Special Weather Statement, NWS La Crosse, WI

Area Forecast Discussion
National Weather Service La Crosse WI
210 PM CDT Tue Oct 9 2018

.SHORT TERM...(This evening through Wednesday night)
Issued at 210 PM CDT Tue Oct 9 2018

Water vapor satellite this afternoon shows the trough over the
Rockies deepening with an upper level low forming over southern
Colorado. The low will continue to deepen and become closed over
the Dakotas tonight and remained closed as it moves northeast
across Minnesota Wednesday. As the low moves northeast, a strong
short wave trough will move over the region and is expected to
produce strong pv advection in the 500-300 mb layer as moves
across late tonight into Wednesday morning. The surface front
currently extends from southwest Iowa into northern Wisconsin and
will not move much tonight and then get pushed east of the area
Wednesday. The short wave trough will push a surface low along the
front that is expected to move across the area overnight and
Wednesday morning. As these features approach the area, the low
level jet will crank up ahead of the surface low and should be
focused on the area this evening before becoming focused farther
to the north overnight. As the nose of the low level jet works
into the area, should see showers and some storms rapidly
redevelop over the area late this afternoon into the evening. The
latest set of hi-res meso scale models then suggest there could be
a break from the late evening into the early overnight until the
surface low and short wave start influencing the area with more
activity expected to form along the front and then work east
through the late overnight into Wednesday morning. All the
activity should then taper off from southwest to northeast late
Wednesday afternoon through the evening with just some lingering
precipitation chances into Wednesday night across the far north
in the cyclonic rap around flow.

With the front bisecting the area this afternoon, the areas east
of it are warming up with temperatures well into the 70s. Dew
points in the warm sector are in the middle to upper 60s yielding
ML CAPE values of 500-1000 J/Kg over northeast Iowa into southwest
Wisconsin. The 09.17Z RAP holds this CAPE in place in the warm
sector through the evening with just a slight decrease expected
from the loss of daytime heating. Plenty of shear will be in place
with 30 to 40 knots in the 0-3 km layer and up to 30 knots in the
0-1 km layer. This continues to suggest a severe potential through
the evening hours with damaging winds the main threat. There will
also be a tornado threat if any storms can remain discrete and
latch onto a boundary to maximize the turning in the low level
wind field.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 210 PM CDT Tue Oct 9 2018

Once this system moves past the area, much cooler air will spill
in behind it. The entire area looks to have low temperatures below
freezing Thursday night and headlines will be needed to highlight
the end of the growing season. The next chance of precipitation
will be from Saturday night into Monday as the western long wave
trough finally looks like it will become progressive and should be
moving east across the central part of the country.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1207 PM CDT Tue Oct 9 2018

Not expecting much overall change in conditions through Wednesday
morning. The nearly stationary front extended from central Iowa
into north-central Wisconsin and based on analysis looks to be
very close to KLSE. Even if the front does temporarily shift
through KLSE, the biggest impact would be to bring the winds
around to the east/southeast but speeds would still remain under
10 knots. If the front does go through, ceilings at KLSE could pop
up to MVFR for a while. Confidence too low to include in the
forecast at this time. As the surface low moves into Iowa, enough
increase in forcing for some storms to develop along the frontal
boundary and will continue to include a VCTS for both airports
from late afternoon through much of the night. With the increase
in the low level jet ahead of the low tonight there could be
enough speed difference for some low level wind shear but did not
include as wind shear is implied with the inclusion of thunder.

&&

.HYDROLOGY...
Issued at 210 PM CDT Tue Oct 9 2018

No changes will be made to the ongoing flood watch. Conditions
remain favorable for more heavy rain through the overnight. As
mentioned above, the low level moisture transport will strengthen
and become focused on the area this evening before focusing
farther north overnight. Precipitable water values in the warm
sector will remain in the 1.75 to 2 inch range with warm cloud
depths around 3.5 km. With the repeated rounds of showers and
storms tonight into Wednesday morning, another 1 to 2 inches can
be expected to fall on grounds that are already saturated. Rivers
and streams will continue to rise with numerous river flood
warnings already issued and more expected to be issued tonight and
Wednesday. See the latest river flood warnings and statements for
specific river information or consult our hydrology web page at
water.weather.gov/ahps2/index.php?wfo=ARX.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Flood Watch through Wednesday morning for WIZ017-029-032>034-
     041>044-053>055-061.

MN...Flood Watch through Wednesday morning for MNZ079-086>088-094>096.

IA...Flood Watch through Wednesday morning for IAZ008>011-018-019-029-
     030.

&&

SHORT TERM...04
LONG TERM...04
AVIATION...04
HYDROLOGY...04

Hazardous Weather Outlook
National Weather Service La Crosse WI
350 AM CDT Tue Oct 9 2018

IAZ008-MNZ079-086>088-094-095-WIZ017-029-032>034-101200-
Mitchell-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Taylor-Clark-
Buffalo-Trempealeau-Jackson-
350 AM CDT Tue Oct 9 2018

This Hazardous Weather Outlook is for parts of northeast
Iowa, southeast Minnesota and western into north-central
Wisconsin.

.DAY ONE...Today and Tonight

A Flood Watch is in effect.

Rainfall will result in rises on some rivers and streams.
Flooding is possible.

Isolated thunderstorms also possible, mainly this afternoon into
tonight. Gusty winds and heavy rain are the main threats.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Periods of rain with scattered storms Wednesday. Many rivers and
streams are on the rise and some could flood. Elevated water
levels and some flooding will continue through late week.

Widespread freezing temperatures are expected Friday morning.

.SPOTTER INFORMATION STATEMENT...

Rainfall and any reports of flooding are appreciated.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

IAZ009>011-018-019-029-030-MNZ096-WIZ041>044-053>055-061-101200-
Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette-Clayton-
Houston-La Crosse-Monroe-Juneau-Adams-Vernon-Crawford-Richland-
Grant-
350 AM CDT Tue Oct 9 2018

This Hazardous Weather Outlook is for portions of northeast Iowa,
southeast Minnesota, and southwest into central Wisconsin.

.DAY ONE...Today and Tonight

Flood Watch in effect.

Scattered storms this afternoon into the evening. A few could be
strong with isolated severe storms possible. Threats include
damaging winds and isolated tornadoes. Locally heavy rain could
lead to flooding in areas that are saturated from previous rains.
Many rivers and streams are also on the rise and some could
flood.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Periods of rain with scattered storms Wednesday. Many rivers and
streams are on the rise and some could flood. Elevated water
levels and some flooding will continue through late week.

Widespread freezing temperatures are expected Friday morning.

.SPOTTER INFORMATION STATEMENT...

Rainfall and any severe or flooding reports are appreciated.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

Rieck/JAM

Special Weather Statement
National Weather Service La Crosse WI
239 PM CDT TUE OCT 9 2018

IAZ030-WIZ061-092015-
Clayton-Grant-
239 PM CDT TUE OCT 9 2018

...STRONG THUNDERSTORMS WILL AFFECT SOUTHEASTERN CLAYTON AND
SOUTHERN GRANT COUNTIES...

At 237 PM CDT, thunderstorms were developing over southern Grant and
Clayton counties.

Winds in excess of 40 mph are possible with these storms. Severe
weather is possible.

Locations impacted include...
Platteville, Lancaster, Guttenberg, Cuba City, Hazel Green,
Dickeyville, Cassville, Bloomington, Georgetown, Beetown, Arthur,
Montfort, Potosi, Livingston, Ellenboro, Glen Haven, Tennyson, Union,
North Buena Vista and Garber.

Storms may intensify, so be certain to monitor local radio stations
and available television stations for additional information and
possible warnings from the National Weather Service.

LAT...LON 4254 9064 4264 9071 4268 9090 4265 9090
      4265 9118 4283 9140 4297 9043 4251 9042
      4251 9064
TIME...MOT...LOC 1937Z 250DEG 14KT 4265 9051

Wetenkamp