Area Forecast Discussion
Issued by NWS Duluth, MN

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KDLH 180543 AAB

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1243 AM CDT TUE OCT 18 2016

Issued at 1231 AM CDT Tue Oct 18 2016

Please see the new 06Z Aviation Discussion below.

UPDATE Issued at 640 PM CDT Mon Oct 17 2016

Low pressure was centered in the southeast Minnesota and west
central Wisconsin area with a frontal boundary snaking its way
southwest and northeast out of the low. Strong low level FGEN was
aiding in the showers/storms that have been moving through
portions of east central Minnesota into northern Wisconsin. The
stronger FGEN forcing will continue another hour or two then is
forecast to weaken and shift south. Showers and storms will
continue throughout the evening, gradually diminishing overnight.
A strong to severe storm is still possible this evening over
mainly Price/southeast Sawyer counties. In addition to the severe
threat will be heavy rain as the storms continue to train over the
same area. Further north, mid level FGEN was causing rain to fall
southeast North Dakota east northeast into parts of far northern
Minnesota. Most of the guidance shows this rain continuing then
diminishing overnight.

Areas of fog, some dense, will continue around Lake Superior with
some improvement overnight as winds turn northwest then west.


.SHORT TERM...(This evening through Tuesday)
Issued at 302 PM CDT Mon Oct 17 2016

Summary: The far southeastern forecast area, across parts of Pine
County, still has the potential for severe weather later this
afternoon and into this evening when an area of low pressure lifts
into northern Wisconsin. The models generally lift the low across
far southern Price County, or just to its south, putting those
areas within range of the storms that will likely develop along
and just north of the baroclinic zone that the low will be
following. Other parts of northwest Wisconsin could get some
storms, too, while light rain is likely over parts of northeast
Minnesota. Cooler weather will settle into the region tonight and

As of 3 pm, there was an area of surface low pressure over west
central Iowa, and an upper-level trough over the northern/central
High Plains. A quasi-stationary front stretched from the low to
the northeast, through southern Minnesota, northwestern Wisconsin,
and into Upper Michigan. Most of the western Great Lakes to
Northern Plains had cloudy skies. There was unseasonably warm and
humid air across the warm sector of the front, with dew point
temperatures well into the 60s and near 70 degrees across much of
Wisconsin into southern Minnesota. On the other hand, far
northwest Wisconsin and the rest of Minnesota had much cooler air
with dew point temperatures in the middle 40s to middle 50s. A
powerful upper-level jet streak of 130 to 140 knots was over the
Central/Northern Plains from southern Wyoming to southwest
Minnesota. There were scattered showers and some thunderstorms
across southern Minnesota, lifting to the north.

The surface low will deepen and lift northeast along the
baroclinic zone of the somewhat stationary front this afternoon
and evening as the upper trough advances east into the Plains. The
surface low could track across the far southeast forecast area in
Price County,or just south and east of Price County. Showers and
thunderstorms will likely develop near and and just north of the
front as the low lifts into the region. A low to mid-level band of
frontogenesis will also develop across northwest Wisconsin, and a
shortwave lifting into the region could help develop showers and
some thunder near the frontogenetical band across much of
northwest Wisconsin. While most of northwest Wisconsin will likely
only have up to a few hundred J/kg of most unstable CAPE, there
could be around 1000 to 1500 J/kg of MUCAPE across southeastern
Price County, combined with ample deep layer wind shear of 50 to
70 knots. Despite the lack of CAPE for most areas, there may be
good updraft organization with the storms, making it easier for
the storms to develop hail. Unseasonable atmospheric moisture will
see profiles of precipitable water values reach around 1.5 inches
across southern Price County, meaning the storms are capable of
brief heavy rain.

There is a lesser threat of strong winds, and even more remote
threat of tornadoes, across southern Price County. Besides the
ample deep layer wind shear, 0 to 1 km low-level wind shear will
increase to about 15 to 30 knots, which can help develop supercell
tornadoes. However, this greatly depends on the timing at which
the storms move into the area. If the storms hold off more until
evening, the instability will no longer be likely to be rooted in
the boundary layer because the of the typical, nocturnal, near-
surface inversion, which would help prevent any tornadoes and
lessen the potential for damaging wind gusts. If the low and its
storms reach Price County quickly enough later this afternoon,
there could be a short window for the potential of tornadoes and
damaging wind gusts before the nocturnal inversion develops this
evening. Rainfall will likely range from nearly 1 inch in the far
southeast to about a 0.25" to 0.50" across the rest of northwest

Farther west, an upper-level frontogenetical band with humid air
in the layer will develop a band of light rain across parts of
northeast Minnesota this afternoon and linger into this evening.
The rain will at first be absorbed by the dry low- levels, leading
to more virga than rain at first, but rain will become more likely
once the low-levels absorb more humidity.

Northwest flow will usher in cooler air into the Northland
overnight and into Tuesday in the wake of the passing low.
Lingering overnight cloud cover will help bolster the overnight
lows, so leaned on the warmer NAM and Canadian regional models
with lows in the middle to upper 40s. Tuesday looks cooler and a
bit sunnier, with just scattered/broken upper-level clouds and
highs ranging from the lower 50s across far northern Minnesota to
around 60 degrees across northwest Wisconsin and nearby areas of
Minnesota. Expect afternoon wind gusts to around 15 mph.

.LONG TERM...(Tuesday night through Monday)
Issued at 302 PM CDT Mon Oct 17 2016

Near to above normal temperatures through the long term forecast
period with just a few chances for light precipitation.

On the synoptic scale a weak low will meander across northern
Manitoba into far northwest Ontario through mid-week, with a broad
longwave trough moving from west to east across the western half
of the country gradually merging with this upper low to result in
a deepening trough across the Midwest Thursday into Friday. While
there remains timing differences between models, the trough axis
is generally expected to swing through the upper Midwest Thursday
bringing colder air in aloft, around -5C. A very low chance for
light rain rain Thursday (or possibly more like sprinkles), with
skies clearing Thursday night leading to one of the coldest nights
yet for the Northland.

Following this chill a broad mid-level ridge builds across the
Plains into the Midwest over the weekend leading to gradually
warming temperatures. A chance for rain/snow Friday night as a
weak mid-level impulse moves across southern Canada and the upper
Midwest in the fast west-northwest flow aloft, with another
similar disturbance possible towards the end of the weekend. In
either case precipitation amounts would be light. Highs in the mid
40s to mid 50s, lows in the mid 30s to near 40.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1231 AM CDT Tue Oct 18 2016

An area of low pressure had moved to the Upper Michigan between
Lake Michigan and Lake Superior as of late evening. A cold front
extended southwest out of this low all the way into Kansas. A
shortwave and FGEN continued to cause showers and a few
thunderstorms over northwest Wisconsin with just light rain
further northwest. The showers/storms will diminish then end
overnight as the FGEN, front, and low all move away from the
region. Conditions varied widely across the Northland, from mainly
VFR over northern Minnesota to IFR over parts of northern
Wisconsin. As clouds have thinned over northern Minnesota, some
fog has formed and we expect that to continue overnight. Fog was
also occurring along portions of Lake Superior, especially the
south shore. In addition to the fog, the RAP and HRRR both show
MVFR ceilings moving in from the northwest out of Canada. A look
at observations shows MVFR ceilings over southern Manitoba close
to what the RAP/HRRR have been indicating. We bring those ceilings
into KINL/KHIB/KDLH late tonight then improve conditions to VFR
through the day Tuesday.

Another shortwave trough will bring thickening clouds Tuesday
night and will lower ceilings late in the period.


DLH  42  53  33  44 /  10  10   0   0
INL  37  45  33  43 /  20  10  10  10
BRD  41  54  34  46 /  10   0   0   0
HYR  43  58  35  46 /   0  10   0   0
ASX  44  57  37  47 /  10  10   0  10


.DLH Watches/Warnings/Advisories...


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