Area Forecast Discussion
Issued by NWS Central Illinois

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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 271948

Area Forecast Discussion
National Weather Service Lincoln IL
248 PM CDT Thu Jul 27 2017

.SHORT TERM...(This evening through Friday)
ISSUED AT 248 PM CDT Thu Jul 27 2017

19z/2pm surface analysis shows a cold front bisecting the KILX
CWA...roughly along a Jacksonville to Danville line. A band of
showers has recently developed immediately along the front, with
additional scattered showers breaking out further south
along/south of I-70. Thanks to cloud cover and relatively cool
temperatures in the lower to middle 80s, LAPS data is showing
CAPE values of only 1500-2000J/kg. As a result, have lowered
thunder mention for this afternoon/evening to just isolated. May
also see a few funnel clouds along this line of showers as low-
level vorticity is locally enhanced. Cold front will sink slowly
southward tonight, pushing any lingering shower chances south of
I-70 by midnight. Overnight low temperatures will range from the
lower 60s far northwest around the lower 70s far
southeast near Lawrenceville. Front will sink into the Ohio River
Valley on Friday as high pressure builds into the Upper Midwest. A
cooler/drier airmass will flow into central Illinois from the
north behind the departing front...with high temperatures
remaining in the lower 80s.


.LONG TERM...(Friday night through Thursday)
ISSUED AT 248 PM CDT Thu Jul 27 2017

A quiet and mainly dry stretch of weather is coming up for the a western CONUS upper ridge/eastern CONUS upper
trough pattern dominates. This will keep central Illinois firmly
locked into deep-layer northwesterly flow...which will keep
temperatures at or slightly below normal in the 80s for the coming
week. Several disturbances will drop southward through the
prevailing flow: however, they will be very weak and moisture-
starved. The 00z Jul 27 GFS tries to develop a few showers/thunder
across north-central Illinois Monday afternoon, but have opted to
leave the forecast dry as forecast soundings are not supportive of
measurable precip. After that, a somewhat stronger wave may
arrive by the end of next week...with the GFS suggesting a better
chance for precip perhaps arriving by Thursday.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1246 PM CDT Thu Jul 27 2017

Widespread cloud cover blankets central Illinois early this
afternoon: however, latest visible satellite imagery is showing a
few breaks in the overcast developing across the northern KILX
CWA. Ceilings were initially IFR early this morning, but have
risen to MVFR/low VFR as of 17z. Based on satellite trends and NAM
forecast soundings, have gradually improved all sites to VFR by
20z. May see a few showers as well, especially at the I-72
terminals. Forecast soundings suggest skies will clear by early to
mid-evening, with some high-res guidance hinting low clouds may
re-develop across west-central Indiana then push westward to KCMI
and perhaps KDEC late tonight into early Friday morning. Have
brought ceilings back down to MVFR at KCMI after 09z, but have
kept the lower clouds out of KDEC at this time. Any early morning
low clouds will clear/dissipate by 15z...followed by mostly clear
conditions for the balance of the day.




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