Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 180824
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
324 AM CDT Mon Aug 18 2014

.SHORT TERM...(Today and tonight)
ISSUED AT 323 AM CDT MON AUG 18 2014

Low pressure area that produced the rain in southeastern IL
yesterday has moved little more east while a brief, weak area of
ridging slides across the region today. Though the low is southeast
of the area, it could still bring some pcpn to the east and
southeastern parts of the CWA tomorrow afternoon. At the same time,
a cold front will approach the area from the northwest and bring a
chance of showers and thunderstorms to areas northwest of the
Illinois river this afternoon and into this evening. As the front
moves southeast, the chances of pcpn will increase and spread
southeast tonight.

Temperatures will be moderated by the cloud cover over the area
today and through tonight.


&&

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 323 AM CDT MON AUG 18 2014

Tuesday, the new wave dipping into the Great Lakes will spread
chances for rain and thunderstorms across Central Illinois for the
day on Tuesday, mostly diminishing west to east through the evening
until a developing baroclinic zone starts to build from NW to SE
along the southwestern portions of the state and into IA.  Same
boundary will have little reflection at the sfc with very weak flow
and an open pressure pattern, but thermal gradient is better
represented in the mid levels.  Boundary will provide a weak focus
for waves moving through the region as the boundary lifts to the NE
through the area for Wed/Wed night.  Though Wed is lacking signif
pop for now, the timing of the progression is better for early
evening and into the overnight on Wednesday night/shifting to the
northeast for Thurs. Position of the boundary or the remnants
thereof will be where the majority of the precip lands in this time
frame.  Ample sfc based instability in the form of hot and humid
conditions as the ridge over the southwest opens and spreads signif
heat into the Midwest.  850 mb temps in the 19-25C range from
Wednesday through Sunday will drive the temps into the upper 80s
then into the lower 90s with heat indices in the upper
90s/approaching 100.  A far more summer time pattern than much of
the season so far, and well above normal for this time of year...with
breaks from the heat provided by any thunderstorms that have the
chance to form.  Upper winds not really enough to cultivate too much
in the way of an extended severe weather threat at this point, but
that could change in the shorter range as the days wear on.


&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1158 PM CDT SUN AUG 17 2014

MVFR vsby has become predominant with local IFR/LIFR
cigs/vsby over central and SE Illinois as fog begins to develop
this evening. Overnight, fog will develop, with potential for
LIFR or VLIFR conditions...mainly 07Z-15Z. So far, steady light NE
winds 5-10 kts has kept fog diffuse through mixing of the surface
layer, but winds should decrease overnight as pressure gradients
relax across the region. Improving conditions after 15Z with
ceilings becoming sct-bkn030 for most of the afternoon. A weak
trough and surface low moving in from the NW Monday evening will
bring a chance of rain back to areas KPIA-KBMI northward after
00Z, but chances for significant vsby/cig reduction in precipitation
remain too low for mention in central IL TAFs at this time.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY until 9 AM CDT this morning FOR ILZ027>031-
036>038-040>057-061>063-066.

&&

$$

SHORT TERM...AUTEN
LONG TERM...HJS
AVIATION...ONTON






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