March 22-28, 2023 | Severe Weather/Heavy Rain/Flooding

[snowlover2]

Got some thunder and lightning here

[Hassaywx1223]

I got in on the action like 430 today. Great severe warned storm got right into the hail core and all made it feel like we’re heading to storm season and I’m excited 

[snowlover2]

Quote

Mesoscale Precipitation Discussion 0120
NWS Weather Prediction Center College Park MD
1015 PM EDT Thu Mar 23 2023

Areas affected...Southern IL...Southern IND...Southwest OH...Parts
of Northern KY...

Concerning...Heavy rainfall...Flash flooding possible

Valid 240215Z - 240800Z

SUMMARY...Deep confluent layer favoring continued training profile
with occasional strong embedded convective cells tracking through
the line.  Scattered incidents of flash flooding are possible with
scattered 2-3" totals by 09z.

DISCUSSION...GOES-E WV suite depicts a very impressive
anticyclonically curved cirrus shield expanding across the
Mid-Mississippi Valley into IL and IND and is associated with the
right entrance region to the very strong 150kt 3H jet across the
Great Lakes.  A flat speed induced 5H  shortwave is lifting across
S MO and is strengthening the LLJ out of Arkansas into the Lower
Ohio River Valley.  This shortwave will continue to remain
flat/elongated across the area of concern while keeping the mean
deep layer flow fairly unidirectional to support a favorable
training repeating environment.

CIRA LPW along with RAP analysis denote this LLJ is starting to
pool deeper layer moisture along the axis of concern in the Lower
Ohio River Valley, with Total PWat values starting to reach 1.4 to
1.5 across MO into S IL.   02z surface analysis denotes the
surface front is a bit south across S MO and ext S IL/SW IND
before becoming a bit looser defined into SE IND with a weak
inflection nearing CVG.  The moistening of the mid-levels is
reducing lapse rates and so instability is weakening along and
south of the boundary.  Still, the surface flow is contributing to
some moisture flux convergence along the front to initiate
scattered thunderstorms, though are not as dense as the 850mb
gradient boundary is a bit further north closer to the better
upper-level divergence axis.

This is resulting is a split of activity with stronger cells along
the front but should be in short duration, yet, the low to
mid-level convergence flux boundary shows more dense activity
across SE MO into S IL and starting in IND.  Activity will be
displaced from best instability and rainfall rates should be a bit
more moderate in nature.  However, the duration will be longer and
with occasional embedded stronger cores may still reach 1-1.25"/hr
rates through the next few hours as it expands eastward into SE
IND/SW OH.  This should result in streaks/narrow axis of 2 to
possibly localized 3" totals through 09z which may result in
possible scattered incidents of flash flooding through the early
morning hours.

Gallina

 

[ElectricStorm]

That 0z HRRR run is absolutely nasty, luckily it seems the other models are a little more tame. Seems to be a really fine line here between a linear event and a major outbreak, hopefully it's the former. 

[ElectricStorm]

Moderate risk expanded a bit with some really strong wording in there. 

Quote

Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1256 AM CDT Fri Mar 24 2023

   Valid 241200Z - 251200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF THE MID-MISSISSIPPI VALLEY...

   ...SUMMARY...
   An outbreak of severe weather is expected from the Lower Mississippi
   Valley toward the lower Ohio Valley Friday afternoon and evening.
   Tornadoes, strong to potentially intense, as well as damaging winds
   and hail are expected.

   ***Tornado Outbreak Possible Across Portions of the Mid Mississippi
   Valley Friday Evening***

   ...Synopsis...
   A mid-level trough can be seen on water vapor east of the northern
   Baja Peninsula this morning. This trough will move quickly across
   the southern Plains through the day and into the Mid
   Mississippi/Lower Ohio Valley by Saturday morning. A very strong
   mid-level jet (90-100 knots) will develop as this wave impinges on a
   strong upper-level High across the Southeast. 

   Broad warm air advection is expected across the Mid-Mississippi
   Valley during the day Friday with a strengthening low-level jet
   through the day. Significant mass response is expected across this
   area by early evening as the mid-level trough approaches the area.
   As a result, the surface low will deepen rapidly between 00Z to 06Z
   to around 992-994mb in the southern Illinois/Indiana vicinity.
   During this period of rapid deepening, a warm front which is
   forecast to be mostly stationary from northeast Arkansas to central
   Tennessee during most of the day, will start to move quickly north
   during the late afternoon with the northern extent of the warm
   sector depicted by the approximate path of the surface low.

   ...Mid Mississippi Valley...
   Thunderstorms will be ongoing at the beginning of the period across
   eastern Oklahoma and western Arkansas. Some embedded supercells are
   possible with the threat for a few weak tornadoes. Most guidance is
   consistent with the convectively enhanced cold front drifting south
   into north-central/northeast Arkansas in the morning. Therefore,
   this early activity will likely wane as it interacts with this
   southward moving front by late morning. 

   A pocket of drier air can be seen on water vapor moving north in the
   west-central Gulf early this morning. This is associated with a
   relative minimum in PWAT which will overspread eastern Louisiana and
   much of Mississippi during the late morning and through the
   afternoon. This seems to be responsible for the significant mixing
   and surface dewpoint reductions seen my much of the guidance across
   Mississippi in the afternoon where temperatures warm into low 80s.
   However, despite this drier air further east, deep moisture will
   remain across the western Gulf and will advect northward into
   Louisiana during the afternoon as low-level mass response increases.
   By mid to late afternoon, upper 60s to potentially low 70s dewpoints
   are expected across northern Louisiana and eastern Arkansas,
   spreading into northern Mississippi by the evening. This will lead
   to an uncapped warm sector featuring MLCAPE of 500-1000 J/kg up the
   Mississippi River to near Memphis and 1500-2000 J/kg farther south
   across northern Louisiana and west-central Mississippi. 

   Expect storms to strengthen during the afternoon as the better
   moisture advects northward and destabilizes the airmass ahead of
   ongoing activity. CAM guidance is in agreement for a strong QLCS to
   develop from central to northern Arkansas during the afternoon. This
   line of storms will pose a threat for damaging wind and QLCS
   tornadoes given the long, curved low-level hodographs with the best
   overlap of favorable shear and instability in the vicinity of the
   Mississippi River. This line of storms will eventually outrun the
   better instability as it moves toward Middle Tennessee/southern
   Kentucky, but the strong low-level jet (~70 kts), and strong forcing
   with the deepening surface cyclone will help to maintain some severe
   threat well into the overnight despite progressively more meager
   instability. 

   Across southeast Arkansas, northern Louisiana, and northwest
   Mississippi, a more volatile environment will develop Friday
   evening/early overnight. More discrete convection is anticipated on
   the southern periphery of the aforementioned QLCS. The more discrete
   mode, combined with greater instability and strong shear should
   allow for multiple supercells to develop across northern Louisiana
   and southern Arkansas and move northeastward. Low-level hodographs
   are very favorable in this region with 0-500m SRH around 200 m2/s2
   and 0-1km SRH 300+ m2/s2. Therefore, any sustained supercells will
   be capable of producing strong to intense (EF3+) tornadoes, with
   long-track tornadoes possible with any longer-lived, undisturbed
   supercells.

   00Z HREF members showed a variety of solutions which cast some
   uncertainty on the forecast. WRF members are notably less bullish
   with warm sector supercell development from northeast Louisiana into
   northern Mississippi while the HRRR was most aggressive with
   convective coverage and environment. After further investigation it
   appears the more aggressive HRRR solution can be attributed to a
   more robust mass response during the afternoon/early evening hours.
   This results in a pronounced shortwave trough which can be seen at
   700 and 850mb and reflected as a significant confluence zone at the
   surface. Not only does this act as a forcing for storm development,
   but it also acts as moisture convergence with a more broad region of
   70+F dewpoints. In this scenario, numerous strong tornadoes would be
   likely, with the potential for several intense tornadoes. Despite
   being the most aggressive, this solution does not seem unreasonable
   as similar low-level confluence features can been on both the 00Z
   GFS and the 18Z ECMWF. 

   As is often the case, the severity of the tornado threat across the
   moderate risk will be modulated by mesoscale influences in the
   region. As the event approaches, these mesoscale effects may become
   more clear and allow the greatest risk corridor to become better
   defined.

   ..Bentley/Weinman.. 03/24/2023

If the HRRR continues to show an outbreak and morning/early afternoon surface obs support it, I think this could be a candidate for a upgrade. Probably a small chance like usual but the ceiling here is really high...

[StormfanaticInd]

[Neoncyclone]

This evening definitely has a high ceiling.

 

This sounding is an hour before the pre-frontal storms initiate near AR/LA/MS

Shown circled is the presence of steep low-level lapse rates, decent 3CAPE (instability in the lowest 3km), and the shear profile is looking solid as well, and should only improve as storms move ENE throughout the evening.

 

 

 

[Iceresistance]

2.5 inches yesterday, then .6 last night, which means I got 3.1 inches in total.

[Iceresistance]

90% STI for Southern Arkansas on the 3z SREF!

[Ingyball]

Another dry storm here. Can't escape winter here. Need the storm pattern to shift north early if we want to catch up to normal this spring. Problem is we really need an above normal spring on top of that so getting behind is even worse.

[Grace]

The front is trending north on 12z HRRR

 

[Iceresistance]

Moderate Risk larger, now includes Memphis, TN

[snowlover2]

Updated day 1 looks unchanged.

[Bman10]

I think Moderate risk is a good call. Gonna be an interesting evening / night though. 

[ElectricStorm]

And here we go 

Quote

Mesoscale Discussion 0321
   NWS Storm Prediction Center Norman OK
   1250 PM CDT Fri Mar 24 2023

   Areas affected...northeast Texas...central and southern Arkansas and
   parts of northern Louisiana

   Concerning...Severe potential...Watch likely 

   Valid 241750Z - 242015Z

   CORRECTED FOR GRAPHIC

   Probability of Watch Issuance...95 percent

   SUMMARY...Storms are expected to increase in coverage and intensity
   along a cold front, with a damaging wind, hail and tornado risk
   developing through the afternoon.

   DISCUSSION...Storms have increased recently along a cold front from
   southeast OK into northeast TX, and this trend is likely to continue
   as the air mass destabilizes downstream toward the Arklatex. 

   Surface analysis shows modifying outflow extending eastward across
   central AR, with a leading line of storms heading toward the Memphis
   area. Southerly winds are gusting to over 30 kt south of the dying
   outflow boundary in AR, and surface observations near the Red River
   are recovering. As such, the severe risk area will likely include
   parts of AR which are currently cooler/stable, due to expected
   destabilization later today.

   Low pressure will move east/northeast across the modifying outflow
   zone, reaching northeast AR by 00Z. This zone will be a favored area
   for severe storms including tornadoes and damaging winds, with mixed
   storm modes possible. Low-level shear is currently strongest in this
   area, averaging around 250 m2/s2 0-1 SRH. However, shear across the
   entire region will become more favorable for supercells and
   tornadoes later today.

   Through early afternoon, the severe risk is expected to evolve from
   the activity over northeast TX as it moves into AR and interacts
   with the enhanced low-level shear zone.

   ..Jewell/Guyer.. 03/24/2023

 

[ElectricStorm]

First watch of the day is up for areas west of the moderate risk 

Quote

URGENT - IMMEDIATE BROADCAST REQUESTED
   Tornado Watch Number 75
   NWS Storm Prediction Center Norman OK
   130 PM CDT Fri Mar 24 2023

   The NWS Storm Prediction Center has issued a

   * Tornado Watch for portions of 
     Southwest Arkansas
     Northwest Louisiana
     Far Southeast Oklahoma
     East and Northeast Texas

   * Effective this Friday afternoon and evening from 130 PM until
     700 PM CDT.

   * Primary threats include...
     A few tornadoes possible
     Scattered large hail and isolated very large hail events to 2
       inches in diameter possible
     Scattered damaging wind gusts to 65 mph possible

   SUMMARY...Storms are expected to intensify near and ahead of a cold
   front across the ArkLaTex region, with additional and somewhat more
   isolated storms possible by late afternoon. Overall severe potential
   including tornado risk is expected to increase as storms progress
   east-northeastward through late afternoon/early evening.

   The tornado watch area is approximately along and 65 statute miles
   east and west of a line from 50 miles northeast of De Queen AR to 20
   miles east of Lufkin TX. For a complete depiction of the watch see
   the associated watch outline update (WOUS64 KWNS WOU5).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A Tornado Watch means conditions are favorable for
   tornadoes and severe thunderstorms in and close to the watch
   area. Persons in these areas should be on the lookout for
   threatening weather conditions and listen for later statements
   and possible warnings.

   &&

   AVIATION...Tornadoes and a few severe thunderstorms with hail
   surface and aloft to 2 inches. Extreme turbulence and surface wind
   gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean
   storm motion vector 23035.

   ...Guyer

 

[ElectricStorm]

Observed 18z soundings from SHV and JAN

[Neoncyclone]

Looks like we're going to be dealing with more of a  zonal flow rather than meridional flow, which should help storms initiating ahead of the cold front stay discrete.

[Neoncyclone]

Also important to note that most of the mid-level dry air that was moving into LA earlier today has mostly moved out

[snowlover2]

Updated day 1 again with no real changes.

[ElectricStorm]

Quote

Mesoscale Discussion 0323
   NWS Storm Prediction Center Norman OK
   0338 PM CDT Fri Mar 24 2023

   Areas affected...central and southern Arkansas into northern
   Louisiana

   Concerning...Tornado Watch 75...

   Valid 242038Z - 242245Z

   The severe weather threat for Tornado Watch 75 continues.

   SUMMARY...The threat for tornadoes is increasing across the watch
   area, and will likely extend east of the existing tornado watch this
   evening.

   DISCUSSION...Storms continue to organize along the cold front,
   particularly near the surface low over west-central AR where a small
   MCS has formed just on the cool side of the modifying outflow. Other
   storms extend southward along the primary cold front toward TXK, and
   farther south into TX.

   Of special note are multiple bands of convection which are gradually
   deepening within the moist plume near the Sabine River. This plume
   of 70+ dewpoints is resulting in over 1500 J/kg MLCAPE, which is
   sufficient to support supercells as lift continues to increase with
   time. While a relative warm layer still exists near 700 mb as can be
   seen on the 18Z SHV sounding, the moist layer has already become
   deep enough to break the cap, resulting in warm-sector storms well
   east of the cold front.

   As the low-level jet increases this evening, so will shear and
   supercell/tornado potential. Effective SRH on the order of 300 m2/s2
   with 0-1 SRH over 200 m2/s2 may support a few strong tornadoes with
   maturing cells east of the cold front. As such, a new watch will
   likely be needed to include areas east of WW 75.

   ..Jewell/Guyer.. 03/24/2023

 

[Iceresistance]

Tornado Warning for Prescott

Edited March 24, 2023 by Iceresistance
Wrong City

[Iceresistance]

Ryan Hall Y'all is Live

 

[ClicheVortex2014]

JAN's environment has some work that needs done

[Iceresistance]

I saw some debris falling from the sky from an IDriveArkansas Camera at I-30 at MM 99.