IllinoisWedges Posted March 15, 2016 Share Posted March 15, 2016 SPC's new MD has a 95% chance of a tornado watch coming in the next 1-2 hours. DISCUSSION...DEWPOINTS HAVE RISEN INTO THE MID 50S TO NEAR 60 FEARLY THIS AFTERNOON WITH TEMPERATURES FROM THE UPPER 60S TO 70S F.THIS HAS RESULTED IN WEAK DESTABILIZATION ACROSS THE MID-MS VALLEY.CONTINUED HEATING AND PERHAPS GAINS OF 1-3 DEGREES IN DEWPOINTS INTOTHE LATE AFTERNOON SHOULD RESULT IN AN UNCAPPED WEAK TO MODERATELYUNSTABLE AIRMASS...WITH FORECAST MLCAPE FROM 1500-2000 J/KG ACROSSTHE WARM SECTOR. 18Z SURFACE PRESSURE FALL ANALYSIS INDICATES THELOW NEAR KCOU SHOULD LIFT NORTHEAST ALONG THE IA/IL BORDER ANDSTORMS ARE EXPECTED TO DEVELOP IN THE VICINITY OF THE LOW BY 22Z.STEEP MIDLEVEL LAPSE RATES GREATER THAN 7.5 DEG C/KM WERE NOTED INTHE 19Z DVN RAOB. 0-6KM SHEAR INCREASING TO 50-60 KT WILL FAVORDISCRETE SUPERCELLS INITIALLY WITH VERY LARGE HAIL POSSIBLE. 0-3KMSHEAR AROUND 30 KT WILL LIMIT DAMAGING WIND CONCERNS...BUTMODERATELY FAST STORM MOTION COULD RESULT IN SPORADIC STRONG GUSTSIN THE MOST INTENSE CELLS.WHILE LOW LEVEL MOISTURE CONTINUES TO BE A CONCERN WITH REGARDS TOTHE TORNADO THREAT...A CORRIDOR OF NEAR 60 F DEWPOINTS SHOULD EXISTFROM FAR NORTHEAST MO INTO NORTHWEST IL. BACKED SURFACE WINDS WILLENHANCE LOW LEVEL HODOGRAPHS AND THE TORNADO THREAT WILL BE GREATESTIN AN AREA FROM NEAR KUNI TO KDVN EASTWARD INTO CENTRAL IL. IFFACT...THE 19Z RAOB FROM DVN SHOWED 0-3KM SRH NEAR 300 M2/S2. GIVENTHE JUXTAPOSITION OF THESE FAVORABLE CONDITIONS...A TORNADO WATCHWILL LIKELY BE NEEDED WITHIN THE NEXT 1-2 HOURS. Link to comment Share on other sites More sharing options...
Superstorm93 Posted March 15, 2016 Share Posted March 15, 2016 WHILE LOW LEVEL MOISTURE CONTINUES TO BE A CONCERN WITH REGARDS TO THE TORNADO THREAT...A CORRIDOR OF NEAR 60 F DEWPOINTS SHOULD EXIST FROM FAR NORTHEAST MO INTO NORTHWEST IL. BACKED SURFACE WINDS WILL ENHANCE LOW LEVEL HODOGRAPHS AND THE TORNADO THREAT WILL BE GREATEST IN AN AREA FROM NEAR KUNI TO KDVN EASTWARD INTO CENTRAL IL. IF FACT...THE 19Z RAOB FROM DVN SHOWED 0-3KM SRH NEAR 300 M2/S2. GIVEN THE JUXTAPOSITION OF THESE FAVORABLE CONDITIONS...A TORNADO WATCH WILL LIKELY BE NEEDED WITHIN THE NEXT 1-2 HOURS. ..LEITMAN/HART.. 03/15/2016 Link to comment Share on other sites More sharing options...
Geos Posted March 15, 2016 Share Posted March 15, 2016 I see three cells with hooks now. Link to comment Share on other sites More sharing options...
Hoosier Posted March 15, 2016 Share Posted March 15, 2016 ENH area was expanded east on the 20z outlook, almost to the Indiana border. Link to comment Share on other sites More sharing options...
Hoosier Posted March 15, 2016 Share Posted March 15, 2016 They even mentioned the storm we've all been watching for on the models: HAVE EXPANDED THE ENH AREA NEWD AND SEWD TO BETTER OVERLAP WITH THE ENHANCED LOW LEVEL SHEAR AREA...AND TO ACCOUNT FOR POSSIBLE TAIL END STORM THAT MAY EVENTUALLY FORM JUST N-NE OF THE ST. LOUIS AS DEPICTED BY MULTIPLE HIGH-RES MODELS. Link to comment Share on other sites More sharing options...
CoachLB Posted March 15, 2016 Share Posted March 15, 2016 95% Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted March 15, 2016 Share Posted March 15, 2016 Small hail reported with that elevated line that went trough the Rockford area earlier Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted March 15, 2016 Share Posted March 15, 2016 Imagine if HRRR was this consistent with showing a completely discrete/possibly tornadic supercell down in Oklahoma in May. You thought the chasemania of 5/31/13 was bad? Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 15, 2016 Share Posted March 15, 2016 Imagine if HRRR was this consistent with showing a completely discrete/possibly tornadic supercell down in Oklahoma in May. You thought the chasemania of 5/31/13 was bad? The HRRR has done that several times.. Link to comment Share on other sites More sharing options...
Hoosier Posted March 15, 2016 Share Posted March 15, 2016 Temp has risen to 66 here...been getting more sun than I expected. The question is what happens with temps later. Most models are trying to knock temps back into the upper 50s this evening, but I find that unlikely with the gradient from the approaching low which should make temps resistant to falling off much. Looking at some forecast soundings for later this evening, it seems that areas that are able to maintain temps around 62-63 and dews in the upper 50s could be enough for surface/near surface based storm sustenance so those are sort of my benchmark values to watch for later. Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted March 15, 2016 Share Posted March 15, 2016 Temp has risen to 66 here...been getting more sun than I expected. The question is what happens with temps later. Most models are trying to knock temps back into the upper 50s this evening, but I find that unlikely with the gradient from the approaching low which should make temps resistant to falling off much. Looking at some forecast soundings for later this evening, it seems that areas that are able to maintain temps around 62-63 and dews in the upper 50s could be enough for surface/near surface based storm sustenance so those are sort of my benchmark values to watch for later. 64 here, but the dp has stagnated at ~57. Judging by the hail reports from the Rockford area earlier, I think hail is a good shot with any storm that rolls through up here. Link to comment Share on other sites More sharing options...
monsoonman1 Posted March 15, 2016 Share Posted March 15, 2016 70/50 tornado probs on the new watch Link to comment Share on other sites More sharing options...
Superstorm93 Posted March 15, 2016 Share Posted March 15, 2016 70/50 tornado probs on the new watch * PRIMARY THREATS INCLUDE...A FEW TORNADOES LIKELY WITH A COUPLE INTENSE TORNADOES POSSIBLE WIDESPREAD LARGE HAIL EXPECTED WITH ISOLATED VERY LARGE HAIL EVENTS TO 3 INCHES IN DIAMETER POSSIBLE SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE SUMMARY...THUNDERSTORMS ARE EXPECTED TO INTENSIFY RAPIDLY OVER NORTHEAST MO AND TRACK NORTHEASTWARD ACROSS THE WATCH AREA THIS AFTERNOON AND EVENING. CONDITIONS ARE FAVORABLE FOR A FEW INTENSE SUPERCELL STORMS CAPABLE OF VERY LARGE HAIL AND TORNADOES. THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 95 STATUTE MILES NORTH AND SOUTH OF A LINE FROM 50 MILES WEST NORTHWEST OF QUINCY ILLINOIS TO 20 MILES SOUTH SOUTHEAST OF MARSEILLES ILLINOIS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR TORNADOES AND 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. Link to comment Share on other sites More sharing options...
jojo762 Posted March 15, 2016 Share Posted March 15, 2016 Impressive probs on the watch. Makes me a bit surprised they didn't add a hatched area to the 20Z tornado probabilities. Link to comment Share on other sites More sharing options...
Geos Posted March 15, 2016 Share Posted March 15, 2016 Small hail reported with that elevated line that went trough the Rockford area earlier Those storms crapped out quick. Holding steady at 46° with a little more sun now. Dewpoint 42° Some CU starting to pop in west of STL. Link to comment Share on other sites More sharing options...
Hoosier Posted March 15, 2016 Share Posted March 15, 2016 Numerous places now in central/southern IL with dews AOA 60. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 15, 2016 Share Posted March 15, 2016 Secondary target to watch would be further north up near and just SW of 80/39 as the gradient tightens there with continued heating just to the south and strongly backed sfc winds with some lower LCL's then further south Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted March 15, 2016 Share Posted March 15, 2016 A livestreamer is in Bowling Green, MO... just NNW of STL... just waiting and watching the clouds. Finally starting to see some good progress. https://tvnweather.com/live/chasers/847783786 Link to comment Share on other sites More sharing options...
Indystorm Posted March 15, 2016 Share Posted March 15, 2016 The system is exceeding expectations according to Gil at NIU. It was forecast to be cloudy over the warm sector today which obviously did not occur and only enhances instability. This could be a very interesting evening. Surprised at the high prob for tornado and moderate for EF-2 or greater with this watch. Link to comment Share on other sites More sharing options...
Stebo Posted March 15, 2016 Share Posted March 15, 2016 Nice group of agitated cu in NE MO, I would expect something to pop within the hour. Link to comment Share on other sites More sharing options...
Geos Posted March 15, 2016 Share Posted March 15, 2016 19z HRRR Pretty sharp dewpoint gradient between Chicago and Joliet right now. Near 40° downtown and 60° near I -80 now. Link to comment Share on other sites More sharing options...
Roger Smith Posted March 15, 2016 Share Posted March 15, 2016 Late starter, would expect this to last well into the night as cells move into IN and nw OH. Just mentioning this because I don't think it will be confined to n/c IL although it's obviously about to explode there. I would have a tornado watch box ready for n/c IN 00z-04z. Dangerous night-time severe storms, use the continuous lightning to your WSW warning theme. Link to comment Share on other sites More sharing options...
Superstorm93 Posted March 15, 2016 Share Posted March 15, 2016 Almost time... Link to comment Share on other sites More sharing options...
Stebo Posted March 15, 2016 Share Posted March 15, 2016 Might have initiation WNW of Hannibal Missouri NE of Macon. Ascent is moving in right on cue. Link to comment Share on other sites More sharing options...
Superstorm93 Posted March 15, 2016 Share Posted March 15, 2016 Link to comment Share on other sites More sharing options...
Thundersnow12 Posted March 15, 2016 Share Posted March 15, 2016 I'd be watching this northern target closely..theta-e gradient continues to tightened with continued warm air/moisture advection and destabilization with strongly backed sfc winds. Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted March 15, 2016 Share Posted March 15, 2016 Looks like we have our first radar returns SE of Kirksville in Mo. Expecting it to develop quickly and head right into the radar hole. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted March 15, 2016 Share Posted March 15, 2016 That's not good Link to comment Share on other sites More sharing options...
Superstorm93 Posted March 15, 2016 Share Posted March 15, 2016 Yeah, looks like we have our first cell starting to go up near Novelty, MO Right into the great Radar Hole of Death Link to comment Share on other sites More sharing options...
Chinook Posted March 15, 2016 Share Posted March 15, 2016 Yeah, looks like we have our first cell starting to go up near Novelty, MO Right into the great Radar Hole of Death Want to start a fundraiser to fund a Kirksville NEXRAD? Link to comment Share on other sites More sharing options...
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