Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Lincoln Illinois
330 am CDT Sat Mar 15 2014
issued 330 am CDT Sat Mar 15 2014
Short term...today through Wednesday
Another pleasant day expected today as mid level clouds increase
across northern areas while ample sunshine southern areas today.
Highs range from lower 50s from I-74 north to upper 50s and lower
60s SW areas and in southeast Illinois. Lighter winds expected today as
weak high pressure ridge is near Illinois today.
00z GFS & NAM models have trended further south with low pressure
tracking east across southern Arkansas and passsing south of Tennessee Sunday
and Sunday night. Therefore qpf fields have trended further south
and have lowered snowfall amounts to 1-2 inches in far southern 3
counties of Clay, Richland and Lawrence. Still have a mix of
precipitation initially before changing to snow Sunday afternoon
and light snow diminishing over southeast Illinois during Sunday evening.
The Illinois River valley could see a chance of light snow tonight into
early Sunday morning and then models weaken and end qpf fields
over northern counties Sunday as drier air moves in on ENE winds
around 1030 mb high pressure settling into the Great Lakes region.
Increase NE wind speeds tonight and Sunday due to tighter pressure
gradient over central and southern Illinois with gusts of 25 to 35 mph
expected. Much colder temperatures Sunday with highs in the lower
30s and near 30f from I-74 north.
Temperatures modify Monday and especially Tue (highs in the mid to
upper 50s) with increasing southerly winds ahead of a strong upper
level trof and deepening surface low pressure ejecting NE into the
western Great Lakes Wed. This to bring a chance of rain showers
Tuesday night and Wed.
Long term...Wednesday night through Friday
Dry conditions return during 2nd half of next work week. Highs in
the upper 40s and lower 50s Wed/Thu modify back into the mid to
upper 50s on Friday. GFS does have light qpf into Illinois Friday as a
cold front approaches Illinois while European model (ecmwf) model keeps its ligth qpf north
of central Illinois with surface low pressure. Both models are milder and
if light precip occurred it would be warm enough for light rain
issued 1157 PM CDT Fri Mar 14 2014
VFR conditions will prevail at all taf sites next 24hrs. Skies
will be clear at all sites overnight and during the morning hours.
Then broken mid clouds around 10kft will advect over the north,
affecting only pia and bmi during the afternoon. The other three
taf sites could see scattered mid clouds at the same time. Then
clouds will scatter out in the north and become clear elsewhere
around 00z. Then expect lower clouds around 5kft to advect into
the pia and bmi sites during the evening in advance of the next
system bringing pcpn to the area. Spi/Dec/cmi will just see cirrus
increasing at the same time. Winds will be light and variable
overnight as high pressure ridge moves over the area. Then winds
will become east-southeast tomorrow with winds around 10kts. As
the next system gets closer, winds will become more east to
northeast late in the evening but increase in speed with gusts to
20-25kts before midnight.