Area Forecast Discussion
Issued by NWS Twin Cities, MN

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FXUS63 KMPX 160354

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1054 PM CDT SAT OCT 15 2016

Issued at 1054 PM CDT Sat Oct 15 2016

Updated to include 06Z aviation discussion below.


.SHORT TERM...(This evening through Sunday)
Issued at 300 PM CDT Sat Oct 15 2016

Early afternoon IR imagery together with RAP13 and surface obs
showed a cold front across the region, which was most noticeable by
the wind direction and dewpoint. The low 60 dewpoints ahead of the
boundary together together with surface temps near 70s was able to
produce a few hundred J/kg of MUCAPE across southeast MN. HiRes
models show convection developing this afternoon along the
instability axis, but this will be well south and east of the
forecast area so continued with a dry forecast.

Areas of fog are possible tonight in western WI and southeast MN, so
continue with that in the forecast. On Sunday high pressure will
move across the region with southerly return flow developing from
west to east across the region. This will lift today`s boundary back
to the north as a warm front which will set the stage for some
showers and thunderstorms, but those should hold off until after 00Z
so continued with a dry forecast through Sunday evening.

.LONG TERM...(Sunday night through Saturday)
Issued at 300 PM CDT Sat Oct 15 2016

The long term features several chances for showers and thunderstorms
into Tuesday with dry and cooler weather thereafter.

Scattered showers and thunderstorms will develop along and ahead
of a warm front Sunday night moving northeast across the FA.
The best chances (likely) are across central and eastern MN and
western WI. Everything remains in place for a few strong to severe
storms with large hail. Impressive winds aloft with the left exit
region of a 100+ knot jet moving in, H5 winds 50+ knots from the
WSW while H85 winds are S at 45 knots. MUCAPE values approach
2000 J/KG across the eastern FA Sunday night. CWASP values are
also better than 80 percent from the Twin Cities on north and
east. SPC also updated their day2 outlook today to include a
marginal risk. Most of the CAMS don`t quite cover the period of
interest at this point. However, the NMM WRF, which goes through
Sunday night, does show some cells developing around the Twin
Cities and west central WI in the 00z-03z time frame. Also, based
on the precipitation signal from both the EC and GFS, expanded the
likely pops further west and south across the Twin Cities for
Sunday night. Rain amounts could be locally heavy, especially in
western WI, Sunday night as PWAT values close in on 1.5 inches.
This is well above the MPX sounding climatology for this time of
year with max moving average around 1.3 inches.

On Monday, the threat for showers and thunderstorms linger as a
weak cool front pushes halfway across the FA. A surface wave is
then expected to move northeast along the front Monday night,
bringing more scattered showers and thunderstorms to eastern MN
and western WI. Once again, stretched likely pops out more across
east MN based on the precipitation signal.

The cool front will work slowly east and south of the area on
Tuesday. The flow pattern aloft will begin to change to one that
is more northerly, ushering in cooler and dry weather for the
remainder of the long term.

Temperatures will be quite mild during the early part of the long
term. Lows Sunday night will be in the lower 60s across eastern MN
and western WI, which is a little above the normal high for this
time of year. It looks like another day in the 70s across eastern
and southern MN and western WI on Monday. Highs and lows will
begin to decline heading into the latter half of the week with
highs more in the 50 to 55 degree range along with lows in the


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1054 PM CDT Sat Oct 15 2016

Thinking remains similar to earlier forecast and discussion, but
forecast now extends out into time period when we should see some
MVFR and possible IFR conditions along with chances for SHRA/TSRA.
LAMP guidance is already somewhat bullish on lower ceilings moving
into the area Sunday late evening and overnight, and forecast
soundings from the NAM are suggestive as well. Didn`t go as low as
some guidance at this point, but hinted at things, particularly
after 04Z or 05Z.

KMSP...Main concern is still chances for SHRA/TSRA Sunday night,
along with some ceilings AOB 1700 ft AGL with visibility
restrictions due to both precipitation and some fog.

Monday...MVFR possible late with a chance of showers and
thunderstorms. Variable wind 10 kt or less becoming southeast.
Monday Night...MVFR expected, IFR possible with showers and
thunderstorms likely. Southeast wind 10 kt or less becoming
northwest 10 to 20 kt.
Tuesday...VFR. Northwest wind 10 to 20 kt becoming west.
Tuesday Night...VFR. West wind 5 to 10 kt.
Wednesday...VFR. Southwest wind 5 to 10 kt becoming northwest.


.MPX Watches/Warnings/Advisories...


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