate Prediction Center (CPC), the agency—which releases assessment of potential future weather troubles—reports the following:
  • “There is an increased potential for heavy rain, high winds, and flooding for California and Arizona, along with heavy snow at higher elevations, Friday-Wednesday, February 16-21, 2024.
  • (a) There is a high risk (at least a 60% chance) of hazardous heavy precipitation across California, with heavy snow in the higher elevations, Saturday-Monday, February 17-19, 2024.
  • (b) Moderate risks (40% to 60% chance) of heavy precipitation and high elevation snow are forecast for Friday-Wednesday, February 16-21 for California and Arizona.
  • (c) A moderate risk of high winds is also forecast for most of California, from Friday-Monday, February 16-21, 2024.
  • The heavy precipitation could lead to localized flooding, particularly in regions that have saturated soils from precipitation earlier in February.

EL NIÑO WINTER SEASONS

El Niño winter seasons can be prolific precip producers for California and the West. Check this climate.gov analysis of the precip across the country in the strong El Niño winter season of 1997-98.


WISCONSIN LOGGED ITS FIRST RECORDED FEBRUARY TORNADO TOUCHDOWN with Thursday’s late day and evening T-STORMS

  • The National Weather Service-Milwaukee/Sullivan Forecast office issued the following on Thursday’s storms, posting a Doppler radar low level circulation graphic covering the day’s unusual storms:
  • “Prior to 2024 the state of Wisconsin had never seen a tornado in the month of February. On the evening of February 8th, 2024 a rare, impressive setup for severe weather came together across southern Wisconsin.”

NWS-Milwaukee/Sullivan added the following:

  • “A few stats about this severe weather event, dating back to 1986. Prior to the evening of February 8th, 2024:
  • “Zero Tornado Warnings had been issued in the state of Wisconsin, during the month of February. NWS Milwaukee/Sullivan issued 5 Tornado Warnings during this event.
  • “17 Severe Thunderstorm Warnings had been issued in the state of Wisconsin, during the month of February (9 in 1999, 4 in 2008, 3 in 2017). NWS Milwaukee/Sullivan issued 8 Severe Thunderstorm Warnings during this event.”

Low-level rotation tracks from MRMS . . . read the entire article here:
https://www.weather.gov/mkx/FebruarySevereWeather?fbclid=IwAR0MBiuaLHayXskkX1s8-lns6F_TBCEy86FSPZpdFLgB1BO36iic6reAXFg


LOOK AT THE WAVE PATTERN IN THE CLOUDS ACROSS WISCONSIN—the wavy clouds are known as “GRAVITY WAVES”—and result from winds with velocities which vary with height

  • We’ve been “dry slotted”! We’re in the windy “dry wedge” below the strongest jet stream winds within the southern flank of the giant late winter storm which raced from California into the upper Midwest and is centered Friday north of Lake Superior.
  • The so-called “dry slot” or “dry wedge” is a largely cloud and precip-free area several hundred miles across. These wedges of dry air lend large storm systems their “comma-shaped” appearance on weather satellite imagery. The sun shining brightly in Chicago Friday—but wind gusts will build to 35 mph at times day.
  • HERE’S AN EXCELLENT DESCRIPTION OF “GRAVITY WAVES” from meteorologist David Moran and posted by the National Weather Service: https://www.weather.gov/…/gravity_wave/gravity_wave.html

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