Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 171220 AAA

Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
720 AM CDT MON OCT 17 2016

.SHORT TERM...(Today and tonight)
Issued at 345 AM CDT Mon Oct 17 2016

Temperatures this morning are rather summerlike with 50s to lower
70s, and even a 73 at Red Wing at 3 am. These readings are a good 20
to 35 degrees above normal, quite impressive. Equally impressive is
how models are overdoing the amount of moisture in the boundary
layer. While there are patches of dense fog and stratus, it hasn`t
been persistent and certainly not as widespread as model fields and
forecast soundings would indicate.

The diffuse front in place will become better defined this afternoon
across northern Iowa into southeastern Minnesota and northern
Wisconsin as low pressure over the central Plains tracks northeast
to the Upper Mississippi Valley. Showers and thunderstorms will form
along the boundary late this afternoon before quickly lifting north
and becoming elevated. There is a narrow window for a few surface-
based storms across south central MN to west central WI if the
boundary layer warms enough to overcome the capping aloft. While
instability is expected to be marginal on a widespread scale,
impressive hodographs could lead to short lived supercells if local
enhanced heating can materialize. Large hail, damaging winds, and a
tornado would be possible with any surface based cell.

By early evening, showers and thunderstorms should be widespread
just north of the boundary and in advance of the low center along
the MN River from Mankato to the Twin Cities and into northern WI.
This activity will exit to the northeast by late evening with the
low passage. Additional showers may form further west with the upper
low across the Dakotas and western MN before weakening as they
rotate eastward across the remainder of the area overnight.

.LONG TERM...(Tuesday through Sunday)
Issued at 345 AM CDT Mon Oct 17 2016

The longer term looks to be a mainly dry period with temperatures
starting out above normal...trending toward slightly below
normal through midweek...and then warming a bit toward the end of
the period. The upper level flow begins to amplify by midweek as
the eastern CONUS trough develops and tries to merge a tropical
system moving through the Bahamas. This may affect timing a bit
into the later half of the period...but ridging develops to the
west and gradually shift east as more troughing energy digs into
the northwest.

Models are trending dry Tuesday with decreasing clouds during the
day. It looks dry then through the remainder of the work
week...although the ECMWF does bring in some light QPF with the
weak short wave around the Wednesday night/Thursday period. The
GFS is not as amplified with this trough and does go through dry.
There remains some model variability to timing of the next short
wave...with the GFS again weaker and dry in the Friday night to
Saturday night period. We will continue that trend for the most
part. Temperatures will rebound into early next week as the ridge
breaks down west and moves into the central CONUS.


.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 720 AM CDT Mon Oct 17 2016

Dense fog has formed across southern and western MN with portions
of northwest WI as well. This fog should improve after 15Z, but
MVFR conditions are likely to continue across eastern MN and
western WI into the evening. Showers and thunderstorms will form
along a boundary and lift northeast, impacting mainly MSP, RNH and
EAU late this afternoon through mid evening. VFR conditions
expected later tonight as drier air moves in.

KMSP...It appears the IFR and lower conditions will surround but not
impact the metro. MVFR conditions are likely to persist into
evening until after the next round of storms early this evening.

Tue...VFR. Wind W 5-10kts.
Wed...VFR. Wind NW 5-10kts.
Thu...VFR. Wind NW 5-10kts.


.MPX Watches/Warnings/Advisories...
MN...Dense Fog Advisory until 9 AM CDT this morning for MNZ049-



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