Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 011246
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
746 AM CDT SUN MAY 1 2016
.SHORT TERM... (Through Late This Afternoon)
Issued at 302 AM CDT Sun May 1 2016
Patchy dense fog over northeast Missouri, west central Illinois to
dissipate and thin out towards daybreak. So main issue for today
will be the closed upper level low currently over south central
Nebraska that will finally open up and slide east across northern
Missouri. Will see scattered showers and a few thunderstorms
possible, especially along and north of I70 in Missouri and along
and east of Mississippi River in Illinois. Some of the storms will
be strong over southwestern Illinois where CAPES will be in excess
of 1500 J/kg this morning through the afternoon hours, as well as
decent low level lapse rates and some shear. Could see some small
hail and wind gusts to 45 mph with the stronger storms.
As for high temps today, with mostly cloudy skies will have a wide
variation from the upper 50s far north to the mid 70s far southeast.
.LONG TERM... (Tonight through Saturday)
Issued at 302 AM CDT Sun May 1 2016
Expect thunderstorms to be ongoing at the beginning of the forecast
period, but to be E of the CWA at 00z this evening.
Mdls are in fairly good agreement with upper trof hanging up over IA
on Mon with a s/w moving thru the area. While the bulk of the precip
shud remain S of the area, this s/w and cold temps aloft shud be
enuf to support SHRA across much of the area. Given the diurnal
nature of these SHRA, expect Mon night to be dry with isod to widely
sct SHRA again on Tues as the upper trof sinks thru the region. Some
uncertainty remains how much of the area will be see any precip, but
given the expected location of the upper trof Tues morning, have
kept PoPs confined to the srn two thirds of the CWA.
The next chance for precip is Wed as another cdfnt drops thru the
area. Mdls differ regarding how much moisture will be available as
the fnt moves thru. Will keep low PoPs going for ern portions of the
CWA where a s/w rotating around the back of the upper low may
provide enuf support for some SHRA. The remainder of the forecast is
dry as a large sfc ridge builds into the area.
Overall, temp forecast will remain aob seasonal avg. thru this week
with a sfc ridge in place as mentioned above. Wed shud be slightly
warmer with more insolation expected and wly to swly winds ahead of
the approaching cdfnt. The next warm up shud be Sat as an upper
ridge builds into the area with sfc winds becoming sly again.
.AVIATION... (For the 12z TAFs through 12z Monday Morning)
Issued at 736 AM CDT Sun May 1 2016
Dealing with IFR/LIFR cigs and vsbys in fog this morning at a
number of the taf sites. Conditions should improve by 14z-15z with
cigs lifting to MVFR. Otherwise, main issue is scattered showers
and a few thunderstorms with upper level shortwave as it slides
through today. For now just have vicinity shower mention for KUIN
and metro area tafs from midday til sunset. Then cigs to lower
back down to IFR/MVFR. As for winds, light and variable to pickup
from the west, veering to the northwest to north as shortwave
Specifics for KSTL:
Dealing with IFR cigs and vsbys in fog this morning in metro
area. Conditions should improve by 15z. Otherwise, main issue is
scattered showers and a few thunderstorms with upper level
shortwave as it slides through today. For now just have vicinity
shower mention for metro area tafs from 18z Sunday to 01z Monday.
Then cigs to lower back down to MVFR at KSTL by 08z Monday. As for
winds, light and variable to pickup from the west, veering to the
northwest as shortwave moves through.
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 71 52 61 49 / 20 10 20 10
Quincy 59 44 59 44 / 50 10 20 10
Columbia 64 46 60 44 / 10 10 20 10
Jefferson City 66 47 61 44 / 10 10 20 10
Salem 72 49 61 48 / 30 10 30 10
Farmington 73 47 62 45 / 10 10 30 10