Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 261140

Area Forecast Discussion
National Weather Service Duluth MN
640 AM CDT Sat May 26 2018

.SHORT TERM...(Today through Sunday)
Issued at 311 AM CDT Sat May 26 2018

It will be quite the warm weekend for the Northland. There are
some chances of showers and storms, too.

As of early this morning, there was an area of low pressure near
the Manitoba and Ontario border. An associated mid-level trough
was moving through the Northland from the west, and showers and
weak storms were moving east through northern Minnesota.
Otherwise, much of the Northland had mostly clear skies and very
light winds. It was relatively humid, and there was some fog in
the Hayward Lakes region.

The showers and weak storms could continue this morning, primarily
over the MN Arrowhead, as the mid-level trough continues moving
east through the Northland. Most areas, though, will be greeted by
mostly sunny skies this morning.

A mid-level ridge in the High Plains will shift east into the
Great Plains today, and breezy westerly winds will develop across
the Northland. This means another hot and sunny day for the
Northland. Temperatures will push into the middle 80s to near 90
degrees. The areas of low pressure to the north will move into far
northwest Ontario this afternoon, and its trough will extend down
into the Arrowhead. The trough, combined with a lake breeze near
Lake Superior, could provide enough forcing to trigger some
showers and storms over the Arrowhead, and the trough could also
trigger storms in parts of northwest WI. What storms do develop
could be strong with heavy rain and small hail. There will be up
to several hundred J/kg of mixed layer CAPE, 30 to 40 knots of
deep layer wind shear, and precipitable water of 1.25 inches.

Tonight will be clear and nearly calm thanks to high pressure, and
the mid-level ridge will continue moving into the Northland. A
front may stall over northern MN. There will be increasing chances
of showers and storms during the day on the cool side of the front,
but think capping will prevent much activity until Sunday
evening. Highs should be in the upper 80s to lower 90s.

.LONG TERM...(Sunday night through Friday)
Issued at 311 AM CDT Sat May 26 2018

Surface and upper level ridging will cover the forecast area
Sunday night. However, embedded pieces of energy moving through
the weak quasi-zonal flow aloft, will bring an opportunity for
thunderstorms to the region. Thermodynamic profiles suggest the
potential for some strong to near severe storms, especially over
the the northern two thirds of the area. MUCAPE values will be
around 1500 J/kg and steep mid level lapse rates, support a
hail/wind risk. Effective shear is weak however. The same scenario
prevails on Monday, but to a lesser extent as a majority of the
forcing shifts north of the Canadian border. Some storms will be
possible again, but potential for severe is reduced. By Monday
night, storms are expected to become more numerous again as the
ridge is flattened by stronger short wave energy moving across the
forecast area. PWATS will be around 1.5 inches so some heavy rain
is possible with storms. The ridging begins to push east on
Tuesday with the approach of an upper level long wave trof, with
some showers possible. The trof slowly progresses eastward through
Wednesday as it is affected by the remnants of subtropical storm
Alberto. This will keep the southwest flow pumping a warm and
humid airmass into the region. Thunderstorms are possible. The
trof mergers with the remnants of Alberto Wednesday night and
weakens, but not before one more area of vorticity moves through
the region. The trof moves east and is replaced by some ridging.
However, a cold front will move through the area Thursday and
Thursday night with an opportunity for more showers, but ending
from west to east Thursday night. Friday appears to be the only
dry day in the long term with high pressure nearby.


.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 640 AM CDT Sat May 26 2018

A weak surface trof will move slowly past the terminals today.
Ahead of the trof, a scattered to broken deck of clouds at
10-12 kft. Behind the trof, mostly clear skies. Isolated showers
may affect INL by 20Z as the trof passes and it interacts with
upper level energy moving along the international border. Patchy
BR may form again overnight, but closer to the end of the
forecast. INL and HYR are the sites most likely to have BR in the
vicinity. Otherwise, VFR.


DLH  88  56  90  61 /  10   0   0  40
INL  83  55  87  56 /  30   0  10  40
BRD  91  60  91  63 /   0  10  10  30
HYR  91  59  92  65 /  10   0   0  40
ASX  85  49  88  57 /  20  10   0  40




SHORT TERM...Grochocinski
AVIATION...GSF is the U.S. government's official web portal to all federal, state and local government web resources and services.