Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
331 am CST Tuesday Dec 10 2013
Short term...(today and tonight)
issued at 330 am CST Tuesday Dec 10 2013
The quick burst of low clouds and snow will quickly exit to the east
this morning...with the only lingering affect being reduced
visibilities due to the brisk west/northwest winds and blowing snow.
While winds stay rather Stout through the day across west/south
central Minnesota...do think we will be able to let the Winter Weather
Advisory go shortly after daybreak.
Attention then shifts to the next weak wave prognosticated to dive
southeast across the area. Said feature is prognosticated to mainly affect
southern Minnesota...where categorical probability of precipitation have been included generally
along/south of Interstate 90 for this evening. Expect the southern
quarter of Minnesota /south of Minneapolis/ to see 0.5 to 2.0 inch
accumulations...with patchy blowing snow as well under the influence
of 15-20 miles per hour northwest wind. That being said...do not think forecast
winds/snowfall amounts quite justify a Winter Weather
Advisory...although wind chills will necessitate headlines tonight
into Wednesday. In fact...some locations will likely only sneak back
warmer than criteria for a short time span on Wednesday afternoon
before falling back below again on Wednesday evening. Therefore...
prolonged wind chill headlines were held onto from tonight through
Wednesday night from north central Minnesota into west central WI. Northern
parts of the forecast area will likely see wind chills dip below
-35...generally from Little Falls to Rush City and Ladysmith. As a
result...have gone with a wind chill warning there...and advisories
Long term...(wednesday through monday)
issued at 330 am CST Tuesday Dec 10 2013
The main change in the extended period is holding back on temperatures
modification next week...or at least hold onto cooler temperatures through
Monday/Tuesday of next week as was previously advertised to be warmer.
There has been a trend to shift the core of the coldest air
northeast across central/eastern Canada with a more modified
Pacific/northwest territories of Canada air mass in the northern
plains/upper Midwest this weekend and into next week. The changes to
this pattern seems to be related to the West Coast upper low which
was prognosticated to affect the SW U.S. Early next week. This has been
replaced by an upper ridge which means the persistent northwest flow
across western Canada/northern U.S. Will likely continue. This
pattern change across the West Coast will need to be monitored if
models decide to move back toward an upper low.
One thing is for sure...the persistent northwest flow will provide for
fast moving shortwave/S and occasional light snow. Timing and
strength of these shortwave/S are too problematic and therefore chance
probability of precipitation look reasonable until a day or so before they affect our
region. This will likely change the forecast over the next several
days to dry... or a chance of light snow. Temperatures will reflect
the non-diurnal trend which will lead to high temperatures around
midnight...or early in the morning depending upon the timing of
these shortwave/S and associated cold front. Although chance/S of light
snow will continue in the extended period...the air mass and/or
precipitable waters associated with the chance/S will be low.
Another item of interest is the deeper snow pack across Canada
which is a bit earlier than in previous years. This will likely
play an important factor in the weeks ahead for cold snaps and any
type of rebound of warmer temperatures from the south.
Aviation...(for the 06z tafs through 06z Tuesday night)
issued at 1145 PM CST Monday Dec 9 2013
Light snow will push across Minnesota and WI tonight. It will be fairly
brief...lasting only a few hours...but MVFR and/or IFR conditions
can be expected with the snow. Behind the snow will come gusty
west winds leading to blowing snow...particularly across western and
southern Minnesota late tonight. VFR conditions anticipated for much of
Kmsp...best timing of snow will come between 07-11z. IFR visible
possible at times with the snow...then VFR. Southerly winds will
shift westerly late tonight.
/Outlook for kmsp/
Wednesday...VFR. MVFR and -sn possible Wednesday night. Winds west 5-10kts.
Thursday...VFR. Winds SW 5 kts.
Friday...VFR. MVFR possible. Winds lgt/var.
Minnesota...Winter Weather Advisory until 9 am CST this morning for mnz047-
Wind Chill Advisory until 6 am CST early this morning for
WI...Wind Chill Advisory until 6 am CST early this morning for