Current setup, 5/1 — HIGH risk in eastern Ark., SE Mo., W. Tenn., W. Miss.

A potentially ballistic severe weather setup is in place along the Mississippi River today, just a little father north than it was a week ago when Yazoo City, Miss., was demolished. The bullseye based on current (4:30 p.m. EDT) parameters appears to be southeast and east-central Arkansas — CAPE of up to 3500, deep layer shear 50 to 70 knots, low-level shear 25 to 35 knots and the significant tornado parameter as high as 5.  Overnight heavy rain and storms has left plenty of boundaries for new storms to fire along and ingest.

Some of this area is flat, cleared agricultural terrain and would be chaseable, though river crossings, especially over the Mississippi, can make following storms tricky.

As usual, add any comments or observations you may have about today’s severe weather situation. I will be watching very closely with personal interest, having grown up in northeast Arkansas, where my mother still lives.

— Kevin Myatt

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18 responses to “Current setup, 5/1 — HIGH risk in eastern Ark., SE Mo., W. Tenn., W. Miss.

  1. interesting to note that TN is no sleeping matter! helicities and shear far great there right now than in AR

  2. True, but the stuff in Tenn. is congealed into a mass, whereas anything that fires farther west will be discrete, at least at first.

    That said, I think the high risk severe area may be a little north and west of where the highest potential is developing. Based on the overlay of parameters, I would say south and east of a Texarkana to Memphis line is the highest risk, extending into northern Mississippi.

  3. hokiestormchaser

    …as we enter May, it is interesting to see this activity still centered in areas where March-early April would climatologically be favored. The northward extent of the svr threat is certainly greater though. -Dave

  4. i agree. that’s where, like you said, the higher parameters are. there’s one spot in central AR showing higher helicities co-located with some backing winds. will watch that spot for development because if a storm goes over it, it may intensify

  5. Isolated small cells are starting to pop over Arkansas now (6:40 EDT). Any one of them could spin up into something severe or tornadic very quickly.

  6. And just like that — 2 tornado warnings on isolated supercells in south-central Arkansas, and 2 severe warned cells west of Little Rock. Movement is north-northeast very rapidly, almost due north in some cases.

  7. … make that a whole swarm of supercells now (8:20 pm EDT) with eight separate tornado warnings …

  8. hokiestormchaser

    …nice inflow notch & v-notch on the cell moving through Lincoln County AR….it is on the southeastern flank of the mass of supercells…could be a favored position tonight. Nighttime reigns now, and it is a dangerous time in Arkansas. -Dave

  9. Chase wise, the best shot would have been one of the cells that crossed I-40 east of Little Rock just before dark. That would have maximized daylight on the late-firing storms, terrain, road accessibility and storm strength. I’ve been saying to myself today that I would have parked in Forrest City, Arkansas, (30 miles west of Memphis)today, and those storms would have been playable from there.

  10. hokiestormchaser

    …in the end, heavy rain may ultimately be the main story of the day…amazing totals coming from TN…more than a foot! Cars swamped on the interstates… -Dave

  11. Helicities are still over 700 in parts of SW Tennessee with a couple of supercells moving into the area (including one Tornado warned one over Memphis right now). Reports of Baseball-Grapefruit sized hail too according to WREG out of Memphis.

  12. hokiestormchaser

    …checking the storm reports from yesterday, you can clearly see the northern MS/TN border area saw more tornado reports…could be the helicity maximum Andrew was referring to… -Dave

  13. It feels pretty ripe over here in the eastern part of the state right now for some storms this afternoon. CAPE is up around 2500 with decent winds and helicities, and little/no CIN. The RUC Supercell composite is up to 8 and SigTor is running 1-2. Only thing we’re really missing is a trigger.

  14. hey andrew

    watching the conditions around here too. it’s VERY windy, we’ve got some instability and shear (not as high as you in the east though). waiting patiently for the cold front to march it’s way over here to hopefully start up the storms

  15. 2 problems with storms here: (1) CIN is -150 (2) the forcing is lagging, as the front is only slowly making progress eastward. And now it’s probably going to arrive overnight or morning hours when heating is the least. So yes there may be some severe storms, especially witht the shear, but not what it could have been with a stronger, faster forcing mechanism and better timed with daytime heating.

  16. Steve Keighton

    Hey Hokie Chasers! Wish I could join you (my perpetual wish it seems). You may already be aware of these model sources, but there are some good high res models out there, some of which include some good convective parameters. The first is the rapid refresh (version of the RUC), which is run hourly and goes out to 15 hrs. The main page is
    http://rapidrefresh.noaa.gov/hrrrconus/
    …but it includes links to 15 min res output, and a link to convective probabilities.

    Also, try the SPC WRF-NMM runs, which are only run at 00Z and 12Z, but is a 4km model and the web site includes a number of simulated radar fields:

    http://www.emc.ncep.noaa.gov/mmb/mpyle/cent4km/conus/12/

    Finally, I’m guessing you are aware of the SPC SREF output (4 times per day), which go out to 87 hrs, but include many convective parameters and of course these are ensembles so for use for Day 2 or 3 they provide a good measure of uncertainty:

    http://w1.spc.woc.noaa.gov/exper/sref/

    Good luck this season!

  17. hokiestormchaser

    …thanks for the links Steve! Will you be in Norman any this May/June? -Dave

  18. thanks a lot steve! wish you could be out there with us, but you’ll be there in spirit! dave and i were looking at the long range forecast today…..
    i told him if we hit a quiet period, we’ll just occupy ourselves by jumping across the dry line 😉

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