Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 240538
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1138 PM CST Fri Jan 23 2015

.SHORT TERM:  (Through Late Tonight)
Issued at 349 PM CST Fri Jan 23 2015

Stratus continues to dissipate over our eastern counties, so it
appears that overnight cloudiness will come from two main
concerns...a final gasp of some mid and high clouds clipping our
southeast counties this evening (on northern fringes of system
working its way through the southeast U.S.), with another band of
mid level cloudiness dropping southeast across the area overnight as
surface trof/weak cold front drops into the region.  There are some
very weak echoes showing up with this band of mid clouds over Iowa,
but given the very dry low level air will maintain a dry forecast
for now.   Lows should be in the upper 20s to lower 30s, with clouds
and mixing preventing any big temperature drop.

Truett

.LONG TERM:  (Saturday through Next Friday)
Issued at 349 PM CST Fri Jan 23 2015

Above normal temperatures are expected for Saturday as the surface
winds back around to a southwesterly direction, along with plenty of
solar insolation particularly across central and southeast MO.  The
latest model runs were a little stronger and deeper with the
northwest flow, clipper type upper level trough/low and associated
surface low dropping southeastward through the northern Plains
Saturday night and into the Ohio Valley region Sunday afternoon or
evening compared to previous model runs.  The GFS model appears too
far southwest with the low track and is an outlier compared to the
other models.  Prefer the NAM and ECMWF solutions which have the low
dropping southeastward through Iowa and central IL, although the NAM
looks too deficient with its qpf across our forecast area.  The
models were also trending colder on Sunday with a non diurnal
temperature trend likely.  The temperature will likely fall during
the day on Sunday across much of our area as cold air advection
strengthens on the backside of the surface low.  The best chance of
rain will occur late Saturday night across northeast MO and west
central IL, then across west central and southwest IL on Sunday
mainly along and left of the track of the low.  Surface temperatures
should be warm enough that most of the precipitation falls as liquid
rain, although could not totally rule out a brief period of light
snow or a few flurries across portions of northeast MO and west
central IL especially if the storm system were to track a little
further southwest or be a little stronger.  At this time it appears
that any snow accumulations should remain northeast of our forecast
area.  The precipitation should shift east of our forecast area by
Sunday evening with colder temperatures for Sunday night.  Another,
weaker northwest flow shortwave will drop southeastward through the
Great Lakes region on Monday, but it appears that any measurable
precipitation should remain north and east of our forecast area,
although could not rule out sprinkles or flurries well east of the
Mississippi River.  Warmer temperatures are expected by Wednesday as
an upper level ridge moves eastward through the region, and as
surface winds become southerly on the backside of the surface ridge
shifting east of our area.  A cold front will drop southeastward
through our region Wednesday night and Thursday.  There may be a
little rain along and just ahead of this front, but it appears that
most of the precipitation will be north of our forecast area closer
to the shortwave and surface low.

GKS
&&

.AVIATION:  (For the 06z TAFs through 06z Saturday Night)
Issued at 1137 PM CST Fri Jan 23 2015

Weak cold front/trof has moved into northern Missouri and will
continue to slide southeast through forecast area through the
overnight hours. Will just see mid and high clouds with it.
Otherwise, light and variable winds to become southwesterly then
veer to the west behind the boundary. By this evening, the winds
will back to the southwest ahead of next weather system.

Specifics for KSTL:
Weak cold front/trof has moved into northern Missouri and will
continue to slide southeast moving through the metro area by 12z
Saturday. Will just see mid and high clouds with it. Otherwise,
light and variable winds to become southwesterly then veer to the
west behind the boundary. By 02z Sunday, the winds will back to
the southwest ahead of next weather system.

Byrd
&&

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

$$
WFO LSX





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