Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 170831
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
231 AM CST Mon Nov 17 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 229 AM CST Mon Nov 17 2014

A deep upper level TROF existed over the central CONUS early this
morning with several individual disturbances rotating around it.
One disturbance located over northwest AR was producing light radar
echoes into southeast MO and into far southern IL.  Some flurries or
light snow is possible out of this.  The other disturbances are
farther to the northwest and are working on very limited moisture,
producing some areas of clouds and not much else currently.  One
surface cold front has already moved thru our forecast area and
stretched over far southeastern IL and MO.  Another cold front was
about 200 miles to the northwest and is bringing in a reinforcing
shot of cold air.  Satellite shows the back edge of clouds from the
first front and Sunday`s storm system over STL metro and is slow to
exit.  Mostly clear skies with patches of clouds was to the
northwest of STL metro.  Temps are already plunging well into the
teens in this clear area with readings remaining in the low 20s
elsewhere.  Either way, plenty cold enough to result in black ice
for any untreated areas where snow fell and melted.

The upper level disturbance in AR will push to the east of our
region before 6am today with additional disturbances dropping down
from the NW today as the central CONUS TROF pattern deepens right
over us.  Moisture will be in very short supply for widespread pcpn
but diurnal influences and deep cyclonic flow should help in getting
scattered flurries later today...mainly during the afternoon hours.
Anything measurable should be precluded on a large scale, but
isolated pockets of additional dustings possible.

The second cold front will move thru early this morning and its main
effect will be to reinvigorate the low-level CAA and strengthen wind
gusts.  This will be further enhanced by increasing clouds later
this morning due to increased low-level instability as the h850/925
thermal TROF drops down over us.  Any warming that occurs today will
be mainly during the morning hours, with temp trends expected to be
steady during the afternoon.

TES

.LONG TERM:  (Tonight through Sunday)
Issued at 229 AM CST Mon Nov 17 2014

(Tonight through Wednesday)

Main focus thru this period will be temps.

Clouds will dissipate this evening with sunset. Expect very few, if
any, clouds to remain by 12z Tues. However, winds are expected to
remain around 10 kts overnight and gradually become wly by sunrise.
This shud help keep temps from dropping too low. With the large
difference among guidance, have low confidence in solns tonight.
Given the forecast wind, have trended at or just below the warmer
guidance. If winds are able to become calm, even the cooler guidance
may be too warm based on progd dewpoints.

Focus turns to the arrival of the next cdfnt. Mdls are in good
agreement regarding this fnt, but small differences in timing exist.
With the sfc ridge stretched across the Gulf and little moisture
return ahead of the fnt, chances for precip are currently low.
However, given the strength of the trof, low PoPs may need to be
added with future updates.

Have trended twd the warmer guidance for Wed ahead of the
approaching cdfnt, except for nrn portions of the CWA where the fnt
shud be arriving around 12z Wed. However, if timing of the fnt
changes, temps will have to be adjusted to compensate.

(Thursday through Sunday)

Mdls finally prog the deep trof moving ewd with the pattern becoming
more zonal by mid to late week. With height rises forecast, have
gradually trended the forecast warmer thru the end of the week.


Tilly

&&

.AVIATION:  (For the 06z TAFs through 06z Monday Night)
Issued at 1121 PM CST Sun Nov 16 2014

Vfr conditions have returned to the taf sites, though some
lingering mvfr cigs around KCPS through 07z. Otherwise, northwest
winds to pickup by mid morning with gusts to near 25kts at times.
Will see sc develop on back side of system, so kept tempo mention
of mvfr cigs through the afternoon hours before scattering out
towards sunset. Winds will diminish towards sunset as well.

Specifics for KSTL:
Vfr conditions have returned to the metro area, though some
lingering mvfr cigs around KCPS through 07z. Otherwise, northwest
winds to pickup by 16z Monday with gusts to near 25kts at times.
Will see sc develop on back side of system, so kept tempo mention
of mvfr cigs through the afternoon hours before scattering out
towards sunset. Winds will diminish towards sunset as well.

Byrd

&&

.CLIMATE:

The following are record low maximums and record low minimums
through Tuesday.

Date:       11/17     11/18

               St. Louis

Low High:  17/1880   25/1880
     Low:   6/1959   14/1932
Snowfall: 1.0/1951

               Columbia

Low High:  23/1959   27/1903
     Low:   4/1959    8/1891
Snowfall: 0.1/1989

                Quincy

Low High:  19/1959   24/1903
     Low:   3/1959    7/1903


&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     24  13  30  21 /  10   5   0   0
Quincy          19   8  25  19 /  10   5   0  10
Columbia        22   8  29  21 /  10   0   0   0
Jefferson City  24  10  30  21 /  10   0   0   0
Salem           24  14  26  18 /  10   5   0   0
Farmington      25  11  29  20 /  10   0   0   0

&&

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

$$

WFO LSX






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