NWS-La Crosse Forecast Discussion


						FXUS63 KARX 110959

Area Forecast Discussion
National Weather Service La Crosse WI
500 AM CDT Tue Aug 11 2020

.SHORT TERM...(Today through Wednesday)
Issued at 300 AM CDT Tue Aug 11 2020

Skies were mostly clear early this morning, with temperatures
ranging from the upper 40s across the cranberry bogs of Central
Wisconsin to the low 60s in far Southwest Wisconsin. Some patchy fog
was noted on satellite in some of the Mississippi River tributaries.

Patchy fog should burn off by mid morning, with a mostly sunny day
expected under high pressure. Highs are expected to be seasonable in
the low to mid 80s, with dewpoints in the 50s providing very
comfortable weather.

With high pressure providing a deep light wind layer tonight, will
have to watch out for some valley fog, but increasing return flow by
early morning may not be conducive for a more widespread valley fog
event. Influence of high pressure should also keep tonight dry,
but will have to watch for remnants of an MCS Wednesday morning
tied to a stronger, convectively-enhanced shortwave approaching
from the west. The bulk of the moisture transport and instability
stay west of the area, but as the aforementioned shortwave
progresses through the area during the day Wednesday, we should
still see some small shower/storm chances given the forcing. Not
seeing a strong signal for a huge warm up or cool down for
Wednesday, or the rest of the week for that matter, so highs are
expected to stay in the upper 70s to mid 80s.

.LONG TERM...(Wednesday night through Monday)
Issued at 300 AM CDT Tue Aug 11 2020

Additional shortwaves are expected Thursday night through the
weekend, providing chances for showers/storms. Given the uncertainty
in exact timing/placement of these waves, the NBM gives small PoPs
for nearly all periods. It will likely not be nearly so wet,
however, with most periods ending up predominately dry with a few
more focused shower/storm chances mixed in. Of note, some of the
11.00Z guidance suggests that the shortwave Thursday night could
draw up some slightly warmer and more humid, unstable air for
Friday/Friday night, potentially providing a little more fuel for
some stronger storms. Still, given the uncertainties this far out,
confidence is not very high in this period. Following the weekend
shortwaves, drier and cooler northwest flow returns for the
beginning of next week, with highs falling back into the 70s.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 500 AM CDT Tue Aug 11 2020

Cigs: skc/sct vfr through the period with the region under the
influence of high pressure. Some high clouds will start to filter in
from the west Wed, but still anticipating VFR through the day.

WX/vsby: potential valley fog at KLSE Wed morning. Deeper light wind
layer and clear skies provide a favorable setup. Much will depend on
how warm we get today, and if the T/Td spread can be overcome. Also,
if high clouds filter in faster than expected, that could put a halt
to some of the valley fog. For now, see enough in the data that BCFG
is warranted.

Winds: west/southwest and generally under 10kts today...light
southerly tonight.




SHORT TERM...Lee/Rieck