Area forecast discussion
National Weather Service Lincoln Illinois
1236 PM CDT Thursday may 23 2013
Discussion...
issued 1005 am CDT Thursday may 23 2013
Secondary cold front is dropping southward across the northern
County Warning Area...and was fairly evident on radar from Peoria to Lexington to
near Paxton. A steady southward progression is expected...with it
through most of the area by middle afternoon. Temperatures north of
the front currently in the 50-55 range with some upper 40s just
southwest of Lake Michigan. Areas of light rain and drizzle have
been occurring with this front...but should diminish as the
afternoon progresses.
Some decent clearing noted on satellite imagery across about the
northern half of Iowa...with some thinning of the stratocumulus
progressing southward across Wisconsin. High clouds aloft over the
area should move out this afternoon with the front...but most of
the County Warning Area will see the stratocumulus sticking around. Areas
northwest of the Illinois River most likely to see some decent
amounts of sunshine by late afternoon.
Have sent some updated zones/grids. Made little change to the
precipitation trends. Temperatures were updated to reflect a short falling trend
behind the front...before leveling out or creeping up a bit again
in the afternoon.
Geelhart
&&
Aviation...
issued 1235 PM CDT Thursday may 23 2013
Cold front pushing south through the area has now crossed all of
the central Illinois taf sites...with winds shifting to the north-
northeast and gusting to 20-25 knots. Should see the winds settle
down later in the afternoon. Have been seeing some periods of IFR
conditions immediately along and behind the front. Back edge of
the showers is now south of kpia and will push through the
remaining sites the next few hours...and ceilings expected to rise
back to around 2000 feet at that point. Satellite imagery showing
the clearing line that has been dropping southward through Iowa
becoming more murky...due to diurnal cloud development. This will
fade with sunset...and skies largely expected to be clear over
central Illinois by middle to late evening. Northerly winds expected
to gradually shift toward the east Friday morning as high pressure
drifts southeast to near Lake Michigan.
Geelhart
&&
Previous discussion...
issued 330 am CDT Thursday may 23 2013
Short term...today through Friday night
560 dm 500 mb low near the Iowa/WI/IL border and associated upper
level trough to pull eastward across Illinois this morning and over in/Ohio
this afternoon. Broken to overcast low clouds have been spreading
southeast toward I-70 early this morning along with isolated to scattered
light rain showers over northern Illinois mainly north of I-80 so far.
These light showers are north of a frontal trough extending from
1004 mb low pressure over southeast Ontario through Southern Lower Michigan
into northern Illinois near I-80 and into southern Iowa. As upper level
trough and surface trough swing southeast through central Illinois this morning
expect a few light rain showers to occur...then diminish from northwest
to southeast during the afternoon as low clouds clear over the Illinois River
valley later this afternoon and over eastern Illinois during this
evening. Cool today for late may with highs in the low to middle 60s
over central Illinois and 65 to 70f in southeast Illinois from I-70 southeast. North-northwest breezes
to make it feel even cooler today.
1034 mb Canadian high pressure over northern Manitoba and ridging
southward into the central/northern plains to settle into WI and
NE Illinois as 1031 mb high pressure overnight bringing a cool night to
central Illinois as skies clear and winds become light with lows in the
upper 30s and lower 40s. High pressure ridge stays over Lake Michigan
and eastern Illinois Friday providing sunny skies and NE winds less than 10
miles per hour and highs in the middle to upper 60s. Dry weather should continue
across central/southeast Illinois through Friday evening with surface ridge
nearby.
Long term...Saturday through Thursday
Upper level ridge sets up over the Great Plains by this Memorial
Day weekend with upper level low/trough moving into New England by
Sat. This puts Illinois in a northwest upper level flow and models continue to
show upper level disturbances riding southeast along thermal gradient
near central Illinois this Holiday weekend. Have 20-30% chance of
showers and isolated thunderstorms northwest of I-55 after midnight
Friday night. Then spread a 30-50% chance of showers and
thunderstorms eastward across central and western Illinois Sat (slight
chance over eastern/southeast Illinois Sat afternoon) and into eastern Illinois by
Sat night. Looks like 30-40% chance of showers and thunderstorms
continues Monday and Tuesday over much of area with the lower probability of precipitation
near the Wabash River. Surface high pressure over the Great Lakes
and into the central/eastern Ohio Valley to also keep areas NE of
central Illinois drier this Holiday weekend. Upper level ridge shifts
east into the Ohio Valley by middle of next week and shifts
chances of convection north of central Illinois. Temperatures and
humidity levels to gradually increase also from sun-Wednesday with highs
in the upper 60s and lower 70s Sunday and climbing to around 80f
Tuesday and low to middle 80s Wednesday.
07
&&
Ilx watches/warnings/advisories...
none.
&&
$$
