snowlover2 Posted October 7, 2019 Author Share Posted October 7, 2019 2 hours ago, Hoosier said: Interesting CIPS... there are a few big fall outbreaks in there, a couple smaller ones and quite a few that produced no severe wx in the region. Take your pick lol. I'd probably lean away from the bigger ones toward one of the smaller ones at this point given the concern about instability/mid level lapse rates. Usually it's sort of hard to reverse the mid level lapse rate problem on the models once it's there. Maybe pure advection can drive the temps up above guidance and help out the instability a bit. SPC talking about it some in the day 4-8. Quote ..D5/FRIDAY: OH AND MS VALLEYS STRONG FORCING FOR ASCENT IS ANTICIPATED ALONG THE FRONT AS IT MOVES EASTWARD ACROSS THE LOWER/MIDDLE OH AND MID MS VALLEYS. A STRONG CONVECTIVE LINE IS EXPECTED ALONG THE FRONT AS A RESULT WITH SEVERE STORMS POSSIBLE FROM IL/IN INTO LA/MS. HOWEVER, THE COVERAGE AND INTENSITY OF THESE STORMS WILL DEPEND LARGELY ON THE EXTENT OF THE MOISTURE RETURN AHEAD OF THE FRONT. THE STRONGER ASCENT AND BETTER DYNAMICS WILL BE DISPLACED NORTH (I.E. FROM THE LOWER TO MIDDLE OH VALLEY INTO THE UPPER MIDWEST) OF THE BETTER LOW-LEVEL MOISTURE (ACROSS THE MIDDLE/LOWER MS). AREA OF OVERLAP BETWEEN THE FAVORABLE DYNAMICS AND FAVORABLE THERMODYNAMICS DIFFER AMONGST THE GUIDANCE AND MORE MODEL CONSENSUS IS NEEDED BEFORE DELINEATING ANY AREAS. 1 Link to comment Share on other sites More sharing options...
Hoosier Posted October 9, 2019 Share Posted October 9, 2019 After slowing down on earlier runs, the models have sped up the front a bit in the past couple days. Instability continues to look like it will be on the lower end. The modeled temps/dews (dews in the low to mid 60s) would be good enough for a decent amount of severe wx in a lot of setups at this time of year, but overall CAPE is limited by those meager lapse rates. The better mid level flow also lags behind by more than I'd like to see, especially given the aforementioned problem with instability. I was surprised to not even see a token 5% area on the day 3 outlook though. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted October 10, 2019 Share Posted October 10, 2019 10 hours ago, Hoosier said: After slowing down on earlier runs, the models have sped up the front a bit in the past couple days. Instability continues to look like it will be on the lower end. The modeled temps/dews (dews in the low to mid 60s) would be good enough for a decent amount of severe wx in a lot of setups at this time of year, but overall CAPE is limited by those meager lapse rates. The better mid level flow also lags behind by more than I'd like to see, especially given the aforementioned problem with instability. I was surprised to not even see a token 5% area on the day 3 outlook though. Still nothing on Day 2, IWX is mentioning bowing segments though Link to comment Share on other sites More sharing options...
Hoosier Posted October 21, 2019 Share Posted October 21, 2019 Haven't really been paying attention but wonder about a low end severe threat north of where the SPC outlook has it tomorrow. Link to comment Share on other sites More sharing options...
RogueWaves Posted October 21, 2019 Share Posted October 21, 2019 TOR warning at the airport in Dallas shortly ago. Apparently confirmed. Not sure of strength/size tho. Link to comment Share on other sites More sharing options...
Hoosier Posted October 21, 2019 Share Posted October 21, 2019 03z HRRR Instability is on the low side but this has better wind fields into the warm sector than the system from a week and a half ago. Not looking for much but a northward expansion of the marginal risk on the new day 1 outlook may be in order. I guess we'll see. Link to comment Share on other sites More sharing options...
IWXwx Posted October 21, 2019 Share Posted October 21, 2019 IWX has been beating the strong wind threat for several days. SPC isn't playing ball. These high shear low CAPE fall systems have had a history of producing some blow semis over winds. 1 Link to comment Share on other sites More sharing options...
Hoosier Posted October 21, 2019 Share Posted October 21, 2019 5 hours ago, IWXwx said: IWX has been beating the strong wind threat for several days. SPC isn't playing ball. These high shear low CAPE fall systems have had a history of producing some blow semis over winds. Yeah I see their morning afd mentioned a possible severe threat. Saw some small branches knocked down around the area this morning without thunder, so even any low topped line that can get going may be able to get severe/borderline severe winds to the surface. Link to comment Share on other sites More sharing options...
RogueWaves Posted October 21, 2019 Share Posted October 21, 2019 On behalf of the lakeshore, glad the Euro was wrong in this case. It will be bad enough as-is! .DISCUSSION...(Today through next Sunday) Issued at 330 AM EDT Mon Oct 21 2019 Another fall storm system will affect the region over the course of the next 36 to 48 hours. We finally have some consensus with the depth of the low, in the 980`s mb`s, over Wisconsin. Yesterday a run of the ECMWF deterministic had a 975mb low over Wisconsin. Now both the GFS and ECMWF are in the low 980`s. Still a formidable low by Great Lakes fall standards. A reason why this will be a bit more impactful in terms of winds along the lakeshore is that the low in Wisconsin pinwheels towards us late tonight into Tuesday morning. this will place the tightest pressure gradient right over Lake Michigan. See details in the marine section on the Gale Warning and Lakeshore Flood Warning that are now in place. We may need to consider a Wind Advisory on the land in the lakeshore counties for especially on Tuesday. At this point holding off on that, but the day shift may need to consider it. Link to comment Share on other sites More sharing options...
Hoosier Posted November 23, 2019 Share Posted November 23, 2019 Low end severe threat Tuesday? The thermodynamics are pretty lackluster but those are some impressive wind fields. Might be able to force some strong winds to the surface with anything even semi-organized. Link to comment Share on other sites More sharing options...
Hoosier Posted November 23, 2019 Share Posted November 23, 2019 Boy if we had better instability Link to comment Share on other sites More sharing options...
Stebo Posted November 23, 2019 Share Posted November 23, 2019 37 minutes ago, Hoosier said: Boy if we had better instability Of course we get this now and not in the spring when we would have some instability. 2 Link to comment Share on other sites More sharing options...
Hoosier Posted November 25, 2019 Share Posted November 25, 2019 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1140 AM CST Mon Nov 25 2019 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF THE LOWER TO MIDDLE MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe storms with a threat for mainly damaging wind and a couple of tornadoes will be possible over a portion of the lower to middle Mississippi Valley region Tuesday. ...Lower to middle Mississippi Valley region... A strong shortwave trough now approaching the Great Basin will emerge over the central and southern Plains early Tuesday. A mid-upper jet within base of this feature will strengthen to 120 kt as the shortwave trough ejects negatively tilted through the middle MS Valley region. Lee cyclone initially over the southern High Plains will deepen within exit region of the upper jet as it develops northeast through the middle MS Valley by Tuesday evening. Trailing cold front will advance east and southeast through the central and southern Plains and MS Valley. By the end of the period the front should extend from a surface low over upper Great lakes southwest through LA and the TX coastal area. The boundary layer over the northwestern Gulf is in the process of modifying with latest observations showing dewpoints already in the upper 60s F. Positive theta-e advection promoted by southerly low-level winds will persist through Tuesday contributing to surface dewpoints near 70 F as far north as southern AR with upper 50s F into central MO. Widespread clouds should limit diabatic heating in warm sector, but MLCAPE should approach 1000 J/kg over the lower MS Valley. Farther north from eastern KS into MO the development of steeper lapse rates with colder air aloft (-14 to -16 C at 500 mb) will contribute to marginal MLCAPE with 500-800 J/kg possible within a more shallow convective layer. Two primary zones of surface based thunderstorm development are possible Tuesday afternoon and evening, including along the warm conveyor belt from northern LA into AR, western MS and TN, and farther north within zone of stronger pre-frontal forcing ahead of the cold front from eastern KS into MO and western IL. Broken bands of storms including potential for a few supercells and bowing segments will be possible in both of these regimes where vertical shear profiles will be more than adequate for organized structures with sizeable 0-1 km hodographs and 50+ kt effective bulk shear. Primary limiting factor for higher severe probabilities is the expected marginal thermodynamic environment. Nevertheless, at least isolated damaging wind and a couple tornadoes will be possible with the stronger storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% - Slight Hail: 5% - Marginal ..Dial.. 11/25/2019 1 Link to comment Share on other sites More sharing options...
Hoosier Posted November 25, 2019 Share Posted November 25, 2019 NAM ticked up a bit with instability. May have a shot at some surface or near surface based activity farther north/east in IL/IN despite the overnight timing. I'll say it again... boy if we had better instability with this setup. Would've been a big severe wx outbreak. Link to comment Share on other sites More sharing options...
Hoosier Posted November 25, 2019 Share Posted November 25, 2019 Something I have noticed on the models is that the surface based instability (what amount there is) tends to lag behind the potential convective line on Tuesday night into early Wednesday. There isn't really as much of a lag when using MLCAPE. So what it means is that if temps can warm up a bit quicker out ahead of the front (which is a distinct possibility with the strong southerly/southeasterly low level flow) then some surface based instability could develop more quickly for any convection to try to take advantage of. Link to comment Share on other sites More sharing options...
Hoosier Posted November 25, 2019 Share Posted November 25, 2019 Pulling forecast soundings from the IL/IN area and man, the speed shear is just phenomenal. About as good as it gets. 0-6 km shear progged in the 100-110 kt range (may be a struggle to even get convective tops much past 6 km though). Link to comment Share on other sites More sharing options...
Hoosier Posted November 26, 2019 Share Posted November 26, 2019 Marginal and slight risk areas expanded on the new outlook Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1156 PM CST Mon Nov 25 2019 Valid 261200Z - 271200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER/MID MS VALLEY... ...SUMMARY... Isolated to scattered severe storms with a threat for damaging winds and a few tornadoes will be possible across parts of the lower to mid Mississippi Valley this afternoon and tonight. ...Synopsis... A powerful mid-latitude cyclone will strengthen further today as it acquires a negative tilt and ejects northeastward from the southern/central Rockies across the Plains, eventually reaching the Upper Midwest and Great Lakes region by the end of the period. A very strong mid/upper-level jet (100+ kt at 500 mb and 175+ kt at 250 mb) will likewise develop from the southern/central Plains across the mid MS Valley by Tuesday night. Pronounced large-scale forcing for ascent preceding the mid/upper-level trough will encourage a surface low to deepen as it develops northeastward from the central High Plains to the Upper Midwest by late tonight. A cold front attendant to this low will sweep quickly eastward across the southern Plains through the day. This front should reach parts of the OH/TN Valleys into the Southeast by early Wednesday morning. ...Lower to Mid Mississippi Valley... South-southwesterly low-level winds will continue to transport Gulf moisture northward this morning across parts of central/east TX and the lower MS Valley. Latest short-term guidance is in reasonable agreement that low to mid 50s surface dewpoints should extend as far north as northern MO and southern/central IL by this evening. Greater low-level moisture characterized by mid 60s to near 70 F surface dewpoints will likely remain confined farther south to parts of AR/LA/MS and east TX. At least two corridors of isolated to scattered severe thunderstorms may occur today/tonight: one in close proximity to the mid-latitude cyclone from MO northeastward into eastern IA and IL, and the other from AR to the Mid-South, possibly extending as far south as southern/central MS. Convection should develop along/ahead of the front across MO by late afternoon/early evening as strong ascent overspreads this region. Even though low-level moisture should be somewhat more limited with northward extent, temperatures should rapidly cool at mid-levels as the upper trough approaches. MLCAPE of 250-750 J/kg should develop by the time convective initiation occurs, with some guidance suggesting MLCAPE may reach near 1000 J/kg. Very strong shear owing to rapidly increasing wind speeds through the cloud-bearing layer suggest supercells will be possible initially, with both a damaging wind and isolated tornado threat. Isolated large hail may also occur early in the convective life cycle given the modestly steepened lapse rates and very cold temperatures aloft. A small bowing cluster should develop by late evening and quickly race northeastward into parts of IL, with mainly a damaging wind risk possibly continuing into early Wednesday morning as far east as western IN. A somewhat separate area of convection may form across the open warm sector in AR and the lower MS Valley by late afternoon owing primarily to low-level warm air advection and weak confluence along a pre-frontal trough. Very strong effective shear (60+ kt) and 500-1000 J/kg of MLCAPE will support supercell structures with any storms that can form in this regime. Isolated instances of damaging winds and a couple tornadoes should be the main threats with this convection. There is some uncertainty with overall coverage through early evening, particularly with southward extent across LA and southern/central MS, as these areas will remain displaced to the south of the stronger large-scale ascent. Still, some increase in thunderstorm coverage with an isolated severe threat may occur late in the period (early Wednesday morning) as the surface cold front approaches and a 35-50+ kt southwesterly low-level jet remains over this region. ..Gleason/Nauslar.. 11/26/2019 Link to comment Share on other sites More sharing options...
CheeselandSkies Posted November 26, 2019 Share Posted November 26, 2019 Despite that tempting probability map...I get the feeling last 12/1 this is not. Looking further ahead on the GFS, Saturday might be doable...which is ironic since 12/1/18 was also a Saturday. Link to comment Share on other sites More sharing options...
cyclone77 Posted November 26, 2019 Share Posted November 26, 2019 It's a frosty 29/28 early this morning here, and we're in the 2% tornado probs for this evening. Pretty impressive warm/moist advection incoming. 3 1 Link to comment Share on other sites More sharing options...
Hoosier Posted November 26, 2019 Share Posted November 26, 2019 Enhanced risk area, but the discussion didn't sound too confident about it. Link to comment Share on other sites More sharing options...
Indystorm Posted November 26, 2019 Share Posted November 26, 2019 There's a bit of clearing in ne OK and sw MO which I will watch as it moves northeastward. As has been stated, instability is really the issue today. but kinematics are awesome. Enhanced now shifted south in afternoon update. Link to comment Share on other sites More sharing options...
Hoosier Posted November 27, 2019 Share Posted November 27, 2019 Tornado warning in Southeast Missouri. Link to comment Share on other sites More sharing options...
Hoosier Posted November 27, 2019 Share Posted November 27, 2019 VYS gusted to 63 mph a little while ago. BULLETIN - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Warning National Weather Service Chicago/Romeoville 103 AM CST Wed Nov 27 2019 The National Weather Service in Chicago has issued a * Severe Thunderstorm Warning for... Kendall County in northeastern Illinois... Northeastern La Salle County in north central Illinois... Southern De Kalb County in north central Illinois... Northern Grundy County in northeastern Illinois... * Until 145 AM CST. * At 102 AM CST, severe thunderstorms were located along a line extending from near Earlville to near Naplate, moving northeast at 55 mph. HAZARD...60 mph wind gusts. SOURCE...Radar indicated. IMPACT...Expect damage to roofs, siding, and trees. * Locations impacted include... Oswego, Ottawa, Yorkville, Little Rock, Minooka, Plano, Sandwich, Marseilles, Serena, Montgomery, Sheridan, Somonauk, Earlville, Newark, Leland, Naplate, Millington, Lisbon and Boulder Hill. Including the following interstate... I-80 between mile markers 84 and 105, and between mile markers 115 and 122. This includes...Buffalo Rock State Park, and Grundy County Speedway and Fairgrounds. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. && LAT...LON 4161 8906 4163 8899 4163 8894 4164 8894 4173 8860 4172 8860 4172 8826 4144 8825 4129 8894 TIME...MOT...LOC 0702Z 235DEG 48KT 4157 8897 4128 8886 HAIL...<.75IN WIND...60MPH $$ Kluber Link to comment Share on other sites More sharing options...
kevlon62 Posted November 27, 2019 Share Posted November 27, 2019 46 degree truck temp heading north across the state line under clear, starry skies with some gorgeous lightning on the northern horizon.Got my October and November local sled rides in and holiday weekend inbound.Digging it.Sent from my SM-N960U using Tapatalk 2 Link to comment Share on other sites More sharing options...
Gino27 Posted November 27, 2019 Share Posted November 27, 2019 For what it's worth, the GFS tries to bring in some pretty big cold after the 10th. Is it drunk? Link to comment Share on other sites More sharing options...
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