Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 081137
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
637 AM CDT THU OCT 8 2015
.SHORT TERM: (Through Tonight)
Issued at 304 AM CDT Thu Oct 8 2015
Forecast focus thru this period will be precip chances.
Trends mentioned yesterday continue today with latest guidance.
Mdl solns continue to suggest region will remain cut off from Gulf
moisture. Mdls also suggest the upper trof out of sync with the
sfc fnt across the area. Believe better chances for precip will
exist E of the CWA with the sfc low and better upper level
dynamics as well as to the W with better low level forcing and a
stronger s/w within the trof. Still believe precip will develop
along the fnt, but coverage continues to look less. Have therefore
lowered PoPs closer to latest MOS guidance. As for timing, appears
SHRA with isod to sct TS will develop across srn IA late this
afternoon and push swd into nrn portions of the CWA into the
evening hours. This precip shud gradually dissipate. However, as
the upper trof approaches, it appears precip will switch to more
stratiform. Timing of this remains uncertain and have kept lower
PoPs further nwd to account for it.
As for temps today, while the upper low over nrn Mexico is
expected to drift swwd today, a leading s/w currently over ern
NEB/KS is expected to provide ample cloud cover thru at least the
morning hours. With less lower and mid level clouds, expect temps
to rise into the 80s with swly flow at low levels. Have trended
twd the cooler guidance again today due to questions of cloud
cover, but also due to the amount of CU that developed and temps
across the Plains yesterday.
Temps tonight will be difficult to pin down as the fnt pushes swd
tonight. Generally, trended cooler across the nrn third and warmer
across the srn third based on cloud trends and timing of fropa.
.LONG TERM: (Friday through Wednesday)
Issued at 305 AM CDT Thu Oct 8 2015
Same precip questions mentioned above continue into Friday
morning, perhaps into the afternoon. Trended cooler for Fri and
Sat as the sfc ridge builds into the region. Sly to swly sfc flow
returns quickly by Sun with the thermal ridge building into at
least wrn portions of the CWA into next week. Mdl solns continue
to differ slightly on timing of a dry fropa on Mon.
Overall, trended above seasonal average thru the forecast period
with the exception of Tues as the sfc ridge builds into the area.
This cooler period is expected to be brief as swly flow returns by
Wed ahead of another weak and dry fnt.
.AVIATION: (For the 12z TAFs through 12z Friday Morning)
Issued at 627 AM CDT Thu Oct 8 2015
Radiation fog has developed across the region this morning and
IFR to MVFR vsbys were noted at TAF issuance. Vsbys should
improve by mid to late morning. Scattered showers and perhaps
isolated thunderstorms are possible this afternoon and tonight
ahead of an approaching cold front. SHRA coverage is expected to
be widely scattered at best, and the possibility of TSRA at the
terminals was too low to include in this set of TAFs. Winds will
become northwesterly to northerly after fropa. BUFKIT profiles
suggest some post-frontal IFR to low-end MVFR cigs could reach
KUIN/KSTL/KSUS/KCPS after 09/12z.