Jump to content
  • Member Statistics

    17,502
    Total Members
    7,904
    Most Online
    Weathernoob335
    Newest Member
    Weathernoob335
    Joined

Severe Weather Risk tomorrow SW Missouri NW Arkansas


Jim Martin

Recommended Posts

  • Replies 246
  • Created
  • Last Reply

Not too surprised to see an ENH risk. Wind fields look pretty good and models have trended upward with instability. Any discrete supercell that were to form would have a pretty solid shot at producing tornadoes across much of the threat area, but especially SE KS/NE OK/SW MO/NW AR.

Link to comment
Share on other sites

3 hours ago, Weatherdemon said:

Some pretty solid forecast soundings ahead of the line of forecasted convection in NE-EC Central OK on the last several NAM runs.

My team may go out pending tomorrows model runs.

 

 

 

Looks rather capped before cold front sweeps through, no?

Link to comment
Share on other sites

00Z 4K NAM is very volatile across a large area tomorrow evening, to say the least...  especially in SE KS. Notable that it pops discrete supercells along this entire corridor. 4NAM/12NAM/GFS all depict an impressive parameter space at 00Z in E/SE KS tomorrow generally showing an uncapped environment juxtaposed to low 60s DPs, 200-300 m2/s2 0-1KM SRH, 1500-2500 J/, KG MLCAPE, SFC-6KM shear of 50-60kts, and impressive low-level CAPE as well. In my opinion I would not be surprised to see the SPC highlight this area with a 10% TOR risk at some point tomorrow. Any storms that initiate in this area will  likely stay discrete owing to only subtle/glancing forcing. A little concerned by potential backing of mid-level winds, but we will have to see how that evolves on VWPs tomorrow.

 

NAM4KMCGP_con_stp_024.png2017030600_NAM4KM_024_37.63,-95.92_sever

Link to comment
Share on other sites

SPC went with a small 10% TOR across southern Missouri including Springfield... Broad 5% TOR encompassing southern Iowa, much of Missouri, eastern KS, and NW AR/NE OK. ENH risk for damaging winds and large hail across MO and NE OK/NW AR. 

 ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER A PORTION
   OF THE LOWER TO MIDDLE MISSISSIPPI VALLEY REGION...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM A PORTION OF
   THE CENTRAL AND SOUTHERN PLAINS INTO THE MIDDLE TO UPPER MISSISSIPPI
   VALLEY...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM A PORTION
   OF THE CENTRAL AND SOUTHERN PLAINS TO THE LOWER THROUGH UPPER
   MISSISSIPPI VALLEY...

   ...SUMMARY...
   Severe thunderstorms are expected mainly late this afternoon or
   evening through tonight across a part of the upper and middle
   Mississippi Valley to the Ozarks and Mid-South. A greater
   concentration of severe thunderstorms may occur across parts of
   northwestern Arkansas and southern Missouri Monday evening. Primary
   threats will be damaging wind gusts and large hail, but a few
   tornadoes will also be possible, especially from extreme northern
   Arkansas into southern Missouri.

   ...Synopsis...

   Synoptic upper trough currently from the northern Rockies to the
   Great Basin will continue northeast through the central and northern
   Plains during the day and eject negatively tilted into the upper MS
   Valley this evening. Surface low will deepen over the eastern
   Dakotas into western MN, while trailing cold front merges with the
   dry line as it advances through the central plains during the day
   and into the MS valley and southern Plains overnight. Warm front
   extending east from the low will move northward through the upper MS
   valley and Great lakes regions.

   ...Ozarks through the middle and Upper Mississippi Valley areas...

   With initial return of partially modified Gulf moisture, widespread
   low clouds are expected in warm sector today, limiting
   boundary-layer warming. The 00Z observed raob data from Sunday
   evening already show a warm layer associated with a remnant elevated
   mixed layer in place across the central Plains and middle MS Valley
   region. Northward advection of partially modified Gulf moisture
   beneath 7-7.5 C/km mid-level lapse rates will destabilize the
   atmosphere during the day with corridor mlcape from 1000-1500 J/kg
   expected to evolve from central and southern Plains into the middle
   to lower MS Valley. Instability will remain marginal over the upper
   MS valley region where moisture return will be more limited. 

   Initial storms will likely develop over the upper MS Valley region
   where deeper forcing attendant to the ejecting shortwave trough will
   likely result in erosion of capping inversion along and just ahead
   of the cold front. Initial discrete storms should rapidly evolve
   into linear segments with damaging wind and hail the primary
   threats, though a brief tornado cannot be ruled out. 

   Given the presence of capping in warm sector and tendency for the
   deeper forcing to move into the upper MS Valley, most of the warm
   sector from the central plains into the middle to lower MS valley
   will remain capped during the day. However, storms will likely
   develop along cold front by early evening as this boundary overtakes
   the dryline across eastern KS. Initially discrete storms will evolve
   into linear segments. Given very strong effective bulk shear
   exceeding 50 kt, organized storms are expected including supercells
   and bowing linear segments. Large hail and a couple tornadoes will
   be the main threats with initial storms. However, as activity
   evolves into a dominant linear mode, damaging wind will become the
   primary threat, though a couple of qlcs tornadoes will also be
   possible with any embedded mesovortices. The best chance for
   pre-frontal storm initiation appears to be within  confluent flow
   regime along conveyor belt and in association with terrain features
   from northwestern AR into southern MO where some of the
   convective-allowing models initiate discrete cells. Should this
   occur during the early evening, large 0-1 km hodographs would
   support supercells with low-level mesocyclones and an attendant
   threat for a few tornadoes.

   ..Dial/Cook.. 03/06/2017
Link to comment
Share on other sites

A very narrow window may exist for a few supercells ahead of the cold front from northeastern OK into eastern KS and northwestern MO before the storm mode becomes linear, but the greater focus for prefrontal cells should lie from AR into much of MO and perhaps even IA. The HRRR has been ramping up parameters in the narrowing warm sector of the lower Missouri Valley and even as far north as southern MN.

I'd watch two areas in the warm sector: Northern MO and southern MO/northern AR. This is also a setup that could feature a rogue supercell or two in eastern OK, although CAMs have been inconsistent with initiation there. 

Link to comment
Share on other sites

Agree with Quincy above RE two areas of interest. WF lifting thru Missouri could provide a focus just east of St. Joseph and points east. Better parameters are noted in southwest/southern Missouri. CF/DL may intersect there but it's not a true triple point w/o the WF. Introduction of a differential heating boundary would make it a triple point. Parameters may be better southern MO but northwest MO is slightly better chase terrain. 

I know at least one member in southwest MO hates severe, so I have some good news. Agree with faster models that gets it out of SW MO earlier in the evening. Window for TOR is narrow all targets, both geographically and temporally. Looks like mainly a straight line wind deal. Chaser best shot is a break in the line. Better yet, watch some conference basketball tournaments at home.

Link to comment
Share on other sites

Not sure I would have dialed back to 5% on the tor, probably would have kept 10% just made it a narrow corridor.  If a couple supercells get going with the wind profiles the way they are a couple tornadoes is a real possibility.  Days like today sometimes surprise folks.  It doesn't seem like a day where we'll have cells popping all over the place, instead we'll probably have a few isolated cells go up ahead of the front.  Without a bunch of junk convection around and decent to good wind profiles a couple of producers with EF0/EF1s wouldn't surprise me at all.  

Link to comment
Share on other sites

Agree ^ on the 10%. SPC may be hedging since the location of the boundary is in question. Latest HRRR has a beast coming out of eastern Kansas in the west-central Missouri. That HRRR shows a true DL/CF/WF triple point feature; hence, it blows up the sup. Barring a junk rain debacle, the 10% may return. Still mainly straight winds though, for those in SW MO who hate severe. Chasers would also be happier with west-central MO thanks to roads/terrain and still well south of the KC metro sprawl.

Link to comment
Share on other sites

14Z HRRR highlighted the potential of an isolated long-tracking supercell initiating near I-35 in KS late this afternoon and tracking northeastward into MO... impressive UH-track as well. 15Z HRRR continues this idea of an isolated discrete supercell. If that happens, things could get very interesting with that storm. 

Link to comment
Share on other sites

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1033 AM CST Mon Mar 06 2017

   Valid 061630Z - 071200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS MID-MS VALLEY
   AND OZARK PLATEAU...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS UPPER MIDWEST TO
   EASTERN OK AND AR...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS CENTRAL
   STATES...

   ...SUMMARY...
   Numerous severe storms are expected starting late afternoon and
   continuing into tonight across the central states. The greatest
   concentration of tornadoes, a couple of which may be strong,
   damaging winds, and large hail is expected to be across the Ozark
   Plateau to the Mid-Mississippi Valley.

   ...Lower Missouri Valley, Ozark Plateau, Mid-South...
   Scattered storms should develop along the dryline late afternoon
   centered on eastern KS as mid-level height falls overspread this
   boundary downstream of a vigorous northern Great Plains shortwave
   trough. Despite a weakness in hodographs near 700 mb, low and
   deep-layer shear will be strong. In conjunction with a destabilizing
   air mass characterized by a plume of returning Gulf moisture with
   lower 60s surface dew points amid steep mid-level lapse rates, the
   environment will be quite favorable for supercells. As the cold
   front overtakes the dryline, storms will grow upscale this evening.
   This should result in a multi-faceted severe risk, all of which
   yield probabilistic upgrades this outlook. Large hail and tornadoes,
   some of which may be significant, will be the primary risks with any
   supercells that can maintain discrete mode immediately ahead of a
   probable QLCS. Damaging winds and a few embedded tornadoes should be
   the primary hazards with a fast-moving QLCS, supported by very
   strong and strengthening mid-level winds, along the northern extent
   of moderate instability across Missouri towards the mid-Mississippi
   Valley.. With southwest extent towards the Red River, deep-layer
   winds will be oriented increasingly parallel to the front, which
   should tend to favor a predominant QLCS mode and a more
   isolated/less intense severe risk tonight.

   ...Upper Midwest...
   Strong forcing for ascent will overspread this region along the
   northern extent of the warm sector, yielding scattered storm
   development along the cold front late afternoon. Rather steep
   mid-level lapse rates will compensate for comparatively lesser
   boundary-layer moisture farther south. Elongated, straight-line
   hodographs should support a few supercells, although the degree of
   forcing will probably tend to favor upscale growth into one or more
   short-line segments. All hazards appear possible with widely
   scattered severe reports expected.

day1otlk_1630.gif?1488818418514

Link to comment
Share on other sites

1 minute ago, jojo762 said:

Moisture is looking pretty meh this far. SFC DPs In the 55-60 range in Kansas attm.

Seemed like they were mixing out but it looks like they're recovering in central /west OK which may make it into KS in time.

Link to comment
Share on other sites

Area Forecast Discussion
National Weather Service Springfield MO
1120 AM CST Mon Mar 6 2017

...Mesoscale and 18Z Aviation Updates...

.MESOSCALE DISCUSSION...
Issued at 1120 AM CST Mon Mar 6 2017

No major changes to expectations for tonight at this time. Low to
mid 60s dewpoints will continue to stream into the area on very
gusty south winds through the rest of this afternoon into the
evening hours. These dewpoints will combine with relatively cold
temperatures aloft to produce a rather unstable airmass across the
region. Mid level height falls will begin to overspread the area
by early evening, and a cold front will begin to advance southeast
into the forecast area by mid to late evening.

Not unlike the severe weather event last week, there will be two
distinct opportunities for severe weather this evening/tonight.
The first will be with any discrete supercells that are able to
form ahead of the frontal boundary during the early to mid evening
hours. These would likely have the greatest severe weather
potential should they form. The second wave of severe weather will
be with the front itself, with initial supercells (likely just
north and west of the CWA) congealing into a linear complex/QLCS
as the front advances to the southeast. Straight line winds, large
hail, and brief meso-vort tornadoes will all be possible with
this line.

At this juncture, it appears that convection will begin to develop
as early as 5-6 PM just to our west, with the window for discrete
supercells lasting into the mid evening hours. The front should
begin to accelerate by 7-9 PM, with a line of strong/severe
convection sweeping across the western half or so of the CWA
between 7 and 10 PM, and the remainder of the area from 10 PM
through 3-4 AM tomorrow morning.
Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...