727
FXUS63 KDVN 131947
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
247 PM CDT Fri Mar 13 2026

.KEY MESSAGES...

- A quick dusting of light snow, mainly in the Highway 20
  corridor, Saturday morning with minimal impacts.

- A significant winter storm Sunday night into Monday with
  extremely strong winds creating blowing snow and near-blizzard
  conditions. Significant travel impacts during the Monday AM
  commute. A winter storm watch remains in affect for areas
  along/north of I-80.

- There is a marginal (level 1 out 5) and slight (level 2 out of
  5) risk for severe storms on Sunday.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 246 PM CDT Fri Mar 13 2026

Winds will slowly diminish the remainder of the afternoon and
overnight. However, breezy conditions will be seen both tonight and
into Saturday.

On Saturday, an elevated band of forcing and moisture will move
across the northern half of the area. There is plenty of dry air in
the low levels so the overall band of saturation looks to be quite
narrow and confined to the Highway 20 corridor. The potential is
there for a quick dusting of snow, mainly from Dubuque east Saturday
morning with dry conditions during the afternoon. Attention then
turns to the next system.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 246 PM CDT Fri Mar 13 2026

Saturday night through Monday
Assessment...A certainty (>98%) of a significant storm system

All models have a significant storm system moving through the
Midwest Saturday night through Monday. New data indicates the storm
will be strengthening as it moves through the area. When this
situation occurs, the models play catch-up as they generally lag
behind on all sensible weather parameters.

Saturday night strong southerly winds will transport moisture north
from the Gulf. Widespread lift aloft from the approaching system
will allow precipitation to break out across the area. The
precipitation may initially start out as a rain/snow mix north of
Interstate 80 but will quickly change over to all rain as the warmer
air arrives. Although low, there is the potential for a few rumbles
of thunder south of I-80 before sunrise Sunday.

On Sunday, the storm center will move through the area. Rain will be
seen across the area Sunday morning. Sunday afternoon thunderstorms
will be possible ahead of the cold front and along the track of the
passing low. During the passage of the main low and front, there is
a risk of severe storms. The primary risk looks to be damaging winds
and the most likely time frame looks to be a 6 hour time frame from
12 PM to 6 PM.

Once the cold front passes any one location, temperatures will
rapidly fall in the strengthening cold advection. Areas west of a
Dubuque, IA to Ottumwa, IA line will see the rain change over to
snow between 3 and 7 PM. During the change over there may be a brief
period of sleet.

Very windy conditions will be seen Sunday, especially east of the
Mississippi. Winds could gust up to 45 mph.

Sunday night into Monday is prime time for the storm system.

The change over to snow along/east of the Mississippi will occur
early Sunday evening with the entire area seeing all snow by 9-10
PM. Snowfall rates of up to an inch per hour will be possible,
especially late Sunday night to around sunrise Monday.

As the system strengthens Sunday night winds will continue to
increase. By sunrise Monday the models are suggesting a 12 mb
gradient across the forecast area which supports wind gusts of at
least 50 mph Sunday night into Monday morning. Winds of this
strength will fracture the usually large dendrite snowflakes
associated with the heavier snowfall rates into much smaller ones.
The downside of smaller flakes is there will be more of them
resulting in a more widespread blowing snow. Thus there is a high
probability of near white-out conditions in rural and open areas.

Regardless, there will be significant travel impacts on Monday,
especially for the Monday morning commute. The travel impacts
potentially could go into the Monday evening commute.

The current watch headlines look good and will likely transition to
a winter storm warning in the next 24 hours. Given the data
available this far out, there is roughly a 33-40% probability of
going beyond a winter storm warning to a blizzard warning.

Additional headlines south of the current watch may be needed as the
overall track and strength of the storm becomes more certain.

Snowfall amounts are more tricky given the fractured nature of the
snowflakes. Right now amounts in the current watch area look to
range from 3 to 7 inches of snow. South of I-80, amounts look to
range from 1 to 3 inches.

Although snow amounts are lower than the generally accepted criteria
for a winter storm, the high winds will make up the difference and
help create the higher level of impacts to the area.

Monday night through Friday
Assessment...High (>80%) confidence of a warm-up the second half of
the week. Medium (40-60%) confidence of snow Tuesday night.

Northwest flow aloft will persist through the week but a building
upper level high will allow temperatures to moderate. After an
initial cold start, a rapid warm-up will be seen the second half of
the week.

Tuesday morning will be very cold with windy conditions creating
wind chills of 10 to 20 below zero.

Outside of a dry week, the models have an upper level disturbance
moving through the area Tuesday night. Although moisture is not
overly great, the previous cold temperatures combined with the
forcing looks to be enough to generate some accumulating snow.

As for amounts, an educated guess is an inch or less for the area.
The lower amounts would be south of I-80 with the higher amounts
north of I-80.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1208 PM CDT Fri Mar 13 2026

Considerable low level mechanical turbulence from wind gusts
will be seen through 00z/14 with brief periods of MVFR CIGS
north of I-80. After 00z/14 winds will diminish further and
shift around to the east northeast by sunrise Saturday.
Potential for a brief period of light snow north of Highway 30
12z-18z/14 but CIGS expected to remain VFR across eastern Iowa
and northern Illinois.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Winter Storm Watch from Sunday evening through Monday evening
     for IAZ040>042-051>054-063>068.
IL...Winter Storm Watch from Sunday evening through Monday evening
     for ILZ001-002-007-009-015>018.
MO...None.

&&

$$

SHORT TERM...08
LONG TERM...08
AVIATION...08