Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 111848
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1248 PM CST THU FEB 11 2016

.SHORT TERM:  (Through Late Tonight)
Issued at 1230 PM CST Thu Feb 11 2016

A northwest flow shortwave now dropping southeastward into western
SD will move quickly through our area tonight.  Light snow will
spread southeastward into northeast MO early this evening, then
through the St Louis metro area around midnight.  Still looking like
a quick shot of dry, powdery snow with most places picking up to 1
inch of accumulation, but there may be a narrow band of 1-2 inches
extending from near IRK southeast through the St Louis metro area.
Latest NAM and HRRR model runs have the band a little further west
than previous model runs.  Most of the accumulating snow should
shift southeast of our forecast area by 12Z Friday.  Low
temperatures will be similar to the previous night, and around 5
degrees below normal.

GKS

.LONG TERM:  (Tonight through Wednesday)
Issued at 225 AM CST Thu Feb 11 2016

...Light Snow Expected This Evening...

Next shortwave will be diving southeast in a similar manner to
yesterday`s and provide the area with another round of light snow.
It appears that this snow will be a little later in its arrival with
the main window of accumulation occurring from 6 pm to Midnight.
Once again have about an inch, give or take a few tenths, of snow
accumulation forecast from northeast Missouri to southwest Illinois.
This includes the Greater St. Louis Metropolitan Area.

Snow should taper off after midnight from northwest to southeast,
with a few flurries possible Friday morning. Thereafter, a very
cold air mass builds into the region Friday night and Saturday.
Low temperatures below zero are certainly possible Saturday
morning across the northern CWA.

The arctic high pressure quickly moves east though and by
Saturday night we could already have a band of warm advection snow
racing across the CWA. Better chance of accumulating snow appears
to occur on Sunday, but to be honest, medium range model guidance
has been flip flopping all over the place with this system the
past five days and still hasn`t landed on a common solution. Best
to leave PoPs at a chance for the period in question and give it a
few more runs before trying to nail down specifics.

Warm up looks on tap next week as the pattern changes with highs in
the 50s and maybe even 60s!

CVKING
&&

.AVIATION:  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1237 PM CST Thu Feb 11 2016

SC has dissipated over taf sites, so will see VFR conditions
through early this evening as mid and high clouds stream in ahead
of next clipper system. Timing still similar to last set of tafs
with snow moving into KUIN/KCOU by 02z Friday and STL metro area
by 04z Friday. With onset of light snow, will see cigs dip down to
MVFR with brief IFR visbys as heavier bands of snow move through.
Snow to taper off between 09z and 10z Friday for taf sites, though
mvfr cigs to persist. KCOU on western periphery so should see
mvfr cigs scatter out by 16z Friday. As for winds, to remain from
the northeast to east as system moves through, then become light
and variable. By mid morning on Friday, winds to pickup from the
northwest.

Specifics for KSTL:
SC has dissipated over metro area, so will see VFR conditions
through early this evening as mid and high clouds stream in ahead
of next clipper system. Timing still similar to last set of tafs
with snow moving into STL metro area by 04z Friday. With onset of
light snow, will see cigs dip down to MVFR with brief IFR visbys
as heavier bands of snow move through. Snow to taper off by 10z
Friday, though mvfr cigs to persist for rest of taf forecast
period. As for winds, to remain from the northeast to east as
system moves through, then become light and variable by 10z Friday.
By 17z Friday, winds to pickup from the northwest around 10 kts.

Byrd
&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$
WFO LSX


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