Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 242011
Area Forecast Discussion
National Weather Service Saint Louis MO
311 PM CDT WED AUG 24 2016
.SHORT TERM... (Through Late Tonight)
Issued at 159 PM CDT Wed Aug 24 2016
A s/w ejecting out ahead of the main trof over the srn Plains will
continue to lift newd this evening. This s/w is progd to take on
more of an MCV structure as it lifts into MO/IA region late
tonight. Sct TSRA remain possible across much of the region this
evening. Storms have not developed as prev anticipated. However,
storms may still develop this afternoon across central portions of
the CWA where sfc convergence is greater.
Focus shud quickly become area of moisture convergence
across wrn portions of the CWA ahead of the approaching wave. This
wud suggest a longer duration of TSRA across nrn portions of the
CWA this evening. There is some uncertainty regarding duration of
precip tonight across the nrn portions of the CWA. Still, there is
still enuf threat for heavy rainfall/flash flooding tonight across
the current watch area to keep the watch as-is.
With ample CAPE across the region and deep layer shear around 40
kts, any storms that do develop will be capable of becoming severe
with large hail and damaging winds as the primary threat. However,
can not rule out some organized storms with a tornado threat.
.LONG TERM... (Thursday through Next Wednesday)
Issued at 310 PM CDT Wed Aug 24 2016
Cold front to continue it`s slow progress to the south on Thursday,
finally stalling out just south of forecast area Thursday night. In
the meantime, still decent instability and moisture, so will see
storms along and ahead of boundary through Thursday evening, then
wind down a bit after midnight. Depending on cloud cover and
precipitation, highs will range from the low 80s far north to the
low 90s south on Thursday.
By Friday, models now a bit faster lifting front back north through
forecast area, so will have increasing pops during the day with best
chances along and south of I-70. By 12z Saturday, front will be
north of forecast area once again.
For the last half of the weekend and into early next week, weak
surface ridging will keep boundary just to our north with warm and
humid weather persisting. So active pattern to persist with chances
of storms each day, especially during the heating of the
afternoon/evening hours through next Wednesday.
Temperatures from Friday on will continue to be seasonable,
primarily in the mid 60s to low 70s for lows and low to mid 80s for
.AVIATION... (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1240 PM CDT Wed Aug 24 2016
Swly winds will continue and eventually become nwly to nly on
Thurs behind an approaching cdfnt. A number of questions regarding
precip chances thru the period. A line of congested CU has
developed stretching from K1H2, swwd to just south of KCPS to near
KUUV. An outflow bndy, or perhaps a bore wave, is evident in the
latest sat data. Believe this will help initiate TSRA along the
congested CU somewhere east and south of KSTL, but may impact
KCPS, hence the tempo group. Otherwise, best chances for precip
will be at UIN this evening into the overnight hours. This area of
precip shud lift NE of the region Thurs morning.
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 77 91 71 84 / 40 40 30 30
Quincy 70 84 65 80 / 90 40 20 20
Columbia 69 86 67 81 / 50 40 50 30
Jefferson City 70 87 68 83 / 50 40 50 40
Salem 73 90 70 85 / 40 30 20 30
Farmington 72 90 70 83 / 20 20 30 40
MO...Flash Flood Watch from 7 PM CDT this evening through Thursday
morning for Knox MO-Lewis MO-Marion MO-Monroe MO-Ralls MO-
IL...Flash Flood Watch from 7 PM CDT this evening through Thursday
morning for Adams IL.