Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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 50
FXUS63 KFSD 300430

Area Forecast Discussion
National Weather Service Sioux Falls SD
1030 PM CST Tue Nov 29 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 429 PM CST Tue Nov 29 2016

Interesting upper pattern evolving this afternoon with core of main
low pressure stacked around 50 miles northeast of KMML, with an
increasingly impressive lobe pushing west and southwest across
eastern North Dakota, wrapping around the main cyclone. Near low-
level core of low pressure, a bit of residual warmer air near the
surface has led to a mix toward liquid precipitation around KMML,
but as the wave shifts more and more eastward through the late
afternoon and evening, snow will become the preferred precipitation
mode, matching that of the remainder of the CWA. The initial
distribution of precipitation is highly defined by the broad low-
level and weakening trowal flow around the back side of the system.
This signature will weaken and retreat eastward going through the
evening pushing focus for snowfall into southwest MN. While the
frontal support does look to weaken after evening, there remains
Gradually, will then see increasing deeper dynamical forcing drop
southward out of North Dakota with secondary lobe toward K9V9 and
KHON later night. The thermal profiles remain suggestive of marginal
precipitation efficiency with lower- and relatively warm-centric
lift forcing.

After the initial more focused band during the morning dropping
south and southeast, there will remain a moist environment with a
lack of larger scale lift support. A greater portion of the snowfall
should be characterized as light on Wednesday, with highest amounts
expected toward portions of southwest Minnesota.

With warm layer so shallow near the surface, two impacts would
likely be a slight enhancement to amounts on elevated surfaces, and
snow at warmer and more moist readings than would usually expect.
Temperatures will again be fairly restrained over the next 24 hours,
with likely no more than 5-8F change through the period with lows
upper 20s to lower 30s and highs in the lower to mid 30s.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 429 PM CST Tue Nov 29 2016

Wednesday night will see the main wave exit the area, taking with it
the deeper moisture and lift and of course the snowfall. Clouds will
still hold on strong through Friday however. While the Wednesday
night into Friday time frame is expected to remain dry, a small band
of light snow will be possible from about Huron into northwest Iowa
late Thursday afternoon and Thursday evening will be possible but
placement and the small size will leave it out of the forecast for
now. There is also a bit of a disconnect between the forcing and
the mid level versus low level moisture.

Friday through Monday has seen the models come into a bit more
agreement on the overall pattern. The main focus here is a fairly
strong northern stream with a couple of weaker waves moving through
late Friday night into Saturday morning and another Saturday
evening. Nether real impressive so the chance for precipitation will
remain on the low side. Temperatures will climb above normal
Saturday into Monday as strong low pressure deepens over the
Rockies. This could set up an interesting mid week system next week
which at this time hints at mainly snow.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1029 PM CST Tue Nov 29 2016

Widespread MVFR to IFR ceilings will prevail through Wed. Periodic
snow showers could bring brief IFR visibilities.




SHORT TERM...Chapman
AVIATION...JM is the U.S. government's official web portal to all federal, state and local government web resources and services.