National Weather Service Raw Text Product

226 
FXUS63 KILX 071050
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
550 AM CDT Fri Jul 7 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 329 AM CDT Fri Jul 7 2017

08z/3am surface analysis shows a cold front extending from northern 
Michigan southwestward to central Iowa.  While the majority of the 
convection associated with the boundary has been focused across 
Wisconsin into Michigan where wind shear is stronger, isolated 
thunderstorms have developed further west along the front across 
eastern Iowa early this morning.  Radar timing tools show these 
cells crossing the Mississippi River into west-central Illinois over 
the next couple of hours.  While instability will be at a minimum 
and wind shear will remain quite weak across the area, have included 
a slight chance PoP along/west of I-55 through mid-morning.  After 
that, it will be a matter of timing convective re-development along 
the slowly advancing front this afternoon.  Latest run of the HRRR 
suggests this will occur around 17-18z along and just east of I-55. 
Have therefore carried chance PoPs across the E/SE KILX CWA through 
the afternoon into the early evening before the scattered storms 
push further southeast into the Ohio River Valley.  Given dewpoints 
pooling in the lower 70s along the front, corresponding CAPE values 
will likely exceed 3000J/kg across the E/SE later today.  Wind shear 
will increase slightly as well: however, stronger shear will remain 
focused further northeast along the front across Ohio/Indiana.  As a 
result of favorable instability and weak shear parameters, a few of 
the storms will be capable of gusty winds and marginally severe hail. 
High temperatures this afternoon will range from the middle 80s far 
northwest around Galesburg...to the lower 90s south of I-70.  After 
a few lingering thunderstorms across east-central Illinois early 
this evening, skies will clear across the board tonight and 
overnight lows will range from the upper 50s far northwest to the 
middle 60s southeast.

.LONG TERM...(Saturday through Thursday)
ISSUED AT 329 AM CDT Fri Jul 7 2017

Once the front passes, a pleasant weekend will be on tap with highs 
in the lower to middle 80s both Saturday and Sunday.  With 
northwesterly flow establishing itself across the Midwest/Great 
Lakes, a number of weak short-waves embedded within the flow will 
pass through the region.  The models are latching on to the first 
feature Saturday night, with the GFS/ECMWF/NAM all producing some 
light QPF.  Given timing of the wave overnight and the fact that it 
will be pushing into prevailing high pressure, think this is 
overdone.  As a result will maintain dry conditions.  Widely 
scattered thunderstorms will be possible Sunday afternoon: however, 
lack of a boundary to serve as a focusing mechanism will keep areal 
coverage quite low.

00z July 7 GFS suggests a more substantial wave will trigger MCS 
development across Minnesota Sunday night, with this complex 
potentially spilling southeastward into portions of north-central 
Illinois Monday morning.  The ECMWF is further north with this 
system, mainly impacting northern/northeastern Illinois.  Have 
bumped PoPs up to high chance across the northern CWA on Monday 
accordingly, but will not go likely until better model agreement is 
achieved.  After that, a warm and unsettled week is on tap...as 
numerous waves bring periodic rain chances.  It will be difficult to 
time the individual waves, so low chance PoPs are on order each day 
through at least Thursday before building heights potentially bring 
an end to the rain chances by the end of the week.  High 
temperatures will remain in the upper 80s to around 90 degrees 
Tuesday through Thursday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 550 AM CDT Fri Jul 7 2017

A cold front will trigger scattered thunderstorms across central 
Illinois today. Latest radar imagery shows a cluster of storms
around KUIN and another isolated cell further north just west of 
KGBG. Based on southeast trajectory, have included VCTS at KPIA
through 14z and VCSH at KSPI through 15z. After that, its a 
matter of timing re-development along the front later today. 
Several high-res models suggest scattered convection will begin 
re-developing around midday across north-central Illinois, then 
will become more widespread/robust as it drops toward I-70. Based 
on this, decided to include VCTS at KBMI between 18z and 
20z...and at KDEC/KCMI between 18z and 00z. After that, any 
threat for additional convection will end and skies will clear in 
the wake of the cold front. Winds will initially be from the W/SW 
at around 10kt this morning, then will veer to the NW and 
increase to 10-15kt after FROPA later this morning into the 
afternoon.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Barnes