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fxus63 kilx 181749 
afdilx

Area forecast discussion
National Weather Service Lincoln Illinois
1149 am CST Mon Nov 18 2019

Synopsis...
issued at 1045 am CST Mon Nov 18 2019

Mostly cloudy to overcast skies and light winds are expected
today across central and southeast Illinois. Temperatures will
slowly rise into the lower 40s by mid afternoon. An upper level
disturbance will bring a chance of light rain and light snow to
portions of the area late this evening into Tuesday morning. Snow
accumulations appear unlikely with lows in the mid to upper 30s.
Temperatures will warm to 45 to 50 degrees on Tuesday and reach
mid to upper 50s on Wednesday.

&&

Update...
issued at 1041 am CST Mon Nov 18 2019

Forecast looks on track today and just minor tweaks for some
hourly parameters today. An overcast low cloud cover covered
central and NE Illinois this morning though some breaks in overcast
starting to show up from Springfield south-southwest. Weak 1016 mb high
pressure over East Texas was ridging north-northeast into western Illinois at late
morning. A 998 mb low pressure was near Lake Winnipeg Canada with
a frontal boundary extending southward over the eastern Dakotas
and eastern NE/KS. Aloft a 545 dm 500 mb low was near the in/OH/KY
border and embedded in an upper level trof just east of Illinois over
the Ohio River valley. Could be a few breaks in the low clouds
over SW County Warning Area and into southeast Illinois this afternoon, but broken to
overcast mid/high clouds spreading quickly se toward northwest Illinois with a
weak clipper system will overcast area during the afternoon. So
not much sunshine expected today. Temps currently mostly in the
upper 30s to near 40f with 35 at Galesburg and 42 in
Lawrenceville. Temps only climb a couple more degrees with highs
of 39 to 44, mildest in SW County Warning Area as winds remain fairly light rest
of today.

&&

Short term...(today and tonight)
issued at 248 am CST Mon Nov 18 2019

Early this morning, surface observations reveal a cold front is
shifting east out of central Illinois into Indiana. Meanwhile, a
mid level vort Max centered near pnt will also continue to shift
east, exiting the state around daybreak this morning. Precip has
largely ended across central Illinois in the wake of the cold
front, save a few patches of drizzle near the mid level vort Max,
and anticipate dry but cloudy conditions to persist through most
of today. Stratus is in place from northwestern Iowa into central
Missouri and will likely remain locked in place under a strong
subsidence inversion through the rest of today and tonight.
Temperatures will remain below normal behind the front, struggling
to reach 40f for most areas under the cloud cover and modest
northwest flow.

Forecast becomes a little trickier for this evening and overnight.
A shortwave trough digging from the Canadian rockies into
Montana early this morning is progged to shift across the Midwest
tonight. There remain fairly large and significant model
differences at this close of distance that impact both placement
of precipitation and precip type. Northern solutions offered by
the GFS and a number of hi-res models suggest most of the precip
may skirt north of the ilx County Warning Area and any precip should remain rain.
The consistently southern solutions offered by the Gem and European model (ecmwf)
continue to paint the axis of precip right across central Illinois
with thermal profile favoring snow NE of I-74 and rain to the SW.
Given the uncertainty with tonights system, continue to run with
fairly low pops given the close time range, but do broad brush the
possibility of precip across the entire forecast area.
Fortunately it does appear to be relatively low impact...even if
colder solutions verify, snow accumulations should be fairly
negligible and mostly confined to the grass, while most of the
area should still see rain.

Long term...(tuesday through sunday)
issued at 248 am CST Mon Nov 18 2019

Forecast uncertainty lingers into the day Tuesday. While most
models are dry under the influence of a weak surface ridge
building across the region, the European model (ecmwf) indicates a second
shortwave trough will dig across central Illinois bringing another
quick shot of snow. This is an outlier at this point, but will
have to keep an eye on this time frame for potential changes to
the currently dry forecast. Stratus may linger a good portion of
the day Tuesday, but eventually anticipate some clearing will
arrive from the west as the 925mb ridge approaches. Depending on
how quickly this occurs, could have impacts on high temps for the
day. With latest thinking that cloud cover will linger into the
afternoon, have lowered temps several degrees for Tuesday,
favoring highs in the mid to upper 40s for most of the forecast
area.

As we approach midweek, a couple important features will be in
place across the western Continental U.S.. an extratropical system is
progged to lift northeast from the east Pacific across the Desert
Southwest Wednesday while a strong wave digs onshore over the
West Coast, eventually cutting off over Southern California. Downstream
amplification of the longwave ridge is expected and should allow
for at least a brief warmup to above normal temperatures Wednesday
into Thursday. Despite the warmup, weather otherwise may still be
unpleasant as surface low pressure deepens over the central Great
Plains and lifts into the upper Midwest Wednesday night into
Thursday. Pwats of around 1.00-1.25 are progged to arrive ahead of
the low, roughly 90th percentile of observed climo for late
November resulting in soggy conditions. The axis of heaviest
precip remains a bit uncertain with the mid level dry slot progged
to be in the vicinity of the local area, but some areas could see
half to three quarters of an inch of rainfall by late Thursday.
Meanwhile, strong gusty winds will accompany the deepening low as
it moves across the region, peaking Wednesday night into Thursday
across central Illinois. Forecast soundings continue to indicate
the potential for gusts in excess of 40 kt possible, and the
possibility for needing a Wind Advisory persists.

Seasonably cooler conditions will arrive behind a cold front
Friday through the weekend. Temperatures will return to highs
struggling to reach the low 40s. Will need to keep an eye on an
area of low pressure progged to lift from the lower/mid
Mississippi Valley to the upper Ohio Valley over the weekend.
There is quite a bit of variability at this long distance on the
track of the low, but could bring some snow to portions of
central Illinois next weekend.

&&

Aviation...(for the 18z tafs through 18z Tuesday afternoon)
issued at 1150 am CST Mon Nov 18 2019

Light fog has lifted over central Illinois at midday, while MVFR ceilings
of 1-2k ft at midday (low as 900 ft at cmi) will gradually lift
to high end MVFR to low end VFR ceilings later this afternoon and
continue this evening before lowing again overnight into Tue
morning. A weak clipper system over the Dakotas will dive quickly
se into central/eastern Illinois overnight, then exit east of Illinois by late
Tue morning. This will lower ceilings between 1-3k ft range while
vsbys lower to MVFR with some light rain showers possible from
07z-14z. Winds to remain light next 24 hours as weak surface ridge
over Illinois at midday drifts east into the Ohio/Tennessee River valley tonight
while a frontal boundary moves into western Illinois overnight and near
the Illinois/in border by 18z/noon Tue.

&&

Ilx watches/warnings/advisories...
none.

&&

$$

Update...07

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