786 
FXUS63 KILX 020159
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
859 PM CDT Mon May 1 2017

.UPDATE...
Issued at 852 PM CDT Mon May 1 2017

Deep upper low over eastern Wisconsin this evening continues
to move away from central Illinois. However, the pressure
gradient remains tight so winds will remain on the gusty side 
tonight and through most of Tuesday. IR satellite loop indicating 
the backedge of the cloud deck was over northeast Missouri, and 
based on the present movement, should start to edge into our 
southwest counties late tonight and across our northeast by dawn. 
The combination of the gusty winds and cool temperatures, along 
with a few light showers make it feel anything like the first of 
May. The shower activity is expected to gradually end from 
southwest to northeast late tonight as the surface low continues 
to push further away from central Illinois. The current forecast 
has a good handle on the late evening and early morning trends, as
a result, no ZFP update is needed at this time. 

&&

.SHORT TERM...(This evening through Tuesday)
ISSUED AT 300 PM CDT Mon May 1 2017

Deep 993 mb low with upper level closed low vertically stacked in SW 
Wisconsin will continue to move ENE over the upcoming day. The cold 
pool combined with upper level disturbances wrapping cyclonically 
around the upper low will keep scattered showers around the area 
until near midnight along/north of I-74, while isolated to scattered 
showers extend southward through much of the area for late 
afternoon/early evening. The coldest 850 mb temperatures associated 
with the post-cold-frontal air mass will arrive in the area this 
evening, lifting slightly NEward Tuesday. Lows will end up quite 
cool as a result, with low to mid 40s. Cooler temperatures and frost 
should be absent due to the persistent pressure gradient keeping 
breezy WSW winds 10-20 mph through the night. Gradient will diminish 
significantly by evening as a surface high begins to move into the 
area, therefore will see diminishing winds late afternoon Tuesday. 
Highs will be up several degrees, reaching the upper 50s/lower 
60s...mid to upper 60s south of I-70 as partially clearing skies 
allow better heating, but still 5-10 degrees below normal.

.LONG TERM...(Tuesday night through Monday)
ISSUED AT 300 PM CDT Mon May 1 2017

Tuesday night should be dry as the next upper wave digs out of the 
Rockies into the southern Plains. The wave looks to deepen and close 
in the lee of the Rockies. Precipitation develops in warm advection 
ahead of the surface low mainly along and south of a Jacksonville-
Danville line Wednesday into Thursday night as the surface low looks 
to track into the Ohio River Valley and slow down due to a blocking 
ridge to the east. Latest model trends have increased precipitation 
amounts substantially for the southern half of the state, and 
precipitation amounts now look to be around 1 to 1.25 inches from 
Springfield-Danville ranging up to 2 to 2.5 south of I-70. Lesser 
amounts north of the Springfield-Danville line shouldn't be much of 
a problem, but to the south the amounts could exacerbate flooding 
conditions. Instability looks to be weak in general, but potentially 
supports some thunder south of I-70 Thursday. 

Next chance for a wave with precip is showing up in the amplified 
northerly flow aloft around the main trof that remains over the 
eastern Great Lakes through the weekend. High temperatures in the 
Wednesday to Friday remain in the upper 50s to lower 60s, followed 
by mid to upper 60s over the weekend into next week, but some 
potential for a bit cooler weather over the weekend if northerly 
flow pushes a bit further west than current model blends.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 633 PM CDT Mon May 1 2017

The strong storm system that has been bringing the gusty winds
and occasional MVFR cigs will slowly pull away from the area
tonight. The tight pressure gradient will keep the winds rather
gusty overnight, although not as strong as what we experienced
today. The low VFR and occasional MVFR cigs will continue thru
the evening, along with a few showers, before we see cigs lift 
and possibly scatter out at SPI, DEC and CMI after 04z, and 
gradually across our north in the 09z-11z time frame. Scattered 
occasionally broken VFR cigs will be possible across the north 
during the day on Tuesday with mainly a scattered cloud base 
further south between 3500-4500 feet. Westerly winds at 12 to 17 
kts with occasional gusts up to 23 kts tonight, with west winds 
expected on Tuesday at 12 to 17 kts with again a few gusts up to 
23 kts into the afternoon hours. 


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until midnight CDT tonight for ILZ051.

&&

$$

UPDATE...Smith
SHORT TERM...37
LONG TERM...37
AVIATION...Smith