Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 240452

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1152 PM CDT SAT APR 23 2016

Issued at 921 PM CDT Sat Apr 23 2016

Going dry forecast the rest of the night still looks good as upper
ridge moves over the area allowing for only a few high clouds to
drift across the area. Still may be some patchy fog tonight, but
think this will be held in check by the wind which should stay up
tonight as the pressure gradient continues to tighten. Only made
minor adjustments to lows based on going temperature trends.



.SHORT TERM...  (Through Late Tonight)
Issued at 255 PM CDT Sat Apr 23 2016

Surface ridge extending from MI southwest into eastern MO will move
eastward.  The stratus clouds across southeast IL should continue to
dissipate late this afternoon.  Few-scattered diurnal cumulus
clouds, especially across parts of northeast and central MO will
dissipate early this evening with the loss of daytime heating.
Mainly just a little high level cloudiness tonight.  Lows tonight
will be warmer than the previous night, mainly due to southeast
surface winds on the backside of the surface ridge.  The warmest
temperatures will be across central MO with the coolest temperatures
in southwest IL.  Lows tonight will be about 5 to 10 degrees above
normal for late April.


.LONG TERM...  (Sunday through Next Saturday)
Issued at 255 PM CDT Sat Apr 23 2016

Dry and warmer weather to persist on Sunday, but will see an
increase in high clouds as next weather system approaches region.
With gusty south winds will see highs in the upper 70s to low 80s.

Sunday night rain chances to approach region, but models are a bit
slower with onset, so lowered pops just a bit. Then Monday through
Tuesday, frontal boundary to slowly slide south through area with
mainly scattered showers and thunderstorms. Front to stall out
across southern Missouri on Tuesday. Highs will be in the upper 70s
to low 80s on Monday, then dip down into the low 70s to low 80s
Tuesday and Wednesday.

Decent instability north of front Tuesday night, so could see
elevated activity develop and slide along boundary on nose of decent
low level jet. Large hail would be the main threat with this round
of storms.

Models are still indicating decent instability, CAPES in excess of
1500 J/kg and shear with system Wednesday afternoon, Wednesday night
as warm front lifts north through forecast area. All of this still
points to our first real potential severe weather day this spring,
but a lot can happen in 5 days. Stay tuned to further updates.

With everything a bit slower, main cold front to slide through early
on Thursday with precipitation tapering off to just slight chance
pops through Friday. Then extended models showing next system
lifting northeast towards forecast area Friday night and Saturday
with increasing chances of showers and thunderstorms once again.

Once system exits region on Thursday, will see precipitation taper
off. Even though it will be a bit cooler Thursday, highs will still
be a bit above normal in the mid 60s to upper 70s. Extended models
beginning to indicate another system approaching region on Friday,
but timing is hard to pin down. So for now kept slight chance pops.



.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1152 PM CDT Sat Apr 23 2016

Dry and VFR conditions are still expected at the terminals through
the TAF period. There may be some patchy fog late tonight and
early Sunday over southern Illinois and southeast Missouri. Low
level wind shear is still possible at KUIN and KCOU between 09-15Z
as a 35-40kt low level jet sets up between 1000-2000 feet. Still
expect gusts over 20kts during the late morning and afternoon
hours that will decrease slightly after sunset.

Specifics for KSTL:

Dry and VFR conditions are expected through the TAF period. Gusts
above 20 kts are possible after 18Z on Sunday afternoon.





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