Area Forecast Discussion
Issued by NWS Central Illinois

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KILX 220709

Area Forecast Discussion
National Weather Service Lincoln IL
209 AM CDT Tue May 22 2018

.SHORT TERM...(Today and tonight)
ISSUED AT 208 AM CDT Tue May 22 2018

A weak surface boundary continues to push across the forecast area
early this morning, generally located along a Quincy to Pontiac
line at 1 am. This should cross the CWA by about 9-10 am. Can`t
rule out a couple showers as it exits the area, but this should
largely be a dry passage in our area. Skies expected to be mostly
sunny over a large part of the area behind the boundary, though
the Cu-Rule suggests the cumulus may be harder to break out across
the north. With the more significant cloud over there,
temperatures likely will stay below 80 degrees north of I-74, with
mainly lower 80s elsewhere.


.LONG TERM...(Wednesday through Monday)
ISSUED AT 208 AM CDT Tue May 22 2018

Amplifying upper ridge over the Plains will build toward the
Mississippi Valley through Thursday. This should keep the
showers/storms away from the forecast area initially. However, the
ridge will break down late week, as an upper wave moves east
into the Great Lakes. Longer range guidance continues to keep us
dry into Friday night. Temperatures will slowly build as the ridge
drifts overhead, and highs should be in the 90 degree vicinity by

Forecast for the holiday weekend will be complicated by evolution
of potential tropical system in the Gulf of Mexico. Evening model
guidance has a fair spread on the track, ranging from a landfall
near New Orleans as early as Saturday morning (ECMWF solution) to
one near Tampa midday Sunday (GFS). Remnant system in either case
should be cut off from the upper flow over the Great Lakes, with
our area left in limbo. With no strong forcing in place, any
convection may be more diurnal in nature, but pinning it down at
this distance will be a bit tricky. Highest PoP`s both Sunday and
Memorial Day will be during the afternoon, but will be more
scattered in nature.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1106 PM CDT Mon May 21 2018

MVFR and IFR cigs/vsbys just to our north with the main forecast
challenge through 15z just how far south the lower vsbys and
clouds will go overnight. Surface and low level flow quite weak
despite a cool front pushing across the forecast area tonight. The
stratus deck and lower vsbys were slow to advect south this
evening but looking at our current temp- dew point spreads suggest
the lower cigs and especially vsbys may develop across our area
during the early morning hours, especially in the areas that
received the significant rainfall over the past 24 hours.

If the clouds do indeed advect south into our area, not sure how
low our vsbys will get overnight, while at the same time, if the
lower cloud deck is slower to arrive, we may just drop down more
quickly with our vsbys during the early morning hours. Any IFR/LIFR
or MVFR cigs/vsbys will gradually dissipate by 15 or 16Z Tuesday
with a sct-bkn deck at 2000-3000 feet in the late morning and then
scatter out in the afternoon with cloud bases in the 3500 to 4500
foot range by 20z.

Light south to southwest winds will shift into a light westerly
direction after FROPA late tonight with a northwest wind at 8 to
13 kts from mid-morning thru late afternoon Tuesday.




SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Smith is the U.S. government's official web portal to all federal, state and local government web resources and services.