Tim from Springfield (IL) Posted April 25, 2017 Share Posted April 25, 2017 Hefty rain totals expected between now and month's end for most of the subforum: Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted April 25, 2017 Author Share Posted April 25, 2017 Also a Slight Risk today including part of MO: http://www.spc.noaa.gov/products/outlook/day1otlk.html Wednesday looking interesting in at least the south part of this subforum--SPC has a hatched area from AR all the way to St. Louis (Enhanced Risk), with most of central/S IL in Slight: http://www.spc.noaa.gov/products/outlook/day2otlk.html ...Southern Plains and lower to middle Mississippi Valley... Strengthening low-level jet induced by the approaching shortwave trough will advect mid to upper 60s F boundary-layer dewpoints through the pre-frontal warm sector beneath 7-7.5 C/km mid-level lapse rates. These processes will contribute to moderate instability with 1500-2500 J/kg MLCAPE, despite the potential for widespread low clouds which will limit diabatic warming in some areas. Thunderstorms will likely be in progress within baroclinic zone and along warm conveyor belt from portions of OK into MO, and some of this activity could pose an ongoing modest risk for a few strong wind gusts and hail. However, primary development of severe storms is expected during the afternoon as storms intensify along and just ahead of the cold front and in association with a destabilizing warm sector. Strong dynamic forcing for ascent within frontal zone augmented by the negatively tilted shortwave trough and strengthening low-level jet will likely result in the initiation of numerous storms and an eventual upscale linear growth. Strong deep-layer winds, vertical shear and large low-level hodographs will favor organized storms including embedded supercells and bowing segments, with all severe hazards possible. ...Illinois into the Great Lakes... Instability and low-level moisture will be less in this region compared to farther south but sufficient for an organized severe threat given favorable wind profiles. The stronger storms will likely expand into this region during the late afternoon and evening, with a few supercells and bowing linear segments capable of damaging wind, large hail and a couple of tornadoes. ..Dial.. 04/25/2017 Then marginal on Thursday before most of the severe possibilities appear to be to our south, or even in the southern fringes of our subforum, for the weekend. Link to comment Share on other sites More sharing options...
Chambana Posted April 25, 2017 Share Posted April 25, 2017 NAM-3km had a nice looking QLCS affecting parts of MO and IL tomorrow evening. Link to comment Share on other sites More sharing options...
RCNYILWX Posted April 25, 2017 Share Posted April 25, 2017 NAM-3km had a nice looking QLCS affecting parts of MO and IL tomorrow evening. With a lead supercell right across the Chicago metro during the early evening. Link to comment Share on other sites More sharing options...
Hoosier Posted April 25, 2017 Share Posted April 25, 2017 4 hours ago, RCNYILWX said: With a lead supercell right across the Chicago metro during the early evening. It's been suggesting the possibility of lead cell(s) on multiple runs now. Link to comment Share on other sites More sharing options...
Hoosier Posted April 25, 2017 Share Posted April 25, 2017 This seems fairly unique... marginal from the UP of Michigan all the way to the Gulf Coast. Link to comment Share on other sites More sharing options...
Central Illinois Posted April 25, 2017 Share Posted April 25, 2017 12z GFS/CMC is gonna be big in terms of rainfall Link to comment Share on other sites More sharing options...
Central Illinois Posted April 25, 2017 Share Posted April 25, 2017 Link to comment Share on other sites More sharing options...
Hoosier Posted April 25, 2017 Share Posted April 25, 2017 ^pretty good agreement given the timeframe we are talking about. Row row row your boat. With convection involved, could alter the location a bit and possibly even result in some higher totals. Link to comment Share on other sites More sharing options...
snowlover2 Posted April 25, 2017 Share Posted April 25, 2017 Enhanced area shifted north into SW IL for tomorrow. Quote Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Tue Apr 25 2017 Valid 261200Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS ARKANSAS AND INTO SOUTHERN MISSOURI AND SOUTHWEST ILLINOIS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE ARKLATEX AND LOWER MISSISSIPPI VALLEY NORTHWARD INTO ILLINOIS... ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IMMEDIATELY SURROUNDING THE SLIGHT RISK AREA... ...SUMMARY... Severe thunderstorms with damaging winds, a few tornadoes and some hail are expected across much of Arkansas and southern Missouri Wednesday. Isolated severe thunderstorms with damaging wind are also expected across Illinois during the day and across the lower Mississippi Valley overnight. ...Synopsis... A potent shortwave trough will move from the southern Plains northeastward across the middle MS valley with a surface trough extending from WI into AR at 00Z. Strong large-scale lift will exist resulting in widespread strong to severe thunderstorm activity throughout the day. The most intense storms are expected over AR and across southern MO, beneath strong southwesterly flow aloft with activity focused along the advancing front. All modes of severe will be possible, with damaging wind the most prominent threat. A few strong bows may trek northeastward across much of Illinois as well. Southern portions of this front will progress across the lower MS valley overnight, focusing a damaging wind threat into MS and western TN with a slowly decreasing threat with eastward extent. ...Arklatex northeastward across Illinois... Storms are expected to be ongoing Wednesday morning along an outflow/front composite boundary extending from eastern OK into southwest MO. This activity should be elevated with hail, but damaging wind will also be possible with storms right on the boundary. With time, lift along the front will intensify as cooling aloft overspreads the area and the air mass destabilizes further. Strong mean winds and linear forcing suggest damaging serial bows are possible. Depending on storm motion relative to boundary orientation, a few storms could rotate with a tornado threat as low-level shear will remain sufficient and moisture will be abundant, especially over AR. A 50 kt low-level jet will extend northward into IL as well, supporting a few fast-moving bows into that area during the day. Instability will wane with northward extent, however, the favorable synoptic setup could yield severe wind to Chicago. ...Lower Mississippi Valley... A cold front/outflow boundary is likely to progress eastward across the lower MS valley Wednesday evening into the night, with a continued damaging wind threat. While the strongest activity should remain to the northwest closer to the main shortwave trough, ample moisture and instability will remain across the region. Some capping inversion is expected to precede the front, which should limit any severe storms to the squall line. As such, any tornado threat should be low/brief, as low-level winds will be more veered closer to the front where storms will exist. Storms should generally weaken into AL into Thursday morning, with the best chance of isolated damaging gusts across southern portions where instability will be greatest. ..Jewell.. 04/25/2017 Link to comment Share on other sites More sharing options...
janetjanet998 Posted April 25, 2017 Share Posted April 25, 2017 worried about flooding here....although its been dry the past week or so the IL river is still rather high from the wet start of the month..soil moisture is above average in NE IL usually outflows will cause the set up to be a little more SE then modeled..the areas along the OH river seems to get these extreme rain events more then north central IL one expection was april of 2013 that caused record flooding on the IL river here..when areas from PIA to ORD got back to back training events within few days If someone could post the EURO total precip from this morning that would be great looks the the 1st event will could be the primer for this wekend Link to comment Share on other sites More sharing options...
Hoosier Posted April 26, 2017 Share Posted April 26, 2017 Link to comment Share on other sites More sharing options...
Hoosier Posted April 26, 2017 Share Posted April 26, 2017 Messy setup tomorrow. Definitely some concerns with how upstream activity affects instability downstream. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted April 26, 2017 Share Posted April 26, 2017 Day 2 Outlook ..OHIO VALLEY AND GREAT LAKES THE FEED OF RICHER LOW-LEVEL MOISTURE WILL BECOME LIMITED AS THE CYCLONE OCCLUDES OVER THE GREAT LAKES REGION. HOWEVER, AT LEAST MARGINAL INSTABILITY WITHIN A STRONG SHEAR ENVIRONMENT WILL EXIST IN PRE-FRONTAL WARM SECTOR, AND STORMS MIGHT POSE SOME RISK FOR A FEW INSTANCES OF ISOLATED DAMAGING WIND GUSTS AND HAIL AS THEY DEVELOP EAST DURING THE DAY. THIS REGION WILL ALSO BE MONITORED FOR A POSSIBLE SLIGHT RISK IN LATER UPDATES. Link to comment Share on other sites More sharing options...
Hoosier Posted April 26, 2017 Share Posted April 26, 2017 Trends would support eastward shift or expansion of slight risk into Indiana, especially northwest IN. We'll see if that's what they do soon. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted April 26, 2017 Share Posted April 26, 2017 13 minutes ago, Hoosier said: Trends would support eastward shift or expansion of slight risk into Indiana, especially northwest IN. We'll see if that's what they do soon. Nope, I think they actually did the opposite. Link to comment Share on other sites More sharing options...
Hoosier Posted April 26, 2017 Share Posted April 26, 2017 6 minutes ago, HillsdaleMIWeather said: Nope, I think they actually did the opposite. Removed the slight risk out of almost all of Illinois due to instability concerns. Definitely a potential issue. I think the ongoing convection could push the severe threat east of earlier thinking, so if the slight risk comes back, it may come northeastward into parts of Indiana. Make sense? lol Link to comment Share on other sites More sharing options...
KokomoWX Posted April 26, 2017 Share Posted April 26, 2017 I've been seeing some impressive wind gusts on the euro for Sunday and Monday. Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted April 26, 2017 Author Share Posted April 26, 2017 1 hour ago, KokomoWX said: I've been seeing some impressive wind gusts on the euro for Sunday and Monday. If this Euro model holds true for Sunday, these gusts would rank right up there with those of Ike. Link to comment Share on other sites More sharing options...
Tim from Springfield (IL) Posted April 26, 2017 Author Share Posted April 26, 2017 Friday (D3) bears watching in the south part of this sub--slight risk roughly along/S of I-70 in IL/IN, and in S MO, with enhanced reaching S IL and SE MO: http://www.spc.noaa.gov/products/outlook/day3otlk.html ...Southern Plains through the Tennessee and Ohio Valleys... Shortwave trough will shift northeast through the OH Valley early Friday with upstream height rises in wake of this feature from the southern Plains into the TN Valley. A warm front will develop northward and by early evening should extend from the southern OH valley into northern TX or southern OK with a dryline evolving across west-central into northwest TX where it will intersect the front. Limited synoptic forcing for ascent and capping due to eastward expansion of EML may limit thunderstorm initiation during the day over much of this region. Some chance for initiation will exist at the intersection of dryline and front over northwest TX by late afternoon. Large CAPE and strong vertical shear would favor a conditional risk for supercells with very large hail and a few tornadoes should such initiation occur. Rich low-level moisture with large CAPE will reside south of warm/Quasistationary front. The best chance for more widespread thunderstorm initiation will occur during the evening into the overnight from OK into northern AR, MO and into the TN and OH valleys along and north of the warm front as strengthening, broad low-level jet enhances convergence and isentropic ascent along and north of this boundary. Strong vertical shear profiles and instability will support organized storms including supercells with large hail and damaging wind the main threats, though a few tornadoes may also occur with surface-based storms developing closer to the warm front. ..Dial.. 04/26/2017 Link to comment Share on other sites More sharing options...
Central Illinois Posted April 26, 2017 Share Posted April 26, 2017 12z GFS at hr 120 and NAM at hr 84 Link to comment Share on other sites More sharing options...
Hoosier Posted April 26, 2017 Share Posted April 26, 2017 5 hours ago, KokomoWX said: I've been seeing some impressive wind gusts on the euro for Sunday and Monday. The post frontal period early next week may be mildly interesting if the system deepens as much as shown. Trees leafed out with what will be wet soils. Link to comment Share on other sites More sharing options...
Hoosier Posted April 26, 2017 Share Posted April 26, 2017 The GEM is crazy. Band of 8-10" from ORD through STL. Link to comment Share on other sites More sharing options...
Stebo Posted April 26, 2017 Share Posted April 26, 2017 2 minutes ago, Hoosier said: The GEM is crazy. Band of 8-10" from ORD through STL. Pretty good snowstorm, oh wait you are talking about rain haha. In all seriousness though someone in Missouri and Illinois will get crushed with this system starting today. Link to comment Share on other sites More sharing options...
Hoosier Posted April 26, 2017 Share Posted April 26, 2017 1 minute ago, Stebo said: Pretty good snowstorm, oh wait you are talking about rain haha. In all seriousness though someone in Missouri and Illinois will get crushed with this system starting today. The snow is in Iowa. Poor folks. Link to comment Share on other sites More sharing options...
Stebo Posted April 26, 2017 Share Posted April 26, 2017 Just now, Hoosier said: The snow is in Iowa. Poor folks. That is misery and torture at this point. Link to comment Share on other sites More sharing options...
Hoosier Posted April 26, 2017 Share Posted April 26, 2017 Just now, Stebo said: That is misery and torture at this point. Basically. Though I guess you could argue it's unusual enough to be interesting. Link to comment Share on other sites More sharing options...
Stebo Posted April 26, 2017 Share Posted April 26, 2017 Just now, Hoosier said: Basically. Though I guess you could argue it's unusual enough to be interesting. Probably be just a few inches of slush. Link to comment Share on other sites More sharing options...
Central Illinois Posted April 26, 2017 Share Posted April 26, 2017 34 minutes ago, Hoosier said: The GEM is crazy. Band of 8-10" from ORD through STL. Link to comment Share on other sites More sharing options...
Hoosier Posted April 26, 2017 Share Posted April 26, 2017 I'm sure this wet stretch is not what farmers wanted to see. This is prime time for planting. Link to comment Share on other sites More sharing options...
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