Area Forecast Discussion
Issued by NWS Central Illinois

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
000
FXUS63 KILX 160749
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
249 AM CDT Wed Apr 16 2014

.DISCUSSION...
ISSUED 249 AM CDT Wed Apr 16 2014

SHORT TERM...Today through Friday

Winds will increase markedly across central Illinois today as
gradient tightens between departing high pressure system and low
tracking from the Dakotas into southern Minnesota. Models are not
quite as strong with the winds as they were in previous runs, so
am not concerned about reaching Wind Advisory criteria. BUFKIT
momentum transfer at KPIA shows 33kt winds at the top of the mixed
layer this afternoon, as opposed to 43kt on the prior run just 24
hours ago. Despite this decrease in momentum, think S/SE winds
will gust to between 30 and 35mph across the western half of the
KILX CWA, with gusts to around 25mph further east near the
Indiana border. This strong southerly flow will help bring much
warmer air into the region. Extent of warming will be mitigated
somewhat by an easterly component to the wind and mixing heights
lowering to less than 5000ft. Resulting afternoon highs will range
from the middle 50s east to around 60 far west.

As southern Minnesota low lifts toward Lake Superior, it will
drag a weak cold front into the Illinois River Valley by dawn
Thursday. This boundary will become stationary along the I-55
corridor during the day Thursday, creating little in the way of
sensible weather. A mid-level short-wave will approach from the
southwest late in the day and will eventually interact with the
front to perhaps produce a few light showers. Current surface
analysis shows a very dry airmass has settled across the eastern
half of the CONUS all the way to the Gulf of Mexico. In fact,
buoys in the northern Gulf are currently showing dewpoints as low
as the middle to upper 30s. With so much dry air to the south, do
not think front will have enough moisture to work with in order to
produce precip across the area on Thursday. GFS is the only model
that is holding on to QPF across the Illinois River Valley
Thursday afternoon, but think this is overdone. Will therefore go
with a dry forecast across the board. There are even some
indications that dry conditions will continue Thursday night into
Friday as the upper wave arrives. At this point, will leave chance
POPs for showers in the forecast Thursday night into Friday
morning as synoptic lift associated with the wave will likely be
enough to squeeze a few light showers out of the dry airmass. Once
the wave passes, dry weather will return Friday afternoon and
night.

LONG TERM...Saturday through Tuesday

After a warm/dry day on Saturday, attention turns to next
approaching system for early next week. Models have been trending
slower with its approach, with most 00z Apr 16 guidance suggesting
Easter Sunday may remain largely dry. GFS is the most aggressive
model in driving precip eastward into the area, but even it has
backed off and keeps rain at bay until Sunday afternoon at the
earliest. GEM focuses best rain chances Sunday night into Monday,
while ECMWF is even slower and advertises mainly a Monday rain
event. As a result of the distinct slowing trend, have trimmed
POPs accordingly. Will keep Saturday night and Sunday morning dry,
then will bring chance POPs into the picture across the western
CWA Sunday afternoon. Will highlight the Sunday night/Monday time
frame with the highest POPs, followed by a return to dry weather
on Tuesday. Aside from the early week rain chances, the extended
forecast will feature warmer weather, with model guidance
suggesting temps reaching the 70s by Tuesday.

Barnes
&&

.AVIATION...
ISSUED 1150 PM CDT Tue Apr 15 2014

VFR conditions will continue at all TAF sites next 24hrs. High
cirrus will move into the area, affecting all sites several hours
after TAF issuance time. Then mid clouds around 15kft will advect
into the area, but should remain scattered as moisture is limited
and best moisture will be up north where the bulk of the system is
expected to track. Then expecting some scattered cirrus again in
the evening. Winds are southeast as high pressure ridge has
quickly moved east of the area this evening. Tomorrow, winds will
become southerly and increase in speed, as winds mix down from
around 6kft. So gusts should be around 30kts at all sites for
morning and afternoon. After 01z, winds will decrease and lose the
gustiness.

Auten
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING until 9 AM CDT this morning FOR ILZ052-054-056-
061>063-066>068-071>073.

&&

$$







USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.