Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
FXUS63 KLSX 280443

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1143 PM CDT WED JUL 27 2016

Issued at 924 PM CDT Wed Jul 27 2016

Isolated-scattered thunderstorms are currently affecting portions
of northeast Missouri and west-central Illinois as of 0200 UTC. In
addition...a more organized region of rain and embedded storms is
just clipping portions of SE MO. Much like last night...anticipate
a weakening and lessening in coverage of current activity. Next
disturbance currently near the SD/NE border may help initiate more
activity late tonight and early on Thursday...particularly for
northern sections of the CWFA.



.SHORT TERM...  (Through Late Tonight)
Issued at 337 PM CDT Wed Jul 27 2016

Scattered thunderstorms will continue into the evening, particularly
along and south of I-70 where the low level convergence will be the
strongest nearest the quasi-stationary front currently over southern
Illinois and southeast Missouri.  This front will lift northward
into the area tonight which will keep at least a slight chance of
showers and thunderstorms going through the night, particularly as a
weak vort moves into the area from the northwest.  Lows tonight will
likely fall be in the lower to mid 70s which is close to MOS lows.


.LONG TERM...  (Thursday through Next Wednesday)
Issued at 337 PM CDT Wed Jul 27 2016

(Thursday and Friday)

NAM and GFS are in good agreement that a mean upper trough will set
up over the Midwest late this week into the weekend. A series of
vort maxes will move through the area which will help generate
scattered thunderstorm development which will be most likely
during daytime heating. Spatial distribution of thunderstorms will
also be favored along the wavy frontal boundary which is currently
just south of the area, but which will likely lift north tonight
into early Thursday before it will move back southward as a cold
front tomorrow afternoon. The front will once again be stalled
over Missouri and Illinois by Friday.

Temperatures during this period will be at or just below normal with
the front nearby.  Forecast soundings are showing mixing up to the
850-800mb layer with values of 15-17C.

(Saturday through Wednesday)

The global models are in generally good agreement that the upper
trough across the center of the CONUS over the weekend will move
eastward and off the East Coast by the middle of next week.  This
will allow yet another large and very warm upper high to spread
northeastward from the Desert Southwest into the central CONUS by
the middle of next week. It still looks like the quasi-stationary
front will remain over the area through the weekend into early
next before the front lifts northeast of the area once the upper
high builds eastward. Temperatures will gradually warm through the
period, going from below normal temperatures to above normal
temperatures as the upper trough moves off and the highs builds



.AVIATION...  (For the 06z TAFs through 06z Thursday Night)
Issued at 1132 PM CDT Wed Jul 27 2016

Isolated showers and thunderstorms may affect the terminals
tonight and into the day on Thursday. Low coverage and fairly
nebulous forcing makes pinning down if and when storms may affect
the terminals difficult to say the least...particuarly looking out
more than a few hours. Did add a VCTS group in for early in the
period. Continued mention of fog at KCOU and KUIN but with higher
cloud cover than previously not have in for the
metro TAFs. Weak frontal wave will move through the area on
Thursday with a continued chance of showers/storms. Behind
this...should be slightly lesser chances of rain along with winds
becoming northwesterly.


Added a VCTS group due to isolated storms firing near the
terminal. Possibility exists pretty much through most of the TAF
period of convection affecting terminal. Heavier thundershowers
if they hit the terminal could bring brief periods of IFR visbys.
Outside of this is expected to remain VFR along
with light/variable winds. Northwest winds are likely by late
Thursday behind a weak sfc low.





WFO LSX is the U.S. government's official web portal to all federal, state and local government web resources and services.