Area Forecast Discussion
Issued by NWS Duluth, MN

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138
FXUS63 KDLH 242235
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
535 PM CDT TUE MAY 24 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 535 PM CDT Tue May 24 2016

Main concerns this afternoon include isolated thunderstorm chances
this evening and the approaching storm system for Wednesday.

Several lingering boundaries from this morning`s convection, along
with moderate instability of 800-1250 J/kg of MUCAPE have
supported storm isolated storm initiation in spite of the large
scale subsidence over northeast Minnesota and much of northwest
Wisconsin. A few storms may be strong to severe with large hail
and damaging wind gusts possible.

Storms will subside as the boundary layer stabilizes with sunset.
Look for areas of fog to develop, especially adjacent to Lake
Superior. The area of fog over the lake has periodically moved
inland affecting Grand Marais with visibility less than one-
quarter mile. Otherwise look for fairly quiet conditions with
clearing skies overnight.

Guidance is in fairly good agreement with the timing and placement
of a strong shortwave trough and associated vorticity maxima with
the approaching system on Wednesday. Confidence is higher than
average in a band of showers with embedded thunderstorms pushing
northeastward through central Minnesota and into the Northland
during the mid-morning hours. Widespread rainfall amounts of one-
quarter to three-quarters of an inch are expected as this feature
moves through, which will help ease the wildfire concerns
considerably. NAM and GFS are indicating a bit of elevated
instability ahead of the line and a strong storm or two is not out
of the question.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 535 PM CDT Tue May 24 2016

Active weather pattern looks to be in place for much of the extended
periods, with a couple of more significant systems to affect the
region, one for Wed-Thur, and a second for the Sat-Sun time frame.

The first aforementioned system should be well underway at the
beginning of the extended periods Wed evening, with rather gusty
east winds and widespread rain and embedded thunderstorms lifting
steadily northward across the Duluth CWA.  Most model guidance
points to widespread rains of more than a half inch area-wide with
this system, which should act to further improve the spring fire
weather situation.

While the various short term models are likely over-forecasting the
magnitude of potential instability across the southeast half of the
CWA Thursday afternoon, there is little reason to believe that the
placement is not in the ball park.  In addition, roughly 40 knots of
deep layer shear will also be in place.  There is some disagreement
between the various models on timing and placement of forcing for
ascent, but the main trof axis aloft will still be to our west, and
the warm front should lie across portions of northwest Wisconsin.
With all this in mind, we will need to closely monitor the severe
potential for Thursday evening to the south/east of Duluth.

After a brief break in the organized precip and shower/TStorm
activity, chances for rain and TStorms should ramp up once again Fri
night into the weekend as the next significant S/W trof rotates
northward from the plains states into the upper midwest. At this
time, it still appears that the primary period for rain will be
Saturday into early Sunday, but again, uncertainty on timing still
exists this far out.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1256 PM CDT Tue May 24 2016

Main arc of forcing for ascent has now translated into NW Ontario
and the MN Arrowhead as of midday, with large scale subsidence
occurring across most of the DLH TAF sites. VFR conditions with
cumulus clouds are expected this afternoon, with generally light
and variable winds that should trend toward southeast by this
evening. The one exception to the above is the convergence axis
that lies just southeast of KHYR, where additional T-Storms are
expected to redevelop this afternoon. However, we believe that
they will stay east of the 5 nmi TAF area for KHYR. Increasing
east flow in advance of the next system will bring MVFR conditions
beginning tonight at KDLH, and spreading across all TAF sites
except for KINL by 18z Wed morning.


&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  50  57  50  65 /  20  70  70  40
INL  53  73  53  75 /  10  60  60  60
BRD  56  70  56  78 /  20  80  60  30
HYR  52  73  57  80 /  20  80  70  30
ASX  48  62  51  69 /  20  70  70  50

&&

.DLH Watches/Warnings/Advisories...
WI...None.
MN...None.
LS...None.
&&

$$

SHORT TERM...Huyck
LONG TERM...Miller
AVIATION...Miller



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