Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 150852

Area Forecast Discussion
National Weather Service Saint Louis MO
352 AM CDT Thu Mar 15 2018

.SHORT TERM...  (Through Late Tonight)
Issued at 351 AM CDT Thu Mar 15 2018

A cold front was located early this morning across far northern
Missouri and central Illinois.  This front will move slowly south,
reaching southeast Missouri and southwest Illinois this evening.
Skies are mainly clear across the area early this morning, and
scattered-broken mid and high clouds will not enter the area until
this afternoon.  This should allow for enough March sunshine to help
warm temperatures above normal, particularly along and south of the
front where forecast RAP soundings show mixing AOA 850mb. Highs this
afternoon will range from the upper 50s near Quincy to the around 70
across central and southeast Missouri.

GFS/NAM are both showing a upper low moving into the Central Plains
tonight from the rockies.  Large scale ascent will increase ahead of
this low at the same time low level moisture transport will increase
from the Gulf.  Kept with an increasing chance of showers through
the night, with isolated thunderstorms over central Missouri.


.LONG TERM...  (Friday through Wednesday)
Issued at 351 AM CDT Thu Mar 15 2018

Showers will spread through the forecast area Friday morning ahead
of an upper level low and associated surface low over the Plains.
There may be a brief period of freezing rain or sleet across parts
of northeast MO and west central IL early Friday morning due to
evaporative cooling with surface temperatures near the freezing
mark.  Any ice accumulation on roads is unlikely with road
temperatures above 32 degrees. Showers will continue Friday
afternoon and evening as the low pressure system moves eastward into
west central MO by Friday evening. There will be some embedded
thunderstorms, especially across central and southeast MO where
instability will be more favorable along and south of the warm front
extending southeast of the surface low. There will be some lingering
showers across northeast MO and west central and southwest IL late
Friday night and Saturday morning as the upper level and surface low
move eastward into IL.  The rain will shift east of the forecast
area by Saturday afternoon as an upper level ridge shifts eastward
into the region, and a surface ridge builds into our area from the
northern Plains. Highs will be cooler on Friday, especially across
northeast MO and west central IL north of the surface front. The
cloud cover and precipitation will also hinder daytime heating.
Warmer, above normal temperatures will return on Sunday as the
surface wind becomes southeasterly as the surface ridge shifts east
of the area. Showers will spread eastward into central and eastern
MO Sunday night well ahead of another upper level low and associated
surface low over the central Plains. Rain will continue on Monday as
the upper level and surface low move eastward through southern MO
and northern AR, trending further south than previous model runs.
May have a brief break in the rain Monday evening, but another round
of light rain may move through our area late Monday night and
Tuesday as a deepening northern stream upper level trough moves
through the region.  Colder temperatures can be expected Monday
night and Tuesday with a potential for light snow across northeast
MO and west central IL.



.AVIATION...  (For the 00z TAFs through 00z Thursday Evening)
Issued at 608 PM CDT Wed Mar 14 2018

VFR and dry thru the period. Swly to wly winds will back slightly
and diminish after sunset. A LLJ will increase over the area
tonight. LLWS will diminish late tonight into Thurs morning from
north to south as a weak front pushes into the region. Expect SHRA
to develop Thurs evening beyond the TAF period.





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