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000
FXUS63 KDVN 221742
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1242 PM CDT Mon Apr 22 2024

...Updated for 18z Aviation...

.KEY MESSAGES...

- Clouds will move into today ahead of a cold front that will
  sag through the area into Tuesday. Precipitation will battle
  dry air before eventually starting to fall south of I-80 later
  tonight and tomorrow.

- End of the period looks very active with the return of rain
  and thunderstorms. Some of these storms could be strong and
  there is a increasing chance (20-30%) for heavy rain as well.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 311 AM CDT Mon Apr 22 2024

Southwest flow this morning has kept temperatures warmer than
expected for 3 AM. Still think temperatures will drop some and
as the earlier shift noted, there remains a risk for frost
development in valleys and low-lying areas. Otherwise, ridging
will start the day as we see WAA into the area. A wave and cold
front north of the area will move south towards us during the
day. High clouds will overspread the area leading to cloudy
skies later in the day. Nonetheless, deep mixing will occur as
we see temperatures well into the 60s across the area. This
mixing will again result in a windy day across the area as
sustained winds of 20 to 30 MPH are expected with gusts
approaching 40 MPH. The strongest winds will be west of the
Mississippi River. As the front slides into the area overnight,
we look to stay mixed. It will also be windy overnight. The HREF
prob exceedance of 45 MPH gusts is actually maximized tonight
(40-60%) as opposed to during the day. We may need a wind
advisory, especially if winds start to overachieve upstream.

As far as precipitation goes, the deep mixing will mix down dry
air with dewpoints in the low 30s to upper 20s. With winds
staying up, and a lack of moisture advection, it appears as
though most of the area will stay dry through about 06z or so.
As the front slowly makes its way south it will encounter better
deep layer moisture. Rain will eventually break out mainly along
and south of highway 34 overnight. As earlier advertised, this
will be light rain at best with total accumulation up to a tenth
of an inch of rain.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 311 AM CDT Mon Apr 22 2024

To start Tuesday, the cold front will be slowly sagging south
into the area. The better CVA arrives in the afternoon and will
likely fire some isolated showers and storms on the cold front.
There is about 100-150 J/kg of 0-3 CAPE and some good 0-3 shear,
near 30-40 kts, in a very narrow axis coincident with the front.
These showers/storms that develop could mix down some near
severe wind gusts. CAMs have these showers developing after 18z
as the main wave moves into the area. Will mention the
possibility of strong storms with these showers, especially
across the far east and southeast CWA between 18z and 00z
Wednesday.

Beyond this, guidance continues with a deep trof over the
western CONUS as a series of waves roll off into the central
CONUS. From Friday to Sunday, it looks like we will be wet with
chances for thunderstorms, some of which could be strong to
severe. Increasing deep layer moisture along with increasing
temperatures will increase instability across the area. Each of
these waves will have enough shear for updraft organization and
thus a chance for organized convection. This has the potential
to be a multi-day strong to severe event. Looking towards QPF,
there is a large range in solutions, however looking at a
25-75th percentile bin of 72 hour accum from the NBM it looks
like most of the area will see at least an inch of rain and
possibly higher. This pattern has the potential to bring heavy
rain along with strong to severe storms.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1235 PM CDT Mon Apr 22 2024

Predominantly VFR conditions are expected along with gusty
SW/W winds. Wind gusts will be 25-35 kt at times. Guidance is
generating a fleeting period of LLWS after 03z-10z from N to S
across the terminals with a nocturnal LLJ, but confidence is
low as surface winds are likely to remain gusty and thus have
held off on any mention at this time. Several CAMs suggest
a few showers are possible this evening with elevated warm air
advection, but probabilities are generally around 20% and also
sub-cloud dry air could lead to mainly sprinkles with no
impacts, and so because of this I`ve not included this in the
TAFs. Tuesday, winds will return to gustiness by mid to late
morning with gusts to 30 kt ahead of an approaching front.
There will be an accompanying chance for showers at KMLI and
KBRL and have introduced PROB30 mention 14z-18z. Just beyond
the end of the TAF period, the front will sweep through the
terminals with winds shifting to the NW and ramping up with
gusts 30-40 kt and locally higher possible near any convection.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.

&&

$$

SHORT TERM...Gibbs
LONG TERM...Gibbs
AVIATION...McClure