Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 280003
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
703 PM CDT SAT AUG 27 2016

.SHORT TERM...(This evening through Sunday)
Issued at 346 PM CDT Sat Aug 27 2016

Rather significant upper level trof axis located in the Red River
Valley as of late this afternoon will continue to translate
eastward across northern Minnesota tonight. The main period of
strong forcing for ascent will traverse northern Minnesota over
the next 9 to 12 hours, with a significant increase in lightning
activity in the Walker/Bemidji area noted over the past hour. We
have increased PoPs and QPF amounts across northern Minnesota for
tonight, as most areas should see at least a quarter to half inch
of rain, with some locally higher amounts. We have also held onto
PoPs over the Minnesota Arrowhead for a bit longer late tonight as
the primary potential vorticity lobe does not exit far northeast
MN until between 12-15z Sunday morning.

The overall severe threat appears to be rather low, but there is
a narrow axis of better destabilization extending across the
western sections of the DLH CWA, and with 40-50 knots of deep
layer shear, a couple of strong or marginally severe storms cannot
be entirely ruled out through this evening as the lobe of
strongest forcing moves across the area, as evidenced by the
latest uptick in radar echo strength/depth between Fergus Falls
and Bemidji.

There is a very weak west/northwest low level push behind this S/W
trof axis Sunday morning, which means that the surface-850 mb
temp/moisture gradient will likely get "left behind" and still be
lying WNW to ESE across central MN on Sunday. Initially, general
large scale synoptic subsidence in the wake of the departing wave may
inhibit additional TStorm development, but as low level warm/moist
advection increases Sunday afternoon with increasing southwest low
level flow, we have retained 25-40 PoPs over the central/south
sections of the DLH CWA along and just north of the warm frontal
zone.

.LONG TERM...(Sunday night through Saturday)
Issued at 346 PM CDT Sat Aug 27 2016

Warm and muggy conditions will continue Sunday night and
Monday...followed by a dry and seasonal period for much of this
week.

By Sunday night a warm front should still be south of the area
with an increasing 850 mb low level jet of 30 to 40 kts
continuing and another round of warm air advection. With another
upper level Canadian short wave due to move through, it is likely
that more showers and storms will develop in the increasingly
unstable atmosphere. The nocturnal thunderstorms may continue
during the day with even more instability ahead of the approaching
cold front. MUCAPES of 2000+ j/kg being forecast by the NAM and
are supported by the GFS/ECMWF. If the atmosphere can recover
from the overnight convection, some strong storms could develop
ahead of the cold front Monday afternoon.

Once the cold front and upper level trough moves east of the area
Monday night most of the rest of the week will be dominated by high
pressure at the surface and aloft giving the Northland dry
conditions with seasonal temperatures.

Another upper trough will dig into the west coast and amplify the
ridge, but toward the end of the week the ridge will begin to break
down as the western trough makes land fall and pushes shortwaves
over the ridge. This will begin a period of showers and storms that
will begin late Thursday or Friday and perhaps last through the
Labor Day weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 703 PM CDT Sat Aug 27 2016

An upper level trough will continue to move through the Northland
tonight with showers and thunderstorms gradually diminishing
through the night. A mix of IFR/MVFR conditions will occur this
evening, especially in areas of rain and over northwest Wisconsin.
As the night progresses IFR conditions should expand as fog
develops. The visibility and ceiling may drop to a half mile or
less and 500 feet or less in spots.

The fog will lift on Sunday morning with mainly VFR conditions
expected. There should be a VFR cumulus field that develops with
the heating of the day. Some showers or storms may also form
through the day with chances increasing Sunday evening. More of a
mention of showers/storms may have to be added to the TAFs with
later updates.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  57  78  61  80 /  60  30  50  50
INL  54  80  61  81 /  70  20  50  40
BRD  59  80  66  83 /  50  30  30  30
HYR  59  79  63  83 /  30  30  40  50
ASX  58  79  63  83 /  50  30  30  40

&&

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

$$

AVIATION...Melde


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