Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 280536
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
1236 AM CDT SUN AUG 28 2016

.UPDATE...
Issued at 1030 PM CDT Sat Aug 27 2016

Showers and thunderstorms have diminished quite a bit from earlier
this evening. We expect this trend to continue and updated POPs to
reflect current trends. Fog was already forming this evening with
KHIB recently reporting a quarter mile in fog. We still expect fog
to expand overnight as the upper wave moves off the mid and upper
level clouds diminish. Fog could become widespread and dense
enough for an advisory and we will monitor for that possibility.

&&

.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 06Z TAFS through 06Z Sunday night)
Issued at 1236 AM CDT Sun Aug 28 2016

A trough of low pressure will move off tonight and brief ridging
will build in its wake. Showers or storms will end overnight as
well. The latest satellite imagery showed plenty of IFR and MVFR
ceilings over northwest Wisconsin and across portions of northern
Minnesota. The clouds were expanding toward the west. Fog will
become more widespread overnight, but the clouds may limit how dense
the fog becomes. However, where clouds remain thin or absent, the
fog may become dense. KHIB has been down to a quarter mile already.
The fog and low ceilings will rise Sunday morning. There may be a
cumulus field that develops and some broken MVFR ceilings may occur
at the onset, but then mainly VFR conditions will occur through the
afternoon.

A few showers or thunderstorms will be possible Sunday, mainly in
the afternoon with chances increasing during the evening and
overnight period. More fog will be possible Sunday night.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  61  80  56  75 /  50  50  40   0
INL  61  81  52  73 /  50  40  10   0
BRD  66  83  58  77 /  30  30  30   0
HYR  63  83  59  77 /  40  50  30  10
ASX  63  83  61  76 /  30  40  30  10

&&

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

$$

UPDATE...Melde
AVIATION...Melde



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