Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 200352

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1052 PM CDT WED OCT 19 2016

.SHORT TERM...  (Through Late Thursday Afternoon)
Issued at 324 PM CDT Wed Oct 19 2016


Focus tonight will be on convective trends. Believe the most focused
and widespread area on convection will continue to be near the quasi-
stationary 850-hPa warm front through the early overnight hours
tonight. Have therefore shifted highest PoPs and heaviest QPF axis
to the north more toward the I-44 corridor in MO. This convection
should remain elevated in nature with the sfc boundary across the
far southern CWA. With the elevated convection...large hail is the
primary threat. Further to the south across southeast Missouri and
far southwest Illinois...wind gusts in addition to large hail are
both threats as convection along/south of the sfc front will likely
be more surface based. Severe threat should wane by late evening as
instability...both elevated and sfc-based...begins to fade to the
southeast of the area.

Maintained locally heavy rainfall mention just shifted the axis a bit
further to the north tied to the highest PoPs. It has been dry this
month and FFG values are high so it will take quite a bit of rain
over a short period of time. Concern would be in training of
convection which certainly could occur due to the quasi-stationary
low-level baroclinic zone.

Temperatures will be cooler tonight compared to the last several
nights but still a bit above normal. Lows in the 50s for most areas
are expected.


Bulk of precipitation should have exited the CWA by Thursday morning
but have schc-chc PoPs for showers into early afternoon for far
southern and eastern sections of the CWA. Main story will be the
much more fall-like look and feel to the day on Thursday. High
temperatures are only expected to be in the low 60s across the area
due to lingering cloud cover and strong CAA at low
levels...certainly a big change from the upper 80s to low 90s of
just a couple of days ago.


.LONG TERM...  (Thursday Night through Next Wednesday)
Issued at 324 PM CDT Wed Oct 19 2016

Any lingering precip will have moved out of the area as surface low
moves east Thursday. Strong surface ridge builds eastward as low and
cold front move out shifting winds to the northwest. The northwest
flow as well as clearing behind the front will lead to cooler temps
Thurs night. Temps to remain slightly below normal through Sat
morning. There will be a slight warming trend as surface ridge
progress furthr to the east and shifts wind become southerly. a weak
cold front will move through the area Sun into Monday but this is
expected to bring no precip and cold temps should stay north of the
forecast area. The next chance of precip will be Wed as surface low
moves in from the western plains.


.AVIATION...  (For the 06z TAFs through 06z Thursday Night)
Issued at 1040 PM CDT Wed Oct 19 2016

Back side of precipitation has moved out of KUIN and KCOU with VFR
conditions for entire forecast period. Otherwise, will just see
some isolated showers/storms through 08z-09z Thursday for STL
metro area with lingering MVFR cigs through 12z-14z Thursday. Then
cigs will lift and scatter out by 00z Friday for metro area. As
for winds, northeast winds to back to the north and remain
northerly for rest of forecast period.

Back side of precipitation to continue slowly sinking south with
isolated showers/storms through 08z-09z Thursday. Then lingering
MVFR cigs through 12z-14z, before lifting and scattering out by
00z Friday for metro area tafs. As for winds, northeast winds to
back to the north and remain northerly for rest of forecast



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