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Area forecast discussion 
National Weather Service Lincoln Illinois
606 PM CST sun Nov 23 2014

Short term...(tonight)
issued at 313 PM CST sun Nov 23 2014

Deepening 993 mb low pressure between Oklahoma City and Tulsa at mid
afternoon will strengthen further as it ejects northeast across
central Illinois near or east of I-55 during this evening, and into
northern lower Michigan overnight at it deepens to 979 mb. Widespread
light to moderate rain showers have spread north-northeast across central/se Illinois
early this afternoon. Still no reports of thunder over Illinois but will
continue to carry isolated thunderstorms over eastern Illinois into this
evening as deepening low pressure approaches.

Showers will break up later this evening and overnight east of the
Illinois River while deformation zone of precipitation lingers west of the
Illinois River. Strong cold front sweeps across central and eastern Illinois
during overnight, passing through the Wabash River valley early
Monday morning. Light rain to mix with light snow NW of the Illinois River
late tonight and change to snow early Monday morning as temps fall
into the mid 30s. Temperatures currently in the low to mid 50s and
dewpoints are in the upper 40s and lower 50s. Lows tonight to range
from mid 30s from Peoria and Springfield west, to the mid to upper
40s near the in/Illinois border with temps continue to drop Monday
morning. Southeast winds 10-17 mph and gusts of 18-25 mph this
afternoon to subside this evening to around 10 mph or less as low
pressure moves in. But as low deepens and pulls away from central/se
Illinois overnight, winds will turn westerly behind the cold front and
increase to 15-25 mph and gust 25 to 30 mph later tonight. RUC model
shows even higher wind gusts of 35-40 mph going into southeast Illinois
behind cold front early Monday morning around sunrise. Met/mav
guidance shows strongest winds during the day Monday (strongest in
eastern il) after 15z/9 am Monday.


Long term...(monday through sunday)
issued at 313 PM CST sun Nov 23 2014

The strong low pressure area will continue to lift northeast through
the Great Lakes area with a very strong pressure gradient behind the
system. In addition, gusty westerly winds and strong cold air
advection (caa) will move into the area Monday. Expecting rain in
the eastern half of the County Warning Area and a mix of rain and snow in the
western half,in the morning. Then as the cold air advection occurs, the all snow
line will move across the area from west to east, so that by early
afternoon, most of the County Warning Area will be all snow, with the mix of rain
and snow only in the eastern parts of the County Warning Area. By late afternoon,
the whole area will be cold enough for snow. As the system lifts
northeast through the day, the higher chances of pcpn will move from
southwest to northeast. So, the areas mostly likely to see any
accumulation of snow will be northwest of I-55 during the morning and
then north of a Galesburg to Bloomington line during the afternoon.
Total snowfall accumulation expected tomorrow will be an inch or
more northwest of a Macomb to Pontiac line; and then lesser amounts
southeast of that line. Highest amounts are expected to be 1.5 to 2
inches north of a Galesburg to Lacon line.

The tight gradient behind this system will also bring very gusty
winds to the County Warning Area tomorrow, beginning tomorrow morning and lasting
through the day. Sustained winds or around 25 mph with gusts between
35 and 40 mph will be possible across the whole area tomorrow. Will
not be issuing a Wind Advisory as it will be just below criteria.
However, would not be surprised if overnight shift issues one in the
morning. The gusty winds will also create blowing snow, mainly in
the northern parts of the cwa, so visibilities could be reduced at

Pcpn will end by tomorrow night as the low pressure area lifts
northeast into Canada. After this system, dry weather is expected
for Monday night through Tue night as brief high pressure area moves
through the County Warning Area. Then another clipper system is expected to move
through the area and bring another chance of rain and/or snow for
Wednesday. There will be some warm air ahead of this system so the
pcpn type could be a mix before it changes to all snow. Any
accumulations with this system will be confined to the north with a
half inch or less this time. The remainder of the
forecast should be dry with temps below normal, as Canadian high
pressure moves in and dominates the weather through the rest of the
week and into the weekend.

Temps will steady or slowly falling tomorrow due to the strong cold air advection
expected. Then temps will be cool/cold most of the rest of the
forecast, except for Wed, just ahead of the next clipper system.


Aviation...(for the 00z tafs through 00z Monday evening)
issued at 600 PM CST sun Nov 23 2014

IFR and LIFR ceilings of 300-700 ft have developed over central Illinois
airports this afternoon and expect ceilings to remain there tonight.
MVFR visibilities due to rainfall should continue during the steady
moderate rains this evening. Radar trends show the precipitation
will diminish from west to east between 02z to 06z, but visibility
will likely remain low due to the onset of drizzle and fog. No
thunderstorms are expected at any taf site this evening.

Cold air will filter into central Illinois late tonight and Monday
morning, causing the rain showers to mix with or change to light
snow from west to east. As the precipitation becomes all snow, vsbys
could drop as low as 1-2 miles at pia and bmi where snowfall
accumulation could climb up as high as 1 inch. Vsbys should remain 2-4
miles farther south along I-72 where snowfall will be lighter. Southeast
winds have diminished to 7-10 kts already. Winds will veer SW overnight
and become west later tonight into Monday morning, with speeds
increasing to 20-25 kts and gusts 26-34 kts by 18z/noon on Monday.


Ilx watches/warnings/advisories...


Short term...07
long term...auten

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