Area Forecast Discussion
Issued by NWS Duluth, MN

Home | Current Version | Previous Version | Text Only | 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 250607

Area Forecast Discussion
National Weather Service Duluth MN
107 AM CDT SAT JUN 25 2016

.SHORT TERM...(This evening through Saturday)
Issued at 320 PM CDT Fri Jun 24 2016

Active weather is expected through Saturday night, with two
rounds of possibly severe convection to cope with in the next 36
hours or so. First, this evening we have continued warm advection
bringing a plume of high RH air into the area, with dewpoints
having risen into the 50s, with values approaching 60 in our
southwest. This is going to make for a muggy night tonight, with
low temperatures remaining in the low to mid 60s for most
locations. As usual close to the lake it will be cooler. Might be
a good night to visit Lake Superior this evening! The main
question this evening will be where&when the convection fires. For
now am favoring the high res models which generate convection over
eastern North Dakota and/or northwest Minnesota and surge it north
on the nose of the moisture plume. Some models are generating
convection farther south, but the current analysis seems to favor
a more northerly solution. The question then becomes how far
southeast the convection will spread. In favor of keeping the
convection to the west is the quickly weakening instability to the
east and the mid level flow that should push the convection to the
north once it is generated. However, the convergence and
frontogenesis extend over much of northeast Minnesota after
midnight tonight and may help generate even higher based
convection farther east which should also push northeast. This
convection should weaken and move northeast into Ontario early
Saturday morning, and we should get a period of relatively quiet
weather for a few hours. The afternoon has been our main concern,
with some potential for severe weather in the forecast for several
days now. This event has some similarities to last Sunday`s event,
with a cold front plowing into a deeply unstable airmass with
strong shear. There are some minor differences though that could
keep this from being as significant event as that one was. The
shear is farther west relative to the plume of instability, plus
we appear to be less strongly capped than we were that day. This
is going to cause the thunderstorms to develop earlier, and will
have a narrower time frame in the most favorable environment to
produce severe storms. That said, it still looks like there is
plenty of opportunity to produce initial discrete supercells,
which should evolve into a more linear feature as it moves farther
east. This will also be more limited to the southern few rows of
counties, as Lake Superior may keep things from getting too
unstable over the Arrowhead. The convection should sweep east, and
by the early morning hours be out of the area. Highs on Saturday
may be very warm and muggy with highs pushing into the low 80s at
least. The more sunshine we get the more likely we are to get even
into the mid and upper 80s.

.LONG TERM...(Saturday night through Friday)
Issued at 320 PM CDT Fri Jun 24 2016

Fairly quiet stretch coming up for much of the long term. Main
concerns at this time are the winds on Sunday afternoon and
thunderstorm chances late in the period.

Stacked low pressure will be found over northwest Ontario Sunday
morning and will gradually push eastward through Monday morning.
With lingering vorticity over the area and weak cool advection aloft
and at the surface, there is a good chance for scattered to isolated
showers, and possibly a rumble or two of thunder, across northern
Minnesota late Sunday morning through early Monday morning. Strong
cold air advection behind departing cool front and efficient mixing
in the low-levels, should result in sustained winds of 10 to 20 mph
range with gusts as high as 35 mph. Not expecting advisory criteria
conditions, but later shifts will need to re-evaluate. Lingering
shortwave trough will remain in place early Monday, but think
shower/storm chance will be lower by then.

Upper ridge will build across the Intermountain West with trough
continuing to dig over the East Coast. That pattern leaves the
Northland in a northwest flow regime and generally cut off from
significant sources of moisture. As a result, the chances of showers
and thunderstorms will be low through much of the week. A bolus of
DCVA will move southeast through the Canadian prairies Wednesday
evening and Thursday. The passage of this feature, and associated
surface response, may trigger a few thunderstorms across the area.
At this point, the odds of severe weather with this feature are low.
Model solutions diverge by Friday with the ECMWF bringing an upper
low southward over Ontario, which would yield increased cloud cover
and chances of showers. The GFS solution would keep the upper low
far to the northeast over Quebec. Given time range and inherited
forecast, opted to keep low chance of thunderstorms in the forecast
through end of the week.

Temperatures throughout the long range should trend near seasonal


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 107 AM CDT Sat Jun 25 2016

Main concern overnight is the possibility of thunderstorms at
KINL/KHIB/KDLH. Most confident on thunderstorm activity at KINL
and tried to time thunderstorms moving through by the last several
HRRR runs. Less certain on storms at KDLH/KHIB as unsure if
activity will develop that far southeast as the strongest forcing
is farther north. Due to the uncertainty left in as VCSH from 09
to 13Z. Think that these showers/storms will bring ceilings down
to the MVFR range as the column moistens at KDLH/KHIB/KINL. Think
there is a possibility of MVFR at KHYR/KBRD around 13Z as well,
but held off as showers should remain out of these locations
overnight and early tomorrow morning.

Will see a return to VFR ceilings as the mixed layer develops. Due
to the incoming system and the increasing pressure gradient, will
see gusty winds develop at all terminals. During the afternoon
will see another round of showers and thunderstorms develop. Tried
to show a downward trend of thunderstorm activity to all terminals
except KHYR around 01Z as the cold front will have moved through
these locations. KHYR is likely to see storms around until after


DLH  61  82  57  78 /  50  80  60  20
INL  66  81  58  69 /  60  80  30  50
BRD  69  86  59  79 /  30  80  20  10
HYR  65  86  59  80 /  40  80  80  10
ASX  58  86  60  80 /  40  80  80  10


.DLH Watches/Warnings/Advisories...


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