Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
423 am CST Monday Mar 2 2015
Short term...(today and tonight)
issued at 351 am CST Monday Mar 2 2015
High pressure centered over northeast Missouri will continue sliding
southeast today. Middle level ridging is building across the Southern
Plains which is allowing moisture from the southwest to advect north
northeastward into the central rockies. This moisture will reach the
northern plains this evening.
Today is looking good. Other than an increase in middle level clouds
and strengthening winds across western Minnesota this afternoon...nothing
of particular significance is expected.
The Arctic cold front will surge southeast into the western Dakotas
by midnight. Energy from the southwest will reach Colorado this
evening and spawn an area of low pressure along the Kansas/NE border.
The middle level energy will begin to shear as the trough approaches
from the northwest and send a band of frontogenesis/vorticity
northeast into central and northeastern Minnesota. Increasing
moisture...in addition to being properly positioned near the left
exit region of the upper jet should produce a rapidly developing
band of moderate to heavy snow across the northwest County Warning Area around
midnight. All hi-res models seem to latch onto this idea well and
the GFS is also showing it...representing the global models. Think
snowfall rates of 1-2 inches per hour are possible in this band. The
rest of the area should be mostly dry into the late overnight hours
until the system itself approaches and lift becomes more widespread.
Then the main snow shield will develop across eastern Minnesota and western
WI...likely after 09z.
Decided to issue an advisory for the area impacted with the band
tonight as the wind and resultant blizzard conditions are
sufficiently displaced in time.
Long term...(tuesday through sunday)
issued at 351 am CST Monday Mar 2 2015
The long term concern remains headlines for Tuesday and Tuesday
Snow should be ongoing across most of the County Warning Area around 12z Tuesday. The
cold front will be near the Minnesota/Dakotas border as well. The
front advances east into east central Minnesota through about 18z and
exits to the east in the afternoon. The models have trended a bit
farther north in the track of the weaker surface low. Development
of the upper wave has brings the strong 165kt 250mb jet over the
area into Tuesday. This should generate some stronger
frontogentical forcing as the upper trough moves east Tuesday
morning. It may be a good 6 hour snow event for mainly the northern
2/3rds of the area in the morning. Snow totals of 3-5 inches look
good in this area with 2 to 3 inches over far south central Minnesota. The
pressure rise center develops over the Dakotas and is driven
southeastward over southwest Minnesota and Iowa through the late morning
and afternoon. This should be enough to generate the strong winds
over this area during the day. BUFKIT still is showing winds around
43 kts at the top of The Channel during the afternoon in the
southwest County Warning Area. This should be good enough for some 45 miles per hour wind
gusts as this rise center moves through. The wind combined with the
2-5 inches of fresh snow forecast across this area will generate
blizzard conditions...therefore the blizzard watch has been
converted to a warning at 12z in west central Minnesota...and into the
remainder of the watch area including all of south central Minnesota after
15z Tuesday. The remainder of the County Warning Area is under the Winter Weather
Advisory...and will end the headlines around 03z Wednesday.
After this system moves through...cold high pressure dominates the
weather into Thursday. Wind chills will become a concern once again
over the area later Tuesday night and possibly again Wednesday night
if the winds dont die off fast enough. Below zero air temperatures
are forecast both morning...with the coldest being Wednesday
night/Thursday morning...close to the retreating surface ridge.
The warming trend still looks to be on tap for the remainder of the
week into next weekend as the upper flow becomes less
amplified...and more westerly. Temperatures are expected to trend
closer to normal through the end of the period.
Aviation...(for the 06z tafs through 06z Monday night)
issued at 1110 PM CST sun Mar 1 2015
After this small pocket of MVFR ceilings diminishes...we expect
VFR through the remainder of the morning and afternoon. Snow moves
in after the taf period.
VFR is expected through the morning commute. We slowed down the
wind shift through the morning and kept more of a westerly
component longer...before eventually going south. Snow moves in
late tonight. The Tuesday morning commute could be a rough one.
/Outlook for kmsp/
Tuesday...MVFR/IFR snow likely and blsn possible. Winds S 10kts
becoming northwest 20g30kts.
Wednesday...VFR. Winds northwest 15g20kts.
Minnesota...Blizzard Warning from 9 am to 9 PM CST Tuesday for mnz057-058-
Winter Weather Advisory from 11 PM this evening to 9 PM CST
Tuesday for mnz041>044-049-050.
Winter Weather Advisory from 3 am to 9 PM CST Tuesday for mnz045-
Winter Weather Advisory from 11 PM this evening to 6 am CST
Tuesday for mnz047-048-054>056-064.
Blizzard Warning from 6 am to 9 PM CST Tuesday for mnz047-048-
Winter Weather Advisory from 11 PM this evening to 9 am CST
Tuesday for mnz057.
WI...Winter Weather Advisory from 3 am to 9 PM CST Tuesday for