Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 161751 AAD

Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1251 PM CDT Wed May 16 2018

Issued at 1251 PM CDT Wed May 16 2018

Update for new 18Z Aviation Discussion below.

UPDATE Issued at 1108 AM CDT Wed May 16 2018

Bumped up max temps as previous forecast max temps have already
been reached in many locations. Made some other adjustments.

UPDATE Issued at 926 AM CDT Wed May 16 2018

A cold front has reached the international border. Showers are
percolating over the northern third of the forecast area ahead of
the front. Clouds are also on the increase over the north as
instability increases. With that instability, a few thunderstorms
may form ahead of the advancing front. Over the southern half of
the area, a mainly sunny sky is found. Still expecting another
round of showers and storms to develop near the Twin Ports this
afternoon into northwest Wisconsin. This will be in response to
the advancing front. Have made several adjustments to account for
these trends.


.SHORT TERM...(Today through Thursday)
Issued at 205 AM CDT Wed May 16 2018

A frontal boundary will linger across the Northland today and
Thursday. A few showers can be expected along the Canadian border
this morning. The boundary shifts south this afternoon and
afternoon heating, with near record highs expected, and subsequent
instability should spark off showers and thunderstorms along the
boundary. Due to a deep layer of low level dry air (inverted V DLH
sounding) and cloud bases of 6000 ft, the showers/thunderstorms
could be quite gusty which is not captured in the forecast.

The boundary continues its southward extent overnight into
Thursday morning. Another injection of 850 mb flow and instability
may spark off a few more showers on Thursday morning. Pressure
gradient strengthens with an increasing chance for rain through
the day Thursday as an area of low pressure approaches.

.LONG TERM...(Thursday night through Tuesday)
Issued at 205 AM CDT Wed May 16 2018

A chance for showers and a few storms late-week into Saturday,
then dry Sunday into early next week. Temperatures will be cooler
Saturday in the wake of a cold front then return to above normal
values Sunday into early next week with highs in the upper 60s to
low 70s.

On the synoptic scale late-week into the weekend a mid-level
longwave trough will track across southern Canada into the Upper
Great Lakes. At the surface a cold front will move from west to
east across the Upper Midwest Friday into Saturday resulting in
showers and few thunderstorms developing along and ahead of the
cold front. Instability will be meager, on the order of perhaps a
few hundred to maybe 500 j/kg MUCAPE at low levels on Friday
afternoon, but enough to support occasional storms. Severe storms
are not anticipated. Late-week into the weekend around an inch of
rainfall total is possible, which should greatly aid in the green-
up in what has otherwise been a very dry spring so far. At a
minimum most locations should see at least a half inch of

Late weekend into early next week cooler and drier air moves
across the Upper Midwest as a broad area of high pressure builds
in, though surface temperatures quickly rebound to the mild side
of normal. Relative humidity values will fall back into the 20 to
30 percent range each afternoon Sunday, Monday, and possibly even
Tuesday. However, with the rainfall expected combined with winds
that will be generally light due to high pressure in the vicinity
should preclude the chance for near-critical fire weather
conditions. Mid- to late- week this area of high pressure builds
towards the Lower Great Lakes resulting in a return of low level
moisture and warmer air advecting in at low levels.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1251 PM CDT Wed May 16 2018

Cold front over northern Minnesota early this afternoon will
continue to sag southward through this evening. Cumulus coverage
has increased over the past hour signaling increasing instability.
Look for a line of showers/thunderstorms to develop along the
front this afternoon and move toward DLH/BRD/HYR through this
evening. Winds have become gusty at all sites and think the
stronger winds will linger into tonight. Winds will turn northern
behind the front, at HIB initially, and at BRD/DLH/HYR this
evening. Mainly VFR conditions are expected given the spotty
coverage of the showers/storms. Should any of the storms or
heavier showers move over the terminals, a brief period of MVFR or
even IFR visibility is possible. Winds may briefly gust above 35
knots near storms.


DLH  86  43  56  42 /  40  20  20  20
INL  75  44  63  44 /  10  20  30  60
BRD  86  50  74  52 /  10  10  30  20
HYR  86  50  74  50 /  30  40  20  20
ASX  89  41  57  41 /  50  40  20  20


LS...Small Craft Advisory from 10 PM this evening to 10 PM CDT
     Thursday for LSZ144-145-148.



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