Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 191153
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
553 AM CST Sun Nov 19 2017

.SHORT TERM...  (Through Late Tonight)
Issued at 345 AM CST Sun Nov 19 2017

The low level cloudiness was finally advecting east of our forecast
area early this morning as a large surface ridge over the Plains was
building eastward into our area. Northwesterly surface winds, albeit
not as strong as yesterday continue to bring colder and drier air
into the forecast area early this morning.  Despite full sunshine
today temperatures will be below normal with northwesterly mid-upper
level flow.  Highs today will be 5 to 10 degrees below normal.  Will
see slightly warmer low temperatures tonight across northeast and
central MO as surface/low level winds back around to a southwesterly
direction as the surface/850 mb ridge shifts southeast of our
region. There may be some high level cloudiness tonight ahead of a
weak northwest flow shortwave.  The coldest low temperatures
tonight, still slightly below normal will occur across southeast MO
and southwest IL.

GKS

.LONG TERM...  (Monday through Saturday)
Issued at 345 AM CST Sun Nov 19 2017

A longwave upper TROF will persist over eastern North America
throughout this period.  This will allow several disturbances and a
pair of surface cold fronts to pass thru our region.

The models continue to depict a series of shortwave disturbances
slated to pass thru our region between Monday and Wednesday, but
also depict the atmospheric column as being too dry to support pcpn.
The best chance for pcpn may be with passage of the second cold
front on Friday night where moisture levels will be somewhat higher
but as it stands now, probs still look low.

Temperatures will see-saw this week, beginning above average with
temps exceeding 60F in places on Monday thanks to breezy southerly
flow and abundant sunshine.  This warm up will be short-lived as a
cold front moves thru on Tuesday with another brief bout of below
average temps Wednesday and Thursday.  A return of southerly flow
towards next weekend will begin the next rebound of temps into the
50s and possibly 60s for Friday.  Another cold front passing thru on
Friday night should result in slightly cooler temps on Saturday.

TES

&&

.AVIATION...  (For the 12z TAFs through 12z Monday Morning)
Issued at 529 AM CST Sun Nov 19 2017

Surface ridge centered over the southern Plains will move
eastward into the TN Valley region by the end of the forecast
period. Northwesterly surface wind will weaken this afternoon,
then back around to a southwesterly direction this evening. Some
high level cloudiness may advect southeastward into our area
tonight.

SPECIFICS FOR KSTL: Surface ridge centered over the southern Plains
will move eastward into the TN Valley region by the end of the
forecast period. Northwesterly surface wind will weaken this
afternoon, then back around to a southwesterly direction this
evening, and strengthen again Monday morning. Some high level
cloudiness may advect southeastward into the STL area tonight.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX


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