899
FXUS63 KDVN 151759
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1159 AM CST Sat Feb 15 2025

...18z Aviation Update...

.KEY MESSAGES...

- Patchy light freezing rain is possible south of I-80 this
  morning, which could lead to slick travel conditions.

- Occasional rounds of light snow are expected today into
  tonight, with the best chances northwest of a line from
  Sigourney to Freeport, where 1 - 2 inches is possible
  (isolated up to 3"). Southeast of this line around 1 inch or
  less is expected.

- A clipper system may bring accumulating snow to areas south of
  I-80 on Monday.

- An arctic air mass will usher into the region this week
  leading to periods of bitterly cold wind chills between 10 to
  30 below zero. Cold Weather headlines will likely be needed
  at times.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 300 AM CST Sat Feb 15 2025

Overview: As of 3 AM, GOES WV imagery showed an upper low over
northwest Kansas into south-central Nebraska. The corresponding
surface low per the SPC mesoanalysis was centered over the
Oklahoma Panhandle. A heavier band of snow, largely driven by
700mb convergent flow and frontogenesis, was located west-
northwest of the outlook area, focused from eastern Nebraska
into north-central Iowa. Well southeast of this area, deeper
convection has led to occasional lightning with rain and
freezing rain as close as southern to central Illinois. Across
eastern Iowa and northwest Illinois, we have been left in
between these two areas of moisture, leaving us mainly dry for
the overnight hours.

Today:

The feature to watch is the mid-level vorticity max over the
Central Plains, which is forecast to track across Iowa into NW
Illinois, but in a weakening fashion. As this happens, narrow
bands of precipitation, mainly in the form of light snow are
anticipated to develop leading to additional accumulations of
~1-2" especially west and north of the Quad Cities. Overall,
this system is not expected to become very organized until it
pushes to our east and begins to rapidly deepen over the Ohio
Valley into the Lower Great Lakes region.

There may be a period of a wintry mix or freezing rain south of
I-80 this morning as the steadier bands of precipitation move
in from the southwest, which could lead to a very light glaze of
ice. With that said, temperatures will be warming to near
freezing through the late morning hours across the southern
outlook area, thereby limiting impacts to roads. For now will
leave the Winter Weather Advisory intact (NW half of the
outlook area), but with some potential to drop southern portions
of the headline early if the accumulating snow doesn`t
materialize or ends up being very light/patchy into this
afternoon.

Tonight:

Occasional light snow and flurries will remain possible with
cyclonic flow aloft as the primary surge of moisture misses us
well to the east into parts of eastern Illinois and Indiana.
Additional snow accumulations of a dusting to under 1 inch are
possible. Temperatures will drop into the teens as N to NW winds
pick up and gust up to 30 mph.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 230 AM CST Sat Feb 15 2025

Sunday...This will be a day where the local area is in a pressure
gradient battle zone, as a strong 1030+ MB arctic ridge axis juts
down the plains and MO RVR Valley, while deep cyclone occludes acrs
western NY. A raw, strong cold air advection day with northwest sfc
winds of 20 to 30 MPH producing wind chills in the low single
digits above zero, to almost 10 below during the day. The winds
will also continue to produce drifting snow acrs rural/open
areas. Will have POPs for light wrap around snow at times
Sunday, but right now looks like minimal additional wind blown
accumulation. Sunday night with the sfc ridge edging closer,
there should be some wind decrease. But ambient temps will crash
with much of the deeper snowpack areas having low temps ranging
from 5 below to 15 below zero into Monday morning. With that,
even 5-10 MPH winds will make for potential cold advisory
criteria at least for areas along and north of I-80.

Monday...Models continue to suggest an elevated F-gen snow
event skirting acrs the southwest third to half of the DVN CWA
during the day into evening as a short wave trof digs acrs the
southwestern plains. Limited moisture but high SLR`s suggest a
couple inches possible in the southern CWA by late Monday night,
and maybe near advisory levels in the MO counties. Single digit
high temps look on track for a frigid Monday. Depending on
cloud cover, with ensemble suggested three sigma -20 to -22C H85
MB temps north of I-80, some low temps in the northern and
northwestern CWA may approach 20 below with even light winds
still making for 30 below or colder wind chills, thus extreme
cold warning potential for Tue morning in these areas.

Tuesday through Thursday...The arctic regime looks to continue as
medium range blends suggest cold core closed upper low/vortex
settles acrs the upper MS RVR Valley and into the southwestern GRT
LKS through the end of the week. Energized zonal baroclinic zone
acrs the south half of the CONUS may allow the southern CWA to get
occasionally skimmed by isentropic light snow or flurry events
through at least early Wed. This while the area remains bathed in re-
enforcing arctic air and northern CAA flux with the arrival of the
large cold core upper trof/low. With long range projected thermal
profiles and taking into account ongoing snow cover, it appears that
several days of single digit to low teens for highs, and well below
zero low temps will be on tap. Thus several periods where cold
headlines may be needed for much of next week. Will advertise a dry
Thursday for now, but depending on the position of the upper low
there may be some sporadic light snow showers or flurries that day.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1155 AM CST Sat Feb 15 2025

A low pressure storm system moving south of the area will
continue to produce MVFR CIGs at varying levels along with
embedded areas of light snow and fog. Away from the snow,
freezing drizzle may be possible into the evening. As the low
moves to the east, north winds will continue to increase and
become gusty by evening. These winds may continue to produce
some drifting acrs west-to-east runways through tonight, even
though most of the snow will have ended or at least remaining
away from the TAF sites. MVFR CIGs look to remain for much of
the rest of the TAF period, although VSBYs should improve. A low
chance(20-30%) for some wrap around light snow to clip the DBQ
and MLI TAF sites late tonight and Sunday morning, but better
chances just off to the east of these terminals.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Winter Weather Advisory until 6 PM CST this evening for
     IAZ040>042-051>054-063>068-076-077-087.
IL...Winter Weather Advisory until 6 PM CST this evening for ILZ001-
     002-007-015.
MO...None.

&&

$$

SHORT TERM...Uttech
LONG TERM...12/Uttech
AVIATION...12

NWS DVN Office Area Forecast Discussion