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fxus63 kmpx 190056 
afdmpx

Area forecast discussion
National Weather Service Twin Cities/Chanhassen Minnesota
656 PM CST Mon Nov 18 2019

Updated for 00z aviation discussion...
issued at 651 PM CST Mon Nov 18 2019

&&

Short term...(this evening through Tuesday night)
issued at 352 PM CST Mon Nov 18 2019

Surface analysis this afternoon shows a low pressure center near
the South Dakota/ND/MN triple-point with a trailing north-south frontal
boundary sweeping eastward from the northern plains into the upper
Mississippi River valley region. Aloft, solid northwest flow will
continue although there is no solid tap to Arctic air from the
north so the northwest flow is bringing in modified Pacific
Canadian air rather than significantly cold Arctic air over the
next 24-36 hours.

The surface low will move eastward across far southern Minnesota through
this evening and into central WI by midday tomorrow before
dissipating over the Ohio Valley Tuesday night. Kmpx radar is
already showing precipitation moving over southwestern Minnesota this
afternoon with the expectation that the light precipitation shield
will steadily shift eastward across the entire weather forecast office mpx coverage
area overnight through daybreak Tuesday morning. Not looking for
much in the way of quantitative precipitation forecast at all, generally around a tenth of an inch
or less. There is some question as to the precip type, mainly
north of the I-94 corridor tonight. The coldest air will reside in
that aforementioned portion of the coverage area, so that's where
the highest chances are for having precipitation change from rain
to snow overnight. Any snow accumulations will be light, a trace
to less than an inch.

As the system moves away during the day tomorrow, precipitation
will steadily end from west to east, with no precipitation
expected beyond noon. Clouds will remain in place throughout the
day but there will be little temperature change tomorrow from what
the area experienced today. Highs will again range from the mid
30s to the upper 40s.

Long term...(wednesday through monday)
issued at 352 PM CST Mon Nov 18 2019

The only item of concern in the longer term is the system that
will impact the region Wednesday into Thursday. Deterministic
solutions have come into good agreement on the overall progression
of this system with respect to both timing and location. However,
there remains some spread in the ensemble guidance, and the
northwest side of the system's impact appears to be where there is
the greatest amount of spread. This mean's that although the pops
forecast is fairly certain, there is some uncertainty over the
northwest/north portion of the area, which is still a bit
problematic given that that is where there is a greater chance of
seeing precipitation fall as snow for most of the event. The upper
low off the southwest coast will be the main impetus for the
surface low moving by to our southeast, but the northern stream
will have an impact on the location of the baroclinic zone, the
upper divergence pattern, and how long precipitation lingers over
the area as cold air works into the region. Feel there is still
plenty of room for the guidance to shift given the complexity of
the pattern and various degrees to which shortwave energy may
phase, so the ensemble uncertainty that is still suggested seems
warranted. With that in mind, did not make any substantial changes
to the consensus nbm forecast, other than some pop and quantitative precipitation forecast
adjustments where the best agreement is across the southern and
eastern portion of the area.

All of that being said, we should see primarily rain work into
and/or develop over the area late Wednesday afternoon and
Wednesday evening, then expand in coverage and intensity
overnight through Thursday morning. A transition from rain to snow
should occur from northwest to southeast during that same time
period, so it is still a bit difficult to have high confidence in
snowfall amounts given that the changeover could occur while
decent precipitation is still occurring. However, given the mild
conditions and rainfall prior to any snow, it still does not
appear that significant accumulations will occur. The better
chance for anything plowable would be north and northwest of the
Twin Cities. The only cam guidance currently covering the period
(hopaheadwrf), would suggest around an inch in the Metro, but
upwards of 5 or 6 inches near Alexandria. Needless to say, it will
be something to keep an eye on over the next two days as the
initial conditions and upstream development can be better sampled,
and as additional high resolution guidance is available. After
the Wednesday/Thursday system, things appear quiet with near
normal temperatures and little if any precipitation as a few weak
frontal boundaries traverse the region.

&&

Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 651 PM CST Mon Nov 18 2019

MVFR/IFR conditions with light winds as a weak system moves across
the region and brings low clouds with some drizzle or rain
overnight. Conditions should improve later on Tuesday as drier
air moves across the region during the afternoon.

Kmsp...

MVFR/IFR conditions with light winds as a weak system moves across
the region and brings low clouds with some drizzle or rain
overnight. Conditions should improve later on Tuesday as drier
air moves across the region during the afternoon.

/Outlook for kmsp/
Wed...MVFR/IFR ceilings with -ra late. Wind southeast 5-10 kts.
Thu...MVFR/IFR likely. Chc -sn early. Wind northwest 10-20 kts.
Fri...VFR. Wind northwest 5 kts becoming SW.

&&

Mpx watches/warnings/advisories...
WI...none.
Minnesota...none.
&&

$$

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