109 
FXUS63 KLSX 301730
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1130 AM CST Mon Jan 30 2017

.SHORT TERM...  (Through Late Tonight)
Issued at 340 AM CST Mon Jan 30 2017

Warmer temperatures are expected today due to rising upper level
heights, low to mid level warm air advection, and south-
southwesterly surface winds.  The only limiting factor will be a
north to south band of low level clouds advecting eastward through
at least the northern half of the forecast area this morning into
the early afternoon.  This will only temporarily limit the diurnal
solar insolation. Highs today will be about 15 degrees above normal
for late January. A weak and dry cold front will move southeastward
through our area tonight. Despite this along with little cloud cover
the lows tonight will remain above normal.

GKS

.LONG TERM...  (Tuesday through Sunday)
Issued at 340 AM CST Mon Jan 30 2017

Low amplitude NW flow aloft will persist over our region thru next
weekend.  For much of the upcoming week, this will result in a
primary storm track that will be to our north and result in average
to above average temps, with a gradual trend towards cooler temps
later in the week. 

One item that has begun to come into better focus is a
frontogenetical mesoscale snow banding event on Tuesday night.  This
has been a on and off again type depiction by the models the past
few days but by its very nature isn't going to be handled very well
at all until you start to get inside of about 36 hours of the event.
There are a number of ways it can go with respect to snow accums,
but that will depend on precise moisture availability and
duration/location of snow bands.  Much of this probably will not get
refined enough to answer until inside 12 hours of the event.  For
now, have introduced flurries for areas in northern MO and central
IL.  Ultimately, may see some light snow accums from this event. 

The models are beginning to converge on how to handle the system for
next weekend, which begins as a piece of energy that breaks off from
a strong Pacific storm system later this week and rapidly travels
east in the low-amplitude flow across the CONUS.  The CMC still is
advertising the strongest depiction of this storm, and the coldest
column, while the EC is still the weakest and warmest.  The
previously middle-of-the-road GFS has taken a more decisive turn
towards the stronger/colder CMC.  For now, the one thing we can do
with a bit more confidence than before is boost PoPs into likely
category.  Pcpn-types are all up in the air at this time with what
remains a large spread in column temps, but at least a wintry mix
seems likely for part of our region.  Something to keep a close eye
on, as a realization of a stronger, deeper, colder system per one
end of the existing model spread would point towards a significant
winter storm.

TES

&&

.AVIATION...  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1115 AM CST Mon Jan 30 2017

A narrow band of MVFR clouds at KUIN/KSTL will move east of the
terminals within the next hour or two, leaving VFR conditions for
the rest of the TAF period at all terminals. Winds will turn
westerly tonight after a weak cold front moves across the area.
LLWS conditions are expected for a few hours after 31/03z due to
stronger winds aloft. Wind gusts of 20-25 kts are possible
overnight and tomorrow, especially after 31/12z.

Kanofsky

&&

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

$$

WFO LSX