Quincy Posted February 28, 2017 Share Posted February 28, 2017 If there was a mesoscale area to really focus in on, it's got to be west-central to northern/northeastern Illinois. Moisture pooling ahead of that pseduo-dryline feature allows for MLCAPE in excess of 2,000 J/kg near an effective triple point. As mentioned in the SPC discussion, this is where the initial nose of the LLJ punches in, with 850mb winds around 50kt by 00z Wed. The 00z ECMWF seems to imply a corridor of strong convection from northern MO into the greater Chicago area Tuesday night. The precip swaths hint at at least semi-discrete convection continuing from eastern IL into IN between 6 and 12z. A complex setup, but the model consensus from both the global and CAM models across Illinois is concerning. Link to comment Share on other sites More sharing options...
Hoosier Posted February 28, 2017 Share Posted February 28, 2017 Public Information Statement National Weather Service Chicago IL 540 PM CST Mon Feb 27 2017 /640 PM EST Mon Feb 27 2017/ ...The KLOT WSR-88D Doppler radar is out of service... The KLOT WSR-88D radar is currently inoperable. The part needed to fix the radar is on back order and may not be delivered until Thursday. It is possible that the radar may be operated with degraded data quality at times before being fully restored. Any radar data coming from KLOT should be used with extreme caution until the radar is repaired. In the meantime...radar coverage for the KLOT service area can be obtained by using any one of the following radars: KILX (Lincoln IL) KDVN (Davenport IL) KMKX (Milwaukee WI) KIWX (North Webster IN) KIND (Indianapolis IN) TORD (FAA O`hare Terminal Doppler Radar) TMDW (FAA Midway Terminal Doppler Radar) TMKE (FAA Milwaukee Terminal Doppler Radar) Link to comment Share on other sites More sharing options...
andyhb Posted February 28, 2017 Author Share Posted February 28, 2017 Well that is a bad time for the radar to go down to say the least. 00z NCAR ensemble has quite a pronounced signal for significant storms generally through ILX into LOT's CWA tomorrow as well. Link to comment Share on other sites More sharing options...
Roger Smith Posted February 28, 2017 Share Posted February 28, 2017 Ohio 12z-15z Wed likely to see squall line development and widespread gusts to 60 mph even outside of severe cell paths. Temperatures will drop from near 70 F to about 35 F by afternoon and several hours of blowing snow may develop in parts of MI and n OH with flash freeze conditions in MI and much of ON once the warm sector blasts through. For south-central ON this may resemble the March 18, 1973 storm that caused a serious highway accident north of Toronto when blowing snow followed a similar flash freeze. I agree with what I read about earlier stages of the storm, some potential for minor severe weather in n IL into sw MI and nw IN late Tuesday, moderate risk s-c IL into w IN, this may continue through the night with a bit of a drop in intensity before ramping up in the morning from about Muncie to Louisville. Would stress very hazardous travel conditions in MI and OH, n IN during the transition to cold. Link to comment Share on other sites More sharing options...
RyanDe680 Posted February 28, 2017 Share Posted February 28, 2017 4 hours ago, Hoosier said: Public Information Statement National Weather Service Chicago IL 540 PM CST Mon Feb 27 2017 /640 PM EST Mon Feb 27 2017/ ...The KLOT WSR-88D Doppler radar is out of service... The KLOT WSR-88D radar is currently inoperable. The part needed to fix the radar is on back order and may not be delivered until Thursday. It is possible that the radar may be operated with degraded data quality at times before being fully restored. Any radar data coming from KLOT should be used with extreme caution until the radar is repaired. In the meantime...radar coverage for the KLOT service area can be obtained by using any one of the following radars: KILX (Lincoln IL) KDVN (Davenport IL) KMKX (Milwaukee WI) KIWX (North Webster IN) KIND (Indianapolis IN) TORD (FAA O`hare Terminal Doppler Radar) TMDW (FAA Midway Terminal Doppler Radar) TMKE (FAA Milwaukee Terminal Doppler Radar) Need not worry. Brant Miller to the rescue!! Link to comment Share on other sites More sharing options...
geddyweather Posted February 28, 2017 Share Posted February 28, 2017 Enhanced brought north into the south suburbs of Chicago, while nudged a tad south in north central IN. 10% TOR with hatched also brought East toward Indy. Link to comment Share on other sites More sharing options...
cyclone77 Posted February 28, 2017 Share Posted February 28, 2017 Glad to see that they shifted the northern edge of the outlook and enhanced categories northward into more of the DVN/LOT areas. HRRR has been pretty consistent with very impressive parameters just east of the surface low later this afternoon. These parameters would be pretty impressive in the heart of the severe season, but in late Feb it's even more so. Link to comment Share on other sites More sharing options...
Indystorm Posted February 28, 2017 Share Posted February 28, 2017 Since LOT's radar will be down for this svr episode late today and tonight we in the affected areas will appreciate all members who have special radar subscriptions to share what they can to help. Smoke/Eater and others, are you listening? That dryline bulge really is cause for concern. Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 28, 2017 Share Posted February 28, 2017 12z NAM and HRRR look bullish an upgrade to moderate risk is needed IMO for all Hazards(sig TOR, large HAIL and WIND later) plus multiple rounds mean rather wide area affected clouds will hamper heating a bit but with very cold 500mb temps doesn't really matter Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted February 28, 2017 Share Posted February 28, 2017 18 minutes ago, janetjanet998 said: 12z NAM and HRRR look bullish an upgrade to moderate risk is needed IMO for all Hazards(sig TOR, large HAIL and WIND later) plus multiple rounds mean rather wide area affected clouds will hamper heating a bit but with very cold 500mb temps doesn't really matter HRRR would also probably support expanding all the risks a little too Link to comment Share on other sites More sharing options...
mob1 Posted February 28, 2017 Share Posted February 28, 2017 17 minutes ago, HillsdaleMIWeather said: HRRR would also probably support expanding all the risks a little too Dew points along the southern areas of the risk are already pretty high with mid to upper 60's now showing up in Arkansas, looks like mesoscale models won't be overdone in that regard (as is often the case) Link to comment Share on other sites More sharing options...
Anti tornado Posted February 28, 2017 Share Posted February 28, 2017 1 hour ago, Indystorm said: Since LOT's radar will be down for this svr episode late today and tonight we in the affected areas will appreciate all members who have special radar subscriptions to share what they can to help. Smoke/Eater and others, are you listening? That dryline bulge really is cause for concern. Luckily Chicago has a tdwr that covers most of the s burbs Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted February 28, 2017 Share Posted February 28, 2017 Very ominous 12z run of the HRRR ensemble and tornado probabilities: https://rapidrefresh.noaa.gov/hrrr/hrrrtle/displayMapLocalDiskDateDomainZipTZA.cgi?keys=hrrr_tle_jet:&runtime=2017022812&plot_type=alltornado&fcst=00&time_inc=60&num_times=25&model=hrrr&ptitle=HRRR Time-Lagged Ensemble - Experimental&maxFcstLen=24&fcstStrLen=-1&domain=full&adtfn=1&threshold=&attfn=-1&wjet=0 Link to comment Share on other sites More sharing options...
CoachLB Posted February 28, 2017 Share Posted February 28, 2017 Go big I guess. Link to comment Share on other sites More sharing options...
Hoosier Posted February 28, 2017 Share Posted February 28, 2017 Very informative afd from LOT discussing the potential and the uncertainties. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted February 28, 2017 Share Posted February 28, 2017 Moderate risk forthcoming for parts of the Ohio Valley. Link to comment Share on other sites More sharing options...
yoda Posted February 28, 2017 Share Posted February 28, 2017 3 minutes ago, TheWeatherPimp said: Moderate risk forthcoming for parts of the Ohio Valley. ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF EASTERN MO...CENTRAL/SOUTHERN IL...CENTRAL/SOUTHERN INDIANA...WESTERN/NORTHERN KY... Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted February 28, 2017 Share Posted February 28, 2017 Moderate introduced, Slight and Enhanced Risks expanded. Link to comment Share on other sites More sharing options...
Jackstraw Posted February 28, 2017 Share Posted February 28, 2017 17 minutes ago, Hoosier said: Very informative afd from LOT discussing the potential and the uncertainties. Nice little addendum at the end for any chaser/spotters unfamiliar with Midwest super cells. Finally, with individual storm motions forecast to be around 65 mph, and the timing of after dark, presents challenges/dangers to storm spotters, and vigilance and safety is stressed. Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 28, 2017 Share Posted February 28, 2017 Looks like I'll probably chase today, unless things change.Probably will initially target somewhere near or just south of I-80. Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 28, 2017 Share Posted February 28, 2017 HERES THE TEXT DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1030 AM CST TUE FEB 28 2017 VALID 281630Z - 011200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF EASTERN MO...CENTRAL/SOUTHERN IL...CENTRAL/SOUTHERN INDIANA...WESTERN/NORTHERN KY... ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SURROUNDING THE MODERATE RISK AREA ACROSS PORTIONS OF THE MO OZARKS TO THE LOWER/MIDDLE OHIO VALLEY REGION... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE ENHANCED AREA FROM EASTERN OKLAHOMA AND ARKANSAS TOWARD THE LOWER GREAT LAKES REGION... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT ACROSS PARTS OF THE CENTRAL AND EASTERN STATES... ..SUMMARY SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP FROM PORTIONS OF THE LOWER MISSISSIPPI VALLEY TO THE OHIO VALLEY THROUGH TONIGHT. STRONG TORNADOES WILL BE POSSIBLE, ESPECIALLY ACROSS PORTIONS OF THE LOWER AND MIDDLE OHIO VALLEY. OTHERWISE, LARGE HAIL AND DAMAGING WINDS ARE EXPECTED. ...PORTIONS OF THE MO OZARKS THROUGH THE MIDDLE MS VALLEY AND THE OHIO VALLEY REGION... A PROMINENT WARM SECTOR WILL CONTINUE TO BUILD NORTHWARD/NORTHEASTWARD ACROSS THE REGION THROUGH TONIGHT, AS A MIDLEVEL SPEED MAXIMUM ADVANCES FROM THE SOUTHERN ROCKIES EAST-NORTHEASTWARD TOWARD THE OHIO VALLEY REGION. AS LOWER/MIDDLE 60S DEWPOINTS ALSO DEVELOP NORTHWARD/NORTHEASTWARD, AN EXPANSIVE AREA OF MLCAPE AROUND 500-2000 J/KG -- AIDED BY STEEP MIDLEVEL LAPSE RATES SURMOUNTING RETURNING MOISTURE -- WILL SUPPORT VIGOROUS CONVECTIVE DEVELOPMENT. WITH WARM-SECTOR-COINCIDING EFFECTIVE SHEAR AROUND 40-70 KT, A WIDESPREAD AREA OF CONDITIONAL SIGNIFICANT-SEVERE POTENTIAL WILL EXIST -- ESPECIALLY FROM LATE AFTERNOON INTO THE OVERNIGHT HOURS. PRESENT INDICATIONS ARE THAT CLUSTERS OF STORMS WILL BE EVOLVING FROM EASTERN PARTS OF THE CENTRAL/SOUTHERN GREAT PLAINS NORTHEASTWARD TO THE VICINITY OF SOUTHERN LAKE MICHIGAN BY LATE AFTERNOON/EARLY EVENING IN THE VICINITY OF A BAROCLINIC BAND -- WITH THIS ACTIVITY SPREADING EASTWARD INTO TONIGHT. CONFIDENCE HAS INCREASED IN MORE WIDESPREAD SEVERE-HAIL POTENTIAL WITH THIS ACTIVITY, INCLUDING SIGNIFICANT SEVERE HAIL. OPEN-WARM-SECTOR CONVECTION WILL LIKELY EVOLVE ALONG A LOW-LEVEL JET THROUGH PARTS OF THE OHIO VALLEY TONIGHT AS ADDITIONAL MOISTENING OCCURS. EFFECTIVE SRH OF 300-400 M2/S2 WILL SUPPORT TORNADO POTENTIAL WITH EVOLVING SUPERCELL CLUSTERS. THIS INCLUDES THE POTENTIAL FOR NOCTURNAL SIGNIFICANT TORNADOES, AND TORNADO PROBABILITIES HAVE BEEN INCREASED. ..PORTIONS OF THE SOUTHEAST DESTABILIZATION ALONG THE SOUTHERN/EASTERN FLANKS OF CONVECTION OVER THE TN VALLEY REGION MAY SUPPORT SOME INCREASE IN CONVECTIVE INTENSITY WITH STORM CLUSTERS ADVANCING TOWARD THE SOUTHERN APPALACHIANS. LOCALLY DAMAGING WIND GUSTS MAY ACCOMPANY THIS Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 28, 2017 Share Posted February 28, 2017 AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAINT LOUIS MO 1041 AM CST TUE FEB 28 2017 UPDATE ISSUED AT 1041 AM CST TUE FEB 28 2017 ...CONFIDENCE INCREASING ON SEVERE WEATHER OUTBREAK LATE THIS AFTERNOON INTO THE OVERNIGHT HOURS... THE LATEST DATA, INCLUDING THE E-HRRR/HRRR/WRF-ARW/WRF-NMM ARE IN GENERAL AGREEMENT OF SUPERCELL THUNDERSTORMS DEVELOPING LATE THIS AFTERNOON INTO EARLY THIS EVENING. THE 12Z SOUNDING OUT OF SGF SHOWED A DEEP LOW-LEVEL MOISTURE PROFILE, WITH SATURATION UP TO AROUND 880MB. HOWEVER, IT DID SHOW A SUBSTANTIAL CAP ABOVE THE MOIST LOW-LEVELS (16C AROUND 875MB), WITH STEEP MID-LEVEL LAPSE RATES ABOVE THE CAP. WITH TIME, THIS CAP IS EXPECTED TO BE OVERCOME DUE TO INCREASING SOLAR INSOLATION AS LOW-LEVEL STRATUS MIXES OUT, AND WITH CONTINUED LOW-LEVEL MOISTURE ADVECTION. WHILE THE FOCUS FOR INITIAL SUPERCELL DEVELOPMENT IS A BIT NEBULOUS, THE LATEST GUIDANCE SUGGESTS DEVELOPMENT IS LIKELY WITHIN THE LEFT-EXIT REGION OF A DEVELOPING 925MB LOW-LEVEL JET AXIS, WHICH WILL SHIFT TOWARD THE MS RIVER VALLEY BY 00Z THIS EVENING. THE TIMING OF THIS FEATURE COULD DEVELOP SUPERCELL THUNDERSTORMS ACROSS EAST-CENTRAL MO AND WESTERN IL (INCLUDING THE ST. LOUIS METRO) NEAR RUSH HOUR. FORECAST SOUNDINGS DURING THIS TIME SUGGEST A LARGE TO VERY LARGE HAIL THREAT, DAMAGING WINDS, AND THE POTENTIAL FOR TORNADOES GIVEN THE STRONGLY-SHEARED LOW-LEVELS. THIS INITIAL ROUND OF SEMI-DISCRETE SUPERCELLS WILL PUSH EAST BY LATE THIS EVENING, BUT ATTENTION WILL THEN TURN TO THE NORTHWEST ALONG THE APPROACHING COLD FRONT. A PV ANOMALY WILL EJECT OUT ATOP THIS COLD FRONT, LEADING TO ADDITIONAL SUPERCELL DEVELOPMENT INITIALLY, BUT LIKELY EVOLVING INTO A LINE OVERNIGHT GIVEN ORIENTATION OF THE 0-6KM SHEAR VECTORS TO THE SLAB-LIKE FORCING ALONG THE APPROACHING FRONT. ONCE AGAIN, ALL HAZARDS WILL BE POSSIBLE WITH THIS ROUND OF THUNDERSTORMS INCLUDING LARGE HAIL, DAMAGING WINDS, AND TORNADOES. Link to comment Share on other sites More sharing options...
Hoosier Posted February 28, 2017 Share Posted February 28, 2017 Warm sector is pretty socked in with clouds. Not that that was unexpected. Some pockets of clearing/thinning though... in Iowa and Missouri. Link to comment Share on other sites More sharing options...
Wttnwx Posted February 28, 2017 Share Posted February 28, 2017 1" hail reported near Madison. Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 28, 2017 Share Posted February 28, 2017 new HRRR starts the show early over SW MO with convection developing aorund 20-21z and discrete storms over AR by 22z Link to comment Share on other sites More sharing options...
Central Illinois Posted February 28, 2017 Share Posted February 28, 2017 ILX Link to comment Share on other sites More sharing options...
jojo762 Posted February 28, 2017 Share Posted February 28, 2017 17Z HRRR presents what is probably a worst case scenario for much of the threat area. Develops discrete supercells this afternoon in southwest Missouri and moves them up into Illinois moving very near LSX, also develops several discrete supercells and supercellular clusters in Illinois later on, also an impressive isolated supercell over Arkansas... All before the QLCS/line comes through tonight. Link to comment Share on other sites More sharing options...
Central Illinois Posted February 28, 2017 Share Posted February 28, 2017 Sun just came out here not sure how long it'll last but ILX was saying mostly cloudy today. Link to comment Share on other sites More sharing options...
Quincy Posted February 28, 2017 Share Posted February 28, 2017 8 minutes ago, jojo762 said: 17Z HRRR presents what is probably a worst case scenario for much of the threat area. Develops discrete supercells this afternoon in southwest Missouri and moves them up into Illinois moving very near LSX, also develops several discrete supercells and supercellular clusters in Illinois later on, also an impressive isolated supercell over Arkansas... All before the QLCS/line comes through tonight. It's not often we see severe parameters this high over such a broad area, especially in late winter: Link to comment Share on other sites More sharing options...
Indystorm Posted February 28, 2017 Share Posted February 28, 2017 Modest degree of clearing and thinning of clouds in MO and ne of St. Louis up I-55 into central IL. Insolation will only add to the danger. Temps and dews continue to rise. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.