Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 121939
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
239 PM CDT Fri Sep 12 2014

.SHORT TERM:  (Through Tonight)
Issued at 236 PM CDT Fri Sep 12 2014

Cloud cover continues to cover the area this afternoon as stratus is
trapped under a low level inversion and mid-high level clouds are
streaming in ahead of a mid level trough.  There has been some light
rain associated with the mid-level trough moving across northern
Missouri early this afternoon, but it`s coverage has been limited.
Latest runs of the RAP and HRRR still show some redevelopment of
some light rain over western Missouri this afternoon and this
evening ahead of the upper trough that will move across the CWA this
evening.  Then expect clearing of the clouds from north to south
after 06Z as the upper trough moves to the east allowing subsidence
to set in.  Drier air will move into the low levels as the inversion
weakens which should allow the low level clouds to move out.
Temperatures should fall close to agreeable MOS guidance for lows
once skies begin to clear with the light northeasterly winds.

Britt
.LONG TERM: (Saturday through Next Friday)
Issued at 236 PM CDT Fri Sep 12 2014

(Saturday through Monday)

Overall, mdls are in good agreement thru this period. Period begins
with a large sfc ridge settling across the region. This ridge will
keep temps around 15 degrees below seasonal average despite ample
insolation. As the ridge retreats, the approaching trof and sfc fnt
will bring another chance for precip to the region late in the
period. Some minor differences in timing are apparent among the mdl
guidance. Will keep PoPs lower except where mdls are in agreement.

(Tuesday through Friday)

Not much change from the prev forecast. Mdls remain in good
agreement overall thru the period with respect to mass fields
anyway. Sfc ridge builds into the region on Tues with precip coming
to an end Mon night. Cool temps will prevail thru mid week, tho not
as cool as this weekend. Mdls differ regarding precip chances for
late Wed into Thurs. The ECMWF is more robust with nocturnal
convection developing along a stationary fnt across the region. The
GFS would suggest height rising with the sfc ridge still holding on
into the area. Have kept PoPs low given the uncertainty forecasting
mesoscale features on day 7.

As for temps, have trended twd the warmer guidance thru the period
given heights over the region.

Tilly

&&

.AVIATION:  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 133 PM CDT Fri Sep 12 2014

Ceilings are expected to gradually increase above 2000 ft this
evening. Some light rain is expected to move across the area into
this evening, with most of this rain moving across northern
Missouri into central Illinois. The most likely TAF to be affected
by light rain will be Quincy. Then drier air moving into the area
overnight which will cause ceilings to climb above 3000 feet from
north to south. Dry and VFR conditions are then expected at the
terminals after 09Z.

Specifics for KSTL: Ceilings are expected to climb above 2000 ft
this afternoon and then become VFR tonight. There is some chance
for light rain between 00-06Z, but confidence is not high enough
to include in the TAF at this time. Dry and VFR conditions are
expected after 09Z.

Britt

&&

.CLIMATE:
Issued at 236 PM CDT Fri Sep 12 2014

Record Lows This Weekend:

       STL        COU        UIN
13   43(1975)   33(1902)   33(1902)
14   46(1996)   40(1892)   38(1996)

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     47  66  48  72 /  20   0   0   0
Quincy          40  63  43  69 /  30   0   0   0
Columbia        41  65  43  72 /  30   0   0   5
Jefferson City  43  66  43  73 /  30   0   0   5
Salem           46  66  45  71 /  20   0   0   0
Farmington      44  66  40  72 /  20   0   0   0

&&

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

$$

WFO LSX







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