Upper Level LOL Posted February 28, 2017 Share Posted February 28, 2017 Man, this seems to have gotten more and more threatening as time went by, rather than the inverse which is more common. Gonna be a long night for folks along the OH river northward. Link to comment Share on other sites More sharing options...
andyhb Posted February 28, 2017 Author Share Posted February 28, 2017 Looks like we got initiation ENE of SGF. Link to comment Share on other sites More sharing options...
SmokeEater Posted February 28, 2017 Share Posted February 28, 2017 3 minutes ago, andyhb said: Looks like we got initiation ENE of SGF. South of Joplin too. Link to comment Share on other sites More sharing options...
yoda Posted February 28, 2017 Share Posted February 28, 2017 http://www.spc.noaa.gov/products/md/md0218.html Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 28, 2017 Share Posted February 28, 2017 convection getting going southern IA too Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted February 28, 2017 Share Posted February 28, 2017 Another new MD http://www.spc.noaa.gov/products/md/md0219.html Watch coming for large area Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 28, 2017 Share Posted February 28, 2017 MESOSCALE DISCUSSION 0219 NWS STORM PREDICTION CENTER NORMAN OK 0203 PM CST TUE FEB 28 2017 AREAS AFFECTED...PORTIONS OF NORTHERN IL...NORTHERN IN...SOUTHEAST IA...EXTREME NORTHEAST MO CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY VALID 282003Z - 282230Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...THE AREA IS BEING MONITORED FOR INCREASING SEVERE-THUNDERSTORM POTENTIAL, INCLUDING THE RISK FOR TORNADOES, SEVERE HAIL (POSSIBLY SIGNIFICANT), AND DAMAGING WIND GUSTS. THE ISSUANCE OF A TORNADO WATCH WILL LIKELY BE REQUIRED DURING THE NEXT FEW HOURS. DISCUSSION...A NORTHWEST-SOUTHEAST-ORIENTED WARM FRONT EXTENDING FROM SURFACE LOW PRESSURE IN NORTHEASTERN IA TO SOUTHERN IN WILL CONTINUE TO DEVELOP NORTHEASTWARD, AS THE LEADING EDGE OF A HIGH-LEVEL SPEED MAXIMUM ALSO SPREADS NORTHEASTWARD. RECENT WATER VAPOR IMAGERY INDICATES A NOTABLE SURGE OF MIDLEVEL DRYING ADVANCING THROUGH CENTRAL IA, LIKELY ASSOCIATED WITH AN IMPULSE EMBEDDED WITHIN THE FLOW ALOFT. AS FORCING FOR ASCENT ASSOCIATED WITH THESE FEATURES CONTINUES TO OVERSPREAD THE NORTHEASTWARD-DEVELOPING WARM SECTOR (WHERE MODEST PRESSURE FALLS ARE OBSERVED), CONVECTION SHOULD INCREASE IN COVERAGE/INTENSITY DURING THE NEXT SEVERAL HOURS. ALREADY, ISOLATED ELEVATED CONVECTION HAS BEEN INTENSIFYING NORTHEAST OF THE WARM FRONT IN EAST-CENTRAL IL, WITH ADDITIONAL CONVECTION INCREASING IN THE OPEN WARM SECTOR ACROSS SOUTH-CENTRAL IA. DESPITE THE RETURN OF ONLY MODEST BOUNDARY-LAYER MOISTURE (SURFACE DEWPOINTS IN THE MIDDLE 50S TO AROUND 60F), STEEP MIDLEVEL LAPSE RATES ASSOCIATED WITH A WELL-ESTABLISHED ELEVATED MIXED LAYER OVERLYING THE AREA WILL SUPPORT SUFFICIENT BUOYANCY FOR INTENSE UPDRAFTS. WITH 40-60 KT OF EFFECTIVE SHEAR, ROTATING UPDRAFTS WILL LIKELY BE CAPABLE OF PRODUCING SEVERE HAIL -- POSSIBLY SIGNIFICANT. DAMAGING WIND GUSTS AND TORNADO POTENTIAL WILL EXIST, ESPECIALLY NEAR AND SOUTH/SOUTHWEST OF THE WARM FRONT, WHERE EFFECTIVE INFLOW LAYERS WILL EXTEND TO THE SURFACE. SIGNIFICANT TORNADOES COULD EVEN OCCUR OWING TO AMPLE STREAMWISE VORTICITY IN THE BOUNDARY LAYER (EFFECTIVE SRH AROUND 200-400 M2/S2), AND ESPECIALLY IN PROXIMITY TO THE WARM FRONT GIVEN PRE-EXISTING VERTICAL VORTICITY. THERE IS SOME UNCERTAINTY REGARDING THE TIMING OF THE MORE ROBUST INCREASE OF SURFACE-BASED CONVECTIVE RISK. REGARDLESS, THE RISK FOR ALL SEVERE HAZARDS WILL BE INCREASING, LIKELY WARRANTING TORNADO WATCH ISSUANCE DURING THE NEXT FEW HOURS. Link to comment Share on other sites More sharing options...
Chambana Posted February 28, 2017 Share Posted February 28, 2017 Having a hard time clearing out. Not sure if this was forecasted or not. Springfield is at 72 while champaign is at 59. Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 28, 2017 Share Posted February 28, 2017 Having a hard time clearing out. Not sure if this was forecasted or not. Springfield is at 72 while champaign is at 59. Wasn't really expected to clear much anywhere. Destabilization is advection driven. Link to comment Share on other sites More sharing options...
CoachLB Posted February 28, 2017 Share Posted February 28, 2017 Link to comment Share on other sites More sharing options...
Central Illinois Posted February 28, 2017 Share Posted February 28, 2017 weather radio just went off NEW Tornado Watch for SW IL till 9pm Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 28, 2017 Share Posted February 28, 2017 HE NWS STORM PREDICTION CENTER HAS ISSUED A * TORNADO WATCH FOR PORTIONS OF SOUTHERN AND WEST-CENTRAL ILLINOIS EXTREME SOUTHEAST KANSAS CENTRAL AND SOUTHERN MISSOURI * EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 215 PM UNTIL 900 PM CST. * PRIMARY THREATS INCLUDE... A FEW TORNADOES LIKELY WITH A COUPLE INTENSE TORNADOES POSSIBLE SCATTERED LARGE HAIL LIKELY WITH ISOLATED VERY LARGE HAIL EVENTS TO 3 INCHES IN DIAMETER POSSIBLE SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE SUMMARY...WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO AFFECT THE WATCH AREA THIS AFTERNOON AND EVENING, WITH A FEW SEVERE STORMS LIKELY. VERY LARGE HAIL AND ISOLATED TORNADOES WILL BE POSSIBLE IN THE MORE INTENSE STORMS. Link to comment Share on other sites More sharing options...
weunice Posted February 28, 2017 Share Posted February 28, 2017 70/30 probs on the tornadoes (2+ count and EF2+) Link to comment Share on other sites More sharing options...
jojo762 Posted February 28, 2017 Share Posted February 28, 2017 2 minutes ago, weunice said: 70/30 probs on the tornadoes (2+ count and EF2+) Surprised that it is only 70/30. At least expected the sig tor probability to be higher. Link to comment Share on other sites More sharing options...
weunice Posted February 28, 2017 Share Posted February 28, 2017 Tornado ... possible language introduced into the lone SVR warned cell out right now. Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 28, 2017 Share Posted February 28, 2017 TCU and weak returns over southern AR IA storms looking interesting Link to comment Share on other sites More sharing options...
Quincy Posted February 28, 2017 Share Posted February 28, 2017 7 minutes ago, jojo762 said: Surprised that it is only 70/30. At least expected the sig tor probability to be higher. The sig tor potential likely peaks this evening and note that the watch ends at 9 p.m. Look for a downstream PDS tor watch tonight IF storms remain discrete as they move toward the Ohio River and the LLJ really cranks. Link to comment Share on other sites More sharing options...
andyhb Posted February 28, 2017 Author Share Posted February 28, 2017 Looks like some locally backed flow near/E of St. Louis via most recent obs. Would probably enhance tornado potential with the current cell once it makes it there. Fortunately does not appear to be heading right for the St. Louis area. Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 28, 2017 Share Posted February 28, 2017 looks like we have a splitter lefty may moving onto STL metro Link to comment Share on other sites More sharing options...
Quincy Posted February 28, 2017 Share Posted February 28, 2017 20z sounding from DVN: Link to comment Share on other sites More sharing options...
andyhb Posted February 28, 2017 Author Share Posted February 28, 2017 Need more mixing of the BL/moisture advection at 850 mb though. MLCAPE going to struggle until that happens. Tornado watch coming to the north. Link to comment Share on other sites More sharing options...
janetjanet998 Posted February 28, 2017 Share Posted February 28, 2017 DVN/MLI metro may have a mini SUP problem near low Link to comment Share on other sites More sharing options...
Central Illinois Posted February 28, 2017 Share Posted February 28, 2017 New Tornado Watch about to be issued for E IA NE MO N IL and NW IN Link to comment Share on other sites More sharing options...
geddyweather Posted February 28, 2017 Share Posted February 28, 2017 3 minutes ago, Central Illinois said: New Tornado Watch about to be issued for E IA NE MO N IL and NW IN Just came out. EDIT: Only 50/20 tornado probs. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted February 28, 2017 Share Posted February 28, 2017 300 PM CST Tue Feb 28 2017 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southeast Iowa Northern and Central Illinois Northwest Indiana Northeast Missouri Lake Michigan * Effective this Tuesday afternoon and evening from 300 PM until 1000 PM CST. * Primary threats include... A few tornadoes possible Scattered large hail likely with isolated very large hail events to 3 inches in diameter possible Scattered damaging wind gusts to 70 mph possible Link to comment Share on other sites More sharing options...
jojo762 Posted February 28, 2017 Share Posted February 28, 2017 50/20 probs on the new watch. Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted February 28, 2017 Share Posted February 28, 2017 Mentions possibility of 3" hail Link to comment Share on other sites More sharing options...
OceanStWx Posted February 28, 2017 Share Posted February 28, 2017 Don't hate the environment along and S of I-80 in western IL right now. Weak moisture boundary sitting there and slightly backed flow. Link to comment Share on other sites More sharing options...
buckeye Posted February 28, 2017 Share Posted February 28, 2017 ILN : Haven't seen a discussion like this in some time....just a portion: If storms come through while still somewhat elevated, the tornado threat would be reduced. However, if the boundary layer warms/saturates and allows for surface-based parcels, the tornado threat could be significant. Thus, this will be a crucial part of mesoscale analysis going through the evening. Shear profiles of this magnitude do not frequently combine with perfectly favorable low-level thermodynamics, but when they do, the results speak for themselves. This is the biggest potential threat that will have to be examined tonight into Wednesday morning -- a conditional not-just-low-end tornado threat, combined with a slightly greater level of confidence in large hail potential, and some attendant damaging wind potential as well (depending on boundary layer destabilization). ......... In terms of messaging, it is very important to get the word out that these threats will be occurring at non-standard times, continuing through the night, and quite likely into Wednesday morning (details of which are covered below). Given that there is a risk of severe weather that may be greater than just a low-end marginal event, it is crucial for people to have ways of receiving warning information during the off-typical-peak and extended hours that this severe weather may occupy. Link to comment Share on other sites More sharing options...
tuanis Posted February 28, 2017 Share Posted February 28, 2017 When's the last time the Chicago metro was under a TOR watch in February? Link to comment Share on other sites More sharing options...
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