Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 222336

Area Forecast Discussion
National Weather Service Duluth MN
636 PM CDT Thu Jun 22 2017

.SHORT TERM...(This evening through Friday)
Issued at 313 PM CDT Thu Jun 22 2017

An upper level low was over the Manitoba Lakes region this afternoon
and is forecast to move southeast through northwest Ontario toward
northeast Minnesota overnight. The low will open up as it progresses
southeast through the day Friday. The rain over northwest Wisconsin
will diminish through the evening as the frontal boundary sags south
and FGEN decreases. More showers are possible over portions of
northern Minnesota late this afternoon into the overnight period.
The HRRR has been consistent for the last several runs developing an
area of showers over western Minnesota then moving them east and
north through the evening. Area radars have yet to show any
appreciable echoes there but visible satellite imagery does show
a growing cumulus field. We will have a chance for showers into
the evening over parts of northeast Minnesota then over far
northern Minnesota through the overnight period as the low moves
southeast. Cold air advection will continue overnight and lows are
expected from the upper forties to lower fifties.

A chance for showers and perhaps an afternoon thunderstorm will
continue Friday across much of the Northland due to a weak shortwave
and enough instability present from the colder air moving in.  Highs
will be below normal, ranging from the lower to middle sixties along
the International Border to the mid to upper sixties over northwest

.LONG TERM...(Friday night through Thursday)
Issued at 313 PM CDT Thu Jun 22 2017

The extended forecast continues to feature weekend chances of
showers and thunderstorms, along with some below seasonal
temperatures Saturday through Monday.

The extended period begins with a cut-off upper-level low advancing
southeast towards the Northland. An associated mid-level shortwave
trough, with a concentrated maxima of positive vorticity advection
will translate just across our southwest. The models have come into
better agreement with the position of this mid-level trough compared
to yesterday`s corresponding runs. Despite the main trough diving
south of the area, a corridor of better mid-level isentropic lift
and 850-700 mb Q-vector convergence is progged on the northern
periphery of the trough. Chances of thunderstorms will mainly be in
the afternoon and early evening since that will be when the better
instability will be in place. MLCAPE values of up to 500 J/kg will
be possible when the low-level lapse rates steepen, thanks to low-
level diabatic heating. No severe weather is expected as the
instability and deep layer shear just looks too low to support any
substantial threat. A lingering secondary shortwave will continue
chances of showers into Sunday, with another round of thunderstorms
possible for Sunday afternoon. The best chances of storms will be
over northwest Wisconsin, where the better instability should be in
place. Again, no severe weather is expected. Due to this trough
pattern and persistent northwesterly flow over the region, cooler
air advection will take control. This will lower temperatures mainly
from Saturday through Monday, with highs in the lower to mid 60s.
Temperatures will start to increase Monday and Tuesday as winds turn
more southerly.

A mid-level ridge will develop Monday morning into early Tuesday
over the Great Plains region, which should bring mostly dry and
warmer conditions. This should bring some light winds and mostly
clear skies, so it could be a pretty chilly morning on Monday,
perhaps even better radiational cooling for Tuesday morning. Did
lower the temperatures for Tuesday below the consensus blends a bit
to better correspond to this radiative cooling, with lows into the
lower to mid 40s both mornings.

More showers will ramp up again Tuesday night into Wednesday morning
as a region of upper-level divergence develops out of the
Intermountain West. The GFS is showing some stronger lift in the mid-
levels as well, so some good forcing could be in place for some
showers and thunderstorms through the day Wednesday. It`s possible
that this will bring the best chance of strong thunderstorms, as
instability looks to be much higher, but it`s still too far to
really nail down a solution, especially when the magnitude and
placement of the axis of instability varies between the
GFS/CMC/ECMWF models. Showers and storms could continue into
Thursday as another potent shortwave moves in closely behind the
Wednesday morning system.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 633 PM CDT Thu Jun 22 2017

A weak disturbance will move across the Northland this evening,
generating some isolated showers and possibly even a thunderstorm.
The best chance will be in the northern TAF sites. Another front
will drop southeastward out of Canada late tonight and on Friday.
This front will bring cooler and more moist air, which will result
in areas of MVFR CIG, especially north. KDLH and KHYR should
generally remain VFR throughout the period.


DLH  52  66  49  63 /  10  20  10  40
INL  50  62  48  60 /  30  40  40  50
BRD  53  65  47  64 /  10  10   0  30
HYR  52  69  49  64 /  20  20  10  40
ASX  53  69  50  64 /  10  20  10  40




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