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Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota
559 am CST Monday Nov 30 2015

Short term...(today and tonight)
issued at 432 am CST Monday Nov 30 2015

The first issue this morning is an initial area of precipitation
advancing north up the 1-35 corridor and extending east into western
Wisconsin. This initial band of precipitation has been producing a
wintry mix overnight...but mostly sleet until about 3am when it
began turning to mostly snow. A few sites have seen decent snowfall
rates with this band...which is tracking to sideswipe the eastern
half of the Twin Cities metropolitan during the morning rush hour. Could
see a quick half an inch to an inch out of this before we see a lull
in precipitation for much of the late morning into early afternoon
for the metropolitan area. As this band of precipitation moves north of the
metropolitan...the hrrr/rap agree what it will quickly weaken and diminish
completely later this morning.

Deep upper low this morning over Wyoming in what is really a ridge
across most of the continent. The upper low will advance east during
the day and a more defined area of low pressure at the surface will
quickly advance north through eastern Kansas and Nebraska into Iowa
by this evening. As the upper low progresses will deepen
this afternoon and tonight...and occlude tonight as it enters
southern Minnesota. This will cause the system to slow down quite a
bit setting the stage for a long duration precipitation event for
the upper Midwest.

Only slight tweaks to the previous forecast were made...mainly in
terms of timing of the event. Slowed down the onset of the
precipitation as hi-res guidance consensus agreed the precipitation shield
will arrive just a few hours later than previously thought. At this area of precipitation along the southern portion of the NE/Iowa
border will advance north and continue expanding...reaching
southwestern Minnesota by about noon. So...after this initial band of
precipitation in eastern Minnesota/western WI GOES through early this
morning...the remainder of the morning will be generally dry. The
best forcing associated with the pv boot lifting north through Iowa
will reach southern Minnesota around noon and continue advancing north
through the afternoon. The hi-res cams indicate a healthy band of
snow will move north through southern Minnesota into central Minnesota by
6pm...including the Twin Cities metropolitan in the 3-6pm time
frame...which will likely have a big impact on the afternoon
commute. In terms of Road conditions though...temperatures will be
in the low 30s so the major roadways may be in decent shape until
the heavy snow rates arrive.

After the late afternoon/early evening band pushes through...more
modest snowfall rates will follow for much of the evening hours with
another heavier snow band looking likely around midnight closer to
the northern edge of the surface low. The surface low will lift
north into west central Minnesota during the overnight hours with the main
deformation band of snow on its northwestern flank. So...the
surface low track is generally the same from previous
forecasts...with far western Minnesota and into eastern South Dakota
looking to be the most likely areas to see 6-12" of snow. Farther
east...including the Twin Cities metropolitan...the middle level dry air will
advance north with the surface low during the overnight hours which
will really taper the snow by 6am Tuesday morning as the occluded
front lifts north through the area. Still expect light snow to
linger after this occurs but the best rates will have moved on.
While we will see on and off snow for 24-30 hours with this system
in the metropolitan...our best window for accumulation will be from about
3pm today to about 3am tomorrow morning.

In terms of the latest snowfall amounts...went with a slightly lower
snow to liquid ratio given fairly warm surface temperatures and best
Omega not lining up as well with the dendritic growth zone. While
the quantitative precipitation forecast forecast remained very consistent...the lower ratios
produced a snowfall forecast that is just slightly lower than the
previous. Generally expect 4-7" in the metropolitan and much of eastern
Minnesota...while western WI is slightly less generally 2-5" thanks in
large part to mixed precipitation...especially toward Eau Claire and
Chippewa counties. In western Minnesota...kept the warning in place as 6-
10" still looks likely over the long duration of the event. The
Winter Storm Watch that had been in effect has been upgraded to a
Winter Weather Advisory for that area with expected totals in the 4-
7" range and even though some spots may exceed 6" will take 18-
24 hours to reach those the advisory was preferred over
a warning.

Long term...(tuesday through sunday)
issued at 432 am CST Monday Nov 30 2015

Things will quickly become benign weatherwise as we move beyond
Tuesday. We/ll still be contending with some of the affects of the
winter storm Tuesday into Tuesday night as the surface and upper
lows slowly move east northeast. The primary area of lingering
snowfall Tuesday into Tuesday night will be along the northern
periphery of the upper low across the northern portion of the
forecast area where a few more inches could occur. Middle-level dry
air looks to push across the southeast and eastern portion of the
area Tuesday into Tuesday night... which could lead to areas of
freezing drizzle and/or drizzle as we lose ice crystals aloft. Any
lingering precipitation should come to an end overnight Tuesday night. We
will then see heights build as upper level ridging works its way
into the central Continental U.S. Over the remainder of the week. This will
be accompanied by a sprawling area of Pacific high pressure...
bringing seasonably mild temperatures and dry weather through the
remainder of the forecast period.


Aviation...(for the 12z tafs through 12z Tuesday morning)
issued at 555 am CST Monday Nov 30 2015

Well advertised precipitation event upon US for this period...a very
active one right out of The Gate for eastern Minnesota and western WI. An
initail band of snow will continue to impact msp and rnh through
the next couple hours this morning before the primary precipitation
sheild arrives middle to late afternoon for most taf sites and visibilities
quickly drop to IFR or LIFR. Ceilings will fall too LIFR or IFR as
well and stay there through the remainder of the forecast period.
Persistent easterly winds expected through the period as the
surface low works into southwestern Minnesota by tomorrow morning.

Kmsp...ongoing snow this morning will last through about 15z.
Could be a lull during the middle of the day for a few hours but
wont be surprised to see some light snow fill in ahead of the main
precipitation sheild. The afternoon rush today will be accompanied by
periods of heavy snow.

/Outlook for kmsp/
Tuesday...MVFR/IFR in -sn. Poss VFR late. Winds NE becoming northwest 5-10 kts.
Wednesday...VFR. Winds northwest around 10 kts.
Thursday...VFR. Winds SW 5-10 kts.


Mpx watches/warnings/advisories...
WI...Winter Weather Advisory until midnight CST Tuesday night for

Minnesota...Winter Storm Warning until midnight CST Tuesday night for mnz047-

Winter Weather Advisory until midnight CST Tuesday night for



Short term...speed
long term...

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