879
FXUS63 KDVN 161035
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
535 AM CDT Thu May 16 2024

...12Z AVIATION UPDATE...

.KEY MESSAGES...

- Scattered showers and a few storms late tonight and Thursday.

- Highs warming into the 80s for several days ahead.

- Depending on where a developing storm track lays out, it could
  be a potentially wet pattern across the region next week with
  several rounds of heavy rain possible.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 250 PM CDT Wed May 15 2024

Weak area of high pressure was centered across eastern Missouri
early this morning, with a cold front just off to our west
across northwest Iowa and southeast Nebraska. This front was
just ahead of a weak shortwave, which per water vapor imagery
was over eastern South Dakota. Scattered showers and storms were
noted ahead of the shortwave and front per KDMX/KMPX, but had
showed a decreasing intensity trend as they were moving east
into more stable air across our CWA.

Heading through today, we will begin to see shower and storm
coverage increase as the front and shortwave move across the area.
Look for more scattered activity during the morning hours to become
more pronounced mainly along and east of the Mississippi during
the afternoon with increasing instability and moisture
interacting with the wave. SBCAPE, depending on degree of warmth
with clouds in place, should get up to around 1000-1500 J/kg by
early afternoon with increasing deep layer shear around 30-35
kts. This is especially favored across northwest Illinois where
there is some potential for storms to become strong. SPC
maintains a Level 1 (marginal) risk for severe weather in this
area, with the risk mainly focused across southwest Wisconsin
nearer to better surface convergence. The primary threats would
be large hail and damaging winds. Elsewhere, showers and storms
could produce some heavy rain as PWATs ahead of the front climb
to around 1.00-1.20".

Tonight, another round of weak high pressure will bring quiet
weather to the area. Weak CAA and low-level flow with keep temps
from falling too much, with lows in the mid to upper 50s
expected.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 250 PM CDT Wed May 15 2024

Friday through Saturday...

A stretch of quiet weather is expected during this period as mid-
level ridging builds over the Midwest and Great Lakes. Though some
deterministic guidance paints a weak shortwave moving overhead
Friday into Saturday, they have backed off on POPs with weaker
overall forcing and moisture. Therefore, we should remain dry
with warm temps. Look for highs each day in the 80s, with
overnight lows in the 50s/60s.

Saturday Night on...

Ridging will shift southeast of the area and open the door for a
shortwave train to set up across portions of the Midwest and upper
Midwest. Guidance places us either pretty close to the track or
within the track itself, which would increase potential for clusters
of showers & storms/MCSs to impact the area at times beginning early
next week. There remains quite a bit of uncertainty in storm tracks,
severity and timing at this time, as models do not handle these
features well several days out. Regardless, will run with the
NBM which has all of eastern Iowa, northwest Illinois and
northeast Missouri in at least a chance (20-50%) of
precipitation Sunday on. Please continue to monitor the latest
forecast information, especially over the weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 529 AM CDT Thu May 16 2024

A weak shortwave trough aloft and attendant surface front will
be moving slowly through the area from west to east today, and
will be accompanied by MVFR ceilings and chances (~30%) of rain
showers & storms. The threat is greatest at KMLI/KDBQ/KBRL where
PROB30s have been maintained. The primary threats with storms
are lightning, hail, and wind gusts to around 40 MPH. As the
front passes, winds will shift to the northwest, but will remain
around or below 10 kts. These light winds may allow for
formation of mist at the terminals early Friday morning, with
confidence higher at KBRL which will be nearer to the passing
front.

&&

.HYDROLOGY...
Issued at 1006 AM CDT Wed May 15 2024

Changes: None

Discussion:

River flood warnings continue for the lower Wapsipinicon River
near De Witt and for a portion of the Mississippi River from
Gladstone, IL through Burlington, IA.

The lower Wapsipinicon River near De Witt is just coming off a
broad crest. The forecast has it dropping below flood stage
Thursday afternoon.

For the Mississippi...the river continues to rise from New
Boston, IL through Gregory Landing, MO. With the exception of
Gladstone and Burlington, the river is forecast to crest below
flood stage. At Gladstone and Burlington, the river will crest
just above flood stage Thursday night.

The lower Cedar River near Conesville is nearing a crest just
below flood stage. The river will hold just below flood stage
through tonight before beginning a slow fall on Thursday.

An active weather pattern is expected across the area through
next week. While rainfall amounts are somewhat uncertain, any
heavy rainfall would minimally prolong high river levels on
tributary rivers in eastern Iowa and on the Mississippi south of
New Boston, IL.

&&

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

&&

$$

SHORT TERM...Speck
LONG TERM...Speck
AVIATION...Speck
HYDROLOGY...08