Special Weather Statement, NWS La Crosse, WI

Area Forecast Discussion
National Weather Service La Crosse WI
202 PM CDT Wed Jul 24 2019

.SHORT TERM...(This evening through Thursday)
Issued at 202 PM CDT Wed Jul 24 2019

With the weak cyclonic flow aloft, another short wave trough will
drop across the Great Lakes and be exiting into Ohio River Valley
this evening. This wave could pass close enough to the area to
generate a few showers/storms yet this afternoon that would then
dissipate early in the evening as the forcing and heating of the
day/CAPE dissipate. Otherwise, the area of high pressure centered
over Iowa and Missouri this afternoon will be the dominant feature
for quiet weather through Thursday.

.LONG TERM...(Thursday night through Wednesday)
Issued at 202 PM CDT Wed Jul 24 2019

As the high exits the region Thursday night a cold front will
begin to approach from the northwest. By late Thursday night, the
front should roughly extend from eastern Lake Superior into
southwest Minnesota and should slowly sink south toward the area
Friday. The front should then drop to about the Interstate 90
corridor Friday night where it is expected to remain nearly
stationary into Sunday before another cold front comes in from the
west and pushes across the region Sunday night. This front will
serve as the focus for on and off showers and storm chances
starting Thursday night through the weekend.

An upper level low will be moving across southern Canada late in
the week with with the troughing extending into the Upper Midwest
as a short wave trough swings around the base of the low. Most
models, with the exception of the 24.12Z GFS, suggest the forcing
and front will be too far to the northwest for much of rain chance
Thursday night. The forcing should increase some Friday as the
short wave trough moves past to the north of the area. However,
this forcing does not look that strong as the whole upper level
system will have positive tilt keeping the best pv advection in
the 500-300 mb layer close to the upper level low. The low level
moisture transport looks to be parallel to the incoming front and
primarily through the region to be focused ahead of the short wave
trough. With the general weak forcing, should only see some
scattered activity possible along the front from about Interstate
90 and north Friday and Friday evening. Some potential for a few
of the storms to be strong with ML CAPE in the 1000-2000 J/Kg
range and 0-3 km shear values around 20 knots for the most part.
Some potential for local downpours as precipitable water values
look to be around 1.5 inches but would not expect this to be
scenario for flooding to develop.

Even with the front in the area Saturday, this is expected to be a
rather quiet day with the lack of any organized forcing to spark
convective development. This looks to change for Sunday as upper
level ridge over the Rockies get flattened by another upper level
low tracking across southern Canada. There is good agreement that
a short wave trough will come out of the central Rockies with an
expected MCS forming over the Plains Saturday night. The remains
of this MCS should then progress east along the stalled boundary
Sunday but the models are not agreement whether the short wave
trough will track along with it and help spark redevelopment over
the area (GFS) or go farther north and take the MCS remnants to
the north as well (24.12Z ECMWF). Either way, the second cold
front will get pushed into and then trough the area with the
passage of the short wave trough and upper level low across
southern Canada. This could be enough to generate at least some
scattered convection with these chances lingering into Monday
until the front clears the region.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1149 AM CDT Wed Jul 24 2019

Isolated shra/ts expected this afternoon but should stay mainly east
of the KLSE/KRST sites. Plan on VFR conditions through the period
but may have to watch for some river valley fog at KLSE in the 09-
13Z time frame. However, currently thinking tightening pressure
gradient/southerly winds will prevent this fog from occurring or
will be very spotty in nature -not enough to include in KLSE TAF.

&&

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

SHORT TERM...04
LONG TERM...04
AVIATION...DAS

Hazardous Weather Outlook
National Weather Service La Crosse WI
345 AM CDT Wed Jul 24 2019

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-251200-
Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette-
Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston-
345 AM CDT Wed Jul 24 2019

This Hazardous Weather Outlook is for portions of northeast Iowa
and southeast Minnesota.

.DAY ONE...Today and Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Thunderstorms are possible Thursday night through Friday and again
Saturday night through Sunday night. It is too early to determine
any risk of severe weather.

.SPOTTER INFORMATION STATEMENT...

No action needed.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

WIZ017-029-032>034-041>044-053>055-061-251200-
Taylor-Clark-Buffalo-Trempealeau-Jackson-La Crosse-Monroe-Juneau-
Adams-Vernon-Crawford-Richland-Grant-
345 AM CDT Wed Jul 24 2019

This Hazardous Weather Outlook is for portions of southwest
through central Wisconsin.

.DAY ONE...Today and Tonight

Isolated thunderstorms are possible this afternoon. Severe weather
is not expected.

Flooding continues for a few locations along area rivers in
western Wisconsin.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

Thunderstorms are possible Thursday night through Friday night
and again Saturday night through Monday. It is too early to
determine any risk of severe weather.

.SPOTTER INFORMATION STATEMENT...

No action needed.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

Special Weather Statement
National Weather Service La Crosse WI
621 PM CDT Wed Jul 24 2019

WIZ043-242345-
Juneau-
621 PM CDT Wed Jul 24 2019

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN JUNEAU COUNTY...

At 620 PM CDT, a strong thunderstorm was located near Necedah, or
16 miles east of Tomah, moving southeast at 15 mph.

Winds in excess of 40 mph and pea size hail are possible with this
storm.

This storm will be near...
  Necedah around 645 PM CDT.

LAT...LON 4393 8996 4381 9017 4400 9031 4407 9031
      4416 9015 4408 9002 4405 9002 4402 9000
      4401 9001 4399 8996 4394 8995
TIME...MOT...LOC 2320Z 321DEG 12KT 4405 9019

JSB