Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 151152

Area Forecast Discussion
National Weather Service Quad Cities IA IL
552 AM CST Thu Feb 15 2018


Issued at 305 AM CST Thu Feb 15 2018

A warm front extended from low pressure in northeast KS on across
far northern MO and into central IL. Low level moisture from
snowmelt trapped below an inversion, along with light winds, was
allowing for fog to continue to develop early this morning.

Early morning temperatures were in the 30s to lower 40s with a
continued south wind at about 5 to 10 mph.

A stronger cold front extended from southern ND to Lake Superior.



.SHORT TERM...(Today and Tonight)
ISSUED AT 305 AM CST Thu Feb 15 2018

Forecast focus on fog and light rain chances today.

Headlines: Dense fog advisory will be in effect over most of the
cwa (except the far western counties) until 10 am. The day shift
can monitor and extend or cancel the advisory by then.

Today: Winds should become very light or calm this morning as low
pressure tracks eastward to near Quincy, IL by 18z, allowing for
the pressure gradient to really relax. This should allow for the
fog to become more widespread and dense for at least several
hours this morning. In the meantime, an area of light rain should
develop north of the warm front as the surface low gets closer.
Operational models (including the HRRR/NAMNEST) confine this rain
to mainly our southeast cwa this morning.

This afternoon, the surface low quickly pushes eastward into
Indiana allowing for winds to become north as a weak cold front
pushes southeast across the cwa. Drier air behind the front should
scour out the fog with quickly improving conditions. Any
lingering rain in the early afternoon should also come to an end
as the surface low and cold front push east and south of the cwa.

Temperatures: Highs should push into the 40s (with mid 50s in our
far south) ahead of the cold front.

Tonight: A secondary and stronger cold front sweeps through the
cwa with windy conditions and colder temperatures returning. As a
1038mb high builds into the northern Plains and the surface low
pushes into the Ohio Valley, a tight pressure gradient develops.
Northwest winds should gust to around 30 mph for much of the
night. Minimum temperatures will range from the single digits nw
to the lower 20s se. Wind chills should drop to 5 below to around
10 below towards morning in our nw and teens in our far se.


.LONG TERM...(Friday through Wednesday)
ISSUED AT 305 AM CST Thu Feb 15 2018

The extended will see the period beginning with a sharp cool down
for Friday, as temperatures remain in the upper teens to mid 20s
with continuous cold advection through the day.  A wild card at this
point, is snow cover for Friday night.  What seemed like a glacier
yesterday, is already disappearing out the window faster than
Mikaela Shiffrin down a mountain now that dewpoints are in the upper
30s this morning. Another 6 to 12 hours of above freezing wet bulb
temperatures are headed our way today, and that may just leave us
snow free, except for plow piles and field edge drifts.  For this
questionable snow pack reason, I have not gone below guidance for
lows Friday night.

Return flow on Saturday will see clouds, and warm advection, and
possibly very light rain or snow.  Temperatures will be marginal for
any snow at the surface, as highs climb to the mid to upper 30s. The
period from Sunday through Monday will see strong warm advection,
and eventually a threat of moderate to possibly heavy rain into the
region. Temperature have been pushed warmer for Sunday`s highs,
Sunday night`s lows, and Monday`s highs, based heavily on the ECMWF.
As far as our current showing of mixed precipitation Sunday night,
that`s a work in progress as we need to ingest top down grids in the
forecast process to show that is cold rain, rather than snow. That
will begin on tomorrow`s forecast cycle. There will be some threat
for accumulating snow, and at this point that appears to be over
the Iowa counties by Tuesday.  The ECWMF run slowly moves the
frontal zone east Monday night, while the GFS is a bit quicker.
Though the GFS is quicker on the cold fropa, it also shows plenty of
upper level troffiness hanging back in the 4-corners region.  That
lends some support to the EC solution, and makes our preference for
the 00Z EC stronger.  WPC also seems to be favoring that solution in
Days 4-7.



.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
ISSUED AT 552 AM CST Thu Feb 15 2018

MVFR/ocnl IFR conds this morning with areas of fog and low
stratus. There will also be some light rain especially at KBRL.
A cold front pushes across the area late this morning/early
this afternoon with conditions becoming VFR as winds become north.
A stronger cold front arrives tonight with northwest winds gusting
to 25 knots and a period of MVFR cigs.


IA...Dense Fog Advisory until 10 AM CST this morning for Cedar-
     Clinton-Delaware-Des Moines-Dubuque-Henry IA-Jackson-

IL...Dense Fog Advisory until 10 AM CST this morning for Bureau-
     Carroll-Hancock-Henderson-Henry IL-Jo Daviess-McDonough-
     Mercer-Putnam-Rock Island-Stephenson-Warren-Whiteside.



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