Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Graphics & Text | 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 48 49 50
FXUS63 KLSX 292032

332 PM CDT Mon Sep 29 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 315 PM CDT Mon Sep 29 2014

Another tranquil dry night on tap for the area. Weather features
we have been discussing the last few days remain the same. The
east-west cold front currently stretching across southern Wisconsin
into South Dakota will drop into northern MO and central IL
overnight in response to the digging trof moving into the Great
Lakes and downstream amplification. This front should reach near a
Columbia-St. Louis-Effingham line by 12z. Weak high pressure and
light winds will continue ahead of the front for a good part of
the night resulting in another round of overnight lows primarily
in the 50s.


.LONG TERM:  (Tuesday through Next Monday)
Issued at 315 PM CDT Mon Sep 29 2014

Not many changes needed to the previous forecast as it continues
to blend well with the latest thoughts and NWP guidance. Still
looking at a tranquil dry period Tuesday and Tuesday night. The
cold front will sag southward across eastern MO through the Ohio
Valley Tuesday as high pressure builds through the Great Lakes,
while retreating northward across the Plains region in response to
the migratory surface low. No sensible weather with the front
other than suppressing the temperatures a few degrees.

Active weather remains centered on the Wednesday night-Thursday night
period as the deep western upper trof progresses into the Nations
midsection. There are some questions initially Wednesday into
Wednesday night on the rate of eastward spread of precipitation as
the NAM and local WRF are quite a bit slower than the other operational
models. At this time I am favoring the more agressive GFS/ECMWF. An
intensifying and veering southwesterly LLJ and associated the pre-
frontal warm advection regime, along with weak impulses moving
across the region within the southwest flow aloft, would suggest
more progressive nature to the convection/MCS on Wednesday night.
Thunderstorms will remain likely Thursday/Thursday night as the
main short wave trof and attendant cold move across the region. Much
cooler weather remains on track in the wake of the cold front Friday
into Saturday with gusty northwest winds on Friday. Temperatures
return to seasonable normals on Sunday.



.AVIATION:  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1230 PM CDT Mon Sep 29 2014

Dry and VFR conditions are expected through the TAF period. A
surface ridge will move through the region today and early tonight
keeping winds light and variable before they turn out of the east-
southeast on Tuesday morning.

Specifics for KSTL: Dry and VFR conditions are expected over the
next 30 hours with light winds.





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