Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 171034

Area Forecast Discussion
National Weather Service Quad Cities IA IL
534 AM CDT Sat Mar 17 2018


Issued at 315 AM CDT Sat Mar 17 2018

The weakening low pressure over Missouri continues to produce a few
bands of light freezing rain and sleet over the area early this
morning.  We remain somewhat convectively unstable over central Iowa
into southeast Iowa, where the upper low continues to bring very
small thunderstorm/convective showers. This feature will continue
eastward and southeastward this morning, while the precipitation in
the northeast continues to gradually weaken in place. Temperatures
cooled to the lower 30s during the late evening precipitation. That
is allowing for some elevated ice glaze, but so far, no reports of
road icing have been taken.  The sleet seems to have been the main
impact thus far, with partially covered roads in the north currently
reported by the DOT of IA and IL.


.SHORT TERM...(Today and Tonight)
ISSUED AT 315 AM CDT Sat Mar 17 2018

Though the impacts are rather minimal for most of the advisory as of
2 AM, the narrow bands of ongoing freezing rain/sleet will have me
keeping the headlines going for the meantime. Temperatures should
not cool much more than already seen over the CWA at 2 AM, and that
will allow for a rapid improvement of *ANY * impacts of by 10 AM.

Additional QPF should be under a tenth of an inch, except for
localized convective bursts found near to south of I-80 through 9
AM. In the mean time, we`ll handle this with SPS products for the
localized heavier totals.

After 10 AM today, the system will pull away, with some clearing in
the afternoon from the north to south, and that trend continues
through this evening. This will result in milder temperatures north
than south today, with upper 40s north to lower 40s south. Any
remaining accumulation of snow or sleet in the CWA will have melted
off by late today.

Tonight, under light winds and clear/clearing skies, temperatures
will drop to the mid 20 to lower 30s. Though there shouldn`t be any
impact associated with it, a rather heavy frost appears likely

.LONG TERM...(Sunday through Friday)
ISSUED AT 315 AM CDT Sat Mar 17 2018


High pressure over the Ohio Valley and Western Great Lakes will lead
to a nice end to the weekend with dry conditions and highs in the
lower 50s on average.


Model consensus has a cut-off upper low tracking from the
Southern Plains through southern Missouri and then into Kentucky.
The GFS/ECMWF have all of the precipitation staying south of the
forecast area. The NAM/CMC are further north and impact the
southern tier or two of counties. Due to low confidence on the
northern extent of the precipitation shield, 30-50% chances for
measurable precipitation is the best approach at this time.

The current forecast has thermal profiles warm enough for rain.
However, the NAM indicates strong dynamic cooling and a changeover
to snow. Since this is several days away and model spread is high,
there is no confidence in the NAM solution right now. Stay tuned to
forecast trends through the weekend.

Tuesday and Wednesday

A longwave trough will deepen over the eastern third of the U.S.
leading to colder weather (30s and 40s) for the Upper Mississippi
Valley. On the western periphery of the longwave trough, weak
vorticity maxima embedded in northwest flow may result in brief
periods of light rain and snow showers. Confidence is low on
timing and areal coverage of any precipitation, so did not mention
in the forecast with this update.

Thursday On

After a quiet Thursday with near normal temperatures, models have
an active pattern returning for the end of the week into next

A lee-side low is forecast to form in eastern Colorado on
Friday, and then track through the Midwest on Saturday along an
impressive baroclinic zone that features spring warmth (60s and
70s) to the south and winter cold (20s and 30s) to the north.
Widespread precipitation is possible over portions of the Midwest,
but confidence on types, amounts, and timing are low. Keep up
with the forecast through the week ahead as changes can be
expected. Uttech


.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
ISSUED AT 529 AM CDT Sat Mar 17 2018

An upper level storm system over central Iowa will spread
southeast and weaken through this morning. Two bands of rain and
freezing rain are located in the region, one from near DBQ
eastward over northern Illinois, and the other from near CID to
MLI and locations just south of that line. These will remain in
place early today, and dissipate by mid morning. The freezing rain
will be close to, but not directly impacting the CID and MLI
terminals, but it`s close enough that I`ve placed it into the TAF
through 15Z. After that time, temperatures will rise to the upper
30s, ending any surface icing threat. The rest of the day will see
improving Cigs from the 500 to 1000 ft stratus now, to MVFR by
early afternoon, then VFR by late afternoon through tonight as
high pressure moves in with light winds and clear skies.


IA...Winter Weather Advisory until 10 AM CDT this morning for Benton-

IL...Winter Weather Advisory until 10 AM CDT this morning for Bureau-
     Carroll-Henry IL-Jo Daviess-Mercer-Putnam-Rock Island-



LONG TERM...Uttech
AVIATION...Ervin is the U.S. government's official web portal to all federal, state and local government web resources and services.