Area Forecast Discussion
Issued by NWS La Crosse, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
FXUS63 KARX 230756

Area Forecast Discussion
National Weather Service La Crosse WI
256 AM CDT Fri Sep 23 2016

.SHORT TERM...(Today and tonight)
Issued at 256 AM CDT Fri Sep 23 2016

Forecast concerns today are on ongoing thunderstorms across portions
of northeast Iowa, but this activity should be diminishing
considerably this morning. Focus then turns to lingering shower and
thunderstorm chances across much of the area through the day.
Widespread flooding continues today.

Currently watching a stalled out front across northeast Iowa which
is the focus for thunderstorms/heavy rainfall this morning. The
moisture transport that is helping to drive the heavy rain along the
warm front finally subsides by mid morning today. Also, a weak
shortwave helping to drive this activity, pushes east later this
morning. Meanwhile a deep trough was digging into the western conus.
The trough starts to lift north pulling a surface low, currently
over the high plains, north. The warm front then edges northward and
becomes oriented parallel with the surface/near surface flow. The
unseasonably moist and warm airmass remains over the region
however. Will hold onto low chances for showers and a few
thunderstorms, but he it appears the threat for additional heavy
rain from late this morning into the overnight hours is low.

.LONG TERM...(Saturday through Thursday)
Issued at 256 AM CDT Fri Sep 23 2016

Main forecast concerns in the long term are on thunderstorm chances
late Saturday afternoon into Sunday with the potential for a some
strong to severe storms with the threat for heavy rain. The
environment will remain conducive for heavy rain during this
timeframe with precipitable water values of 1.6 to 1.9 and warm
cloud depth approaching 4 km. The good news is that these storms
should be more progressive than what we have seen recently but given
the saturated ground across the area, it won`t take much rain to
initiate flash flooding. A few strong winds gusts are also possible.
Thinking severe weather threats outside of heavy rain, should be
fairly limited. It appears that the strongest shear lags well
behind the front. Also, given that much of the activity moves in
late in the day on Saturday into Saturday night, CAPE should also
be limited. A few showers may linger across the area Monday into
Tuesday as the upper low/trough meander across the region. We then
finally look to enter a drier period from Wednesday through the
end of the work week as upper ridging builds across the region.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1142 PM CDT Thu Sep 22 2016

Convection north of the front over northeast Iowa into southwest
Wisconsin expected to stay south of both airports overnight and
have removed the mention of any rain. Ceilings starting to come
down and expect IFR to MVFR for both sites overnight with some
MVFR visibility reductions from fog as well. The fog should mix
out Friday morning as the winds increase to around 10 knots but
not expecting much improvement in the ceiling with MVFR for much
of the period.


.HYDROLOGY...Through next week.
Issued at 256 AM CDT Fri Sep 23 2016

Widespread river flooding continues across much of the area. Some of
the worst flooding is occurring across northeast Iowa and
southwest into west central Wisconsin. Most of the rivers will
crest over the next few days.

The Mississippi River will also experience flooding
later this weekend into next week mainly downstream of Winona.
Mainly minor flooding is forecast. Continue to monitor river
levels and forecasts closely.


WI...Flash Flood Watch until 1 PM CDT this afternoon for WIZ054-055-

IA...Flash Flood Watch until 1 PM CDT this afternoon for IAZ008>011-



HYDROLOGY...WETENKAMP is the U.S. government's official web portal to all federal, state and local government web resources and services.