River Flood Warning 12, NWS Lincoln, IL

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
610 AM CDT Tue Apr 2 2024

.KEY MESSAGES...

- Scattered thunderstorms will develop mid to late this morning
  along and east of I-57. There is a level 1 of 5 (marginal) risk
  for severe weather from these storms between 10 am and 4 pm.
  Have multiple ways to receive warnings, and a plan for taking
  shelter.

- There is a 60-70% chance west-southwest winds will gust over 45
  mph across east-central IL this afternoon. Northwest winds will
  gust 40-45 mph, possibly higher, tomorrow. Those driving high
  profile vehicles should use caution.

- Tonight through Wednesday night, snow showers are expected
  mainly north of a Macomb to Paxton line. There is a 30-40%
  chance for more than 1 inch of accumulations which will occur
  mainly on grassy surfaces.

- Near freezing temperatures are forecast Wednesday through Friday
  nights, with the greatest chance (50-80%) for a hard freeze
  Friday night. Precautions will be needed to protect newly
  emerged, sensitive vegetation.

&&

.DISCUSSION...
Issued at 326 AM CDT Tue Apr 2 2024

At 3am, sfc obs show a pseudostationary front draped along and just
north of the I-72 corridor. South of this boundary, southerly winds
are maintaining dewpoints, like temps, in the upper 50s, while north
of it northeast winds are holding temps in the lower 50s. Convective
activity, however, has pushed the instability axis a bit further
south; that is, south of an Effingham to Robinson line where the
severe threat isn't completely over and a tornado watch remains in
effect. After a couple more hours, that threat should be over, as
well as the threat for flooding which at this point remains the
larger concern given the strength of moisture advection with the LLJ
which has resulted in efficient rain producers already (MRMS
estimating a swath of 2-3.5+ inches fell between I-72 and I-70).

The CAMs then suggest a break will occur for most of the area around
sunrise, with scattered cells or a broken line developing along the
cold front between mid morning and lunchtime. Given 0-6km shear
values around 65-80kt (much of this being in the lowest levels, with
the HRRR depicting 0-1km SRH up to around 200 m^2/s^2) and SBCAPE
around 1500-2500 J/kg, the environment will be favorable for
rotating storms capable of all severe hazards east of I-57. These
storms are forecast to pose a severe risk in the ILX CWA mainly
between noon and 3pm, thereafter racing into a more
thermodynamically conducive environment for severe weather across
Indiana. Behind the cold front driving this line, west-southwest
winds will dramatically increase with BUFKIT mixing techniques
suggesting gusts to around 36-42 kt possible across much of the area
(highest east). Ensemble mean from the EPS is higher than the CAMs,
suggesting max gusts around 50-55 mph (vs 40-45 mph from the NAMNest
and HRRR). Not sure why this is, but as it suggests a 95% chance for
gusts of 45 mph or higher (i.e., Wind Advisory criteria) east of
I- 57 today, it's hard to feel confident enough we won't hit
criteria to withhold one. We've thus issued a Wind Advisory for
areas along and east of I-57 and north of I-70, where confidence
is highest in the stronger winds mixing down behind the cold front
early-mid afternoon; this runs (from noon) through 8pm because
(1) guidance is often too fast in bringing down winds in post-
frontal environments and (2) the low is expected to be rapidly
deepening which might prolong the winds more than normal...though
we may be allowed to expire it early if winds underperform or ease
sooner.

As the severe weather threat shifts out of our area, the wrap around
moisture on the back side of the low arrives from the northwest mid
to late afternoon. The best dynamic forcing for banded wintry precip
will be across northwest IL, eastern IA, and southern/central WI,
but we'll have some flakes mixing in late tonight through tomorrow
morning north of I-72. Accumulations at this point still look
minimal, but we'll need to watch tomorrow evening/night for some
heavier snow showers that could drop a quick inch or more (along
with increased wind gusts) in a few locations. Outside of these snow
showers tomorrow, winds will be gusting 35-45 mph; within them,
there is concern for stronger gusts which combined with snow could
temporarily reduce visibility significantly. There's low confidence
(10-20% chance) in this materializing, let alone the location where
it'd occur, but we'll keep watching the highres guidance for more
insight. We've held off on a Wind Advisory for tomorrow given low
confidence in how deep the sfc low becomes, and to avoid confusion
since there's already one in effect for a portion of the area today.
NBM would suggest a roughly 40-50% we gust to 45+ mph tomorrow
afternoon and evening, though; stay tuned for updates.

Unsurprisingly, temps cool to near freezing area-wide tonight and
tomorrow night, with increased chances for a freeze Thursday and
Friday nights. Given subsidence with high pressure building in, few
(if any) clouds and light winds should favor Friday night as the
coldest; there is a 50-80% chance for a hard freeze area wide.

The expanding ridge of high pressure will result in warming
conditions over the weekend, though both the ECMWF and GFS now show
a trough flattening the ridge by early next week. Ahead of that
trough, there will be an increase in precip chances and cloudiness
which could impact folks' ability to spot the eclipse. Being a week
out, though, that is subject to change dramatically; stay tuned.

Bumgardner

&&

.AVIATION...  (For the 12z TAFs through 12z Wednesday Morning)
Issued at 604 AM CDT Tue Apr 2 2024

As a low pressure system lifts northeast through central Illinois
today, winds and flight categories will be shifty. LIFR visibilities
at PIA and BMI should improve as the low pulls northward into
northern IL early this afternoon, with ceilings improving
slightly. As this low deepens, however, west-southwest winds will
increase and gust upwards of 30 kt - highest at BMI, CMI, and DEC.
Winds will veer to west late afternoon and evening, while easing
gradually. Rain mixed with snow will drift south on the back side
of the low tonight to reduce visibilities mainly at the northern
(BMI and PIA) terminals.

Bumgardner

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from noon today to 8 PM CDT this evening for
ILZ045-046-055>057-062-063.

Flood Watch until 1 PM CDT this afternoon for ILZ062-063-066>068-
071>073.

&&

Hazardous Weather Outlook
National Weather Service Lincoln IL
523 AM CDT Tue Apr 2 2024

ILZ027>031-036>038-040>057-061-031030-
Knox-Stark-Peoria-Marshall-Woodford-Fulton-Tazewell-McLean-Schuyler-
Mason-Logan-De Witt-Piatt-Champaign-Vermilion-Cass-Menard-Scott-
Morgan-Sangamon-Christian-Macon-Moultrie-Douglas-Coles-Edgar-Shelby-
523 AM CDT Tue Apr 2 2024

This Hazardous Weather Outlook is for central Illinois, east
central Illinois and west central Illinois.

.DAY ONE...Today and tonight.

An isolated thunderstorm is possible (30% chance) late this morning
into early afternoon.  Severe weather is not expected.

Northwest winds will gust 35 to 45 mph this afternoon, highest over
eastern IL.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Breezy northwest wind gusts of 35-45 mph are expected on Wednesday.

Low temperatures near freezing Thursday and Friday mornings may
cause some damage to early emerging vegetation.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated through tonight.

ILZ062-063-066>068-071>073-031030-
Cumberland-Clark-Effingham-Jasper-Crawford-Clay-Richland-Lawrence-
523 AM CDT Tue Apr 2 2024

This Hazardous Weather Outlook is for east central Illinois and
southeast Illinois.

.DAY ONE...Today and tonight.

Scattered thunderstorms are expected late this morning into mid
afternoon.  A few storms could have damaging wind gusts and hail.

Northwest winds will gust 35 to 45 mph late this afternoon and
evening.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Breezy northwest wind gusts of 35-45 mph are expected on Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed between 10 am and 4 pm.

25

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

Preliminary Local Storm Report
National Weather Service Lincoln IL
836 AM CDT Tue Apr 2 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0700 AM     Rain             Lovington               39.71N 88.63W
04/02/2024  M3.53 Inch       Moultrie           IL   CO-OP Observer

&&

Barnes

Preliminary Local Storm Report
National Weather Service Lincoln IL
842 AM CDT Tue Apr 2 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0700 AM     Rain             1 SSE Effingham         39.11N 88.53W
04/02/2024  M2.67 Inch       Effingham          IL   CO-OP Observer

&&

Barnes

Preliminary Local Storm Report
National Weather Service Lincoln IL
846 AM CDT Tue Apr 2 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0830 AM     Rain             Franklin                39.62N 90.05W
04/02/2024  M2.75 Inch       Morgan             IL   Mesonet

&&

Barnes

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

Preliminary Local Storm Report
National Weather Service Lincoln IL
905 AM CDT Tue Apr 2 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 AM     Rain             1 ESE Mattoon           39.47N 88.35W
04/02/2024  M2.55 Inch       Coles              IL   CO-OP Observer

&&

Barnes