723
FXUS63 KDVN 191032
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
532 AM CDT Sun May 19 2024

.KEY MESSAGES...

- Active pattern through the long term with chances for strong
  to severe storms through Tuesday. Tuesday is the best day for
  severe weather in the next 5 days.

- Rises along area rivers and localized flash flooding will be
  possible through midweek, especially on Tuesday.

- Well above normal temperatures continue through Tuesday,
  dropping to near seasonal values by the end of the week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 252 AM CDT Sun May 19 2024

Today should remain dry for the most part, as winds continue to
recover behind the cold front that passed through. A weak wave will
pass through the area during the afternoon, with the bulk of the
forcing north of the area. While some guidance bring hints of higher
vorticity through the area, confidence in this resulting in any
precipitation is low, as we will be lacking surface forcing and moisture
until late evening/tonight. Thus, we should see quite a
beautiful and hot day once again, with temperatures in the mid-
upper 80s. Dew points will be on the rise as well, with higher
values pushing north through the afternoon as well. Thus, it
will start to feel a little muggy, with this also being noted by
an increase in cloud cover.

Tonight, a deeper wave will push through the area, with the vort max
passing right through our area late. Given the increase in moisture
through the day, sufficient moisture will be in place to get showers
and storms late tonight. While we can see warm advection
showers/storms pushing in from the south this evening, the best
chances for precipitation will be well after midnight, moving
in from the west. This will be the timeframe where the bulk of
the forcing pushes in, both aloft and at the surface, with a
cold front passing through once again. Guidance indicates the
possibility for MUCAPE around 1000-2000+ at times tonight,
which will combine with deep layer shear around 30-35 KTs. Thus,
there will be the potential for some more organized/stronger
storms late tonight. Given lower shear, this does not give much
confidence in widespread strong/severe. Rather, we might see
some robust updrafts that have frequent lightning and some small
hail. Isolated large hail will also be possible, as midlevel
lapse rates are more than favorable for some larger hailstones.

There remains quite a bit of uncertainty with the potential for
storms tonight, especially when it come to severe potential.
Generally following/messaging the HREF, as this seems to get the
best grasp on what much of the short term suite is giving. Latest
trends in some models indicate the wave slowing down, which can
largely place the precipitation chances on Monday morning, leaving
tonight dry for the most part. With a moderate to strong LLJ moving
in around 3-6am, collocated with a strong vort max, I would not be
shocked to see some convection late tonight. As the previous
forecast discussion mentions well, we will have an MCV pass through,
which could lead to an enhancement in the shear, which could aid
in developing stronger convection. Also, as was seen in the 12z
HRRR, similar supercell structures exist late this evening as
well in the 00z HRRR run. Granted, this is not the answer key,
but rather giving us an idea that there is a chance for some
stronger storms, earlier in the night. The SPC continues to
highlight areas west of the Mississippi River in a Marginal Risk
(level 1/5) for severe weather tonight, highlighting that
isolated hail risk.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 252 AM CDT Sun May 19 2024

Overview...

A very active pattern remains through the central US this week,
which will bring plenty of chances for precipitation to the area.
Will mainly focus on the first two waves in question, which are set
to move into the area Monday and Tuesday. While much of the wave
will move in Sunday night, which is discussed above, the vort max
will continue to slowly push through the area Monday. After this
wave passes, we do not have much time until the next wave pushes
through, which will be Tuesday. This is the wave that has our
attention, as it holds the potential to bring a bit of severe
weather. Weak zonal flow and ridging will be seen Wednesday and
Thursday, bringing a period of dry weather, with more waves to
come at the end of the week and into the weekend. Have those
umbrellas handy through the week! Monday and Tuesday will be the
warmest of the long term, with the remainder of the week in the
mid-upper 70s throughout.

Monday...

Slow moving front from Sunday night will continue to push through
the area Monday, with a broad vort max. While much of the near
surface forcing will move out of the area, the upper wave passing
through should give way to some remnant showers and storms into the
early afternoon, especially north of Interstate 80. This, along with
height falls associated with the next wave, will also give way
to increasing chances for precipitation through the day Monday.
Shear seems to be quite low though, which can be a limiting
factor to the severe threat. Although, as was discussed prior,
if we get another MCV to pass through, local enhancements to the
environmental shear will be possible. Thus, a few strong to
severe storms will be possible. This is highlighted once again
through a Marginal Risk (level 1/5) for severe weather, where
all hazards will be possible through the day.

Tuesday...

Now, we move onto the wave that has caught our attention. Tuesday,
we will have quite the wave eject off of the Central Rockies,
directed at the Mississippi River Valley. Strong vort max approaches
the area in the mid-late afternoon Tuesday, with a strong LLJ set up
ahead of it. Warm front will pass through the area early on Tuesday
morning, which will bring a shield of showers and storms through the
area. This should move out by noon local time, leading to some
clearing skies and destabilization of the boundary layer ahead of
the approaching wave. Not only will we see moderate to high
instability, but the deep layer shear will also be much stronger
than the previous days. Thus, we have moderate confidence in seeing
organized convection. Some storms may be strong to severe as well.
Being in the open warm sector much of the day, we will see the
potential for some discrete storms firing up that afternoon and
early evening. Although, this seems to be favored west of our area.
These are expected to rapidly grow upscale, with a line of
strong/severe storms being the main concern for our area that
evening/night. As was mentioned prior, the strong LLJ will persist
into the nighttime hours, aiding in the longevity of the storms.
Combined with the severe threat will be the chance for heavy rain.
Fortunately, storms should move in and out relatively quickly.
Although, they will drop heavy rain. Currently, we are looking at
PWATs between 1.50-1.75". This will favor the potential for
localized flash flooding, as well as the chance to see more rises on
area rivers.

The SPC highlights our whole area in an Enhanced Risk (level 3/5)
for severe weather on Tuesday and through the evening, with severe
winds and a few tornadoes being the primary threats for our area.
Large hail will be possible as well, but will be a secondary threat.

Beyond...

Weak ridging and zonal flow will be seen Wednesday into Thursday,
which will bring a brief period of dry weather. Friday and into the
weekend, the pattern becomes active again, bringing more chances for
precipitation. Much uncertainty exists, so we will refrain from
further details. Temperatures will be more seasonal through,
with most in the mid-upper 70s.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 528 AM CDT Sun May 19 2024

VFR conditions will prevail through the TAF period, with
northerly winds shifting southeasterly through the day. There
will be a chance for showers/storms after 00z this evening, but
confidence remains low. Thus, it was not included in the TAFs.
No sig wx is expected at this time.

&&

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

&&

$$

SHORT TERM...Gunkel
LONG TERM...Gunkel
AVIATION...Gunkel