Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 241547

Area Forecast Discussion
National Weather Service Lincoln IL
947 AM CST Sat Feb 24 2018

Issued at 947 AM CST Sat Feb 24 2018

Areas of light rain continue across the northern part of the
forecast area this morning. Automated station at Galesburg
suggests a bit of sleet may still be occurring, but temperatures
are above freezing and no surface impacts have been received
recently. Thus, the winter weather advisory was allowed to expire
at 9 am. Further southeast, the heavier rains along I-70 have
pushed off into Indiana, after surface and radar reports indicated
that nearly 2 inches of rain fell since yesterday evening. No
changes planned to the flood watch, as the next wave of rain is
currently entering southwest Missouri. Hi-res models suggest this
next batch of rain arriving toward mid-late afternoon. In the
meantime, much of the forecast area should see a break in the
precipitation around midday and early afternoon.

Updated zones/grids were sent to refine the precipitation trends.
Temperatures and winds were largely on track.


.SHORT TERM...(Today and tonight)
ISSUED AT 311 AM CST Sat Feb 24 2018

Deep trough over the southwestern portions of the country
continues the southwesterly flow into the Midwest aloft. Above
normal temperatures and continued rain chances through tonight in
the forecast. That being said, in the shorter term, precip
moving in northwest of the IL River Valley this morning where the
temps are still below 0C...keeping the winter headline for
potential of light icing/bad early morning travel. Beyond that,
areas in the south and eastern portions of the state the most
susceptible to flooding due to where the rain has already fallen
this week...and being under the highest qpf through tonight.
Expanded the Flood Watch a line of counties north as the qpf
forecast has shifted slightly to the north.

For the showers this morning, the next wave is moving into the
region now, spreading that precip further north again. Pretty
decent continuity between models in a break in the activity from
mid morning into early afternoon. Also in agreement that a front
will move in and with another round going into the evening hours,
scour the precip out of the region and set up for a break in the
rainy weather that has been in place this week. However, details
are missing as the position of the low is still a bit
amorphous with an elongated trough associated with this wave.
Thunder likely to accompany the afternoon/evening storms with
better lift in a stronger wave. Anything surface based will have a
rather narrow opportunity for development, looking for clearing
within the lull between waves. Severe threat will also be hinging
on that instability to a certain extent, even if the shear is
pretty decent. For now, much of the forecast area is in a Marginal
Risk, and the southeast in a Slight Risk, with the best chances
to see some warmer temperatures.

.LONG TERM...(Sunday through Friday)
ISSUED AT 311 AM CST Sat Feb 24 2018

Front moving through the region tonight/tomorrow morning will move
the precip out, but not necessarily associated with a lot of cold
air. Through Sunday, h5 pattern remains southwesterly, with a
quick wave passing through the region dry which is a shift from
previous forecast runs. Forecast soundings quite dry through
Monday, with weak high pressure on the surface. Flow aloft sets up
in a more zonal pattern until midweek when the next wave develops
over the Rockies and brings an end to the brief dry period.
Tuesday night, precip returns to the forecast, even as the model
solutions diverge. The ECMWF splits a system that the GFS phases
and looks to deepen out of balance in comparison to the axis
orientation aloft. The blend of the two, as a result, is fairly
widespread pops midweek. Expect major changes to the forecast, but
the pops will likely remain in there mid week. Temperatures
throughout the forecast much milder than normal as the temp
profile really does not take much of a shift with the frontal
passage tonight.


.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 531 AM CST Sat Feb 24 2018

Showery mostly rain out there this morning. CMI briefly reporting
UP, but a break in that is coming up quickly, so have left it out
of the TAFs for now. Heaviest rain staying well to the south, but
IFR conditions dominate with cigs under 1000 ft. Variable
visibility with the showers/br. Winds are already easterly and a
little higher than guidance so have made some adjustments. Expect
a lull in the shower activity later this morning before the next
wave this afternoon/evening. HRRR and other guidance not doing
much in the way of lifting the ceilings even inside the break, and
the TAFs reflect that trend. Later tonight, have the LLWS
represented in the wake of TS potential. May need to expand that
time frame with next issuance.


Flood Watch through this evening for ILZ056-057-061>063-066>068-



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