IllinoisWedges Posted November 28, 2018 Share Posted November 28, 2018 Could have a chance at some severe this weekend in IL/IN. 1 Link to comment Share on other sites More sharing options...
Indystorm Posted November 29, 2018 Share Posted November 29, 2018 Marginal risk presently issued for southern and central IN & IL for Sat, Much will depend on what happens to the sw on Friday I presume., along with how much clearing and insolation we might get after a.m. rain moves east on Sat. Lower Wabash valley and western KY could have a chance for some tors with good helicity come Sat evening if things come together properly. Link to comment Share on other sites More sharing options...
Indystorm Posted November 30, 2018 Share Posted November 30, 2018 Behind early morning thunderstorms, some potential exists for renewed convection Saturday afternoon across eastern MO into southern/central IL as a mid-level dry slot and related cold temperatures aloft overspread this region. Forecast effective bulk shear of 40-50+ kt will easily support supercells, although limited low-level moisture will probably tend to keep instability weak, with MLCAPE of 500-1000 J/kg. Isolated large hail and damaging winds should be the primary threats, but a tornado or two may also occur with the strong low-level shear present. If confidence increases in the placement and coverage of thunderstorms across this region, a Slight risk may need to be considered in a later update. From SPC Link to comment Share on other sites More sharing options...
NCIWxGuy Posted November 30, 2018 Share Posted November 30, 2018 I know this isn't getting much attention here, but tomorrow actually looks halfway decent for low-topped supercells across portions of the LSX and ILX CWAs. Models differ exactly on placement, but it looks to set up somewhere between eastern Missouri and central Illinois. NAMs (what I used for graphics here) are a bit further west than most guidance I've seen. Precip shield is progged to move out of SW IL by 13-15z, allowing clearing to destabilize the atmosphere potentially on the order of 1000-1500 j/kg, with much of that concentrated in the lowest levels. Surface winds should be backed at least somewhere in the warm sector. Storms should fire near boundary in far eastern Missouri or western Illinois, and have the potential to rotate and produce a few tornadoes. The environment is somewhat reminiscent to me of 12/23/15 in west-central Illinois, where wind profiles were similar but I'm fairly sure CAPE was only on the order of several hundred j/kg. Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 5% TOR probs AY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1149 PM CST FRI NOV 30 2018 VALID 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS MAINLY THIS AFTERNOON INTO EARLY EVENING ACROSS PARTS OF THE MIDDLE MISSISSIPPI VALLEY AND PORTIONS OF THE CENTRAL GULF COAST STATES... ..SUMMARY A FEW SEVERE STORMS ARE POSSIBLE TODAY ACROSS PARTS OF THE MIDDLE MISSISSIPPI VALLEY, AND ALSO ACROSS PORTIONS OF THE CENTRAL GULF COAST STATES. ..SYNOPSIS MODELS SUGGEST THAT THE LARGE-SCALE PATTERN OVER THE INTERIOR U.S./CANADA MAY TREND LESS PROGRESSIVE AND BECOME CHARACTERIZED BY INCREASED BLOCKING DURING THIS PERIOD. THIS REGIME WILL INCLUDE A BROAD AND DEEP LOWER/MID TROPOSPHERIC CYCLONE CENTERED OVER EASTERN KANSAS BY 12Z THIS MORNING. AS THE PRIMARY EMBEDDED MID-LEVEL SHORT WAVE IMPULSE PIVOTS NORTHEASTWARD THROUGH THE LOWER MISSOURI/MIDDLE MISSISSIPPI VALLEY TODAY, MODELS INDICATE THAT THE SURFACE CYCLONE WILL OCCLUDE. A SECONDARY LOW MAY DEVELOP AT THE TRIPLE POINT, ACROSS EAST CENTRAL/NORTHEAST MISSOURI, BEFORE MIGRATING TOWARD THE GREAT LAKES. AN INITIAL SURFACE COLD FRONT, ACROSS THE SOUTHEASTERN PLAINS AT THE OUTSET OF THE PERIOD, MAY WEAKEN AS IT CONTINUES SOUTHEASTWARD INTO THE LOWER MISSISSIPPI VALLEY/NORTHWESTERN GULF COAST VICINITY. AHEAD OF THIS FEATURE, A NORTHEASTWARD SURGE OF SEASONABLY HIGH MOISTURE CONTENT, OFF THE STILL MODIFYING BOUNDARY LAYER OVER THE NORTHWESTERN GULF OF MEXICO, IS FORECAST THROUGH MUCH OF THE CENTRAL/EASTERN GULF COAST STATES BY EARLY SUNDAY. IT APPEARS THAT AN INITIAL INFLUX OF LOW-LEVEL GULF MOISTURE (CURRENTLY ADVECTING INTO THE LOWER/MIDDLE MISSISSIPPI VALLEY) WILL BECOME INCREASINGLY PINCHED OFF EAST OF THE MIDDLE MISSISSIPPI INTO LOWER OHIO VALLEY LATER TODAY/TONIGHT. ..MIDDLE MISSISSIPPI VALLEY IT APPEARS THAT AN EVOLVING DRY SLOT WILL OVERSPREAD PORTIONS OF THE LOWER MISSOURI/MIDDLE MISSISSIPPI VALLEY REGION EARLY TODAY. THIS LIKELY WILL ALLOW FOR DAYTIME HEATING TO CONTRIBUTE TO BOUNDARY LAYER DESTABILIZATION PRIOR TO THE ONSET OF INCREASING FORCING FOR ASCENT NEAR THE MID-LEVEL COLD CORE, ALONG/NORTH OF A STILL INTENSIFYING CYCLONIC MID/UPPER JET (IN EXCESS OF 90 KT AT 500 MB FORECAST ACROSS THE OZARK PLATEAU INTO THE OHIO VALLEY BY LATE AFTERNOON). A RESIDUAL CORRIDOR OF SURFACE DEW POINTS NEAR 60 F MAY CONTRIBUTE TO MIXED-LAYER CAPE ON THE ORDER OF 500-1000 J/KG BY EARLY THIS AFTERNOON. IN THE PRESENCE OF STRONG DEEP LAYER SHEAR AND STILL SIZABLE LOW-LEVEL HODOGRAPHS, NEAR/SOUTHEAST OF THE SECONDARY SURFACE LOW, THE ENVIRONMENT MAY BECOME CONDUCIVE TO ORGANIZED SEVERE STORM DEVELOPMENT. THIS COULD INCLUDE A COUPLE OF SUPERCELLS, AND A RISK FOR TORNADOES, WHICH MAY SPREAD FROM PORTIONS OF CENTRAL/EASTERN MISSOURI INTO CENTRAL/SOUTHERN ILLINOIS, BEFORE DIMINISHING AROUND/SHORTLY AFTER DARK. Link to comment Share on other sites More sharing options...
fluoronium Posted December 1, 2018 Share Posted December 1, 2018 Currently sitting under 15/15/5 probabilities which pathetically is one of the highest of the entire year here. Maybe I will be lucky enough to get my first tornado watch of 2018. Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 10 minutes ago, fluoronium said: Currently sitting under 15/15/5 probabilities which pathetically is one of the highest of the entire year here. Maybe I will be lucky enough to get my first tornado watch of 2018. Holy Moly..I forgot how dead it has been this year I wonder how often central IL has had ZERO Tornado watches for the entire calendar year..looks like for Northern IL the streak will continue Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 HRRR seems to break out low tops mini SUPS near I-72 to I-74 in IL here the dryline/wind shift meets the warm front Link to comment Share on other sites More sharing options...
IWXwx Posted December 1, 2018 Share Posted December 1, 2018 1 hour ago, janetjanet998 said: Holy Moly..I forgot how dead it has been this year I wonder how often central IL has had ZERO Tornado watches for the entire calendar year..looks like for Northern IL the streak will continue Yeah, our string got ruined by one unwarranted Watch in Northern IN or we would be right there with MI, Northern IL, and Northern OH. Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 16:30z SPC expanded the threat a few miles more north to include the PIA metro Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 LOT update STILL MONITORING THE THREAT OF STRONG TO SEVERE STORMS LATE THIS AFTERNOON INTO EARLY EVENING FOR AREAS SOUTH OF I-80, ESPECIALLY ALONG AND SOUTH OF A LINE FROM MENDOTA TO ST. ANNE IL. APPROACHING WARMER MOIST AIR, INCREASING INSTABILITY THAT WILL INCLUDE SB/ML CAPE, AND FOCUS ALONG SURFACE TROUGH AND COLD FRONT WILL SUPPORT A FEW HOUR WINDOW FOR THE POSSIBILITY OF STRONG TO SEVERE STORMS. STILL AM WORKING ON DETAILS, BUT AM MONITORING ALL HAZARDS AT THIS TIME. WILL UPDATE THE HWO, AND WORK ON UPDATED GRAPHICS DETAILING THOUGHTS ON THESE POSSIBLE HAZARDS. RODRIGUEZ ILXUPDATE ISSUED AT 1005 AM CST SAT DEC 1 2018 FORECAST FOCUS IS ON SEVERE WEATHER POTENTIAL THIS AFTERNOON AND EARLY EVENING. LATEST SURFACE OBS AND SATELLITE DATA INDICATE WARM FRONT HAS LIFTED NORTH NEAR THE I-72 CORRIDOR COINCIDENT WITH CLEARING OF THE LOW CLOUDS AND MID 50S DEWPOINT SOUTH OF THE FRONT. ACCAS LOOK TO CLOUDS FROM SOUTH OF KSTL TO NEAR KTAZ INDICATES ELEVATED INSTABILITY ALREADY SURGING NORTH. FARTHER WEST, SUBSTANTIAL CLEARING IS PRESENT FROM WEST CENTRAL IL BACK SOUTHWEST INTO CENTRAL AND SOUTHERN MO. AS THIS SHIFTS NORTHEAST IN THE DRY SLOT AND AHEAD OF THE OCCLUDED FRONT, FEEL SUFFICIENT BREAKS IN THE CLOUD WILL OCCUR TO GET SB CAPES TO 1000+ J/KG OVER THE SOUTHERN HALF TO TWO THIRDS OF THE CWA THIS AFTERNOON. STRONG LOW TO MID LEVEL WIND SHEAR SHIFTS OVER THE AREA TODAY, RESULTING FROM 80-90 KT MID LEVEL JET STREAK AND BACKED LOW LEVEL FLOW IN THE WARM SECTOR AND AHEAD OF THE OCCLUDED FRONT. CONDITIONS NOW APPEAR FAVORABLE FOR SEVERE STORM DEVELOPMENT 20Z-02Z WITH INITIATION IN FAR EASTERN MO/WESTERN IL AND QUICKLY SHIFTING ENE ACROSS THE CWA. HI-RESOLUTION MODELS AND CAMS ARE ALL CONSISTENT IN TIMING AND LOCATION. OVERLAP OF MORE SIGNIFICANT LOW LEVEL SHEAR AND SUFFICIENT CAPE WILL LEAD TO THE POTENTIAL FOR A FEW BRIEF TORNADOES ESPECIALLY DURING THE EARLY PART OF THE EVENT OVER THE WESTERN CWA. DAMAGING WIND GUSTS AND HAIL WILL BE THE MORE WIDESPREAD THREAT AS THE STORMS SHIFT THROUGH THE AREA INTO EARLY EVENING. STRENGTH OF LOW TO MID LEVEL WIND FIELDS SUGGEST 35-45 KT STORM MOTION. SPECIAL 18Z ILX SOUNDING WILL SAMPLE THERMODYNAMIC PROFILE AHEAD OF STORMS. Link to comment Share on other sites More sharing options...
Hoosier Posted December 1, 2018 Share Posted December 1, 2018 5 minutes ago, janetjanet998 said: 16:30z SPC expanded the threat a few miles more north to include the PIA metro We could come close to having the rare tornado over snow scenario, but I wonder if it will all melt by then (except the big piles). Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 11 minutes ago, Hoosier said: We could come close to having the rare tornado over snow scenario, but I wonder if it will all melt by then (except the big piles). notice the HRRR with the odd surface isotherms NW of the IL river this afternoon....I thought that was odd until I saw your post..I forgot about the snowpack 5-8 inches still on the ground in Knox county Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 cells developing north of STL its 61/57 in Lincoln but 40/40 At Lacon Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 It will be interesting to see if the snowpack may be a factor in regards to warm front orientation perhaps causing a more SW-NE front instead of a more typical west-east perhaps this may allow any storm moving NE near it to stay more sheared plus surfaced based longer rather then quickly moving north of it and into the cool side Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 Where is the MESO Discussion SPC? Link to comment Share on other sites More sharing options...
Hoosier Posted December 1, 2018 Share Posted December 1, 2018 Here's the 18z ILX sounding. Have had a bit of warming since then so CAPE is likely somewhat higher now and obviously some good shear. Edit: maybe someone else can post the sounding. Looks weird on my end. Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 ESOSCALE DISCUSSION 1684 NWS STORM PREDICTION CENTER NORMAN OK 0148 PM CST SAT DEC 01 2018 AREAS AFFECTED...WESTERN ILLINOIS INTO SOUTHERN AND CENTRAL ILLINOIS CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 011948Z - 012145Z PROBABILITY OF WATCH ISSUANCE...60 PERCENT SUMMARY...THE SEVERE THREAT IS INCREASING THROUGH THE AFTERNOON WITH A THREAT FOR HAIL, DAMAGING WINDS, AND A FEW TORNADOES. A WATCH IS BEING CONSIDERED. DISCUSSION...A CLUSTER OF CUMULUS IN FAR EASTERN MISSOURI HAS DEEPENED OVER THE PAST HOUR. RADAR TRENDS AND LATEST HRRR GUIDANCE SUGGEST THIS IS THE START OF SURFACE BASED CONVECTION THAT IS EXPECTED TO TRACK ACROSS THE WESTERN 2/3RDS OF ILLINOIS THIS AFTERNOON/EVENING. THE ATMOSPHERE WILL LIKELY NEED A BIT MORE SURFACE HEATING/MOISTURE ADVECTION BEFORE A GREATER SEVERE WEATHER THREAT MATERIALIZES. THEREFORE, EXPECT CONVECTION TO BECOME MORE WIDESPREAD WITH HIGHER SEVERE WEATHER POTENTIAL AFTER 21Z. CURRENTLY, MLCAPE VALUES ARE AROUND 500 J/KG AND ARE EXPECTED TO INCREASE TO AROUND 1000 J/KG IN THE NEXT HOUR OR TWO. GIVEN THIS INSTABILITY WITH DEEP LAYER SHEAR AROUND 35 TO 40 KNOTS, EXPECT SUPERCELLS TO BE THE PRIMARY STORM MODE. SURFACE WINDS WILL LIKELY REMAIN BACKED ACROSS THIS AREA AS A WEAK SURFACE LOW, CURRENTLY ANALYZED IN NORTHEAST MISSOURI TRACKS EAST NORTHEASTWARD ALONG THE WARM FRONT. THEREFORE, GIVEN THE STORM MODE AND THE LOW-LEVEL SHEAR PROFILE (0-1 SRH ~ 150-200 J/KG), THERE WILL BE A TORNADO THREAT WITH THE STRONGEST STORMS. THEREFORE, A WATCH IS BEING CONSIDERED. ..BENTLEY/HART.. 12/01/2018 Link to comment Share on other sites More sharing options...
Paulie21 Posted December 1, 2018 Share Posted December 1, 2018 4 minutes ago, Hoosier said: Here's the 18z ILX sounding. Have had a bit of warming since then so CAPE is likely somewhat higher now and obviously some good shear. Edit: maybe someone else can post the sounding. Looks weird on my end. Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 These seem to be low topped mini supercells typical of "500mb cold core" (although in this case more of a hybrid set up) events that often surprise Link to comment Share on other sites More sharing options...
Indystorm Posted December 1, 2018 Share Posted December 1, 2018 I am always concerned about low topped warm front tornadoes since Utica Illinois in April 2004. ACCAS across eastern MO shows instability flowing northward so I'll be watching what happens. I'm expecting a tornado watch to be issued per that meso. Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 RGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 434 NWS STORM PREDICTION CENTER NORMAN OK 215 PM CST SAT DEC 1 2018 THE NWS STORM PREDICTION CENTER HAS ISSUED A * TORNADO WATCH FOR PORTIONS OF CENTRAL ILLINOIS EAST-CENTRAL MISSOURI * EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 215 PM UNTIL 700 PM CST. * PRIMARY THREATS INCLUDE... A COUPLE TORNADOES POSSIBLE SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE SCATTERED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE SUMMARY...THUNDERSTORMS ARE FORMING ALONG THE MISSISSIPPI RIVER, AND WILL SPREAD NORTHEASTWARD ACROSS THE WATCH AREA THIS AFTERNOON. A FEW STORMS MAY BECOME SEVERE, CAPABLE OF DAMAGING WINDS, HAIL, AND PERHAPS A FEW TORNADOES. Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 2 minutes ago, Indystorm said: I am always concerned about low topped warm front tornadoes since Utica Illinois in April 2004. ACCAS across eastern MO shows instability flowing northward so I'll be watching what happens. I'm expecting a tornado watch to be issued per that meso. 62/58 at lincoln now the WF has moved north of PIA (56/54)airport and is bisecting the PIA metro Link to comment Share on other sites More sharing options...
Paulie21 Posted December 1, 2018 Share Posted December 1, 2018 Tornado on Pittsfield storm. Reported via several people. Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 LOL TOR watch for western IL where they still had 2-8 inches of snow on the ground at 6am this morning Link to comment Share on other sites More sharing options...
Paulie21 Posted December 1, 2018 Share Posted December 1, 2018 11 minutes ago, Paulie21 said: Tornado on Pittsfield storm. Reported via several people. aaaand still not tor warned...what a joke Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE ST LOUIS MO 237 PM CST SAT DEC 1 2018 THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A * TORNADO WARNING FOR... NORTHEASTERN PIKE COUNTY IN WEST CENTRAL ILLINOIS... * UNTIL 315 PM CST. * AT 237 PM CST, A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO WAS LOCATED OVER GRIGGSVILLE, MOVING NORTHEAST AT 40 MPH. HAZARD...TORNADO. SOURCE...RADAR INDICATED ROTATION. Link to comment Share on other sites More sharing options...
Indystorm Posted December 1, 2018 Share Posted December 1, 2018 Just broke into sunshine here with a patch of clearing and a beautiful full rainbow to my ne. Gonna be watching the svr storms to my west this afternoon and evening as they approach. Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 TOG again 1 Link to comment Share on other sites More sharing options...
janetjanet998 Posted December 1, 2018 Share Posted December 1, 2018 EVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE ST LOUIS MO 245 PM CST SAT DEC 1 2018 ILC149-012115- /O.COR.KLSX.TO.W.0017.000000T0000Z-181201T2115Z/ PIKE IL- 245 PM CST SAT DEC 1 2018 ...A TORNADO WARNING REMAINS IN EFFECT UNTIL 315 PM CST FOR NORTHEASTERN PIKE COUNTY IN WEST CENTRAL ILLINOIS... AT 245 PM CST, A CONFIRMED TORNADO WAS LOCATED OVER NAPLES, MOVING NORTH AT 40 MPH. HAZARD...DAMAGING TORNADO AND QUARTER SIZE HAIL. SOURCE...WEATHER SPOTTERS CONFIRMED TORNADO NEAR I-72 AND HIGHWAY 100. Link to comment Share on other sites More sharing options...
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