Jump to content
  • Member Statistics

    15,515
    Total Members
    7,904
    Most Online
    chrislittlenews
    Newest Member
    chrislittlenews
    Joined
snowlover2

2019 Short/Medium Range Severe Weather Thread

Recommended Posts

Yeah that LLJ should feed tonight's MCS all through the morning tomorrow, so it'll likely go on for quite awhile.  HRRR/3km doesn't break out new convection until around, or just after 00z.  Good chance it actually happens a bit later than that.  Strong capping will be in place just south of the boundary, and with the nocturnal inversion starting to settle in just as the convection finally takes off it makes you wonder just how robust any surface-based convection can get.  Good chance tomorrow evening's biggest threat will come from torrential rains from the storms that may have a tendency to train over the same areas as storm motion vectors parallel the nearly stationary boundary.  

Share this post


Link to post
Share on other sites
1 minute ago, SchaumburgStormer said:

Tor warning for south central DKB county 

Law enforcement reported poss tornado on the ground N of Shabbona at 1137

Share this post


Link to post
Share on other sites

From latest outlook

 

...Midwest...
   Considered increasing tornado probabilities and adding significant
   hail but low confidence exists in whether supercells can be
   sustained in the warm sector across IL/IN.

   A slowly decaying MCS is ongoing near the IL/WI border within a warm
   advection regime. Morning CAM guidance has poorly handled with most
   struggling to maintain any semblance of convection beyond
   initialization. The stratiform region across Lake MI should have an
   impact on downstream destabilization in Lower MI given that richer
   boundary-layer moisture characterized by low to mid 60s surface dew
   points is currently confined from IL west. It is possible that the
   MCS may not entirely dissipate as warm advection persists through
   the period. Renewed development on the upshear side would seemingly
   be most likely along trailing convective outflow. Along the eastern
   extent of the Great Plains elevated mixed layer at peak heating,
   robust upstream diabatic heating should result in large buoyancy
   with MLCAPE of 2000-3000 J/kg. Veering of the wind profile with
   height on the periphery of moderate mid-level northwesterlies will
   favor supercell structures. An evolution to another MCS with
   wind/hail risks appears probable tonight towards the OH Valley. 

Share this post


Link to post
Share on other sites
2 minutes ago, Hoosier said:

From latest outlook

 

...Midwest...
   Considered increasing tornado probabilities and adding significant
   hail but low confidence exists in whether supercells can be
   sustained in the warm sector across IL/IN.

   A slowly decaying MCS is ongoing near the IL/WI border within a warm
   advection regime. Morning CAM guidance has poorly handled with most
   struggling to maintain any semblance of convection beyond
   initialization. The stratiform region across Lake MI should have an
   impact on downstream destabilization in Lower MI given that richer
   boundary-layer moisture characterized by low to mid 60s surface dew
   points is currently confined from IL west. It is possible that the
   MCS may not entirely dissipate as warm advection persists through
   the period. Renewed development on the upshear side would seemingly
   be most likely along trailing convective outflow. Along the eastern
   extent of the Great Plains elevated mixed layer at peak heating,
   robust upstream diabatic heating should result in large buoyancy
   with MLCAPE of 2000-3000 J/kg. Veering of the wind profile with
   height on the periphery of moderate mid-level northwesterlies will
   favor supercell structures. An evolution to another MCS with
   wind/hail risks appears probable tonight towards the OH Valley. 

Beat me to it.

Share this post


Link to post
Share on other sites
14 minutes ago, SchaumburgStormer said:

Law enforcement reported poss tornado on the ground N of Shabbona at 1137

Based on storm relative velocity, I think rotation was weak-moderate north of Leland (south of Shabbona) 11:44 AM. 

Share this post


Link to post
Share on other sites

Mesoscale Discussion 0638
   NWS Storm Prediction Center Norman OK
   1209 PM CDT Thu May 16 2019

   Areas affected...Parts of northern and central Illinois and Indiana

   Concerning...Severe potential...Watch possible 

   Valid 161709Z - 161815Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Vigorous thunderstorm development is currently being
   maintained near a southward advancing cold pool, to the southwest of
   the Chicago area.  It is not certain how long this will persist this
   afternoon, but there is at least some potential for further
   intensification and organization which could require a severe
   weather watch.

   DISCUSSION...Warm and capping elevated mixed-layer air is in the
   process of advecting across the mid/lower Missouri Valley, toward
   portions of the Upper Midwest, around the northern periphery of
   amplified ridging within the mid-latitude westerlies.  Along the
   leading edge of this air mass, a zone of enhanced lower/mid
   tropospheric warm advection is maintaining vigorous thunderstorm
   development, which may be also increasingly forced by lift above an
   associated surface cold pool.  This appears to be occurring in the
   presence of modest (30+ kt) west-northwesterly deep layer mean flow.

   The influence of a 30-40 kt west-southwesterly 850 mb speed maximum
   nosing east of the Mississippi River may contribute to more of a
   southward propagation near and west of the Illinois/Indiana state
   border area through 18-20Z.  While this track will be increasingly
   into weak mid-level height rises, mid/upper ridging and weaker flow
   aloft, the boundary layer ahead of the southwestern flank of the
   outflow continues to gradually moisten across much of central
   Illinois.  Additional boundary layer warming and moistening may
   contribute to weakening inhibition for boundary layer parcels with
   CAPE increasing in excess of 2000 J/kg.

   Thus, while it remains unclear if synoptic forcing for ascent will
   maintain ongoing convection this afternoon, it appears at least
   possible that mesoscale processes will, with subsequent further
   intensification and organization possible.  This probably would be
   accompanied by increasing potential for strong winds at least
   approaching severe limits along a strengthening gust front.

   ..Kerr/Grams.. 05/16/2019

Share this post


Link to post
Share on other sites
   URGENT - IMMEDIATE BROADCAST REQUESTED
   Severe Thunderstorm Watch Number 168
   NWS Storm Prediction Center Norman OK
   1250 PM CDT Thu May 16 2019

   The NWS Storm Prediction Center has issued a

   * Severe Thunderstorm Watch for portions of 
     East-central and northeast Illinois
     West-central and northwest Indiana

   * Effective this Thursday afternoon and evening from 1250 PM
     until 600 PM CDT.

   * Primary threats include...
     Scattered damaging wind gusts to 70 mph possible
     Isolated large hail events to 1.5 inches in diameter possible
     A tornado or two possible

   SUMMARY...A small linear bowing cluster may continue southeast along
   the Illinois and Indiana border region this afternoon. Damaging wind
   gusts and severe hail are the primary hazards, although a brief
   tornado or two is also possible.

   The severe thunderstorm watch area is approximately along and 65
   statute miles east and west of a line from 35 miles west northwest
   of Valparaiso IN to 30 miles south southeast of Danville IL. For a
   complete depiction of the watch see the associated watch outline
   update (WOUS64 KWNS WOU8).

Share this post


Link to post
Share on other sites

This MCS that has regenerated this morning and early afternoon looks likely to push SE/SSE alight the instability gradient in place, which runs down along the IL/IN border area.

It has featured embedded areas of rotation at times in the SW/S metro, with a few wall cloud reports. Overall severe reports have been surprising low though, given wind and hail sigs on radar.

Re-development of quality surface based activity later this afternoon and evening in a very nice environment ahead of the cold front and near the OFB across Iowa, S. WI/N. IL looks questionable...With slightly rising heights, subsidence in the wake of the current S/W, no formidable wave close upstream and a cap in place.

Share this post


Link to post
Share on other sites

Several short range runs showing explosive development around 00z tonight.. fortunately the MCS has weakened to the point where the atmosphere should remain untapped over this way, but later on I’m trying to find what the models are seeing that’s driving explosive development along the boundary other than the LLJ. 

Share this post


Link to post
Share on other sites

That MCS threw down an OFB that is favorably oriented to storm motion vector. If it gets time to cook, could get interesting(in W IL) late this afternoon should redevelopment occur.

Share this post


Link to post
Share on other sites

Pea sized hail here. Lightning strikes are impressive. Winds are meh. Rain is unbelievable. So tired of it...

  • Like 2

Share this post


Link to post
Share on other sites

That same cell is N of Terre Haute now and warned again with numerous reports of a wall cloud.  It's pretty much on its own now.

Share this post


Link to post
Share on other sites

Look what is forming this evening from northern IN westward across northern IL into IA.   Maybe those mesoscale models that predicted training west to east t storms overnight are going to be correct in spite of the MCS that rolled through the area earlier today.

Share this post


Link to post
Share on other sites
4 minutes ago, Indystorm said:

Look what is forming this evening from northern IN westward across northern IL into IA.   Maybe those mesoscale models that predicted training west to east t storms overnight are going to be correct in spite of the MCS that rolled through the area earlier today.

Saw that, seemed to start popping up pretty quick.  HRRR says Columbus around 5z so we’ll see out this way.

Share this post


Link to post
Share on other sites

I don't usually like to start a severe thread, and don't mean to be late to the party on today's event either, but I started a new catch-all thread starting with today/tonight's action (including another MD in IA/N IL), going to early Wednesday:

 

Share this post


Link to post
Share on other sites

Head's up western/northern IL and Chicagoland. SPC has the slight risk all the way up to ORD and the CAMs look like there could be some golf balls and a tornado threat in the late evening. Trust me, those golf-to-tennis balls can inflict some serious damage.

  • Thanks 1

Share this post


Link to post
Share on other sites
Head's up western/northern IL and Chicagoland. SPC has the slight risk all the way up to ORD and the CAMs look like there could be some golf balls and a tornado threat in the late evening. Trust me, those golf-to-tennis balls can inflict some serious damage.

For tonight?

Share this post


Link to post
Share on other sites
6 minutes ago, IWXwx said:

Yes sir.

 

nam3km_mslp_pcpn_frzn_ncus_11.png

Dang, busy day.  Completely missed this.  Thanks for the heads up.  

Share this post


Link to post
Share on other sites

TOR watch for me and SW

looks like there is a mini dew point front moving north....where dew points are 68-69  south versus 59-61north....CU field in MO developing on the leading edge 

models start backing winds more SSE. around 23-0z as a mini low forms

I-72 baby (you can never go wrong)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×