Flash Flood Warning 2, NWS La Crosse, WI

990 
WGUS73 KARX 111726
FFSARX

Flash Flood Statement
National Weather Service La Crosse WI
1226 PM CDT Thu May 11 2023

IAC131-111945-
/O.CON.KARX.FF.W.0002.000000T0000Z-230511T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mitchell IA-
1226 PM CDT Thu May 11 2023

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 245 PM CDT THIS 
AFTERNOON FOR NORTHEASTERN MITCHELL COUNTY...

At 1226 PM CDT, Doppler radar indicated thunderstorms producing 
heavy rain across the warned area. Between 3 and 4 inches of rain 
have fallen. Rainfall rates have significantly diminished, 
additional amounts up to 0.5 inches are possible in the warned area.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  McIntire, County Roads T 54 And A 31 and Bailey.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4349 9255 4347 9255 4343 9258 4334 9264
      4335 9273 4341 9270 4350 9264 4350 9258
      4350 9256 4350 9255

FLASH FLOOD...RADAR INDICATED

$$

JAW

325 
WGUS73 KARX 111909
FFSARX

Flash Flood Statement
National Weather Service La Crosse WI
209 PM CDT Thu May 11 2023

IAC131-111919-
/O.CAN.KARX.FF.W.0002.000000T0000Z-230511T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mitchell IA-
209 PM CDT Thu May 11 2023

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHEASTERN MITCHELL 
COUNTY...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed any road 
closures.

LAT...LON 4349 9255 4347 9255 4343 9258 4334 9264
      4335 9273 4341 9270 4350 9264 4350 9258
      4350 9256 4350 9255

$$

CZ

Area Forecast Discussion
National Weather Service La Crosse WI
847 AM CDT Thu May 11 2023

.UPDATE...
Issued at 845 AM CDT Thu May 11 2023

Thunderstorms have been re-developing over parts of northeast Iowa
and southeast Minnesota in favorable thickness diffluence. The
greater surface instability remains to the west although there is
elevated instability that increases during the afternoon. There
are 10-12deg C 850mb with upper level support and a weak shortwave
trough. Expect showers/storms to continue through the morning
hours. The short terms CAMs weaken the area considerably by 19Z.With
the thickness diffluence shifting east, some concern that the
showers could persist longer per the ARW. For now have maintained
weakening trend with the northwest third of the forecast area
seeing the showers/storms through early afternoon. Main concern
this morning is locally heavy rain. Rain/storms moving 15 to 20kts
and have put down some 1 to 3" rains.

&&

.DISCUSSION...(Today through Wednesday)
Issued at 335 AM CDT Thu May 11 2023

Key Messages:

 - Periodic, lower predictability showers and storms through the
   weekend, with the best risk today west of the Mississippi
   River.

 - Seasonal temperatures well into next week with slightly cooler
   weather for the end of the weekend and early next week.

Today - Friday: Threat for Storms Spreads East

Early morning water vapor imagery shows a stable upper level wave
structure in place over the Northern Hemisphere with the mean
longwave pattern changing little over the course of the next seven
days. One such longwave ridge could be found over the CONUS this
morning, though it is punctuated by a sharp shortwave
trough/closed low along the Front Range and a disconnection
between the northern and southern stream components of the ridge
axis over the Northern Plains, allowing a 70-80-kt jet to exist
near the U.S. and Canadian border. Looking closer to the local
area, we find ourselves just east of the upper level ridge axis
with the deeper moisture and instability shunted mainly west of
the I-35 corridor over the last few days, keeping the threat of
precipitation at bay.

That being said the pattern does undergo amplification today and
tonight with the ridge axis sliding ever so slightly eastward in
the process. The leading edge of the richer 925-850-mb theta-e
airmass also migrates into the western forecast area this morning.
An ongoing complex of showers and storms over south-central
Minnesota may push as far east as the Mississippi River this
morning before weakening with the strengthening upper ridge
overhead. The big question with this immediate system is how long
it will persist this morning and what impacts it will have on
convective trends later today.

As with its predecessors in this weak forcing regime, the CAMs
have struggled to resolve the placement and behavior of these
convective complexes. This system is already displaced southeast
of where the 00Z HREF suite indicated, building further
southeastward along the upwind propagation vectors. Have pushed
PoPs and QPF values in the western forecast area higher as an
immediate short-term fix, but should this complex linger farther
south and later into the day than progged, its remnants may serve
as a focus for renewed convective development at peak heating. The
forecast for the afternoon remains dry at the moment, but would
not be surprised if afternoon redevelopment takes place farther
south than the evening/overnight HRRR runs depict.

Saturday and Sunday: Periodic Showers and Storms

Attention then turns to the Front Range trough lifting NNE over
the ensuing 48 hours. This pulls the deeper moisture further east
into the forecast area and it is quite likely (> 70%) that a given
location will see rain at some point between Friday and Sunday.
However, the timing and location of any given storm will be tied
to nuance perturbations in the atmosphere given the lack of a
strong forcing trigger. The lifting trough rapidly dissipates as
it attempts to crest the ridge Saturday night into Sunday, leaving
the surface low orphaned and decaying through the day on Sunday.
A band of moderate rain may develop along this remnant baroclinic
zone/isentropic ascent corridor on Sunday as ridging builds to the
north.

While the threat of rain permeates the forecast from this evening
into Sunday, we are not expecting a widespread washout by any
means. Storms will likely be slow-moving, so those areas that do
find themselves under one of these cells could pick up a quick
half inch of rain (per the max QPF output from the 11.00Z HREF) in
a short amount of time.

Temperatures heading into the weekend will be slightly cooler
than what we saw midweek as clouds and showers build eastward.
Nevertheless, highs in the 70s remain on the docket for today
through Saturday. The deterministic guidance shows the storms on
Sunday playing a greater influence on the daytime temperatures and
confining highs in the 60s.

Monday - Wednesday: Drier Start to the Week

The pattern resets for the first half of next week as ridging
retrogrades westward towards the High Plains. North to northwest
flow becomes established in the process, with a potential
shortwave/surface trough ebbing through the flow on Tuesday. This
could serve as a trigger for increasing clouds and some light
showers, but on the whole the first part of the week looks to be
on the drier side.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
Issued at 553 AM CDT Thu May 11 2023

An area of showers will impact KRST for a time this morning,
although mainly VFR conditions are expected. An isolated storm is
possible (20-30% chance), but a gradual weakening trend appears
likely as storms approach KRST. Otherwise, VFR conditions are
expected this afternoon/evening with SE winds up to around 10 kts.
Additional showers are possible after 12.06Z (20-30% chance) with
some guidance suggesting MVFR ceilings may try to develop from
the southwest. However, given the fairly low confidence in lower
ceilings/precip chances, will maintain a dry VFR forecast for
tonight for this update.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

UPDATE...Zapotocny
DISCUSSION...Skow
AVIATION...JM

Hazardous Weather Outlook
National Weather Service La Crosse WI
900 AM CDT Thu May 11 2023

IAZ008>010-018-019-029-MNZ079-086>088-094>096-WIZ017-029-032>034-
041>044-053-055-121800-
Mitchell-Howard-Winneshiek-Floyd-Chickasaw-Fayette-Wabasha-Dodge-
Olmsted-Winona-Mower-Fillmore-Houston-Taylor-Clark-Buffalo-
Trempealeau-Jackson-La Crosse-Monroe-Juneau-Adams-Vernon-Richland-
900 AM CDT Thu May 11 2023

This Hazardous Weather Outlook is for portions of southeast
Minnesota...northeast Iowa and southwest into central Wisconsin.

.DAY ONE...Today and Tonight

Showers and thunderstorm for parts of Minnesota, western Wisconsin
and Iowa today and tonight. The threat for severe weather is very
low, less than 5 percent. The main concern for parts of southeast
Minnesota and parts of northeast Iowa would be locally heavy rain
due to the slow movement and storms developing over the same area.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

There is a 30 to 50 percent chance of thunderstorms Friday
through Saturday night. The threat for severe weather looks low,
5 percent or less.

.SPOTTER INFORMATION STATEMENT...

No action needed.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

IAZ011-030-WIZ054-061-121800-
Allamakee-Clayton-Crawford-Grant-
900 AM CDT Thu May 11 2023

This Hazardous Weather Outlook is for portions of northeast Iowa
and southwest Wisconsin.

.DAY ONE...Today and Tonight

Flooding is occurring along the Mississippi River downstream of
Lansing. Please see the latest flood statements and warnings for
details.

There is a 30 to 60 percent chance of thunderstorms today and
tonight. The threat for severe weather is very low, less than 5
percent.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Flooding ends along the Mississippi River by this weekend.

There is a 30 to 50 percent chance of thunderstorms Friday
through Saturday night. The threat for severe weather looks low,
5 percent or less.

.SPOTTER INFORMATION STATEMENT...

No action needed.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

Zapotocny

nofwd