Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 140846
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
346 AM CDT Thu Mar 14 2024

.KEY MESSAGES...

- Large temperature range over the area today with highs in the
  upper 40s north (Dubuque, IA) to around 70 south (Macomb, IL).

- Areas of rain for early commuters should become more
  scattered with pockets of drizzle by mid-morning; any A.M.
  storms should be spotty with small hail the main threat.

- For the afternoon, there is a risk (level 2 of 5) of severe
  storms mainly along and south of the U.S. Highway 34 corridor;
  isolated storms will remain possible north of there with again
  mainly a small hail threat.

- Highs in the 50s Friday and Saturday, with Saturday also windy
  and turning much cooler later Saturday and Saturday night.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 340 AM CDT Thu Mar 14 2024

A convectively-enhanced disturbance (short wave MCV) will clear
the area by 8 A.M. Before that, widespread rain that is heavy at
times, along with embedded thunder will continue. The more
organized convective threat will be east of the area by 6 A.M.

In the wake of this feature, the synoptic surface low will be
somewhat elongated and stretching from near Kansas City to south
of the Quad Cities. Along and north of this baggy surface
feature should see scattered showers and patches to areas of
drizzle within low clouds. While there should be some
suppression in the wake of the aforementioned MCV, there still
may be spotty thunder, but coverage from mid-morning through
early afternoon looks low (probably <20%).

A wave traversing the boundary along with an upper level speed
max near 100 kt will have the potential to retrigger storms
on and south of the boundary by 2-3 PM. This is the area
particularly along the general U.S. Highway 34 corridor and
south. Dew points on the boundary look to be in the lower 60s,
which will support MLCAPE values just on the warm side of
1,000-1,500 J/kg. With more than sufficient deep layer shear of
60+ kt, organized convection is a threat there. There is some
uncertainty though on lingering capping and boundary modulation
from this morning activity, and that refiring storms may end up
further southeast of our area. But if convection can trigger,
it will have a threat for initial supercells with possible all
hazards. The threat window should close fairly quickly if it
opens in our CWA, likely ending by 6 PM.

The temperature gradient today will be pronounced, with little
to no warming north of U.S. highway 30 under a blanket of low
clouds and northeast winds. Farther south near to in the warm
sector, even if convectively-effected, highs should near 70. In-
between including the I-80 corridor confidence is low in exact
highs, but best guesstimate is a few degrees rise today within
the 50s range possibly into the lower 60s.

As the low shifts eastward, northeast winds will increase from
north to south late in the day through the evening,
strengthening cold advection. Frontogenesis (f-gen) in the
850-700 mb layer may result in an uptick in rain showers later
in the afternoon into the evening along and north of I-80.
Confidence on this is low. Any rain showers look to end in our
far south and east by daybreak Friday.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 340 AM CDT Thu Mar 14 2024

After a quiet day Friday, a pronounced dip in the polar jet over
central Canada will send a strong short wave southward into the
Great Lakes region. An associated cold front will sweep
southward Saturday afternoon. Ahead of that, westerly winds
look to gust around 35 mph with lowering dew points. Such a
regime this early spring we have to at least evaluate a fire
weather threat, but the soaking rains of last night and some
more today that may ease that some. Also temperatures look to be
falling in the afternoon from north to south. The front looks
to be a dry passage at this time. Lows Saturday night should
reach upper 20s north to lower 30s south.

Sunday and Sunday night
Assessment...high confidence on windy conditions

Windy conditions will continue across the area on Sunday as the core
of the cold temperatures aloft moves through the area. An associated
upper level disturbance will provide enough forcing for flurries or
even snow showers for areas generally east of the Mississippi and
north of I-80. Given the warm ground temperatures, only a localized
dusting of accumulation would be possible on grassy and elevated
surfaces in the strongest snow showers.

Monday through Wednesday
Assessment...medium to high confidence on a warm trend. Medium
confidence on dry conditions

The current model consensus has dry conditions across the area with
a warming trend through mid-week.

However, the CMC and ICON deterministic runs bring a clipper system
into the Midwest with snow. The CMC is further west which places the
snow over the area while the ICON model indicates southeast
Wisconsin and northeast Illinois. Interestingly the GFS/ECMWF
deterministic runs have no clipper system.

Interestingly there are some members of the ensembles of the
GEFS/CMCE that lend support the the CMC/ICON deterministic runs but
most of the ensemble members are dry.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1245 AM CDT Thu Mar 14 2024

Primary concerns with aviation are thunderstorms early this
morning, mainly prior to daybreak, and then IFR conditions a
good part of today for most of the TAF sites.

Showers with at least embedded storms will continue to expand
northeast through the early morning. Some of these will produce
temporary IFR visibility, although thunder should become a
little more spotty toward CID and especially DBQ (where
confidence in any TSRA is low). Shower coverage looks like it
will diminish between 12Z and 17Z, however areas of
drizzle/light rain with spotty showers are becoming more
probable. The regime is favorable for IFR ceilings to develop
and possibly IFR visibility, especially if drizzle is present.
BRL will likely remain south of these lowest conditions, but the
other TAF sites should be in them, with highest confidence at
DBQ where LIFR ceilings are favored at times.

As the weather system bringing the precipitation tracks across
the Missouri/Iowa/Illinois border region this afternoon,
scattered storms may develop near BRL. Otherwise, rain showers
are expected to the north, although confidence in what the
coverage and duration of this rain will be is uncertain.
Nonetheless, IFR ceilings are likely to persist and spread
southward to BRL through the evening hours.

&&

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

&&

$$

SHORT TERM...Friedlein
LONG TERM...Friedlein/08
AVIATION...Friedlein


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