Area Forecast Discussion
Issued by NWS Central Illinois
FXUS63 KILX 141137
Area Forecast Discussion
National Weather Service Lincoln IL
637 AM CDT Fri Mar 14 2014
ISSUED 317 AM CDT Fri Mar 14 2014
Main concerns this package include chances of pcpn Sat night
through Sunday, and then again Tuesday through Wednesday. Models
have trended little further south with the weekend system as the
trough digs further into the southern plains. So a blend of the
models looks ok with this system. With the second system, the
models have come into much better agreement with timing, but still
differ with the way the upper level system looks. Will lean toward
maintaining going forecast, but with better agreement will need to
raise pops a little.
SHORT TERM...Today through Sunday
Tight gradient today will bring gusty winds to the area ahead of a
cold front that should move through the area during the afternoon.
Winds will then decrease behind the system as a narrow ridge of
high pressure moves across the region. Then the next system will
drop out of the northern plains toward the south. Models show a
somewhat split flow merging into one with the dominate surface low
becoming the one to the south. There is good agreement with what
should transpire on the surface in with the flow, so confidence is
high enough to warrant raising pops into the likely category for
Sunday in the south. As the system drops south, there is a chance
that some rain/snow will occur northwest of the IL river Sat
night. However, the main focus of pcpn will be in the south half
of the cwa as the system deepens a little and moves out of TX and
toward the southeastern US. How far north the pcpn will spread
into IL will depend on amount of moisture it pulls in and the
strength of the system. So will have likely pops in the southeast
with chance to the north. With surface flow from the northeast
Sunday night, temperatures should drop sufficiently so that p-type
over most of the area will be snow. Southeast IL will be closer to
some warmer air, so have p-type as rain or snow.
Temps will be spring-like today and in some areas tomorrow, but
then below normal temps are expected for Sunday with lots of
clouds, so it will return to being chilly.
LONG TERM...Sunday night through Thursday
Another narrow ridge of high pressure will move through the region
Sunday night through Monday night. Then the next system moves out
of the northern Rockies and into the plains by Tuesday. Southerly
winds ahead of the system should bring warmer temps back into the
region, so p-type will mainly be rain. Based on the track of the
low pressure remaining mainly west of most of the area, colder
temps should not advect back into the region until Wed night,
after the pcpn has departed the area. Moisture could be limited
with this system since the period of return flow is very short.
Temps will start on the cool side but then warm ahead of the Tue
night system. Should be some cooler air advecting into the area
behind the system as the upper level trough moves across the
region, but believe mid March sunshine could keep things from
getting too cool for end of the week.
ISSUED 625 AM CDT Fri Mar 14 2014
VFR conditions will prevail through tonight. The main concern this
forecast period will be with winds today as the latest ILX sounding
data indicates winds around 1500 feet were from 250 degrees at 50 kts.
Will continue the LLWS until 15z and then winds will start to mix down
to the sfc with sustained wind speeds of 12 to 20 kts with a few gusts
up to 30 kts...especially around KDEC and KCMI. A cold front over
central Iowa will push into our area by early this afternoon with
surface winds veering from a southwest direction into the west and
then northwest this afternoon. Look for the winds to diminish this
evening to around 10 kts.