Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 231148
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
648 AM CDT MON MAY 23 2016

.SHORT TERM...(Today through Tuesday)
Issued at 359 AM CDT Mon May 23 2016

Parts of the far eastern forecast area in northwest Wisconsin will
face one more day of the warm, windy, and dry weather that has
presented a fire danger risk for much of the Northland the past
week. On the other hand, increasing moisture over the rest of the
forecast area will provide much higher humidity today and
increasing chances of showers and thunderstorms as a low pressure
trough boundary approaches from the west.

Early this morning...While an upper level ridge lingers over the
Upper Midwest, with the axis east of the Northland, there will be
height falls over the western forecast area. The strong low level
jet from the ssw, of about 40 to 50 knots, will pump moisture from
the Central Plains into the western forecast area, and the
synoptic lift could help produce some showers and storms over the
western forecast area this morning. The threat of severe weather
is very low, but the most unstable cape of about 500 to 1000 J/kg
and model sounding profiles suggest there could be some strong
cells capable of producing small hail.

Today...Daytime heating will increase the low level mixing, and
allow the boundary layer to tap into the strong flow aloft,
especially across the eastern forecast area where there will be
better heating because of less cloud cover. The southerly flow
could produce gusts of 20 to 30 mph by this afternoon, with the
strongest gusts across northwest Wisconsin. Humidity will drop to
around 30 percent in the far eastern forecast area in Wisconsin,
resulting in near-critical fire weather conditions. On the other
hand, there will be increasing moisture from the west as the axis
of moisture transport over the Plains shifts east into the
Northland ahead of the approaching trough boundary. The
precipitable water values will increase to about 1.5 inches. The
synoptic lift from falling heights from the west and building
instability will produce increasing chances of showers and storms
from the west. Mixed layer capes will build to about 500 to 1500
J/kg by late this afternoon. Showers and storms will likely become
more numerous across the western forecast area in the afternoon
when the trough boundary moves into the Northland. The threat of
severe weather will be limited today by the best instability being
displaced from the better deep level wind shear. While the mixed
layer cape could build to 500 to 1500 J/kg, the axis of best
instability will only tap into about 20 to 30 knots of 0-6 km wind
shear, so any individual storms may struggle to become well
organized. The models are not in good agreement though, so
confidence on outcomes is low. There is the possibility that the
storms could develop in areas of sufficient instability and wind
shear to produce hail and damaging winds. The best instability
should be across the south central forecast area by late this
afternoon. As for pcpn chances, considering the poor model
guidance, leaned on the RAP13 and SREF due to preferring those
models` less noisy output and their indicating that the pcpn will
primarily occur near and just ahead of the trough boundary and
within the axis of greatest moisture transport. Temperatures
today should range from around 80 degrees in northwest Wisconsin
to the middle and upper 70s across northeast Minnesota.

Tonight...The axis of moisture transport will continue to shift
east with the advancing trough boundary, resulting in the chances
of showers and storms shifting east through the night. There will
continue to be marginal/slight risk of hail and damaging winds
with the storms overnight. There will be clearing from the west in
the wake of the passing trough and as high pressure moves into the
region. The radiational cooling, light wind speeds, and abundant
moisture from the rains will likely result in areas of fog,
especially across northeast Minnesota.

Rainfall...Much of the Northland can expect about 0.25" to 0.75"
of rainfall through tonight with the passing trough showers and
storms. The greatest rainfall will likely occur far northwest
Wisconsin and along the Interstate 35 corridor of northeast
Minnesota.

Tuesday...Surface high pressure will be over the Northland and
surrounding region. The sunny skies will help temperatures climb
to the upper 70s and low 80s. Some models are producing some pcpn
Tuesday afternoon. Prefer the GFS, which indicates a passing
shortwave could develop some showers and storms near the lake
breeze along the North Shore and Arrowhead. However, have very low
pcpn chances across the rest of the northern forecast area because
the NAM has some pcpn across the northwest forecast area, which
may be associated with differences in the modeled shortwave tracks
and timing.

.LONG TERM...(Tuesday night through Sunday)
Issued at 359 AM CDT Mon May 23 2016

The extended period will continue to be unsettled with a western
trough in place through the period. Several shortwaves will be
moving through/near the Northland providing chances for showers and
storms.

Tuesday night should see a lull in shower/storm coverage as a weak
wave exits northern Minnesota early and brief shortwave ridging
moves over the area. There may be some evening showers/storms over
parts of northern Minnesota and possibly our eastern Wisconsin
counties but coverage will be limited.

A shortwave will move northeast through the region Wednesday into
Wednesday night with a surface low also moving through the area.
The GFS is an outlier compared to the NAM/GEM/ECMWF/SREF with the
surface low and a second wave that will approach from the Northern
Plains Wednesday night. We followed the consensus which lifts the
surface low much further north Wednesday night into Thursday. The
other models are not in perfect agreement either, but a blend will
be followed. Showers/storms will increase in coverage through the
day Wednesday into Wednesday night from south to north. We continue
a chance for showers/storms Thursday, but later forecasts may be
able to trim back if all the models converge on a solution similar
to the ECMWF.

We keep a chance for showers/storms in the forecast Friday through
the weekend as several more shortwaves will impact the area. There
will likely be some periods where we can remove pops, but there
are not any clear signals at this time.

Highs Wednesday will be in the lower to mid seventies, but be quite
a bit cooler around Lake Superior and into parts of the Arrowhead.
Winds will be stronger off the lake Wednesday into Thursday. Highs
Thursday through Sunday will be mainly in the seventies with it
cooler around the lake at times.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 648 AM CDT Mon May 23 2016

A cold front in the far eastern Dakotas will move slowly east
today with showers and storms possible along and ahead of it.
Showers and storms are also expected to develop well ahead of the
front this afternoon along an outflow boundary from overnight
convection. Although VFR conditions are expected to prevail
through most of the period, periods of MVFR are expected with the
stronger storms. A few storms could be strong this afternoon and
early evening with gusty winds and perhaps some hail occurring.

The precipitation will diminish later tonight and there should be
enough low level moisture for some fog to occur in spots as
clouds and winds diminish.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  75  55  76  49 /  70  60  10  10
INL  76  51  81  52 /  70  40  20  20
BRD  76  56  82  55 /  60  40  10  10
HYR  80  60  79  53 /  60  70  10  10
ASX  80  57  73  47 /  60  70  10  10

&&

.DLH Watches/Warnings/Advisories...
WI...Red Flag Warning until 8 PM CDT this evening for WIZ003-004-009.

MN...None.
LS...None.
&&

$$

SHORT TERM...Grochocinski
LONG TERM...Melde
AVIATION...Melde



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