Area Forecast Discussion
Issued by NWS Duluth, MN

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629
FXUS63 KDLH 230845
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
345 AM CDT FRI SEP 23 2016

.SHORT TERM...(Today through Saturday)
Issued at 345 AM CDT Fri Sep 23 2016

An area of high pressure, centered near the border between
Manitoba and far northwest Ontario as of early this morning, will
shift to eastern Ontario by Saturday evening. Cool and breezy
easterly flow is expected across the Northland today, but an
upper level ridge will build into the region, with southeast
returnflow bringing more warm and humid air into the region
tonight into Saturday. This will result in cloudier weather for
tonight and Saturday. Temperatures will be near or slightly above
seasonal normals.

A shortwave will lift into the southwest forecast area this
afternoon and evening, possibly bringing showers to the Northland
as it spreads through the forecast area through tonight. The
models are not indicating much most unstable CAPE, but
frontogenetical banding and the lift generated by the shortwave
could help develop some thunder. Therefore, kept isolated thunder
in the forecast.

Also, models and model soundings suggest there could be light
drizzle/rain across much of the forecast area from the saturated
layer of warmer air aloft...aided by the turbulence generated from
the 25 to 40 knot low-level jet. Kept the forecast as showers,
for now, but may be able to add this detail if the timing of the
shortwave (and model agreement on it producing pcpn) can be better
detailed with subsequent forecasts.

Some showers and/or drizzle could linger into Saturday, especially
near the Twin Ports and parts of the North Shore because of the
upslope flow from the cool and easterly humid flow from Lake
Superior.

An area of low pressure over the Northern High Plains, as of early
Saturday, will push into North Dakota during the day. Its
occluded/cold front will advance through the Dakotas. The models
are indicating pcpn will likely develop ahead of the front with
an embedded shortwave trough in the increasing southerly flow
ahead of the low. The showers, and maybe some storms, could reach
the southwest forecast area by the late afternoon.

.LONG TERM...(Saturday night through Thursday)
Issued at 345 AM CDT Fri Sep 23 2016

Main challenge for the extended period is timing of multiple waves
of precipitation through the beginning of next week as a long
wave trough with closed low gradually migrates across the northern
plains and into the Lake Superior region.

The surface reflection low will track into northwest Minnesota
Saturday night, sweeping a cold front over the Northland through
Sunday morning. Rain, with embedded thunderstorms, will be
associated with this front. Profiles support periods of heavy rain
as forecast soundings show deep moisture, PWAT values over an inch
and a half, along with a few hundred joules of CAPE. A wedge of
dry air, ahead of a secondary cold front, will then rotate into
the Northland during the day sunday. The dry slot will result in a
break to the showers. However, the upper level low reach northern
minnesota sunday night, bringing northwest winds, along with much
cooler air aloft. Temperatures in the lower single digits at
850hPa will produce steep lapse rates and instability showers
Monday and again Tuesday.

Upper level ridging will build into the region around mid-
week...bringing a day or two of dry conditiions.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1257 AM CDT Fri Sep 23 2016

A mix of VFR to MVFR conditions expected through the TAF period as
a warm front approaches from the southwest. At DLH MVFR ceilings
may develop late tonight into early Friday morning, but confidence
is lower given the abundant dry air to the north. At HIB and INL
VFR through the period due to high pressure to the north with only
VFR clouds. BRD will be impacted by the warm front approaching
tonight into tomorrow with a few rounds of light rain
showers/sprinkles early this morning and through the day. Also
with additional low level moisture, MVFR ceilings are expected to
develop at BRD and persist through the day Friday.

Winds will become out of the east this morning, becoming breezy
today. Winds will be strongest at DLH and BRD with gusts to
around 20 knots expected at both sites, though by the afternoon
wind gusts may not be as strong.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  62  52  62  57 /   0  20  30  70
INL  65  52  65  58 /  10  50  20  70
BRD  65  58  70  57 /  40  40  30  70
HYR  67  54  68  60 /  10  20  20  70
ASX  66  51  68  57 /   0  20  20  70

&&

.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...Small Craft Advisory until 10 PM CDT this evening for LSZ121-
     144>148.

     Small Craft Advisory until 4 AM CDT Saturday for LSZ141>143.

&&

$$

SHORT TERM...Grochocinski
LONG TERM...Graning
AVIATION...JJM



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