465
FXUS63 KDVN 191144
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
644 AM CDT Wed Mar 19 2025

.KEY MESSAGES...

- Unseasonably warm temperatures, breezy southerly winds, and
  dry antecedent conditions will favor a critical fire danger
  today south of Highway 34. With that, we have a Red Flag
  Warning in effect this afternoon for counties along a line
  from Memphis MO to Macomb IL.

- Marginal Risk (level 1/5) for Severe weather early-mid
  morning, highlighting the potential for elevated thunderstorms
  producing hail. Later today, the Slight Risk (level 2/5) has
  been expanded westward for the afternoon thunderstorm
  activity, with an introduction of an Enhanced Risk (level 3/5)
  for our far east. All hazards are possible this afternoon.
  More details on this can be found below.

- Rain will transition to snow on the back end of the system,
  with the potential for some to see 1-2". The main impact from
  the snow will be the reduced visibility due to heavy snowfall
  and strong winds.

- Very strong winds are expected today, with a Wind Advisory in
  effect for the whole area, phasing in the area from west to
  east through the day. Gusts upwards 45-55 mph will be
  possible.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 256 AM CDT Wed Mar 19 2025

Newly developed surface low tracks directly towards our forecast
area today, bringing a multi-faceted forecast ahead of us. The
hazards that we have in forecast range from fire potential, strong
gradient winds, severe weather potential, and then wintry weather to
wrap this up. Below, we will go into details about each potential
hazard, especially highlighting the timing. The hazards discussed
below will generally follow chronological order for the times in
which we expect each respective hazard. Although, the winds will be
here to stay for much of the event. For context, current guidance
continues to show the surface pressure at the low`s center dropping
towards 985 hPa, with it currently sitting at 988 hPa. This low
pressure center will track northeast from its current location,
passing through the center of our forecast area.

Over the next few hours, we will see the strong LLJ ahead of this
low pump into the area, converging over the stalled out boundary
over our north. This will lead to scattered showers and
thunderstorms as we head towards sunrise, with coverage of showers
and storms increasing since the forecast package last night. Along
with more coverage, we will also see these showers/storms develop
farther southwest than initially thought. Between 4-6am local time,
we should see a broken line of storms push into the area from the
southwest. This will continue to build into a linear structure, with
individual embedded cores within. This will continue to push
northeast through our area, exiting the area around 10am-12pm. With
the pattern in place, we have plenty of shear and enough instability
to favor organized convection. Thus, elevated supercells will be
possible. With elevated storms, the main threat will be hail.
While other hazards are not impossible, they are much less
likely than hail. So, with the storms that develop and pass
through the area this morning, we will have the potential for
hail, some of which may reach upwards to an inch, along with
frequent lightning. Thus, the SPC highlights much of eastern
Iowa in a Marginal Risk (level 1/5) for severe weather,
highlighting the hail threat.

With such a strong surface low, a strong pressure gradient has
developed over the area and will intensify as the low continues to
approach the area, resulting in strong gradient winds at the
surface. Overall, winds will generally be between 25-35 mph, with
gusts upwards to 45-55+ mph, especially in our western counties on
the back end of the low. If you are south of the front and ahead of
the cold front, you will have largely southerly winds, with
northerly winds on the north and backside of the low. Wherever the
center of the low passes over, there will be a brief period where
winds decrease, but will quickly pick back up on the backside. We
currently have a Wind Advisory issued for the whole area, phasing in
from west to east through the day. Will have to continue to monitor
forecast trends and observations through the morning, as some
locations in our west will be nearing High Wind Warning criteria.
Confidence was not high enough at this time to upgrade. With such
strong winds in place, dry antecedent conditions, and well above
normal temperatures in our south, we will also see a critical to
very high fire danger. Thus, we have issued a Red Flag Warning for
counties along a line from Memphis MO to Macomb IL.

After the initial round of showers and storms from this morning move
out, we will have a brief break in the severe threat. Although,
showers and thunderstorms may persist in the north through much of
the day. The next round of severe storms doesn`t take long to take
shape, with the initial storms developing between 12-2pm. Initially,
we will see scattered/discrete convection, but this is expected to
grow upscale through mid afternoon. This severe threat will be one
to keep your eyes on, as all hazards will be in play. The convection
looks to stick around the warm/cold frontal zones as the low passes
through the area, especially at the point in which these boundaries
intersect. Instability and best moisture will pool along these
boundaries, with MUCAPE upwards to 1000-1500 J/kg possible. This,
coupled with deep layer sheer between 45-65+ KTs, will be more than
favorable for organized convection. Storm mode looks to be supercell
structures that congeal into a QLCS. Discrete supercells will pose
the best threat for hail, as we will have moderate-steep midlevel
lapse rates. Winds will already be very strong through the day, with
winds aloft easily being able to get translated to the surface.
Thus, severe winds will be a threat with any storm. Although, this
environment is favorable for tornadoes as well. LLVL shear is more
than sufficient for tornadoes, especially with line normal 0-3km
shear around 30-40 KTs. Thus, when this grows upscale, the tornado
threat will continue alongside the winds. These storms will be
moving relatively quick, largely exiting the area by around 5-7pm.
SPC highlights our whole area in at least a Marginal Risk (level
1/5) risk for severe weather, with an expansion of the Slight Risk
(level 2/5) farther west into parts of eastern Iowa. Finally, they
have also introduced an Enhanced Risk (level 3/5) for our west-
central IL counties, especially highlighting the 10% tornado threat,
with the potential for a few strong tornadoes.

Finally, we move into tonight, which will be the winter weather
threat. Tonight, we will see the transition to wet snow on the
backside of the low. Granted, we can see snow as early as mid-
afternoon in our far northwest, roughly along and north of a line
from Vinton IA to Manchester IA. Although, much of the area will see
the transition to snow this evening, roughly between 7-10pm. We are
expecting the snow to be heavy at times, with some guidance hinting
at the potential for 1" per hour rates. The good thing is that this
system will be quick to move out, limiting how long the snow will
stick around on the back end. Current guidance roughly indicates the
snow moving out between 3-6am, growing lighter through the night.
Given the snow is moving in after it has rained and after a very
warm spell, any snow falling will likely melt, at least on the
pavements. Guidance has shifted the axis of snow since the last
forecast package, generally in far eastern IA now, along the
Mississippi River, as well as parts of western IL. Although, we are
still generally looking at 1-2" of snow. One of the main impacts
that we do expect from the snow is the reduction in visibility,
resulting from the strong winds that will accompany the snow. The
snow is expected to fall heaviest during the transition time,
generally around that 7-10pm timeframe, give or take an hour or two.
Thus, this may lead to some travel impacts. At this time, our
confidence remains low, but future shifts will have to look into the
potential for a short-fused winter headline to cover potential
impacts. Remember, ice and snow, take it slow!

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 256 AM CDT Wed Mar 19 2025

Precipitation will be out of the area by sunrise on Thursday,
leaving us with a cool and damp start to the day. Weak ridging
builds over the region Thursday, behind the potent low, which will
allow winds to decrease from the morning onward. Granted, we will
continue to see gusts upwards to 20-25 mph though much of the day,
but that will be much lighter than the 45-55 seen just 12 hours
prior. Temperature-wise, the area should remain largely in the mid-
upper 40s, which is a little cooler than the previous package, with
clear skies.

Active weather returns as we close out the week, as well as towards
the end of the weekend. We continue to see the potential for two
quick hitting systems, one to hit late on Friday, with another to
impact the area late on Sunday. Temperatures will be well above
freezing for the whole event on Friday, keeping the precipitation
type as rain, with accumulation largely below a quarter of an inch.
Sunday`s system will largely fall as rain, with cool air moving in
on the backside, which may allow for a transition to light snow.
Both of these events look to bring low QPF and seem to be non-
impactful at this time. We will continue to monitor and update
accordingly as more guidance continues to come in. Otherwise, it
will be a gloomy weekend with clouds and passing systems, aside from
Saturday looking to be the nicest day of this stretch. Temperatures
will remain in the upper 40s to mid 50s, with seasonal breeziness.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 630 AM CDT Wed Mar 19 2025

Plenty of issues continue this forecast with a strong system
moving through the TAF locations.

Latest 1106Z IR-Satellite has plenty of clouds across the
region. Latest 1112Z KDVN radar showing some convection
developed across northern sections of the area just north of
KCID to KDBQ and moving northeast.

As the system approaches the region...model data has convection
continuing to develop across the region during the TAF period.
Some storms could contain some small hail this morning. By the
afternoon some intense thunderstorms could develop by 18Z and
rapidly move east during the afternoon. Expecting some of these
will to be be stronger and potentially severe. Have placed some
persistant -shra with some tempo thunderstorms in TAF locations.
By 00z the low pressure system is projected to be across
northeast Illinois and TAF locations have strong northerly winds
and precipitation starts changing over to snow. Expect VFR
conditions to become IFR throughout the period. Expect gusty
winds to be changing directions and become strong northerly
after the system passes with wind gusts to 40+ kts. Also have
snow in later TAF periods and ending during this forecast
period.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Wind Advisory from 1 PM this afternoon to 10 PM CDT this
     evening for IAZ040-041-051-052-063-064-076-077-087-088-
     098.
     Wind Advisory from 6 PM this evening to 4 AM CDT Thursday for
     IAZ042-053-054-065>068-078-089.
     Wind Advisory until 4 AM CDT Thursday for IAZ099.
IL...Wind Advisory from 6 PM this evening to 4 AM CDT Thursday for
     ILZ015-024>026.
     Wind Advisory until 4 AM CDT Thursday for ILZ034-035.
     Wind Advisory from 7 PM this evening to 7 AM CDT Thursday for
     ILZ001-002-007-009-016>018.
     Red Flag Warning from 1 PM to 5 PM CDT this afternoon for
     ILZ034-035.
MO...Wind Advisory until 4 AM CDT Thursday for MOZ009-010.
     Red Flag Warning from 11 AM this morning to 5 PM CDT this
     afternoon for MOZ009-010.

&&

$$

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