Area Forecast Discussion
Issued by NWS Twin Cities, MN
FXUS63 KMPX 161202 AAA
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
702 AM CDT SUN OCT 16 2016
.SHORT TERM...(Today and tonight)
Issued at 345 AM CDT Sun Oct 16 2016
Areas of fog have developed early this morning across eastern MN and
western WI with some locations dropping to 1/4 mile or less. It
appears a bit too patchy for an advisory at this juncture, but will
continue to monitor.
Temperatures have cooled efficiently overnight with readings in the
mid 30s to mid 40s, but the warm and humid air is not far away. The
cold front at 3 am was located from about Storm Lake and Mason City,
Iowa to La Crosse and Wausau, WI. South of the boundary,
temperatures and dew points remain in the upper 50s to mid 60s with
widespread fog. The front will stall this morning and begin lifting
back northwest today as low pressure approaches from the northern
Rockies. Highs are expected to reach the low to mid 70s across
southern Minnesota where the front should easily clear and mid to
upper 60s north of I-94.
A mid level disturbance will pass overhead mid to late evening. Low
level moisture will be increasing throughout the short term while
lapse rates steepen, contributing to MUCAPE values of 1000-2000
J/kg. Showers will develop across eastern Nebraska, western Iowa,
and southeastern South Dakota around 00Z. This activity is expected
to build into thunderstorms as it tracks northeast during the mid to
late evening when it encounters the better lapse rate environment
across central and eastern Minnesota into western Wisconsin. Hi-res
and global models are in rather good agreement with this scenario.
As mentioned in previous discussions, there will be enough shear to
organize the stronger cores and produce hail - some of which may
reach severe levels based on cape/shear parameters. As is the case
with multicell activity, the severe threat with any given cell
should be brief due to interactions with surrounding cells.
The convection should be tied closely to the mid level disturbance
which will push east of the area by 09z. The warm and humid airmass
left behind and the rains from earlier will allow for fog
development. It may be widespread and dense but that is conditional
on the clearing of mid and high level clouds late. Lows tonight will
only fall into the low or mid 60s along and east of I-35, an
impressive 25 to 30 degrees above normal.
.LONG TERM...(Monday through Saturday)
Issued at 345 AM CDT Sun Oct 16 2016
The longer term concerns remain thunder chances Monday into Monday
night and severe weather threat associated with a slow moving
cold front. Following should feature mainly dry and cooler
temepratures until perhaps late in the period moving into next
For Monday...the thunder threat remains as a cool front pushes
southeast about halfway across the region. Models suggest a
surface wave to move northeast along the front into Monday
night...bringing another decent chance for thunderstorms to
eastern MN and western WI. Severe weather threat appears a bit
more conditional...dependent on how much destabilization will
occur. Shear is quite strong...perhaps too strong as 130kt 300 mb
jet lifts northeast across the CWA. SPC DAY2 outlook mentions
marginal risk into WI at least into the evening. Will continue the
likely pop over most of the northern area into Monday evening.
The cool front will work slowly east and south of the area Tuesday.
The upper level flow pattern shifts more northwest through most of
the week...ushering in cooler and drier air. This changes again
into next weekend as the models trend another wave moving across
the northwest pushing another cold front through during that time
frame. May see a brief warmup ahead of the that front but right
now...doesnt appear to rise too much above average.
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 702 AM CDT Sun Oct 16 2016
Dense fog across Wisconsin should dissipate by 15Z with VFR
conditions expected through the rest of the day. Showers and
thunderstorms will develop across MN mid evening and spread into
Wisconsin late evening and early overnight. Heavy rainfall and
some hail are possible with the stronger storms. After the rain,
widespread, potentially dense fog may develop by Monday morning
with light winds and anomalously high amounts of moisture for this
time of year in place.
KMSP...There has been some fog nearby this morning, but not
expecting it to make much of an impact on site. VFR conditions
until the showers and thunderstorms move in between 02-03Z this
evening with IFR or lower conditions expected then for the rest
of the period.
/OUTLOOK FOR KMSP/
Mon...IFR conditions early, then chc MVFR/TSRA in the afternoon.
Wind lgt/var becoming NE 5 kt.
Tue...VFR. Wind W 5-10 kt.
Wed...VFR. Wind NW 5 kt.