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March 30-April 1, 2023 | Severe Weather | Destructive Tornado Outbreak with a double High Risk


Iceresistance

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Just now, Hoosier said:

Forecast soundings are nasty tomorrow.  Focusing more on the northern target for obvious reason of it being closer to home, but a volatile environment is present around IA/IL in the afternoon.  The "barb of death" is also present as some old timers would say, with 500 mb winds in excess of 100 kts in the area.  That phrase is just what it sounds like, in that it tends to result in bad outcomes with deadly tornadoes.  Do see a tendency for some minor surface CINH with eastward extent in IL and IN, but it may not be enough to preclude a tornado threat into those areas and there could be some local augmentation of the profiles anyway in that kind of shear environment.  Stay safe and be careful chasing.

Good summary for us weather beginners.  It definitely could be a volatile day in the GL/OV/MW for sure.  Here to hoping all stay very safe and unscathed in every aspect by this situation. 

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Quote
Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1232 PM CDT Thu Mar 30 2023

   Valid 311200Z - 011200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
   IOWA INTO NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI...AND ALSO
   ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...EXTREME WESTERN
   KENTUCKY...WESTERN TENNESSEE...AND FAR NORTHWEST MISSISSIPPI...

   ...SUMMARY...
   Intense and widespread severe thunderstorms are expected Friday
   afternoon into the overnight hours across portions of the Middle
   Mississippi Valley and Mid-South vicinity, eastward to the Lower
   Ohio and Tennessee Valleys. Intense, damaging gusts and several
   tornadoes (some strong and long-track) are expected.

   ...A regional outbreak of severe storms is expected on Friday across
   parts of the Mid-Mississippi Valley and also into the Mid-South...

   ...Synopsis...
   A deep mid/upper-level trough and attendant 100 kt midlevel jet will
   move quickly eastward from the central Plains into parts of the MS
   Valley and Midwest on Friday. A surface low will deepen as it moves
   across IA toward the Great Lakes region, as a cold front sweeps
   eastward through parts of the Great Plains into the mid-MS Valley.
   In advance of the cold front, low-level moisture will stream
   northward across a broad warm sector from the ArkLaTex region into
   parts of the lower/mid MS Valley and Midwest. 

   ...Mid-MS Valley vicinity into IN/lower MI...
   Rapid destabilization and increasing large-scale ascent will support
   thunderstorm development by early/mid afternoon across parts of IA
   into northern MO. Very strong deep-layer shear (effective shear in
   excess of 60 kt) and MLCAPE increasing to 1000-1500 J/kg (locally
   greater) will support organized convection, with initial supercell
   development expected somewhere over central IA into north-central
   MO. Very large hail will be the initial threat, given steep midlevel
   lapse rates and cold temperatures aloft. 

   Some uncertainty remains regarding the convective mode evolution
   with time, but a few semi-discrete supercells are expected to move
   into an environment with stronger low-level shear/SRH across eastern
   IA into northwest IL by late afternoon, posing a threat for a couple
   strong tornadoes. Evolution into small clusters or bowing segments
   is expected, resulting in an increasing threat of severe/damaging
   winds in addition to a continued threat of a few tornadoes and
   sporadic hail. 

   Organized convection will spread eastward into parts of IN/southern
   MI Friday night. Instability will weaken with eastward extent, but
   some threat for damaging wind and a couple of tornadoes will persist
   before a more definitive weakening trend occurs overnight into early
   Saturday morning. 

   ...ArkLaTex/Mid South vicinity into the TN/lower OH Valleys...
   A concerning scenario still appears possible across portions of the
   MO Bootheel, northeast AR, western TN/KY and far northwest MS
   vicinity during the afternoon/evening. At least mid-60s F dewpoints
   are expected beneath modest midlevel lapse rates. This will support
   1500-2000 J/kg MLCAPE amid intense vertical shear. Forecast
   soundings indicate 0-1 km SRH increasing to around 400 m2/s2 by
   early afternoon. Thunderstorms are expected to develop by early
   afternoon ahead of the cold front within a pre-frontal
   trough/low-level confluence zone. Storm motion near 50 kt with
   supercell wind profiles will support cells capable of significant
   and long-track tornadoes. With time, upscale growth into a QLCS is
   expected, and intense wind gusts will be possible in addition to
   mesovortex tornadoes. The threat for damaging gusts and a few
   line-embedded tornadoes will spread into parts of the TN and lower
   OH Valleys Friday night, with a gradual weakening trend eventually
   expected overnight as storms move into increasingly weak buoyancy
   with eastward extent.

   ..Dean.. 03/30/2023

 

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18z HRRR cut back on the northward extent of 60+ dewpoints as convection earlier in the afternoon has a deleterious effect, but it still has plenty of 62-64 readings in northern IL.

A compromise solution or even something like the lower end model output would likely still be plenty threatening, but the HRRR is on another level.

Edited by Hoosier
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1 hour ago, Iceresistance said:

I'm getting a surprise complex of storms, how does this implicate the severe weather potential for tonight and into tomorrow morning?

Probably doesn't. It's probably elevated and the marginal risk is for the evening hours anyway.

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Getting really concerned for the northern moderate risk. With this type wound up system it's best to err on the side of higher dew points in the warm sector. LCLs will be low between the 100 meter and 400 meter range. Would not be surprised to see some wedges up there tomorrow. 

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Lots of dust (pink colors in TX/OK panhandle/SE CO/SW KS) in the Panhandles today. Had a dust storm warning earlier in the western Oklahoma panhandle. 

Not seen below but 2 wildfires in the Oklahoma panhandle now. RH is less than 10% with sustained winds over 30

CODNEXLAB-GOES-East-local-Panhandle-ntmicro-22_46Z-20230330_map-plot_noBar-24-1n-5-100.gif

Edited by ClicheVortex2014
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6 minutes ago, ClicheVortex2014 said:

Lots of dust (pink colors in TX/OK panhandle/SE CO/SW KS) in the Panhandles today. Had a dust storm warning earlier in the western Oklahoma panhandle. 

Not seen below but 2 wildfires in the Oklahoma panhandle now. RH is less than 10% with sustained winds over 30

CODNEXLAB-GOES-East-local-Panhandle-ntmicro-22_46Z-20230330_map-plot_noBar-24-1n-5-100.gif

Bleh, it'll be heading up my way tomorrow

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I'm not an expert at this severe stuff so on 0z data for HRRR, NAM for my area in west ky:

1. STP increased

2. Instability increased

3. Dewpoint increased 

4. Storm development is DEcreased 

Help me out here. Why is that?

Edited by Grace
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45 minutes ago, Grace said:

I'm not an expert at this severe stuff so on 0z data for HRRR, NAM for my area in west ky:

1. STP increased

2. Instability increased

3. Dewpoint increased 

4. Storm development is DEcreased 

Help me out here. Why is that?

You do have storms on both of those models... HRRR is messy and NAM is linear. Better moisture might be as simple as higher observations. Not sure.

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New convective model RRFS A is up on Pivotalweather. It says it's a prototype made by NOAA so no idea how far along they are with fine-tuning things but it seems to have a case of the early FV3, supercells galore. Just posting this because it's interesting. Use other models for forecasting this is unreliable, for now anyways. 

image.gif.50a7ccc0db772345144fe924c3f519c2.gif

Edited by Neoncyclone
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1 hour ago, Grace said:

I'm not an expert at this severe stuff so on 0z data for HRRR, NAM for my area in west ky:

1. STP increased

2. Instability increased

3. Dewpoint increased 

4. Storm development is DEcreased 

Help me out here. Why is that?

It should be a dangerous day in or near the northern/southern 15% (also 10%) risks for tornadoes on the SPC outlook. The southern 15%/10% tornado risk does include a bit of Kentucky. There's a chance the SPC could shift the southern tornado risk area, southward, down towards northern Mississippi, away from Kentucky. With the high-end wind shear, pretty much everybody in any of the risk areas should try to keep aware of the situation, and even watch out for 40mph non-thunderstorm winds.

It looks like the models have a squall line continuing into western Ohio, with low CAPE, later in the night. There  could numerous wind damage reports from this even with the low CAPE.

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37 minutes ago, Neoncyclone said:

New convective model RRFS A is up on Pivotalweather. It says it's a prototype made by NOAA so no idea how far along they are with fine-tuning things but it seems to have a case of the early FV3, supercells galore. Just posting this because it's interesting. Use other models for forecasting this is unreliable, for now anyways. 

image.gif.50a7ccc0db772345144fe924c3f519c2.gif

 

Dang! Spercells everywhere!

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4 minutes ago, Ingyball said:

Got surprise showers today, even picked up more than a trace (0.02) won't do anything to limit the fire threat but just shows the strong movement of moisture right now. 

Managed to get upper 50 dew points ahead of the dryline today but couldn't break the cap. Either way, encouraging to see moisture overperform

Edited by ClicheVortex2014
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