Area Forecast Discussion
Issued by NWS Twin Cities, MN
FXUS63 KMPX 232346 AAA
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
646 PM CDT THU JUN 23 2016
.SHORT TERM...(This evening through Friday)
Issued at 402 PM CDT Thu Jun 23 2016
A quiet short term period ahead. Currently, high pressure continues
to build in from the west, with a stubborn stratus deck still parked
over western Wisconsin and extreme eastern Minnesota. Clear skies
are apparent elsewhere. Expecting the skies to generally clear from
tonight from west to east. Did add a mention of patchy fog to the
forecast for mainly western Wisconsin as the surface high comes
through overnight and winds go calm. With this air mass working in,
will continue to keep the heat at bay to our southwest. Lows
overnight will generally fall into the mid and upper 50s.
For Friday, the high will push east of our area and a developing
system to our west will get southerly flow going through the day,
especially across western Minnesota where the gradient becomes
stronger by the afternoon. Warm air advection really gets going in
the afternoon across the area as 850mb temps surge to about +20C by
tomorrow evening. Hence, calling for a much warmer day with temps
topping out in the low to mid 80s and the dew points rising well
into the 60s during the afternoon. No precipitation expected this
.LONG TERM...(Friday night through Thursday)
Issued at 402 PM CDT Thu Jun 23 2016
The main forecast concern remains the potential of a severe weather
outbreak Saturday as similar patterns in the past represent a high
probability of a significant weather including tornadoes,
very large hail and damaging winds.
Overall, the timing of thunderstorm development Saturday afternoon
will be critical in terms of instability and wind shear. Some of the
latest CAMS support thunderstorm initiation between 18-21z west of
the Twin Cities metro area and have them rapidly moving off into
western Wisconsin between 21-00z.
Large scale ascent remains very strong and will be associated with
an upper low forecast to move along the U.S, Canadian (Along the
North Dakota border) Saturday. Both the 50/25H Jets intensify
Saturday afternoon and evening across the Dakotas and into western
Minnesota. There remains uncertainty on morning convection and
instability recovery in the afternoon ahead of the cold front.
However, looking at the June 17, 2010 outbreak in Minnesota, the
morning sounding did not have ample instability, and it was the low
level shear that dominated the outbreak by the late afternoon.
Actually the latest run (CIPS) has a much better atmosphere (12Z
June 25, 2016) in terms of instability and lapse rates compared to
June 17, 2010. There is no question that supercell thunderstorms
will develop across Minnesota/Wisconsin Saturday afternoon and
evening. The main question is whether it will be tornadic supercells
or a realm of other significant severe weather including damaging
straight line winds and/or very large hail. Persons who have outdoor
activities or any activity involving large number of individuals
need to pay attention on how the weather parameters evolve.
By late Saturday night, the mean upper level wind pattern will
become northwest, which leads to cooler and drier weather for next
week. There should be several days of rain-free conditions as this
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 646 PM CDT Thu Jun 23 2016
VFR conditions and light winds are expected tonight. There is an
outside chance for some fog across western Wisconsin late tonight,
which will be monitored for the next taf issuance.
/OUTLOOK FOR KMSP/
SAT...Chc MVFR TSRA in mrng. TSRA likely aftn/evening. Winds S-SW
SUN...VFR. Chance MVFR. Winds W 10-20kts.
MON...VFR. Winds NW 10-15 kts.