Area Forecast Discussion
Issued by NWS La Crosse, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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

000
FXUS63 KARX 192015
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
315 PM CDT Fri May 19 2017

.SHORT TERM...(This evening through Saturday)
Issued at 314 PM CDT Fri May 19 2017

For late this afternoon and early evening, the 700 to 500 mb
frontogenesis will gradually weaken across the area. In addition,
there will be some drying below 750 mb. As this occurs, the
showers will gradually dissipate.

From late tonight into Saturday morning, the 925 and 850 mb
moisture transport will increase as a low pressure system moves
east across Iowa. The greatest surface-based CAPES will remain to
our southeast across southeast Iowa and Illinois. However with
elevated CAPES climbing up to 500 mb and the dry slot moving in
kept the threat for isolated storms in the forecast.

With precipitable water values of around 1 inch, the showers and
storms will be efficient rainfall makers on Saturday. Additional
rainfall amounts will be around an inch for northeast Iowa and
southwest Wisconsin and from a half to 1 inch for the remainder of
the area. These rains will result in further rises on area rivers
and streams.

.LONG TERM...(Saturday night through Friday)
Issued at 314 PM CDT Fri May 19 2017

On Saturday night, the upper level low will transition northeast
from the central Plains into northern Wisconsin. As this occurs,
the threat for showers will gradually shift north of Interstate 90
and remain there through Sunday night. Additional rainfall amounts
look light.

From Monday afternoon through Tuesday, a shortwave trough will
round the upper level low and move through the Mid and Upper
Mississippi River Valley. This system will result in another round
of showers. With surface-based CAPES climbing to 1000 to
1500 J/kg on Monday and up to 500 J/kg Tuesday afternoon, this
will result in the development of isolated thunderstorms. With
850 mb temperatures of around 3C and extensive cloud cover, the
high temperatures on Tuesday will remain in 50s.

Some weak ridging will then develop across the region for the
mid-week. This will provide a couple of dry with high temperatures
in the 60s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1245 PM CDT Fri May 19 2017

Rain showers will continue at the TAF sites through late afternoon
with VFR conditions expected. After a break in the  rain, a
second round is expected late tonight into Saturday. Periods of
IFR conditions are possible in the steadier rains. Conditions
should mainly be MVFR through the morning hours Saturday. Also, we
may see some LLWS develop after 6Z tonight at KLSE and possibly
continue into early Saturday morning. Isolated thunderstorms are
possible on Saturday, mainly after 12Z. The overall confidence in
the coverage of the thunderstorms is uncertain so have not
included them in the TAF at this time.

&&

.HYDROLOGY...
Issued at 314 PM CDT Fri May 19 2017

River Flood Warnings continue along the Trempealeau River at
Arcadia and Dodge, the Black River at Black River Falls and
Galesville, and the Yellow River at Necedah as runoff from the
very heavy rain continues to move through the river system.

Another round of rain and isolated storms will move through the
area late tonight and Saturday. Additional rainfall amounts will
be around an inch for northeast Iowa and southwest Wisconsin and
from a half to 1 inch for the remainder of the area. These rains
will result in further rises on area rivers and streams.

&&

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

$$

SHORT TERM...Boyne
LONG TERM...Boyne
AVIATION...Wetenkamp
HYDROLOGY...Boyne



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