Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 020818

Area Forecast Discussion
National Weather Service Saint Louis MO
318 AM CDT MON MAY 2 2016

.SHORT TERM...  (Through Late This Afternoon)
Issued at 315 AM CDT Mon May 2 2016

Complex and messy upper air pattern remains across the region this
morning. Leading s/w continues to approach the region early this
morning and is responsible for light RA across swrn into central MO.
This area of precip shud continue to move newd thru the area this
morning. Mdls suggest it will dissipate as it moves into the CWA
around sunrise. While this is possible due to the better low level
moisture convergence pushes S of the area, believe the leading s/w
will be sufficient to maintain higher PoPs thru mid-morning.

For the remainder of the day, have kept PoPs in the slight chance
range for now as isod to widely sct SHRA are expected today.
However, coverage may be somewhat higher across nrn half to third
of the CWA as the upper trof pulls newd thru the area today. The
bulk of these SHRA will be diurnally driven and shud dissipate
this evening.

As for temps today, with extensive cloud cover in place, and with
the trof in place today, do not expect much clearing today except
for the srn third or so of the CWA. Where breaks to occur this
morning, believe CU will develop, filling them in. This complicates
the temps forecast for today as a strong May sun can help temps jump
even with a short period of insolation. Still, believe clouds will
be the rule for today and have trended temps aob the cooler guidance
for much of the CWA. The exception will be the srn portions where
more insolation is expected. This same area is also along and S of
the 850mb fnt, which shud help warm temps today.


.LONG TERM...  (Tonight through Sunday)
Issued at 315 AM CDT Mon May 2 2016

Will see some lingering isolated/scattered showers this evening
in cyclonic flow on back side of system. The activity will
gradually taper off. Otherwise, clouds to slowly thin out from
north to south overnight and lows will be in the 40s, a bit below
normal for this time of year.

Because of the lingering cyclonic flow, could still see some
isolated showers in the far eastern portions of forecast area on
Tuesday. However, most locations to remain dry with partly sunny
skies and highs in the mid to upper 60s.

Then Tuesday night, a more vigorous trof/secondary cold front
associated with surface low anchored over the Great Lakes region to
slide south through area. So increased pops with scattered showers
for portions of west central/southwest IL Tuesday night through
Wednesday, as main energy to remain to our northeast and east.

For rest of work week, will see dry conditions with temperatures
slowly moderating. By Friday highs will be in the low to mid 70s and
in the upper 70s to low 80s on Saturday.  Then next significant
weather system to approach region Saturday night and Sunday with
increasing chances of showers and thunderstorms through the rest
of the weekend.


.AVIATION...  (For the 06z TAFs through 06z Monday Night)
Issued at 1100 PM CDT Sun May 1 2016

Surface low over southern IN will continue moving eastward
late tonight. Surface ridging extended from the Plains into
northwestern MO. MVFR cigs over northern portions of MO and IL
which were over UIN and have just moved into COU should continue
to slowly advect south-southeastward into the St Louis metro area
around 06-07Z Monday. These cigs will drop into the IFR catagory
by early Monday morning. There will also be light fog late
tonight and early Monday morning. The cloud ceiling will gradually
rise into the MVFR catagory late Monday morning, and possibly into
the VFR catagory by late Monday afternoon or early Monday evening.
A narrow band of light showers moving into southwest MO may move
into COU and the St Louis metro area early Monday morning. An
upper level disturbance will also bring widely scattered showers
to the area on Monday, especially during the afternoon. A
northwesterly surface wind will continue through the period.

Specifics for KSTL: MVFR cigs will move southeastward into STL
around 06Z Monday. The ceiling will drop into the IFR catagory
by early morning with light fog developing. The fog will
dissipate by late morning along with the cigs rising into the MVFR
catagory. The ceiling may rise into the VFR catagory by late
Monday afternoon or early Monday evening. There may be a few
showers on Monday. Nwly surface wind will continue through the
period, becoming light Monday evening.


Saint Louis     60  48  67  52 /  30  20  10  10
Quincy          55  44  66  49 /  20  10  10  20
Columbia        57  44  67  49 /  20   5  10  10
Jefferson City  58  44  68  49 /  20   5  10   5
Salem           62  48  65  49 /  20  20  20  20
Farmington      62  45  67  47 /  20  10  10   5



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