Tim from Springfield (IL) Posted March 28, 2012 Share Posted March 28, 2012 I don't usually like starting up severe threads, but this morning's SPC Day 2 outlook has the slight risk west of the Mississippi River for tomorrow, although the 5% threat knocks on my area's door tomorrow (our best chance of t-storms here in central Illinois is tomorrow night). Still wouldn't be surprised if western Illinois may eventually still be in play tomorrow: http://www.spc.noaa.gov/products/outlook/day2otlk.html Also a Day 3 slight already posted for Friday in parts of IN, OH, and KY, with at leats Indy, Cincy, Columbus and Louisville in play: http://www.spc.noaa.gov/products/outlook/day3otlk.html Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted March 28, 2012 Author Share Posted March 28, 2012 The afternoon Day 2 update now extends the slight risk eastward to the Quincy/Hannibal area. Also interesting that the 5% risk area is much farther east than in this morning's forcast, now roughly south of I-74 in Illinois and Indiana and extending as far east as Lexington, KY and not quite Cincy (most likely an overnight risk in the Ohio Valley tomorrow night). http://www.spc.noaa.gov/products/outlook/day2otlk.html Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted March 29, 2012 Author Share Posted March 29, 2012 The latest SPC Day 1 (slight risk now includes far western Illinois): http://www.spc.noaa.gov/products/outlook/day1otlk.html Little change on the SPC Day 2 from yesterday--IN/KY/OH still in play (mostly a wind/hail threat): http://www.spc.noaa.gov/products/outlook/day2otlk.html And let's extend this thread to round out March by including Saturday--far NW IL and SW WI (as is much of IA) in a 5% "See Text" area: http://www.spc.noaa.gov/products/outlook/day3otlk.html Link to comment Share on other sites More sharing options...
IMADreamer Posted March 29, 2012 Share Posted March 29, 2012 Just a nice slow steady rain so far here in Western Illinois. Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted March 29, 2012 Author Share Posted March 29, 2012 The latest Day 2 shifts tomorrow's slight risk much farther west--eastern IL and most of IN/OH now in play (as is far N KY): http://www.spc.noaa.gov/products/outlook/day2otlk.html ...OH VALLEY AND MID-MS VALLEY... A SUBTLE SHORTWAVE TROUGH IS FORECAST TO MOVE ESEWD ACROSS THE OH VALLEY ON FRIDAY AS A SFC LOW GRADUALLY DEEPENS...MOVING EWD ACROSS IL...IND AND OH DURING DAY. ALONG AND SOUTH OF THE TRACK OF THE LOW...SFC DEWPOINTS ARE FORECAST TO BE IN THE MID TO UPPER 50S F WITH MODERATE INSTABILITY DEVELOPING AROUND MIDDAY. MODEL FORECASTS INITIATE THUNDERSTORMS JUST TO THE NORTH OF THE SFC LOW IN THE VICINITY OF CHICAGO FRIDAY MORNING WITH THIS ACTIVITY SPREADING ESEWD ACROSS IND AND OH DURING THE AFTERNOON. FORECAST SOUNDINGS AT 21Z FRIDAY AT INDIANAPOLIS AND CINCINNATI SHOW MLCAPE VALUES FROM 1000 TO 1500 J/KG WITH STEEP MID-LEVEL LAPSE RATES NEAR 7.0 C/KM. IN ADDITION...THE ENTRANCE REGION OF A MID-LEVEL JET SHOULD MOVE ACROSS THE OH VALLEY HELPING TO ENHANCE DEEP LAYER SHEAR WITH FORECAST SOUNDINGS SHOWING 0-6 KM SHEAR IN THE 30 TO 40 KT RANGE. THE SHEAR AND THERMODYNAMIC ENVIRONMENT SHOULD SUPPORT A SEVERE THREAT AS STORMS INCREASE IN COVERAGE FRIDAY AFTERNOON. THE STORMS MAY DEVELOP INTO A LINE AS A COLD FRONT ADVANCES ESEWD ACROSS THE REGION. THIS ALONG WITH VEERED LOW-LEVEL FLOW AND 0-3 KM LAPSE RATES OF 8.5 TO 9.0 C/KM SHOULD BE FAVORABLE FOR ISOLATED WIND DAMAGE. A THREAT FOR LARGE HAIL SHOULD ALSO EXIST WITH THE GREATEST THREAT JUST TO THE SOUTH OF THE SFC LOW TRACK WHERE THE GREATEST COMBINATION OF INSTABILITY AND SHEAR IS FORECAST. Link to comment Share on other sites More sharing options...
KokomoWX Posted March 29, 2012 Share Posted March 29, 2012 Never feel good about afternoon convection when morning storms and clouds are in the forecast. Link to comment Share on other sites More sharing options...
Hoosier Posted March 29, 2012 Share Posted March 29, 2012 Never feel good about afternoon convection when morning storms and clouds are in the forecast. I haven't spent more than 5 minutes on this setup but no obvious reason to disagree with a low end threat as per the outlook. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted March 29, 2012 Share Posted March 29, 2012 I guess I am more optimistic about tomorrow's set-up. Should see clearing by Noon with a backed flow ahead and just Southeast of the surface low. That combined with pretty decent shear and a decent moisture infux should help to at least lead to some scattered severe convection with a possible transition to a squall line in the evening. Wouldn't rule out a couple tornadoes though, especially across Eastern Indiana and Western Ohio. Link to comment Share on other sites More sharing options...
Indystorm Posted March 29, 2012 Share Posted March 29, 2012 Some of the most powerful t storms I've experienced happened after morning convection cleared and the second round came later in the day. 4/27/11 had powerful a.m. storms in Alabama with clearing and then mega concerns. Not comparing this set up to that though other than to emphasize boundaries being set by morning storms and increase in low level dews that provide potential for later. Link to comment Share on other sites More sharing options...
PatrickSumner Posted March 29, 2012 Share Posted March 29, 2012 GFS continues to show a complex of storms blowing up in Northern Indiana and then moving southward toward Southern Indiana and parts of Ohio... Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted March 29, 2012 Share Posted March 29, 2012 12z HWRF for 00z tomorrow. Link to comment Share on other sites More sharing options...
PatrickSumner Posted March 29, 2012 Share Posted March 29, 2012 12z HWRF for 00z tomorrow. Do you have the images before this? Link to comment Share on other sites More sharing options...
IWXwx Posted March 30, 2012 Share Posted March 30, 2012 Never feel good about afternoon convection when morning storms and clouds are in the forecast. Some of the most powerful t storms I've experienced happened after morning convection cleared and the second round came later in the day. 4/27/11 had powerful a.m. storms in Alabama with clearing and then mega concerns. Not comparing this set up to that though other than to emphasize boundaries being set by morning storms and increase in low level dews that provide potential for later. It seems like it's a fine line sometimes. If you can get the morning crapvection out of way early enough to get some decent clearing before the front/prefrontal trough rolls through, you can get some good storms. But I've also seen many times when you just don't get the clearing and all you end up with is a second round of crapvection at best. Link to comment Share on other sites More sharing options...
Thunder Road Posted March 30, 2012 Share Posted March 30, 2012 Here's a sounding off the 0z NAM for southwest of Lima, OH at 21z. Decent low level lapse rates and good turning. Despite the SW flow at the surface, there's still adequate veering up to 700 mb, which is good enough to produce 0-3km SRH values of 200-350 in a region that overlaps with a region of 1000-2000 J/Kg of sb CAPE (although there is a sharp gradient just northeast). At this time, the NAM has a blob of precip over northern IN moving into this area, so things could get interesting in the 21z-0z time frame along I-75 in Ohio. The problem is that LCLs are rather low, and the NAM already shows a blob (rather than discrete stuff) so you would definitely have issues with rain-wrapping around cells and probably multicellular competition too. Link to comment Share on other sites More sharing options...
Hoosier Posted March 30, 2012 Share Posted March 30, 2012 lol Link to comment Share on other sites More sharing options...
Stebo Posted March 30, 2012 Share Posted March 30, 2012 lol Gotta start somewhere Link to comment Share on other sites More sharing options...
MoeWx Posted March 30, 2012 Share Posted March 30, 2012 This reminds me more of a hybrid of a summer time set up, you have a thermal ridge axis to the SW and a shortwave trough traveling ESE along the axis. And just north of where that axis is where the severe weather sets up. But this usually leads to damaging straight line winds and hail as primary threats. Of couse you have that non-zero tornado threat as well, but not feeling it for this set up. But you might get some nice shelves! (sp?) Link to comment Share on other sites More sharing options...
IWXwx Posted March 30, 2012 Share Posted March 30, 2012 This reminds me more of a hybrid of a summer time set up, you have a thermal ridge axis to the SW and a shortwave trough traveling ESE along the axis. And just north of where that axis is where the severe weather sets up. But this usually leads to damaging straight line winds and hail as primary threats. Of couse you have that non-zero tornado threat as well, but not feeling it for this set up. But you might get some nice shelves! (sp?) Thanks for chiming in Moe. Don't be a stranger. I'm looking forward to some nickles and borderline damaging wind this afternoon in these parts. If I can get off of work in time, I hope to get some pics of cloud structure. Link to comment Share on other sites More sharing options...
Bryan Wood Posted March 30, 2012 Share Posted March 30, 2012 Not a huge fan of the tornado potential today, somewhat surprised to see 5% threat from the SPC. Looks like the storms will be parallel to the upper-level winds, so we should see growth to linear rather quickly. The best bet for tornaduhs would be some squall line spin-ups if there is some localized helicity. Definitely enough shear/instability to get some decent hail, although most should be golf ball sized and under. Link to comment Share on other sites More sharing options...
KokomoWX Posted March 30, 2012 Share Posted March 30, 2012 Ok, I'll bite since I am already seeing clearing and sunshine. Link to comment Share on other sites More sharing options...
Jim Martin Posted March 30, 2012 Share Posted March 30, 2012 WRF-NMM radar at 7pm edt/6pm cdt this evening... Here is the HRRR radar image for the Great Lakes region valid also at 7pm edt/6pm cdt this evening. Seems like both of these model runs are indicating more of a linear event. Link to comment Share on other sites More sharing options...
LizardMafia Posted March 30, 2012 Share Posted March 30, 2012 Ok, I'll bite since I am already seeing clearing and sunshine. Mostly sunny here, with just a few high clouds passing through.. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted March 30, 2012 Share Posted March 30, 2012 Lots of clearing. Link to comment Share on other sites More sharing options...
Indystorm Posted March 30, 2012 Share Posted March 30, 2012 And here in Michiana from 11- noon EDT we have had a nice series of noisy t storm cells that might help to lay down a boundary to impact those of you to the south and east this afternoon. Link to comment Share on other sites More sharing options...
KokomoWX Posted March 30, 2012 Share Posted March 30, 2012 MESOSCALE DISCUSSION 0389 NWS STORM PREDICTION CENTER NORMAN OK 0112 PM CDT FRI MAR 30 2012 AREAS AFFECTED...WRN/CNTRL OH...CNTRL/SRN IND...SRN IL CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 301812Z - 301945Z THUNDERSTORM DEVELOPMENT IS FORECAST TO TAKE PLACE DURING THE NEXT FEW HRS ACROSS PORTIONS OF WRN OH SWWD INTO CNTRL IND AND SRN IL. SVR STORMS WILL BE PROBABLE...AND A WW ISSUANCE WILL LIKELY BE NEEDED BY 19-20Z. MIDDAY MESOANALYSIS PLACES AN AREA OF SURFACE LOW PRESSURE OVER NWRN IND AT 17Z...WHICH IS COINCIDENT WITH A MIDLEVEL IMPULSE MOVING E ACROSS LK MI. WARM SECTOR AIRMASS...CHARACTERIZED BY TEMPERATURES WARMING INTO THE MID TO UPR 70S WITH DEWPOINTS FROM THE MID 50S TO LOW 60S...IS BOUNDED BY A COLD FRONT EXTENDING SWWD INTO CNTRL/SRN MO...AND A WARM FRONT EXTENDING SEWD INTO ERN KY. STEEP MIDLEVEL LAPSE RATES NEAR 8 C/KM RESIDE ABOVE THE DESTABILIZING WARM SECTOR AIRMASS...AND WILL AID IN MLCAPE VALUES FROM 1000-1500 J/KG BY PEAK HEATING. MEANWHILE...AS THE AFTERNOON PROGRESSES...THE SURFACE LOW AND WARM FRONT WILL ADVANCE INTO OH...WHILE THE COLD FRONT DROPS S-SEWD TOWARD SRN IND AND IL. THE COMBINATION OF CONVERGENCE AND BOUNDARY LAYER DESTABILIZATION ALONG THE FRONT...AS WELL AS WEAK LARGE-SCALE ASCENT ASSOCIATED WITH THE PREVIOUSLY MENTIONED UPPER WAVE...SHOULD BE SUFFICIENT FOR THUNDERSTORM INITIATION ALONG THE COLD FRONT...PERHAPS AS EARLY AS 19-20Z BASED ON RECENT RUNS OF THE HRRR. MIDLEVEL WLYS RANGE FROM 50 KT NEAR THE LK MI IMPULSE...TO 20-30 KT OVER SRN IL...AND WILL YIELD SUFFICIENTLY STRONG DEEP-LAYER VERTICAL WIND SHEAR /I.E. 0-6 KM BULK WIND DIFFERENCE FROM 20-40 KT/ FOR ORGANIZED MULTICELL AND SUPERCELL STORM DEVELOPMENT. GIVEN THE LINEAR NATURE OF LOW-LEVEL FORCING ALONG THE COLD FRONT...STORMS MAY TEND TO ORGANIZE INTO LINE SEGMENTS...AND WILL POSE A THREAT FOR DAMAGING WINDS AND LARGE HAIL. CLOSER TO THE SURFACE LOW AND WARM FRONT OVER IND AND OH...SURFACE WINDS WILL BE MORE STRONGLY BACKED...WHICH WILL MAXIMIZE LOW-LEVEL VERTICAL WIND SHEAR /0-1 KM SRH AOA 150 M2 S-2/...AND INCREASE THE POTENTIAL FOR TORNADOES. ..GARNER.. 03/30/2012 ATTN...WFO...CLE...ILN...LMK...IWX...IND...PAH...ILX...LSX... Link to comment Share on other sites More sharing options...
Hoosier Posted March 30, 2012 Share Posted March 30, 2012 Looks like the threat will be south of LAF. Link to comment Share on other sites More sharing options...
KokomoWX Posted March 30, 2012 Share Posted March 30, 2012 Looks like the threat will be south of LAF. The HRRR this morning showed that exactly. Link to comment Share on other sites More sharing options...
Hoosier Posted March 30, 2012 Share Posted March 30, 2012 Severe Thunderstorm Watch just issued for parts of IN/OH. Link to comment Share on other sites More sharing options...
T Denninger Posted March 30, 2012 Share Posted March 30, 2012 About to drive through the Columbus Tor Warned storm. Link to comment Share on other sites More sharing options...
Nic Posted March 31, 2012 Share Posted March 31, 2012 About to drive through the Columbus Tor Warned storm. I saw it in my backyard, I saw very very slight rotation then it stopped. Link to comment Share on other sites More sharing options...
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