882
FXUS63 KDVN 290537
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1237 AM CDT Mon Apr 29 2024

.KEY MESSAGES...

- Isolated shower chances continue into tonight. There could be
  a few storms, but the potential continues to decrease due to
  limited instability.

- Active forecast remains through the long term, with near daily
  chances for precipitation after Monday.

- Temperatures will remain above normal through midweek,
  trending towards normal for the end of the week.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 140 PM CDT Sun Apr 28 2024

Early afternoon surface analysis showed an area of low pressure
centered across the Iowa/Missouri border, with a near
stationary front extending out to its east along the Hwy 20
corridor. A cold front extended south of the low, and stretched
from southeast Nebraska into central Oklahoma. This surface low
was ahead of a robust upper level low over the Nebraska
Panhandle, with a trough extending to its south. Across our
area, widespread rain showers have waned early this afternoon as
the LLJ to our south has weakened. Partly to mostly cloudy
skies remain in place with temperatures in the 60s to low 70s.

Through this evening, the surface low will lift to the northeast,
bringing the cold front across the region. This cold front and a jet
streak associated with the upper level low will act as the forcing
mechanisms for renewed shower and storm development across much
of the region. There is some potential for storms to be strong,
but the overall threat for severe weather has trended lower
thanks to the morning rain showers and persistent clouds over
the area. That being said, our area does remain in Level 1
(marginal) risk of severe thunderstorms, mainly due to the
strong jet dynamics with this system. If we do see severe
storms, the primary threats will be severe winds and hail, with
tornadoes being the secondary threat.

An additional quarter to three quarters of an inch of rain is
expected from showers and storms, with the later favored mainly
along and east of the Mississippi River. This rain will have
potential to prolong or worsen ongoing tributary river flooding.
Please see the hydro discussion below for additional details.

Leftover showers and storms will exit the area Monday morning, with
more clouds than sun expected for the remainder of the day.
Some breaks of sun may be seen along and south of Interstate 80
during the late morning and afternoon. Temperatures will be
cooler with lower humidities, with highs in the 60s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 140 PM CDT Sun Apr 28 2024

Another period of active weather is expected across the Midwest
as a deep trough setting up across the Rockies ejects several
shortwaves over the area.

Tuesday looks to start dry with increasing shower and storm chances
by the late afternoon and evening as a weak cold front and vort max
approach from the west. Guidance is in good agreement of this being
a quick mover, with all precip out of the area by early Wednesday
morning. At this time, severe storms are favored to remain west
of the area.

Late in the week, the aforementioned deep trough will
progress out of the Rockies into the Plains and Midwest, bringing
yet another round of showers and storms to the area. As the previous
discussion eluded to, this will be the one to watch as it will
be accompanied by abundant Gulf moisture and forcing. Details
on the severe threat aren`t clear at this time, but there is
potential for this system to produce heavy rain. Please continue
to monitor the latest forecast information over the coming
days.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1237 AM CDT Mon Apr 29 2024

VFR to MVFR conditions are being seen throughout, but will
continue to trend all VFR by 12z. Spotty showers are being
seen, but we are not expecting much of an impact from these.
BRL will be the terminal that sees more of an impact, as they
are along an area of stratiform rain, with lower cigs. Winds
will remain out of the south tonight, shifting southwesterly and
gusting upwards to 25 KTs by 18z. Cloud cover will start to
decrease through the day as well.

&&

.HYDROLOGY...
Issued at 1124 AM CDT Sun Apr 28 2024

Several tributary rivers are now over flood stage in our
southern portions of the CWA due to last night`s 1-2 inch
rainfall on top of moist soil conditions and already elevated
river stages. Other rivers will see significant in-bank rises to
action stage, to the north of this rainfall swath. The rates of
rainfall last night were initially very heavy, but the QPF was
split from this heavy first 1" to a more conservative 0.20/ hr
rate that fell the rest of the night. Thus, the rises may be
more steady, rather than sharply felt this morning following
the first few hours of rapid rises observed early today.

La Moine River near Colmar...
This river is above flood stage, and rising steadily today.
Forecast rises to the upper end of moderate flooding is forecast
by the RFC...and that could have a chance on exceeding the Major
flood threshold of 24 feet Wednesday. This forecast is the one
to watch most closely over the next 24 hours.

Fox River near Wayland...
The Fox saw the heaviest QPF upstream, but
already seems be slowing it`s rise, near 16ft. A forecast of
moderate flooding is in place cresting near 19ft late
tonight/early Monday.

The Pecatonica at Freeport and Rock River from Moline through
Joslin... Rise to action stage are forecast by the end of the
work week.

Skunk River at Augusta...
Another site that saw very heavy qpf fall in this basin, over 2
inches in some cases. The stage is rising rapidly this morning,
a bit faster than modeled. Though it will be watched carefully,
it appears likely to top out shy of flood stage Wednesday. This
is the 2nd most needed to be watched carefully through tomorrow,
and could potentially lead to a minor flood warning.

Heavy rains remain possible later this week again as forecast by
WPC. The timing of this rain would fall just past the crest on
most active tributary rivers, and near the crest or just prior
on the Rock River. Keep a general awareness of rivers in the
week ahead, as this wet pattern continues to evolve.

&&

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

&&

$$

SHORT TERM...Speck
LONG TERM...Speck
AVIATION...Gunkel
HYDROLOGY...Ervin