Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 240745

Area Forecast Discussion
National Weather Service La Crosse WI
245 AM CDT Tue Apr 24 2018

.SHORT TERM...(Today and tonight)
Issued at 245 AM CDT Tue Apr 24 2018

Water vapor imagery early today showed an upper low spinning across
the middle MS Valley and additional upper troughs over the northern
Rockies and Canadian prairies. A cold front was situated from Lake
Superior back through northern/central Minnesota.

For today, the upper trough over the northern Rockies will slowly
move into the northern high plains while the system to the north
across Canada heads towards Lake Superior. The surface cold front
will swing southward through the day, although with the airmass
preceding the front remaining quite mild, expect highs back up into
the 60s to low 70s once again, similar to yesterday. Forcing from
any of these features is weak enough over the area that NAM/RAP
soundings struggle to show any deep saturation later today. Did
maintain some very low pops in central WI this afternoon/evening
and a sprinkle or two couldn`t be ruled out elsewhere.

.LONG TERM...(Wednesday through Monday)
Issued at 245 AM CDT Tue Apr 24 2018

Modestly cooler temps are expected Wednesday behind the frontal
passage as high pressure spreads across the area. Temps will rebound
on Thursday as 925 mb temps of 12-13C pool ahead of an approaching
cold front. As a result, highs well into the 60s are expected
across much of the area. Showers are possible later
Thursday/Thursday evening with the trough/frontal passage. The
24.00Z ECMWF is drier compared with the NAM/GFS with a weaker
front and broad positively tilted upper trough. For now stuck with
low to mid range pops for this time. Slightly cooler, but still
seasonable temps return on Friday beneath northwesterly flow

Heading into the weekend and early next week, mid/upper ridging
across the plains will gradually push eastward. At the surface,
expansive high pressure will spread south and eastward with broad
southerly return flow developing by later in the weekend. This will
coincide with increasing low-level warm/moist advection through
early next week. Temps will trend upward, with highs possibly
well into the 70s by Monday. A more active period may develop for
the first half of next week with southwest flow aloft.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday morning)
Issued at 1149 PM CDT Mon Apr 23 2018

VFR conditions expected through this TAF period. Winds will remain
light/variable the rest of tonight, before becoming northerly 5-8kts
Tue morning as a cold front slide south across the area. Gradient
tightens up a bit more Tue afternoon, with N-NW winds more in the 9-
13kt range, perhaps gusty at sites like KRST during the mid-late
afternoon hours. Moisture continues to look limited with the front,
but cannot rule out a few light -SHRA in the areas during the
mid/late afternoon hours. Given the small chance and lower
confidence in any -SHRA occurring, left any mention out of the tafs
at this point.


Issued at 245 AM CDT Tue Apr 24 2018

Minor flooding is possible along portions of the Mississippi River and
the Yellow River at Necedah over the next several days as
snowmelt runoff continues to progress through the river system.
See the latest hydrologic outlook (ESF) for more information.




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