Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 021151
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
651 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
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 12z TAFs through 12z Tuesday Morning)
Issued at 643 AM CDT Mon May 2 2016
Expect bkn to ovc clouds thru much of today, with clouds breaking
up this evening. A couple of areas of light RA are moving thru the
region this morning. Expect SHRA to develop by Noon across the
region and dissipate this evening. Given the isod nature of these
SHRA, have only mentioned VCSH during the times for best chances
of impacting terminals for now. Will need to continue to monitor
as some of the latest guidance suggests coverage may be higher for
KUIN/KCOU this afternoon. Cigs will be difficult today with KUIN
gradually improving thru the day. KCOU shud remain in MVFR range
thru the morning and perhaps into the afternoon before improving.
Otherwise, nwly winds will prevail today becoming light tonight.
Specifics for KSTL/KSUS/KCPS: Cigs shud lower into MVFR range over
the next couple of hours. Expect isod SHRA to develop later this
morning into the afternoon hours. Cigs shud move E of terminals
with cloud clearing out this evening.
.PRELIMINARY POINT TEMPS/POPS...
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