Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 230450

Area Forecast Discussion
National Weather Service Duluth MN
1150 PM CDT Sat Jul 22 2017

Issued at 1147 PM CDT Sat Jul 22 2017

The strong upper level shortwave was moving across far northeast
Minnesota and will move toward south central Lake Superior by 12Z
then continuing east to southeast Sunday. Showers and a few
thunderstorms continued over north central to far northeast
Minnesota. A strong storm or two will remain possible but that
will become less likely as the night progresses as CAPE continues
to diminish. We kept POPS longer tonight, especially over far
northern Minnesota.

Fog was added to the forecast as well, especially around Lake
Superior where fog and low stratus has developed.


.SHORT TERM...(This evening through Sunday)
Issued at 241 PM CDT Sat Jul 22 2017

This afternoon we are watching the cumulus field over northern
Minnesota very carefully, as the airmass is increasingly unstable
with deep layer shear values approaching 40 knots. We have had
some echoes over Koochiching and Itasca county as some updrafts
have tried to get going, but these have not lasted long and it
seems we may need to wait until the colder temperatures associated
with the potent upper low over southern Manitoba moves a little
closer in the next few hours. Am expecting an active evening over
the forecast area once storms can initiate though, with CAPE
values now approaching 1500j/kg, and only forecast to continue to
increase into the evening hours. Expect initiation sometime in the
next 1-3 hours and our main threat to be large hail and damaging
winds. After the storms move through this evening a cooler and
drier airmass will move in, and expect temperatures to fall into
the 50s nearly everywhere. This cooler airmass will keep us cooler
for Sunday with some lingering showers during the afternoon hours.
Highs on Sunday will only get into the low to mid 70s, with cooler
conditions near Lake Superior.

.LONG TERM...(Sunday night through Saturday)
Issued at 241 PM CDT Sat Jul 22 2017

The early part of the extended period will be affected by another
round of strong to possibly severe thunderstorms. A cold front
will move through the region as a shortwave moves through southern
canada Tuesday morning through early Wednesday morning. Ahead of
the front as indicated by the previous shift, a strong push into
the forecast area of high theta-e values along with an increase in
PWATs. Showers and strong thunderstorms will spread west to east
Tuesday with possible severe storms Tuesday afternoon and evening.
SPC has all of the forecast area in a 15% chance for severe
weather on Tuesday.

After the front passes, high pressure will build into the region
on Wednesday and keep the area rain free through the weekend. The
only chance for any precipitation will be late Sunday as a
shortwave moves through the region. High temperatures will be
near their normals levels in the upper 70s to the lower 80s with
60s along Lake Superior.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1147 PM CDT Sat Jul 22 2017

A strong shortwave was seen on Water Vapor imagery late this evening
move across northeast Minnesota toward Lake Superior. This feature
will move south central Lake Superior by 12Z then continue east
southeast on Sunday. Showers and a few thunderstorms will remain
possible tonight, especially over far northeast Minnesota. Cooler
air will be moving in on northerly low level winds. MVFR and
possibly IFR ceilings will expand across the Northland overnight and
lift during the day Sunday. IFR/LIFR conditions were occurring
around Lake Superior and will continue. KDLH will be a challenge as
much of the guidance suggests the wind will turn to northwest for a
time tonight into Sunday which should allow for higher ceilings and
visibilities to redevelop.


DLH  55  69  51  75 /  40  20   0   0
INL  55  76  53  80 /  40  10   0   0
BRD  59  75  54  78 /  10  10   0   0
HYR  57  70  51  77 /  40  10   0   0
ASX  55  67  50  76 /  50  20   0   0




LONG TERM...Stewart
AVIATION...Melde is the U.S. government's official web portal to all federal, state and local government web resources and services.