Area forecast discussion
National Weather Service Lincoln Illinois
1030 am CDT Wednesday may 22 2013
Discussion...
issued 1020 am CDT Wednesday may 22 2013
Have made some minor alterations to going forecast...particularly
with respect to probability of precipitation today.
As best forcing moves northward out of the state late this morning
the area of showers and thunderstorms should diminish in the kpia
and kbmi area shortly. However will cool middle-level temperatures around
-15c at 500mb and continued cyclonic flow...scattered showers and
thunderstorms will redevelop by early afternoon with the steep
low-level lapse rates.
Latest lamp data suggests current forecasted highs reasonable.
Barker
&&
Aviation...
issued 649 am CDT Wednesday may 22 2013
A band of showers is moving north through the area and will affect
the sites for the next couple of hours. So have all sites starting
with vcsh and have included a 1hr tempo group at pia/bmi/cmi for
lower visible and ceilings. Then VFR conditions with ceilings in the middle
levels will prevail the rest of the morning. Then expect lower
clouds...though VFR...to move back in the area for this
afternoon. This next round of precipitation will be in the afternoon...but
should not affect visible or ceilings at taf sites. The last round of precipitation
will be after midnight as the final trough moves through the County Warning Area.
Winds will be southwesterly at the beginning...but when the front
moves through later today winds will become westerly.
Auten
&&
Previous discussion...
issued 330 am CDT Wednesday may 22 2013
Short term...today through Friday night
Showers will be likely today along with a chance of thunderstorms
especially over eastern Illinois. This due to a cold front moving east
across Illinois today as 1004 mb low pressure over north central Iowa
tracks east along the WI/Illinois border. 559 dm 500 mb low near the
Minnesota/South Dakota border to move into NE Iowa by sunset. Storm Prediction Center keeps slight risk
of severe storms east of Illinois over the eastern 2/3rd of Indiana and
east into Ohio and central/eastern Kentucky. Cooler today with more
clouds and rain showers around. Close to normal highs today mostly
in the middle 70s...but range from the lower 70s over the Illinois River
valley to the upper 70s in southeast Illinois especially near the Wabash River.
Continued a 20-40% chance of showers tonight and Thursday as upper
level low moves to near Chicago by 06z/1 am tonight and associated
upper level trough shifts east over Illinois into Indiana Thursday morning.
Lows tonight in the middle to upper 50s. Even cooler Thursday with highs
in the middle to upper 60s with coolest readings from I-74 NE where
even some lower 60s possible where skies will stay cloudier.
Low clouds clear later Thursday afternoon into Thursday evening as 1030 mb
Canadian high pressure settles into WI/Illinois by Friday morning and into
Michigan by sunset Friday. Models continue to trend cooler for lows Thursday night
now in the lower 40s with clearing skies and light winds. Highs
Friday in the middle to upper 60s despite return of sunshine. Illinois starts
to get into a warm air advection flow during Friday night especially
after midnight when 20-30% chance of showers and isolated
thunderstorms arrives west of I-57 with best chances northwest of the Illinois
River. Not as cool Friday night as clouds increase and southeast flow with
lows in the upper 40s and lower 50s.
Long term...Saturday through Wednesday
Models agree with upper level ridge over the Great Plains by this
Memorial Day weekend with Illinois in a northwest upper level flow. Surface
high pressure near the Great Lakes region giving a return
southerly flow to Illinois as below normal temperatures late this week
gradually warm up during early next week. But models differ on
disturbance ridging over the top of the upper level ridge and
associated quantitative precipitation forecast fields. Tried to stay consistent with previous
forecast and with extended model trends which shows higher probability of precipitation
this weekend over the Illinois River valley and less chances in southeast Illinois.
Highest chances appear to be after midnight Sat night and Sunday
and have 50% chance of convection northwest half then. Temperatures and humidity
levels rise from Sunday through Wednesday and have chance of
convection lingering through Wednesday though models trending with
convection chances shifting north of central Illinois during next work
week.
07
&&
Ilx watches/warnings/advisories...
none.
&&
$$
