634
FXUS63 KDVN 281056
AFDDVN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
456 AM CST Fri Nov 28 2025
.KEY MESSAGES...
- A significant winter storm will impact the area tonight
through Saturday night. Winter Storm Warnings are now in
effect across the entire forecast area.
- Some very cold nights are expected for early next week,
especially Sunday and Monday nights, with low temperatures
falling to the single digits.
&&
.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 342 AM CST Fri Nov 28 2025
Today is the calm before a well-advertised winter storm moves into
the area this evening, lasting through Saturday night. A surface
high pressure ridge axis will sweep through the area, leading to
light and variable winds with dry conditions continuing. We will see
some high clouds building in from the west - a precursor for the
winter storm to move in this evening into Saturday morning. Another
below average temperature day is on tap, with highs warming only to
the lower 30s. If you haven`t yet, take advantage of today`s quiet
weather to prepare for this upcoming winter storm. Expect impacts to
post-Thanksgiving travel, especially on Saturday and Saturday night.
Attention quickly turns to the impending winter storm. The primary
driver will be a broad longwave upper trough that has come on-shore
over Oregon per the GOES-East mid-level water vapor imagery. An
attendant surface low will develop via lee cyclogenesis over eastern
Colorado, and eventually make its way eastward. Ahead of the low,
moisture will increase, with Pwats between 0.5 to 0.7 inches, which
is pretty high for late November. The snow is expected to develop
this evening along a wing of warm air advection, with the column
undergoing top-down saturation to result in snow via a saturated
DGZ. The coverage of snow will only increase further through
Saturday morning as the aforementioned surface low approaches from
Colorado. Both the GEFS and ECMWF ensembles suggest the surface low
will translate across northern Missouri, placing our region under
the inverted surface trough and ideal placement for snow. This
winter storm appears to be a longer duration system, with the period
of accumulating snow likely this evening through early Sunday
morning. This system has a few aspects that need to be addressed, so
let`s break these down further.
* Amounts: this is the key aspect to watch for as this system will
have plenty of moisture and lift to work with. The 28.00z HREF
ensemble hints at the potential for snowfall rates over 1"/hr at
times, especially for after midnight tonight through 6 AM Saturday
and again Saturday afternoon. Additionally, the ECMWF EFI and
Shift of Tails (SoT) has an EFI value between 0.95 to 1.0, and SoT
of 5. Um, WOW! These values are quite impressive, suggesting not
only strong consensus among the ECMWF ensembles of heavy snowfall
amounts, but even some extreme amounts are suggested by some of
the ensemble members. We`ve increased the QPF slightly over the
previous forecast, given the higher trend in both the GEFS and WPC
ensembles, which has resulted in a further increase to snow
totals, especially for areas along and north of Highway 92. Most
of these locations now have forecast snowfall totals of a foot or
more, which matches up with the NBM exceedance probabilities of
one foot or more of 70+ percent. The WSSI (Winter Storm Severity
Index) from WPC indicates moderate to major impacts to travel area-
wide, so this will definitely be a storm that if you can stay home
and wait it out, please do so!
* Precipitation types: HREF suggests that this winter storm will
largely have snow as the dominant p-type, but there could be a
wintry mix or change-over to rain for a short time over our far
southern CWA, especially for Scotland and Clark counties in
northeast Missouri. Should this occur, this will probably eat into
the snowfall totals down that way, and we are indeed expecting
relatively lower snow totals there (6-8 inches, which is still
quite impactful!).
* Winds: there will be two periods of stronger winds: 1) late Friday
night through Saturday morning (from the southeast), and 2)
Saturday night through Sunday morning (from the northwest). These
will coincide with a tight pressure gradient ahead of and behind
the surface low. Gusts of 20 to 30 mph are possible each time, but
snow-to-liquid ratios aren`t suggesting an ideal dry snow for
blowing around, and WSSI has only minor impacts from blowing snow.
There could be some drifting snow, sure, but not a lot impacts
from blowing snow expected.
Given a forecast of 6+ inches across the entire event and local
area, we`ve gone ahead and issued a Winter Storm Warning for the
reminder of the counties that were previous in the Winter Storm
Watch. Hang on folks, and stay safe! Looks like we`re diving head-
first into winter!
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 342 AM CST Fri Nov 28 2025
The long-term period starts off with any lingering snow from the
upcoming winter storm tapering off Sunday morning, with a largely
dry day expected. The main focus for Sunday and Monday will be a
much colder stretch, thanks to 850 mb temperatures around -9 to -11
degrees C per the GEFS and ECMWF ensembles through Monday night.
While these values aren`t too impressive, they will be sufficiently
cold to support overnight lows Sunday and Monday nights dipping into
the single digits! These will be the coldest nights of the season so
far, especially Sunday night, given a high pressure ridge axis will
be moving over a fresh snowpack.
Another possible system looks to quickly sweep through the area
Monday night into early Tuesday as a mid-level shortwave trough
associated with a positively-tilted upper trough approaches the
area. P-types look to be all snow, but the duration of the snow
looks much more limited compared to this weekend`s system. Expect
cold conditions to continue through the end of the week.
&&
.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 456 AM CST Fri Nov 28 2025
VFR conditions are expected to continue through the afternoon
hours today before a winter storm enters the region from the
west this evening, lasting through much of the weekend. An area
of high pressure will sweep through the area later today,
supporting light and variable winds for a time. Then, the onset
of the snow associated with the winter storm is expected
sometime in the evening and overnight hours. Snow is expected to
intensify as we head into early Saturday morning, with snowfall
rates likely to exceed a half-inch per hour, perhaps
approaching 1 to 1.5" per hour at their peak before sunrise.
MVFR to IFR conditions are expected with the initial snow.
However, LIFR conditions can`t be ruled out entirely with this
potent winter storm.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Winter Storm Warning from 9 PM this evening to 6 AM CST Sunday
for IAZ040-051-052-063-064-076-077-087-088.
Winter Storm Warning from midnight tonight to 6 AM CST Sunday
for IAZ041-042-053-054-065>068-078-089-098-099.
IL...Winter Storm Warning from midnight tonight to 6 AM CST Sunday
for ILZ001-002-007-009-015>018-024>026-034-035.
MO...Winter Storm Warning from midnight tonight to 6 AM CST Sunday
for MOZ009-010.
&&
$$
SHORT TERM...Schultz
LONG TERM...Schultz
AVIATION...Schultz
NWS DVN Office Area Forecast Discussion