Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 141722

Area Forecast Discussion
National Weather Service La Crosse WI
1222 PM CDT Fri Oct 14 2016

.SHORT TERM...(Today through Monday)
Issued at 302 AM CDT Fri Oct 14 2016

Plenty of weather to digest over through the weekend and early next
week, with the main issue initially being cloud trends and perhaps a
little drizzle tonight into Saturday before a few rain chances
present themselves into Monday, though the good news for the non-
cool weather fans is that warmer conditions are on the way. Early
morning analysis places low level ridging working through the
eastern Great Lakes with enough lingering influence locally to allow
eastern counties to decouple earlier and temps to tumble. That`s
starting to change with a tightening gradient in place to the west,
helping transport some rather impressive warm advection back
northward through the mid Miss Valley. That setup at the moment is
manifesting itself in the form of widespread stratus working
northward through southern Missouri/eastern Kansas, with that stuff
expected to continue its northward trek today into tonight, perhaps
briefly mixing out on the leading edge through the afternoon but
likely expanding rapidly beneath a sharp inversion tonight across
our area.

Still not overly sure about the drizzle threat into tonight and
Saturday. There`s plenty of saturation below 850mb but not much lift
as all of the deeper ascent/lift looks to go into trying to saturate
a deep dry layer in the mid levels. Sufficiently deeper moisture
does look to arrive later Saturday into Saturday evening in advance
of an approaching cold front and weak upper wave, with enough
cooling in the 800-700mb layer to generate up to 1000 J/kg of skinny
CAPE in the presence of 35-40+ knots of effective shear. Not sure
there`s enough CAPE there to deliver any widespread stronger storm
threat, but certainly can`t rule out a stronger storm or two,
particularly east of the Mississippi where the deepest moisture
arrives into the evening.

Otherwise, the passage of the cold front should briefly sweep the
lower stratus east/southeast of the area into much of Sunday with
hints of bubble high development nearby. Having said that, have to
be a little concerned with lower clouds only be a few counties away,
and developing return flow through the afternoon potentially
dragging some of that back north, in line with recent runs of the
NAM solution. Regardless of how that all shakes out, it does appear
we should realize another batch of showers and likely some thunder
into late Sunday and especially Sunday night with another push of
quite strong moisture transport directly into the area in the
presence of steepening mid level lapse rates. Temps through the
period look to average quite a bit above normal, especially with
regard to overnight lows, with some spots tonight and Saturday night
perhaps holding only in the lower 60s.

.LONG TERM...(Monday Night through Thursday)
Issued at 302 AM CDT Fri Oct 14 2016

More questions than answers with it comes to a possible stronger
system impacting parts of the area toward Tuesday, with pretty big
discrepancies between recent runs of the GFS, ECMWF, and GGEM
regarding how to handle incoming stronger Pacific energy as it
crosses the north-central CONUS. Still seeing a trend for stronger
surface low development somewhere over the northern Plains or far
upper Mississippi River Valley, though the 00Z run of the GFS has
come in notable less impressive with that feature, instead hinting
at less upper wave amplification and a more strung-out frontal wave
passing over Lake Superior (something actually mirrored by the
late arrival of the 00Z ECMWF).

While overall confidence in the specifics remains rather low at
this point, most available solutions suggest our local area
remains mainly dry with all of the best moisture/forcing well to
the north. Pending the strength of the low ultimately, our biggest
issue may well be windy weather toward later Tuesday with colder
air working into the picture behind a passing cold front. After
that, really looking like a return toward more seasonable
temperatures for much of the remainder of the work week with broad
upper troughing progged in place over the region. Starting to see
some hints that enough Pacific jet energy crashing ashore may
ultimately try to cut off an upper level low somewhere over the
central or southern CONUS, but lots of time to see how that all
unfolds the next few days.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1222 PM CDT Fri Oct 14 2016

Primary aviation impact through the period will be low ceilings
associated with stratus cloud deck surging northward from IA.
Latest satellite loop suggests this will occur sooner than
previously forecast, so will introduce MVFR ceilings at KRST by
14.19Z and at KLSE by 14.20Z. After sunset and through the rest of
the period, expect a further reduction in ceilings with IFR at
KRST and low MVFR at KLSE. Could see some reductions in visibility
as well overnight, but lower confidence precludes mention at this
time. Will also need to watch for some light drizzle by Saturday
morning. Strong southerly winds will persist, gusting at times to
between 20 and 30 kts, only decreasing slightly overnight.




SHORT TERM...Lawrence
LONG TERM...Lawrence
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