Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 280530
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1230 AM CDT Wed Jun 28 2017

.UPDATE...
Issued at 1223 AM CDT Wed Jun 28 2017

Updated aviation section for 06z TAFs below.

UPDATE Issued at 1010 PM CDT Tue Jun 27 2017

Have been watching an area of thunderstorms that started out over
western MN west of Alexandria that appeared to be rooted in the
strong 700mb warm air advection & frontogenesis zone there. Since
then this zone has shifted east and has brought the northwest to
southeast oriented area of showers and thunderstorms to a Park
Rapids towards the Twin Cities, just catching southern Cass county
for now. Expect this to continue to shift east for the next few
hours even as the main show takes shape over central North Dakota.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 356 PM CDT Tue Jun 27 2017

The main concerns during the short term involve the potential for
rain and thunderstorms tonight and Wednesday, and the possibility
of excessive rainfall and strong to severe storms.

High pressure will remain the primary influence over the
Northland this evening keeping mainly clear skies and dry
conditions. Winds will remain breezy through the evening thanks to
deep mixing. An approaching area of low pressure from the Dakotas
will trigger showers and thunderstorms this afternoon and
evening. Those storms are forecast to move into the Northland late
tonight and re-intensify on Wednesday. Northward moisture
transport ahead of the system will bring PWATs of around 1.5
inches into portions of northeast Minnesota and northwest
Wisconsin. Those values are >90% of climatology for later June.
The strongest 850 mb moisture transport should graze portions of
Sawyer and Price County tomorrow afternoon based on the 12Z GFS
and NAM. The 18Z NAM, however, shunts most of the moisture east of
our area. The GFS and GEM bring moderate instability northward
into our southern CWA Wednesday afternoon, but the NAM keeps the
strongest destabilization south of our area. Even so, there seems
to be enough support for an isolated severe thunderstorm or two
during the afternoon hours. Much of the severe weather potential
will hinge on whether we can scour the clouds by early afternoon.
Should clouds and showers linger, the severe weather risk will be
quite small. The bigger concern relates to the abundant moisture
available for precipitation. Much of northwest Wisconsin and areas
along the North Shore have been included in a Marginal Risk of
excessive rainfall by WPC, with a tiny sliver of Price County in
the Slight Risk area. While there is a risk of flash flooding,
think the potential is too low this afternoon to warrant a watch.
Will handle the threat with an SPS and mentions in HWO for now.
Flash Flood Guidance for much of northwest Wisconsin is in the 2.5
to 3.5 inch/6-hour range, with a few pockets above 3.5 inches.
While northern portions of the forecast area will see rain and
thunderstorms tonight and Wednesday, think the greatest chances
and highest amounts will be located south of a line from near
Walker to Duluth to Mercer WI.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 356 PM CDT Tue Jun 27 2017

The shortwave and elongated surface low that will bring
widespread rain to the region on Wednesday will gradually push off
to the east of the region Wednesday night. As a result, the
showers and thunderstorms will gradually decrease from southwest
to northeast. Some showers will likely linger in the Minnesota
Arrowhead and portions of northern Wisconsin through the night,
and even into Thursday. The next shortwave will already begin to
affect the Northland Thursday night, and especially Friday. The
deterministic models actually show two upper level lows that will
move across the the northern states, with an area of showers and
thunderstorms expected to fill in between the two main upper level
systems. This double barrel type system will affect the region
into Saturday as well, with scattered showers and a few
thunderstorms throughout the day. There will be small chances of
showers and thunderstorms from Sunday into Sunday night as well,
but dry weather is expected across the region on Monday and
Tuesday of the upcoming work week. Still looking like it will be
dry and mild on Independence Day. High temperatures early in the
period will range from the upper 60s to middle 70s, but
temperatures will warm into the 70s for daytime highs by early
next week. Overnight lows will generally be in the upper 40s to
middle 50s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1223 AM CDT Wed Jun 28 2017

A strong low pressure system to advance towards and across the
area during the TAF period. Strong south winds ahead of the low
and aloft has produced LLWS for several terminals which should
continue for much of the overnight period. Moisture surging north
along with a warm front has already generated showers and
thunderstorms in vicinity of KBRD, which will gradually spread
east to affect the remaining terminals through 12z. The initial
waves of showers and thunderstorms to bring MVFR conditions. As
the surface low gets closer expect a period of IFR ceilings and
MVFR visibilities beginning around 10z for KBRD, later for the
other terminals. The back edge of the precipitation should move
into KBRD around 21z, but lingering IFR/MVFR ceilings to linger
for a few more hours, followed by a return to VFR. The other
terminals to follow a similar pattern, though expect those
locations to remain MVFR or IFR through the remainder of the TAF
period.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  55  63  54  71 /  50  90  40  10
INL  57  67  55  72 /  50  80  50  20
BRD  58  72  57  77 /  70  80  20  10
HYR  56  69  58  74 /  60  90  40  10
ASX  56  68  54  71 /  40  90  50  20

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory from 10 AM this morning to 10 PM CDT this
     evening for LSZ140>145.

&&

$$

UPDATE...LE
SHORT TERM...Huyck
LONG TERM...DAP
AVIATION...LE


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