Area Forecast Discussion
Issued by NWS La Crosse, WI

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003
FXUS63 KARX 142303
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
603 PM CDT Sat Oct 14 2017

.SYNOPSIS...
Issued at 207 PM CDT Sat Oct 14 2017

Showers are expanding across the area this afternoon in response
to increasing broadscale lift ahead of a vigorous mid-level trough
(per GOES Water Vapor) pushing southeast out of the Dakotas. At
the surface, low pressure was becoming better organized over the
Central Plains. Otherwise, temperatures across the area this
afternoon were in the 50s.

&&

.SHORT TERM...(This evening through Sunday)
Issued at 207 PM CDT Sat Oct 14 2017

Strengthening area of low pressure will lift northeast across the
area tonight, reaching Lake Huron by daybreak Sunday. Latest
RAP/NAM low track keeps warm sector/better cape for severe storm
potential southeast of the area but could be a very brief window
of opportunity for a few stronger storms southeast of a
Mauston/Richland Center/Lancaster WI line as this area will be on
the cusp of the warm sector along with ample 0-3km bulk shear.
Therefore, will not let our guard down and will maintain a close
eye on strong to severe storm potential down that way. Otherwise,
looks like another good dousing of rain for the area with
generally 1/2 to 2 inches expected, highest across far northeast
IA into far southwest WI (see the Hydrology section below).
Another facet of this strong storm system will be gusty northwest
winds on the backside of the low after midnight into early Sunday
morning. We will likely see sustained winds of 15-25 mph with
gusts around 40 mph in the higher bluff country of southwest WI
and typical open/wind- prone areas of southeast MN/northeast IA.

Deformation area showers look to continue through mid Sunday
morning north of I-94, exiting east as the low quickly pulls into
western Quebec. Otherwise, looks like skies will be clearing from
west to east during the afternoon as high pressure builds in from
Plains. Plan on highs in the 50s.

.LONG TERM...(Sunday night through Saturday)
Issued at 207 PM CDT Sat Oct 14 2017

Main concern will be early on as areas of frost is expected late
Sunday night into early Monday morning as lows dip into the 30s
with light winds/clear skies.

The rest of the work week looks tranquil/pleasant with a ridge of
high pressure building over the central CONUS. Look for highs
starting off cooler than normal Monday but then warming to well
above normal by weeks end. A chance of showers creeps in Saturday
as a cold front pushes in from the Northern Plains.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 602 PM CDT Sat Oct 14 2017

Surface analysis late this afternoon shows an area of low pressure
over central Iowa with a warm front extending east into Illinois.
Lots of showers out ahead of the low and then more on the back
side in the deformation zone ahead of the incoming upper level
trough. Expecting the intitial round of showers ahead of the low
to end this evening as the low moves rapidly northeast across
southern Wisconsin into lower Michigan. After the brief break, the
deformation showers will move back in late this evening and
continue for much of the night. Expect ceilings to remain IFR
until the showers end late tonight and then only increase to MVFR.
The winds will also become an issue on the back side of the low
with a tight pressure gradient. Once the winds become northwest,
a steep low level lapse rate will develop to allow gusts of 25 to
35 knots overnight into Sunday morning. The winds will begin to
subside late Sunday morning through the afternoon when the
ceilings are also expected to improve to VFR.

&&

.HYDROLOGY...Through Tonight
Issued at 207 PM CDT Sat Oct 14 2017

Localized flooding is possible across portions of far northeast
Iowa into far southwest Wisconsin through this evening. Strong
thunderstorms are possible this afternoon and evening across this
area with the potential for heavy rainfall of 1 to locally 3
inches. Clayton and Grant counties have the highest chances of
seeing this heavier rainfall. It appears the main flood threat
will be south and east of the area across northern Illinois into
southeast Wisconsin where a Flash Flood Watch is in effect into
tonight.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&

$$

SYNOPSIS...DAS
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
HYDROLOGY...DAS



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