Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 250440

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1140 PM CDT SUN APR 24 2016

Issued at 909 PM CDT Sun Apr 24 2016

Still expect only a slight chance of showers and thunderstorms
over central and northeast Missouri through the rest of tonight.
The latest runs of the RAP continue to show a mid level trough
shearing out at the same time that the low level moisture
convergence weakens. This should cause the thunderstorms now over
far northwestern Missouri and eastern Kansas to begin to weaken.
This is confirmed based on the latest CAMS reflectivity.  We
should still see some convective debris cloudiness over at least
the northern part of the CWA after midnight, and southerly winds
should not go light tonight because of the pressure gradient. Only
made minor changes to going lows based on current temperature



.SHORT TERM...  (Through Late Tonight)
Issued at 330 PM CDT Sun Apr 24 2016

Most of the convection tonight is expected to remain north of our
forecast area, associated with an upper level low now over southwest
SD and a surface low over central SD which will move eastward
through the northern Plains.  Widely scattered, weakening convection
though may move into portions of northeast and central MO as well as
west central IL late tonight as a southwesterly low level jet brings
low level warm air advection and increasing moisture into this area.
Will just have slight chance pops late tonight for areas north and
west of STL.  Southerly surface/low level winds, increasing cloud
cover, and relatively high surface dew points will lead to low
temperatures 10 to 15 degrees above normal and warmer than the
previous night.


.LONG TERM...  (Monday through Next Sunday)
Issued at 330 PM CDT Sun Apr 24 2016

Warmer conditions to persist through Tuesday with several weak
shortwaves sliding through helping to trigger scattered showers and
thunderstorms. In the meantime, frontal boundary associated with
main system to slowly sink south, eventually stalling out along I-70
corridor by Tuesday afternoon.

More active weather to ramp up late Tuesday night as low level jet
increases with decent instability and convergence along the stalled
front. Elevated storms, some of which may be severe, could develop
into an MCS and slide east along front. Main threats would be large
hail, damaging winds and possibly a few tornadoes.

Depending on when morning activity diminishes/moves out on
Wednesday, another round of storms to develop as front moves back
north as a warm front and main cold front starts to slide through
Wednesday afternoon/evening. So if atmosphere is able to recharge,
storms to develop ahead of system with main threats being large hail
and damaging winds.

Precipitation to taper off Thursday and Thursday night, before next
chance of rain returns on Friday and persists through Sunday.
Otherwise, the default ridge setup in our part of the CONUS will
ensure that temps remain at or above average throughout the period.



.AVIATION...  (For the 06z TAFs through 06z Monday Night)
Issued at 1134 PM CDT Sun Apr 24 2016

Still expect terminals to be dry and VFR through the period as
line of showers and thunderstorms should rapidly diminish as it
moves east the next few hours. Otherwise...still expect winds to
gust to around 20kts on Monday.

Specifics for KSTL: Expect dry and VFR conditions the next 30
hours as line of showers and thunderstorms over western Missouri
should rapidly diminish as it moves east. Otherwise...still expect
still expect winds to gust to around 20 kts on Monday.





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