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Area forecast discussion 
National Weather Service Lincoln Illinois
1028 am CDT Tuesday Aug 4 2015

Update...
issued at 1025 am CDT Tuesday Aug 4 2015
weak boundary stalled just to the south of the forecast area this morning.
Some precipitation associated with that boundary moved across the
southeast and some minor updates for the morning were necessary,
but little to no updates necessary for the bulk of the County Warning Area. Cirrus
and warm temperatures with weak south/southeasterly flow expected
to continue through the morning.

&&

Short term...(today)
issued at 328 am CDT Tuesday Aug 4 2015

Frontal boundary still remains west of the County Warning Area...oriented from
northwest to southeast through MO and southern Illinois. This will be the
focus for any convection today and even into the afternoon. Some
scattered convection is already present along this boundary and is
moving east-southeast and may effect parts of southeast Illinois later today. Will
keep slight chance of storms over southwest Illinois and parts of
southeast Illinois through the day. Worded forecast will read as isolated
thunderstorms...while grids say slight chance. Convection along this
boundary will keep mostly cloudy skies along southwest and southeast
Illinois as well. Temperatures should be a little cooler than yesterday...given
cloud cover and light winds out of the north...north of the
boundary. Compromise of guidance temperatures looks good for now.

Long term...(tonight through monday)
issued at 328 am CDT Tuesday Aug 4 2015

00z models have shifted southward low pressure track into middle MS
valley during middle week and hence are slower bringing chances of
showers and thunderstorms NE into central Illinois tonight and Wednesday. Storm Prediction Center
has taken marginal risk of severe storms SW of central Illinois next few
days. Have therefore lowered probability of precipitation in NE County Warning Area during this time with
mainly slight probability of precipitation from I-74 NE tonight and low chance probability of precipitation from I-
74 NE on Wednesday. Have good chances probability of precipitation SW County Warning Area by overnight and likely
probability of precipitation SW County Warning Area Wednesday. Highest rain chances will be Wednesday night into Thursday
morning with 70-90% probability of precipitation in southern counties and heaviest quantitative precipitation forecast
during this time with 1-1.50 inches from I-70 south and locally
higher amounts south of Highway 50. Just chance probability of precipitation northern County Warning Area
during this time frame.

Surface low moves east into southern Illinois by 12z/Thursday and then into the
Ohio River valley during Thursday. Chances of showers/thunderstorms to
diminish from northwest to southeast Thursday afternoon/evening. Highs Wednesday mostly in
the lower 80s with Lawrenceville near 85f. Highs in the upper
70s/lower 80s Thursday with coolest readings in east central and southeast Illinois
where more widespread lower clouds and rain. Another disturbance to
move into the Midwest Friday returning small chances of showers and
isolated thunderstorms to central Illinois and lingers into Friday
evening.

Latest 00z forecast models for extended period keep forecast fairly
similar to previous package this weekend into early next week. Illinois
gets back into a northwest upper level flow this weekend into early next
week with a few disturbances passing southeast near Illinois and bringing small
chances of showers and thunderstorms to Illinois River valley Sat
afternoon into Sat night and across area Sunday through Monday
night. Highs in the lower 80s Saturday modify a bit into the low to
middle 80s early next week.

&&

Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 616 am CDT Tuesday Aug 4 2015

VFR conditions will prevail at all taf sites next 24hrs. High
cirrus will continue to push into the whole area today. An old
weak boundary is situated in parts of eastern MO and western Illinois
this morning. Any convection that develops will be minor and
should stay well south and southwest of the taf sites. Then ac
clouds will advect into the area later this afternoon in advance
of the next possible system that will bring precipitation back to the
tafs...but mainly after midnight. New model runs are hinting that
precipitation will not arrive until after 12z. So for now, will leave precipitation
out of forecast. Winds will be variable/southwesterly through the
period.



&&

Ilx watches/warnings/advisories...
none.
&&

$$

Update...hjs
short term...auten
long term...07
aviation...auten

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