Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 142024

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
224 PM CST Wed Feb 14 2018

.SHORT TERM...(This evening through Thursday)
Issued at 224 PM CST Wed Feb 14 2018

Tonight through Thursday we will see a cold front currently near
the international border sag south through the area with little
fanfare. Some post-frontal snow over northern Minnesota later
tonight looks to mostly dry up on Thursday as better forcing
shifts eastward, with just a low chance of some light snow across
the area late tomorrow afternoon into the evening in association
with a weak shortwave trough that will move east from South

.LONG TERM...(Thursday night through Wednesday)
Issued at 224 PM CST Wed Feb 14 2018

In the longer term the main story will be a significant change in
the large scale flow pattern across the continent, with fairly
zonal flow becoming much more amplified as an upper trough sets up
across the west and ridging takes hold over the east. This will
put us in between, which should make for a much more active
weather pattern from the latter half of the weekend into the first
half of next week. The guidance is in good agreement on the large
scale pattern change, but as would be expected there is quite a
bit of disagreement on the details. At this point a consensus
approach is the safest course of action, which still points toward
increasing chances of precipitation (most likely snow) from Sunday
into Tuesday.

Prior to the more active period of weather, things will be pretty
quiet across the area. High pressure and a return of colder
temperatures will settle in over the area Thursday night and
Friday. By Friday night we will start to get into return flow on
the backside of the high before we see a fairly weak cold front
push east across the area early Saturday. We could see a few
snowflakes as it moves through, but nothing of note is expected.
Weak high pressure will then be in control into Saturday night
before things start to become more interesting. We should see
precipitation develop somewhere in the region late Saturday night
and Sunday as a shortwave trough moves east along the baroclinic
zone. There is significant disagreement between the GFS and ECMWF
with respect to this on Sunday, with the GFS indicating decent
isentropic ascent and frontogenesis over our area on Sunday, while
the ECMWF is well to the north. The Canadian and MPAS are more
similar to the GFS, but the GEFS exhibits significant spread. Will
certainly increase PoPs for Sunday, but it`s far too early to put
too much stock in the deterministic GFS solution. There is
actually a bit more agreement for late Sunday night through
Tuesday as we see a surface low develop over the southern Plains
and move northeast toward the lower Great Lakes. Will have fairly
high PoPs for that time frame given how far into the forecast
period it is. It`s far too early to start guessing at snowfall
amounts from Sunday through Tuesday, but it certainly looks like a
few rounds of accumulating snow will occur in the area. It will be
something to watch over the remainder of the week.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1115 AM CST Wed Feb 14 2018

No aviation concerns through this evening as south/southwest wind
will become more west/west-southwest this evening. After 06z,
conditions will begin to deteriorate from central Minnesota by
9-12z, and across southern/east central Minnesota and west central
Wisconsin by 12-18Z. Light snow is possible as cigs lower to
MVFR, or possibly IFR at times, but restrictions with the snow
will be 5SM or greater.


May concern this afternoon is the potential higher wind speed
around 10 kts from the southwest, or a direct crosswind. Between
15-18z, conditions will begin to deteriorate with MVFR cigs
likely along with -SN. Winds will shift to the west overnight, and
to the northwest by morning. Gusty winds of 18-22kts are likely
by Thursday afternoon from the northwest.


Fri...VFR. Winds W 5-10 kts, bcmg SW.
Sat...VFR. Chc -SN/MVFR in mrng. Winds SW bcmg W 10G20 kts.
Sun...MVFR, possibly IFR in SN. Winds S bcmg SW 10-15kts.





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