Area Forecast Discussion
Issued by NWS La Crosse, WI

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FXUS63 KARX 252304

Area Forecast Discussion
National Weather Service La Crosse WI
604 PM CDT Sun Sep 25 2016

.SHORT TERM...(Tonight through Tuesday)
Issued at 210 PM CDT Sun Sep 25 2016

Surface cold front associated with an upper level trough will
continue its march eastward tonight, firing showers and a few
thunderstorms along and ahead of it. Expecting this activity to be
east of the local forecast area.

Later tonight through Tuesday...spirals of upper level energy will
sweep across the Upper Mississippi River valley as the upper level
trough/closed low meanders east/southeast...while the system`s sfc
low is progged to drop into MI Tue afternoon. With ample moisture to
tap into, expect areas of showers to spark off this forcing. Mostly
across the north tonight-Monday, but shifting to eastern parts of
the forecast area Tue as the sfc low slides across eastern WI. Not
expecting much for amounts, so should not have an impact on current
high/flooding river systems or pose a threat for more areal/flash

Back to Monday...tight pressure gradient builds in from the Northern
Plains...with bufkit soundings suggesting mixing up to 800 mb.
Should be a rather windy day. Observations across the Dakotas
indicating peak wind gusts from 35-45 mph this afternoon. A bit more
favorable setup over there today than across this area for Monday,
but gusts in the wind prone/open areas of southeast MN and northeast
IA in the mid 30s to near 40 mph certainly possible.

.LONG TERM...(Wednesday through Sunday)
Issued at 210 PM CDT Sun Sep 25 2016

GFS/ECMWF remain bullish on an extended period of dry weather...
building in an upper level ridge coupled with a high at the sfc.
Definitely needed for the region.

One point of the interest though is the trough that drops toward the
southeast U.S. after Tue. The GFS favors kicking that off the coast
and letting it go on its way. The ECMWF, however, cuts off the
closed low from the mean flow, gradually meandering it back north to
across the eastern Great Lakes for the weekend. This solution would
put Wisconsin back under some rain chances. The GEM on the otherhand
doesn`t take the trough southeast at all, rather pushes it mostly
due east to across the New England states for the weekend.
Going to lean on the drier solution and keep it dry.

As for temps, they look fairly seasonable for the later half of this
week...right around the late September normals.


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 604 PM CDT Sun Sep 25 2016

As the upper level trough moves across the Upper Midwest it is
producing widespread VFR ceilings along with some light showers.
There is a back edge to the clouds that is working into western
Minnesota late this afternoon. Expecting this will continue to
push east and with the loss of heating, the showers should
dissipate with the clouds scattering out by the middle of the
evening. A tight gradient will remain in place through the night
between the surface low over western Ontario and the high
centered over eastern Colorado. This will keep the west to
northwest winds in the 10 to 15 knot range all night. Steep low
level lapse rates will develop Monday morning that will allow
gusts of 25 to 30 knots at both airports. Also expecting a VFR
ceiling to form early Monday afternoon from the instability
generated by the steep lapse rates.




LONG TERM....Rieck
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