LouWX Posted January 28, 2013 Share Posted January 28, 2013 LMK has a good AFD to read this afternoon. Very amped about SVR and even wake low threat. Link to comment Share on other sites More sharing options...
hoosierwx Posted January 28, 2013 Share Posted January 28, 2013 Speed and directional shear parameters are more than impressive with this setup as we will likely have somewhat backed (SSE) surface winds around 20-25 knots, overlayed by SSW winds increasing to 55 knots at 925 mb and 80 knots at 850. This is yielding some off the charts storm relative helicity values well over 1000 m2/s2 in the 0-3 km range in well above 500 m2/s2 in the 01-km range. It goes without saying the shear will be there. It appears we will have some surface based instability to work with as well with temperatures hanging in the low to mid 60s through the night and dew points around 60. Feel that the forecast models/soundings have a pretty good handle on the thermodynamic profile at this time, and this should yield surface based CAPE values in the 100-500 J/KG range. The higher ranges look to be across south central Kentucky. It is interesting to note that upper 50s and low 60s dew points are already pooling across southern MO and we still have 36-42 hours of warm/moist advection before the event. Instability values may even be a bit underdone at this point. Despite, a small magnitude of surface based instability, the strongly forced line of storms combined with incredible low level shear values is likely to produce a severe QLCS, with mesovortices and bowing segments. The only real uncertainty is how widespread severe events will be. One concern is that shear may be too strong for updrafts to really get organized and could limit how widespread big impacts could be. As was mentioned, strong forcing may offset this. The main threats will be damaging winds, which could end up being widespread and of a higher magnitude than a typical severe squall line. Additional threats will be isolated tornadoes with mesovortices and bowing segments, and heavy rainfall. Around an inch to an inch and a half is expected in most spots, with up to 2 inches possible as trailing moderate stratiform rain persists behind the leading line. LMK liking our chances. Link to comment Share on other sites More sharing options...
LouWX Posted January 29, 2013 Share Posted January 29, 2013 0z NAM is a little different and has best instability behind initial convective line. Seems strange. Link to comment Share on other sites More sharing options...
Indystorm Posted January 29, 2013 Share Posted January 29, 2013 That 130-150 knot 300 mb jet looks ferocious looping the trough. Certainly the kinematics are there. Will there be the instability? Link to comment Share on other sites More sharing options...
LouWX Posted January 29, 2013 Share Posted January 29, 2013 0z NAM is a little different and has best instability behind initial convective line. Seems strange. The 4km NAM is more realistic and has the CAPE of 100-500 ahead of the line. If temps are in the mid to upper 60s and overperform this line could be really mean. Link to comment Share on other sites More sharing options...
jhamps10 Posted January 29, 2013 Share Posted January 29, 2013 The 4km NAM is more realistic and has the CAPE of 100-500 ahead of the line. If temps are in the mid to upper 60s and overperform this line could be really mean. yeah, if temps overperform.. I mean it was in the upper 60's as far north as Jacksonville, IL today.. I think I seen it got up to 69 there, most forecasts were in the upper 50's for West Central Illinois today. it's 57 here in Charleston right now with fog so thick you could barely see more than a block or 2.. this one has my eyes peeled. Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 29, 2013 Share Posted January 29, 2013 Nice area of elevated convection in IA/IL. Already several small hail reports. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 29, 2013 Share Posted January 29, 2013 Nice area of elevated convection in IA/IL. Already several small hail reports. nickel hail in Ladd, IL. Link to comment Share on other sites More sharing options...
jdrenken Posted January 29, 2013 Share Posted January 29, 2013 Temps overachieving in Missouri right now (70s as far north as I-70). This will be important to watch tomorrow. Yep...Columbia, MO tied their January all time record of 77°. Link to comment Share on other sites More sharing options...
OceanStWx Posted January 29, 2013 Share Posted January 29, 2013 Both the ILX and DVN 00z soundings have a nice 150 mb (~800 to 650 mb) layer of dry adiabatic lapse rates. Certainly helping things along tonight. Link to comment Share on other sites More sharing options...
cyclone77 Posted January 29, 2013 Share Posted January 29, 2013 Cell south of Mount Carroll IL up to 34kft with a nice core. Could be a potential warner if it maintains/strengthens. Link to comment Share on other sites More sharing options...
OceanStWx Posted January 29, 2013 Share Posted January 29, 2013 Cell south of Mount Carroll IL up to 34kft with a nice core. Could be a potential warner if it maintains/strengthens. Nice little ZDR column on that cell, a strong updraft. The ZDR shows a lot of water droplets on the southwest side of the highest dBZ, this is the updraft. Link to comment Share on other sites More sharing options...
Thunder Road Posted January 29, 2013 Share Posted January 29, 2013 Not sure I buy the 67 dBZ, and associated 1.75" hail marker, on cell J0 southwest of Joliet. I have to admit, that complex caught me completely off guard. Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 29, 2013 Share Posted January 29, 2013 Not sure I buy the 67 dBZ, and associated 1.75" hail marker, on cell J0 southwest of Joliet. I have to admit, that complex caught me completely off guard. PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE CHICAGO IL 916 PM CST MON JAN 28 2013 /1016 PM EST MON JAN 28 2013/ ..KLOT WSR-88D REMAINS OUT OF CALIBRATION ALL USERS OF THE KLOT WSR-88D ARE REMINDED THAT AFTER FRIDAYS SOFTWARE FAILURE THE KLOT WSR-88D IS OUT OF CALIBRATION AND RUNNING HOT. REFLECTIVITY VALUES APPEAR TO BE RUNNING 10 TO EVEN 15 DBZ TO HIGH. TECHNICIANS ARE AWARE OF THE PROBLEM AND WAITING FOR PARTS TO ARRIVE. IN THE MEANTIME...PLEASE USE CAUTION IN INTERPRETING REFLECTIVITY DATA. Link to comment Share on other sites More sharing options...
cyclone77 Posted January 29, 2013 Share Posted January 29, 2013 DVN_1.png Nice little ZDR column on that cell, a strong updraft. The ZDR shows a lot of water droplets on the southwest side of the highest dBZ, this is the updraft. Very cool. Love the dual-pol addition. Very valuable tool to be sure. Link to comment Share on other sites More sharing options...
Thunder Road Posted January 29, 2013 Share Posted January 29, 2013 PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE CHICAGO IL 916 PM CST MON JAN 28 2013 /1016 PM EST MON JAN 28 2013/ ..KLOT WSR-88D REMAINS OUT OF CALIBRATION ALL USERS OF THE KLOT WSR-88D ARE REMINDED THAT AFTER FRIDAYS SOFTWARE FAILURE THE KLOT WSR-88D IS OUT OF CALIBRATION AND RUNNING HOT. REFLECTIVITY VALUES APPEAR TO BE RUNNING 10 TO EVEN 15 DBZ TO HIGH. TECHNICIANS ARE AWARE OF THE PROBLEM AND WAITING FOR PARTS TO ARRIVE. IN THE MEANTIME...PLEASE USE CAUTION IN INTERPRETING REFLECTIVITY DATA. Well, that certainly makes a lot of sense. Didn't notice that, thanks for posting. I guess I'll switch over to TMDW. Link to comment Share on other sites More sharing options...
Hoosier Posted January 29, 2013 Share Posted January 29, 2013 MESOSCALE DISCUSSION 0063 NWS STORM PREDICTION CENTER NORMAN OK 0959 PM CST MON JAN 28 2013 AREAS AFFECTED...CNTRL/ERN IA...NRN IL...FAR SRN WI CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 290359Z - 290600Z PROBABILITY OF WATCH ISSUANCE...5 PERCENT SUMMARY...MOSTLY SMALL HAIL BUT ISOLATED HAIL TO 1 INCH IN DIAMETER SHOULD PERSIST NEXT FEW HOURS WITHIN AN EXPANDING AREA OF ELEVATED TSTMS DEVELOPING E/NEWD FROM THE I-80 CORRIDOR. DISCUSSION...ROBUST LOW-LEVEL WARM THETA-E ADVECTION AIDED BY A 55 KT LLJ ACROSS THE MID-MO VALLEY WILL SUPPORT PERSISTENT ELEVATED TSTM DEVELOPMENT N OF AN ARCING WARM FRONT ALONG THE MO/IA BORDER TO SRN IL. MUCAPE WILL REMAIN WEAK WITH MODEST MID-LEVEL LAPSE RATES AROUND 6.5 C/KM PER 00Z TOP RAOB. NEVERTHELESS...SUFFICIENT CLOUD-BEARING SHEAR DOES EXIST FOR ORGANIZED MULTICELL CLUSTERS CAPABLE OF PRODUCING ISOLATED MARGINALLY SEVERE HAIL. ..GRAMS/HART.. 01/29/2013 Link to comment Share on other sites More sharing options...
OceanStWx Posted January 29, 2013 Share Posted January 29, 2013 I was just about to say there is a nice little cell approaching the south side, but LOT beat me to it with the SVR. Link to comment Share on other sites More sharing options...
frostfern Posted January 29, 2013 Share Posted January 29, 2013 Well, that certainly makes a lot of sense. Didn't notice that, thanks for posting. I guess I'll switch over to TMDW. I noticed the radar correlating too bright compared to the surrounding stations yesterday. At one point it was showing a dubious blob of 55 dbz snow bright banding over Lake Michigan. With a correctly calibrated radar it's pretty hard to get a reflectivity above 45 dbz from non-convective precip. Link to comment Share on other sites More sharing options...
Stebo Posted January 29, 2013 Share Posted January 29, 2013 Severe for quarter sized hail South of Chicago and along the Lake Michigan shoreline in Indiana. 50+ dBZ to almost 30000' per IWX's radar as well. Link to comment Share on other sites More sharing options...
Hoosier Posted January 29, 2013 Share Posted January 29, 2013 Quarter size hail report near Chicago Heights. Link to comment Share on other sites More sharing options...
cyclone77 Posted January 29, 2013 Share Posted January 29, 2013 Severe for quarter sized hail South of Chicago and along the Lake Michigan shoreline in Indiana. Yep a report of 1" hail by the public south of Chicago Heights. Pretty impressive cell there heading towards Tornado Tonyville. Link to comment Share on other sites More sharing options...
Stebo Posted January 29, 2013 Share Posted January 29, 2013 Looks like it will skirt just North of Valpo Link to comment Share on other sites More sharing options...
Stebo Posted January 29, 2013 Share Posted January 29, 2013 Yep a report of 1" hail by the public south of Chicago Heights. Pretty impressive cell there heading towards Tornado Tonyville. Tony is now in AL, but Thunder Road is there. Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 29, 2013 Share Posted January 29, 2013 1116 PM HEAVY RAIN 3 WSW CHICAGO HEIGHTS 41.49N 87.68W01/28/2013 M1.13 INCH COOK IL COCORAHSRAIN FELL IN 30 MINUTES Link to comment Share on other sites More sharing options...
cyclone77 Posted January 29, 2013 Share Posted January 29, 2013 Tony is now in AL, but Thunder Road is there. Ahh that's true lol. Gotta love the 4" hail marker from the LOT radar with this thing. Link to comment Share on other sites More sharing options...
Chicago WX Posted January 29, 2013 Share Posted January 29, 2013 Kinda weird looking, with the fog advisories. Link to comment Share on other sites More sharing options...
Sidewinder Posted January 29, 2013 Share Posted January 29, 2013 Warning looks to have been allowed to expire. Decent looking new cell forming near Hebron now Link to comment Share on other sites More sharing options...
Thunder Road Posted January 29, 2013 Share Posted January 29, 2013 Yep a report of 1" hail by the public south of Chicago Heights. Pretty impressive cell there heading towards Tornado Tonyville. I just assumed you meant Schererville, since that's where he lives. Looks like it will skirt just North of Valpo Yup. Nothing more than a few rumbles here. Fog is still thick. Tony is now in AL, but Thunder Road is there. But I could never live up. The man has become a legend in our department, haha. Link to comment Share on other sites More sharing options...
Thunder Road Posted January 29, 2013 Share Posted January 29, 2013 I spoke too soon. This little guy that popped up southwest of us is giving us a good soaking as I speak. Link to comment Share on other sites More sharing options...
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