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

[Iceresistance]

There is still too much model uncertainty for now (As of 3/17/2023), but here is this from the SPC.

 

Spoiler

low-level moisture should return northward across parts of the southern/central Plains, lower/mid MS Valley, and perhaps the Midwest from Day 6/Wednesday into Day 7/Thursday.

Increasing potential for severe thunderstorms will probably be realized on Thursday across portions of these regions as both instability and shear strengthen ahead of a cold front/dryline. However, there are still notable differences/spread in both deterministic and ensemble guidance regarding the ejection of the upper trough, and placement of related surface features. Parts of the southern/central Plains into the mid MS Valley vicinity may eventually need a 15% severe delineation once better run-to-run and inter-model consistency increases. Depending on the evolution of the upper trough and low-level moisture return ahead of it, a severe threat may also exist across parts of the lower MS Valley and Southeast on Day 8/Friday.

 

[ElectricStorm]

This is definitely looking interesting, day 6 slight risk up now 

[ClicheVortex2014]

Plenty of moisture with this setup and a positive tilt but slow moving trough. Should be a multi-day threat.

Edited March 18, 2023 by ClicheVortex2014

[snowlover2]

Wondering if we can add heavy rain/flooding to this thread? GFS and Euro both agree on a widespread several inches.

[snowlover2]

ILN mentions this threat.

Quote

.LONG TERM /MONDAY THROUGH SATURDAY/...
At the start of the work week, the area will be located on the
northwestern side of a large surface high pressure system
centered over the southeastern USA. Large scale subsidence will
allow for partly cloudy skies on Monday. Southwesterly flow/
warm air advection will aid in a warming trend, with highs on
Monday in the upper 40s/low 50s (overnight lows in the 20s) and
mid to upper 50s on Tuesday. Cloud cover increases Tuesday
afternoon ahead of the next system and overnight lows are
moderated a bit and drop to the low 40s.

Looking toward mid-week, the changes in guidance noted by the
midnight shift are still being echoed in the 12z runs (for
context:
previously, a large troughing pattern was forecast to move
onshore in western CONUS, translating to a rather robust surface
low moving through our area near the end of the week). More
recent guidance now suggests a mid level 700H shortwave
developing ahead of the deep trough, with its own separate
surface low deepening and moving northeast toward the northern
Great Lakes region Tuesday night into Wednesday-ish. This low
pressure system drags a cold frontal boundary along with it,
which eventually stalls out somewhere near the OH-IN-IL area.
Then, a secondary low associated with the larger pattern moves
through at the end of the work week/ into the start of the
weekend. This updated scenario increases precipitation chances
for the area, thus keeping PoPs in the forecast for several days
straight.

With all this being said, mid to end of the week looks to be messy,
complicated, and have limited details due to lower confidence.
As of right now, there are only a couple of forecast points that
have a decent consensus:

1). It will be wet. There is agreement between ensemble
guidance in a large QPF footprint. Given the high pressure in
the southeast and the deep troughing to our west, deep layer
southwesterly to northeasterly flow will be in place over the
area for several days. This allows for a surge of theta-e into
the Ohio Valley- anywhere from a 2-4 sigma PWAT anomaly is
suggested between the two systems. Where the higher swath of QPF
ends up still remains to be seen based on the tracks of the two
low pressure systems. However, multiple rounds of heavy
rainfall (likely convective at points) would behoove a flood
threat late week.

2). It will be windy. Despite the variations between guidance
on the tracks of the low pressure systems, both are going to
pass close enough to (or through) the area, bringing a tight
pressure gradient and strong forcing aloft, which will help
translate synoptic winds down to the surface.

 

[ClicheVortex2014]

23 minutes ago, snowlover2 said:

Wondering if we can add heavy rain/flooding to this thread? GFS and Euro both agree on a widespread several inches.

The way it's looking, certainly looks like a flooding threat for IL/IN/OH. Definitely a spring setup. 

[Iceresistance]

I didn't change title, but whoever did it, thank you.

[Iceresistance]

There is the D6 Slight Risk as @ElectricStorm mentioned before

[FortySixAnd32]

2 hours ago, snowlover2 said:

ILN mentions this threat.

 

He said behoove..... I love it!! 

[Ingyball]

Would be a classic setup in May for the Plains, not sure about moisture quality with this system though. Next system interests me more if it trends north. Would like to cash in on rain eventually. It's mostly been a miss since the February system here. 

[StormfanaticInd]

Dewpoints look good 

[ClicheVortex2014]

32 minutes ago, Ingyball said:

Would be a classic setup in May for the Plains, not sure about moisture quality with this system though. Next system interests me more if it trends north. Would like to cash in on rain eventually. It's mostly been a miss since the February system here. 

We got 0.33" at the office with the last system and that felt like a jackpot, but it's probably all for nothing because we're going back to dry, windy, and sunny... of course, with no other meaningful chance for precip in sight. It's brutal.

60 dew points almost make it into the AMA CWA. Almost. 

Edited March 19, 2023 by ClicheVortex2014

[Iceresistance]

We have 3/23 as a severe weather chance for Dixie Alley now, 3/22 is now larger over most of Oklahoma

[beaver56]

If we could get the rain at a reasonable rate so it could absorb would be the key here. We need to get things balanced up before planting. 

[Iceresistance]

Of course, I need the SPC outlook to show Y'all

D5

D6

[snowlover2]

 GGEM seems to be onboard with the heavy rain threat.

[snowlover2]

[ClicheVortex2014]

With these kinds of setups, all the action is usually along the cold/stationary front with not much opportunity for discrete/semi-discrete supercells. Also have to worry about clouds impacting destabilization beyond the first day. 

Edited March 20, 2023 by ClicheVortex2014

[ElectricStorm]

CIPS analogs for Thursday, only one that really stands out to me is 2/10/09 but overall I'd say this run is pretty meh. This is the 12z run since the 0z refuses to lead for some reason.

https://www.eas.slu.edu/CIPS/ANALOG/DFHR.php?reg=SP&fhr=F108&rundt=2023031912&map=thbSVR

0z run for Friday, overall a stronger signal for now (ignoring #11 since that's not happening) 

https://www.eas.slu.edu/CIPS/ANALOG/DFHR.php?reg=SE&fhr=F120&rundt=2023032000&map=thbSVR

 

GFS has perhaps slightly unfavorable timing for Thursdays event, but I wouldn't be surprised to see it start slowing down a bit on future runs. Moisture and instability aren't looking great but it's enough for a decent event. I'm kinda thinking this could end up a mostly linear event, which I would be totally fine with as long as it's not a 2/26 repeat. 

I think Friday could be the bigger event from a tornado perspective, although instability doesn't look too great either. It's still a decent ways out so a lot can change, right now I think this system could end up being a pretty solid multi-day wind event, but maybe not a big tornado producer. Definitely need to watch it though. 

 

[snowlover2]

6z GFS very bullish on rain totals.

[snowlover2]

1 hour ago, snowlover2 said:

6z GFS very bullish on rain totals.

12z GFS with even heavier totals.

[Chinook]

For many model runs this has looked like a classic Ohio Valley/Mississippi Valley flood. Hopefully not catastrophic like 1913 or 1937, for people like Snowlover2 in Dayton.

[beaver56]

53 minutes ago, Chinook said:

For many model runs this has looked like a classic Ohio Valley/Mississippi Valley flood. Hopefully not catastrophic like 1913 or 1937, for people like Snowlover2 in Dayton.

5.3 here in my neck of the wood if taken verbatim.  I am going to hope for about a quarter of that in the gentle falling fashion.

[snowlover2]

Rest of the 12z runs. GGEM appears to be a little south of the rest.

[snowlover2]

Latest from ILN.

Quote

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
An impulse ripples
northeast along the boundary late Wednesday into Wednesday night.
This will cause a surge of low-level jet winds across the region.
While the exact spatial extent of the best convergence is uncertain,
it appears QPF amounts will remain modest at this time.

Another, stronger surface wave will accompany mid-level energy along
the front Thursday night into Friday morning. Guidance shows this
energy dragging the frontal boundary into, or perhaps through, the
region overnight. The exact placement of the heaviest swath of
rainfall is still uncertain, but individual members of both the GFS
and European ensemble systems are giving higher confidence of
greater than two inches across the lower and middle Ohio Valley.
With "skinny CAPE" in the forecast soundings from Thursday afternoon
through Thursday night, warm cloud depths approaching 10kft, and
PWATs exceeding an inch, the system could bring
significant/hazardous rainfall. Best overlap of heavy QPF banding
appears to be near the Ohio River at this time... though placement
could shift to the north or south over upcoming updates to guidance.
Will place mention in the Hazardous Weather Outlook to communicate
this potential.

The main mid-level trough starts to shift east into the southern
plains Friday evening, then into the middle Mississippi Valley early
Saturday. Both the GFS and ECMWF paint a surface low moving through
the region during this time. Therefore, likely to categorical PoPs
and heavy rain potential continues.

Drier weather could make an appearance Saturday afternoon into
Sunday before another disturbance brings another chance for rain to
close the period Monday.

Temperatures will be near to above normal through the period with
the warmest stretch from Wednesday night into Thursday night.

IND

Quote

.Hydrology...
Issued at 255 PM EDT Mon Mar 20 2023

*Flooding likely Thursday night into the weekend

Potential for flooding arrives Thursday evening into the overnight
hours with very heavy rain expected in an axis along a frontal
boundary.  Current forecasts are showing that the axis will be
across south central Indiana with model ensembles hinting that a
slightly more southern track for where the axis of heavy rain may be
the final outcome. This far out though things remain fairly
uncertain. Rainfall amounts within the heavier axis may exceed 3
inches with widespread 1-2 inches outside of the heavier axis.

Heavy rain with the second portion of the event looks to set up
closer to the Tennessee Valley Friday into Friday night but if the
GFS solution which has it further north verifies, an additional 1-2
inches of rain is possible which may lead to more significant and
widespread flooding. MMEFS ensembles show that widespread minor
river flooding is likely with the potential for some moderate
flooding if the GFS solution of higher rain amounts is the final
outcome.  Either way, expect travel issues and flooded roads at
times.