Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 262054

Area Forecast Discussion
National Weather Service Duluth MN
354 PM CDT Fri May 26 2017

.SHORT TERM...(This evening through Saturday)
Issued at 354 PM CDT Fri May 26 2017

A surface trof of low pressure was moving into St.Louis county
southwest through Aitkin county at 1920Z. A line of showers and
isolated thunderstorms were occurring along an ahead of this trof.
Followed the 17Z HRRR for timing of this activity through the
forecast area. The HRRR has been doing a reasonable job with this
activity for the last couple of runs. Storms should extend from Ely
to the Twin Ports to Pine City by 22Z/5pm, the Arrowhead to the
Hayward Lakes by 01Z/8pm, and come to an end by 03Z/10pm. The
surface trof will have moved east of the region shortly thereafter,
and with the loss of diurnal heating, no additional precipitation is
expected. After 06Z, look for fog to develop over the eastern two
thirds of the area with light winds and a clearing sky. The fog
should erode by 9am Saturday.

The forecast area will enjoy a break from the rain for most of the
day Saturday. By afternoon, showers are expected to develop in
response to a long wave trof that is progged to be found from
northeast Minnesota southwestward to eastern South Dakota by 00Z
Sunday. The showers will be found primarily from the Borderland
southwest to northern Cass county, with isolated thunderstorms
possible in the late afternoon. Max temps will be in the 60s near
Lake Superior, to the lower 70s inland.

.LONG TERM...(Saturday night through Friday)
Issued at 354 PM CDT Fri May 26 2017

A cutoff upper low will keep partly cloudy skies and occasional rain
chances in the picture Saturday night through midweek.

Scattered showers and isolated thunderstorms should be ongoing in
our western zones Saturday evening associated with an approaching
cool front. Showers will weaken overnight with another round of
showers and storms expected on Sunday. A few strong storms are
possible as NAM/GFS/GEM profiles indicate 1-1.5 kJ/kg of MUCAPE
during the afternoon. The strongest signal for potent thunderstorms
is over northwest Wisconsin, but portions of the Arrowhead may also
see a few strong storms. Most of the deterministic guidance features
a compact and relatively strong vort max and shortwave trough moving
through the Northland Sunday afternoon and evening. The GFS seems to
carry the best signal for strong storms with the vort max rotating
through the area during the late morning through mid-afternoon
timeframe. The GEM is similar, but a little slower and a few miles
farther north while the NAM and ECMWF has a much less defined
feature in the vicinity.

The closed low will wobble southeastward toward northern Lake
Superior Sunday night and Monday. Several vorticity maxima will move
across Minnesota and Wisconsin, and along with continued cold air
advection aloft, should support numerous showers Monday, and a
chance of isolated thunderstorms. A chance of scattered showers will
continue off and on through Wednesday night as the closed low
continues drifting toward New England and gradually fills. High
pressure returns Wednesday night into the weekend.

Temperatures will be near to slightly above normal with highs in the
upper 60s and low 70s and overnight lows in the 40s and upper 30s. A
lake breeze will be present some afternoons limiting temperatures
near Lake Superior.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1255 PM CDT Fri May 26 2017

A trough of surface low pressure was located over central
Minnesota this afternoon with several subtle elevated troughs from
near the surface feature westward into eastern North Dakota. A
robust cumulus field has developed along and behind the surface
trough with the strongest updrafts ahead of each upper-level
trough. Showers and thunderstorms have begun to develop over
northern Minnesota, and additional development southward is
expected through this afternoon. Think the best thunder potential
at the terminals will be limited to a 2-3 hour window as the
surface trough pushes eastward. Winds will veer westerly late this
afternoon or tonight. HYR may experience a brief period of IFR
visibility late tonight and model guidance points to lower
visibility. Models also point to the potential for fog at DLH.
With the scattered nature of the rain this afternoon, and limited
amounts expected, don`t have much faith in visibility
restrictions. Kept the 3SM mist at HYR from earlier shift, but
moved the timing earlier in the night. High clouds drift into the
Northland Saturday morning with primarily VFR conditions expected
during the morning.


DLH  47  70  48  64 /  10  10  30  60
INL  46  71  46  63 /   0  20  30  50
BRD  48  72  49  67 /   0  10  20  40
HYR  48  72  49  68 /  60  10  30  50
ASX  48  71  49  66 /  30  10  30  50




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