Flood in South Dakota, March 1 to 19, 2017

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1124 PM CST Tue Feb 28 2017

.UPDATE...
Issued at 925 PM CST Tue Feb 28 2017

Significantly increased snow accumulations from Bowdle southeast
to Clark due to a very persistent snow band in the axis of a 500
mb trough and a potent shortwave. Areas in that band could see 2
to 3 inches this evening. Models are not capturing this snow well
at all. Have begun trending to the RAP's 925 mb RH to try to
pinpoint any movement of the band.

UPDATE Issued at 602 PM CST Tue Feb 28 2017

Increased pops for a shortwave enhanced area of light snow ongoing
from Faulkton to Watertown. Any accumulations are expected to be
light, but snow could continue through the evening while only
slowly pushing east.

&&

.SHORT TERM...(This Evening through Wednesday)
Issued at 326 PM CST Tue Feb 28 2017

A somewhat complicated short term coming up. Energy that has wrung
out some light snow over the region today, appears to be maintaining
its strength as it moves toward the James Valley. Another more major
wave is moving into the southern/western high plains and this
feature could spread some light pcpn up into the far southeast cwa
overnight. Meanwhile a mid level neutral tilt trof is expected to
advect east across the forecast area overnight. Kind of hard to say
how much pcpn we'll see from this feature. Model consensus suggests
a band of light snow moving across mainly the northern cwa late
tonight and early Wednesday. Yet another clipper-like system is
expected for Wednesday night into Thursday.  After that the wx
situation does calm down a bit for the latter part of the week.

Temperatures overall should favor near normal through Wednesday.

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 326 PM CST Tue Feb 28 2017

Will start out Wednesday night with the main 500mb trough set up
from Hudson Bay through the Great Lakes, with northwesterly flow
dominating the Northern and Central Plains States. This will
continue through Thursday, until a high amplitude ridge builds
and stretches from TX up through central Canada. At the surface, yet
another disturbance will be sliding in from the northwest. At 00Z
the sfc low will be over northeastern MT, and weaken as it crosses
eastern SD 06-12Z Thursday. Kept chance pops going for mainly the
northeastern corner of the cwa. Look for high pressure over south
central Canada Thursday morning to quickly build in, with dry
weather figured Thursday afternoon through Thursday night. Thursday
night could again bring some brief light snow to northeastern areas
as the high exits and a broad trough settles overhead.

The 500mb ridge will shift to our east on Saturday, in response to
the next low sinking south from AK to just off the coast of the
Pacific Northwest. Warmer temperature will be a given. In fact,
temperatures Saturday night and Sunday night will not be too far off
from our normal highs for this time of year.

There looks to be enough differences in the guidance to keep a
general blended solution going as the 500mb trough crosses the
Dakotas late Sunday night through Monday. By 00Z Tuesday, the
operational GFS has the 500mb low over northeastern ND, while the
ECMWF is over eastern WI, and the Canadian is over far lower MI.
Either way, it looks like temperatures should be cold enough again
on the backside of this feature, as the sfc low shifts to our east
Monday morning, to bring a mix and even snow back into the forecast.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1121 PM CST Tue Feb 28 2017

An area of snow persists south of KABR. Lighter snow/flurries will
exit KPIR by 8z. As the snow shifts east, vsby at KATY may fall to
MVFR. Otherwise, VFR conditions will prevail in the west and
IFR/MVFR conditions at KATY will improve Wednesday afternoon.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

UPDATE...Wise
SHORT TERM...TDK
LONG TERM...KF
AVIATION...Wise

Hazardous Weather Outlook...UPDATED
National Weather Service Aberdeen SD
1110 PM CST Tue Feb 28 2017

MNZ039-046-SDZ005>008-010-011-017>023-020515-
Traverse-Big Stone-McPherson-Brown-Marshall-Roberts-Edmunds-Day-
Faulk-Spink-Clark-Codington-Grant-Hamlin-Deuel-
1110 PM CST Tue Feb 28 2017

This Hazardous Weather Outlook is for portions of west central
Minnesota, north central South Dakota, and northeast South
Dakota.

.DAY ONE...Tonight

Areas of light snow will persist overnight across portions of
northeast South Dakota. Localized amounts of around 2 or 3 inches
are possible across Edmunds, Faulk, Spink and Clark counties.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

SDZ003-004-009-015-016-033>037-045-048-051-020515-
Corson-Campbell-Walworth-Dewey-Potter-Stanley-Sully-Hughes-Hyde-
Hand-Jones-Lyman-Buffalo-
1110 PM CST Tue Feb 28 2017 /1010 PM MST Tue Feb 28 2017/

This Hazardous Weather Outlook is for portions of central South
Dakota and north central South Dakota.

.DAY ONE...Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

TMT