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Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota
247 PM CST Thursday Nov 26 2015

Short term...(this evening through friday)
issued at 245 PM CST Thursday Nov 26 2015

Snow continues to taper off from the west...and given current radar
and hi-res model will likely dissipate earlier than
previously thought. Therefore...have tapered off probability of precipitation considerably
this evening across southern Minnesota and west central WI. As the slow-
moving front currently stretching through Iowa and Wisconsin and
associated forcing continues to slide eastward...any remaining light
snow will end in west central WI by late tonight and dry conditions
will persist through Saturday.

Despite the snow exiting our area...most models are showing ample
moisture persisting at lower levels over most of our area
overnight...generally over 90 percent relative humidity at 925 mb across Minnesota and
west central WI. Bumped up cloud cover across western counties to
account for the forecast increase in low clouds. Despite a decent
amount of cloud cover...continued cold advection will bring lows
down into the teens in Minnesota and low 20s in west central WI tonight. As
northerly flow continues to advect colder air into our
region...expect one of the coldest days so far this season on Friday
with highs only in the middle-upper 20s.

Long term...(friday night through thursday)
issued at 245 PM CST Thursday Nov 26 2015

The only significant weather event in the next 7 days will occur
early next week as a storm system moves out of The Rockies and
into the plains/upper Midwest. Overall the mean pattern will
remain unsettled with very mild temperatures for late November
and early December continuing.

First...not too many changes for the weekend as temperatures drop into the
teens and 20s...and highs bounce back into the 30s. It may be a
little cooler where the heavier snow fell today before some
melting begins.

Interesting setup early next week as the upper low that has plagued
The Rockies over the past few days...slowly moves out into the
plains/upper Midwest. Timing is still uncertain based on little
forcing to eject the upper low out into the plains.
Therefore...timing of when the snow develops maybe offset by 12-24

The mean pattern over the past month has allowed for the very mild
conds to continue across a large part of North America. This pattern
is not changing much...with the exception of the upper low /an area
of colder temperatures aloft/ allowing for a relatively long term
/24-36 hours/ of light snow developing Monday/Tuesday. Models have
been fairly consistent on this upper low moving out into the
plains...and propagating slowly from Nebraska through the southern
Great Lakes region until a stronger storm system begins to push this
system across the NE Continental U.S. Late in the week. Again...timing and the
exact location of this upper low and associated upper jet dynamics
will lead to some uncertainties of snowfall timing and amts. The
best bit is increase to likely probability of precipitation for Tuesday. Amts will be
dependent on the jet structure and warm air advection regime. Precipitable water values are not
as high with this system then with light amts is the
best scenario.

Another interesting setup is the abnormally mild conds expected
north of the Canadian border based on the mean zonal flow and not
much tapping of the Arctic air masses. This again is typical for an
El Nino pattern with the coldest conds in the southern Continental U.S.. even
the NCEP cfs ensemble means from the last 4 runs... still has a long
period of very mild air...with all the highs/lows above the average
mean temperatures. This will play havoc on precipitation type in the future
..especially considering the mild temperatures and higher precipitable waters values
based on a more southern jet stream regime. Welcome to the upper


Aviation...(for the 18z tafs through 18z friday)
issued at 1233 PM CST Thursday Nov 26 2015

Mixed precipitation has pretty much changed to snow except in our
southeast area from Keau to kael...but this area should also
transition in the next couple of hours as colder air filters in
with north-northwest winds. Swath of precipitation from Nebraska into south central
Minnesota and west central wisc. West central wisc will be the last to
end precipitation...but swath has been shifting southeast a it looks
like the heaviest will end at Keau around 00z with maybe some
lighter precipitation lingering into the evening.

Other issue is MVFR ceilings in northern Minnesota into Manitoba and
northwest Ontario. The more extensive MVFR ceilings are over most
of north central and northestern Minnesota into Ontario. With the north-northwest wind...
these are likely to move into much of central and east central Minnesota
and there is a fairly high confidence in this. Less
certain is west central into SW Minnesota...since there is more of a
patchwork of MVFR ceilings at this time...and short term models
suggest this patchwork continuing into western Minnesota. Therefore have
scattered/broken at kaxn and krwf.

Kmsp...snow with IFR visibilities will soon taper off around
19z...improving to MVFR visibility for a couple hours and then
ending. MVFR ceilings will likely remain through much of the
night... with one possible break to VFR. It is possible the MVFR
may scatter out briefly late this afternoon per current
observations in central and east central Minnesota north of the snow. But
more MVFR ceilings are on their way southward from northeastern
Minnesota and Ontario. So any scattering out will likely be short-lived
late this afternoon or early evening. The question will then
be how long the MVFR ceilings last. Short term models suggest until
at least 06z...but based on current trends on satellite...will
not be surprised if it takes 09z-12z before we see all VFR.

/Outlook for kmsp/
Friday night...VFR. Winds north-northwest 5-10 kts.
Sat...VFR. Winds SW 5-10 kts.
Sun...VFR. Winds light and vrb.
Monday...chance of MVFR in snow. Winds east 5-10 kts.


Mpx watches/warnings/advisories...
WI...Winter Weather Advisory until 9 PM CST this evening for

Minnesota...Winter Weather Advisory until 9 PM CST this evening for mnz077-



Short term...additional
long term...jlt

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