Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 170854

Area Forecast Discussion
National Weather Service Lincoln IL
354 AM CDT Thu Apr 17 2014

ISSUED 238 AM CDT Thu Apr 17 2014

SHORT TERM...Today through Saturday

Low pressure analyzed over western Wisconsin on 07z/2am surface
analysis will continue to lift northeastward today, dragging a
weak cold front into central Illinois. Boundary will make only
slow progress eastward and will eventually stall along the I-57
corridor this afternoon. Little in the way of sensible weather
will accompany the front other than a few mid/high clouds.
Afternoon high temperatures will range from the upper 50s west of
the Illinois River to the middle 60s south of I-70.

Short-wave trough currently evident on water vapor imagery over
the Texas panhandle will track E/NE, passing south of Illinois
late tonight into Friday. Enough synoptic lift will be generated
by this feature to perhaps trigger a few light showers along/near
the stationary frontal boundary. Mitigating factor for precip will
be lack of moisture, as airmass remains very dry in the wake of
the early week cold front that penetrated well into the Gulf of
Mexico. Surface dewpoints have only recovered into the middle 50s
across coastal Texas, with models projecting 40-45F dewpoints
reaching central Illinois tonight. Forecast soundings remain dry
below 850mb, so am not expecting much in the way of precip. Will
hold on to low chance POPs tonight, with scant rainfall amounts of
only a couple hundredths of an inch at best.

Once upper wave passes by to the south, surface high pressure will
resume control of the weather on Friday. After some lingering
sprinkles/clouds across the east during the morning, sunshine will
return across the board by afternoon with highs climbing into the
lower to middle 60s. As the high shifts off to the east, increasing
southerly winds will bring even warmer air into the region on
Saturday resulting in highs reaching the upper 60s and lower 70s.

LONG TERM...Sunday through Wednesday

As has been the case for the past few days, the latest model suite
has once again delayed the onset of the next storm system early
next week. One upper wave is expected to track across southern
Canada over the weekend, while another slower-moving southern
stream wave will track out of the Desert Southwest into the lower
Mississippi River Valley by Monday. The GFS had previously been
the fastest model with this southern stream feature, introducing
precip as early as Easter Sunday. 00z Apr 17 run of the GFS has
now slowed the system and is in much better agreement with the
more consistent ECMWF/GEM, which have featured a dry Sunday for
the past couple of runs. As a result of this model consensus, have
removed mention of rain on Easter and have boosted highs into the
lower 70s. Showers will spread into the western KILX CWA Sunday
night, but will become most prevalent on Monday. Have hit POPs
hardest and lowered highs into the upper 60s on Monday accordingly.
Have also added mention of isolated thunder due to Lifted Index
values dropping to between 0 and -2C Monday afternoon. There are
some indications that the precip may be delayed even further into
Monday night and early Tuesday. Will hold on to chance POPs across
the E/SE on Monday night, but will return to a dry forecast on
Tuesday. Once this system exits the region, an approaching warm
front may trigger a few showers across northern Illinois on
Wednesday, but the main weather story in the extended will be the
warm conditions as temps routinely climb above normal into the 70s
next week.



ISSUED 351 AM CDT Thu Apr 17 2014

Have updated all TAF sites to include mention of LLWS for the next
few hours. Wind profiles from area Doppler radars showing low level
jet of 45-55 knots around 2500 feet, ahead of the cold front that
is pushing through eastern Iowa and central Missouri. Will
continue to see this for a few more hours, with some diminishing
occurring after sunrise as the front moves into western Illinois.




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