Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 230541 AAB

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1241 AM CDT Fri Jun 23 2017

Issued at 1241 AM CDT Fri Jun 23 2017

Update for new 06Z Aviation Discussion below.


.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 Wisconsin.

.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 06Z TAFS through 06Z Friday night)
Issued at 1241 AM CDT Fri Jun 23 2017

The Northland will be impacted by a couple upper level low
pressure systems over the TAF period. We should see largely VFR
conditions overnight, but a weak trough/front moving through early
Friday will bring some MVFR CIG`s to portions of northern and
western TAF sites. These conditions will linger into Friday
evening as well. Some scattered showers will be possible at times.


DLH  52  66  49  63 /  20  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 /  10  20  10  40
ASX  53  69  50  64 /  10  20  10  40




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