Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 230841
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
341 AM CDT TUE AUG 23 2016

.SHORT TERM...(Today through Wednesday)
Issued at 341 AM CDT Tue Aug 23 2016

Early this morning...there is a low chance of elevated-based
showers and storms across northern Minnesota early this morning
near the the nose of an elevated warm front lifting north.

Today...the Northland is poised for a very warm day. Gusty
southerly flow will develop today as an area of low pressure lifts
from North Dakota to southern Manitoba, and its cold front
approaches the Northland from the west. The 850 hpa temperatures
will increase to about 18 to 22 degrees Celsius, with the nose of
the warm air aloft acting as effective cap to any convection
through early this evening. Expect mostly sunny skies and
widespread afternoon wind gusts of 20 to 30 mph. Given the factors
promoting heating today, such as the mostly sunny skies and
relatively warm temperatures this morning, leaned on the warmer
model guidance, such as the local wrf and gfs. High temperatures
will likely range from the lower to upper 80s, about 10 to 15
degrees above seasonal normals, and with the warmest weather from
central to northern central Minnesota.

This evening...the cold front will begin to near the western
forecast area, and the front combined with falling heights from
an approaching large upper low in south central Canada, will
result in increasing chances of showers and storms from the west
this evening. While most unstable CAPE will likely build to 1000
to 2000 J/kg across the western forecast area this evening, the
threat of severe weather will largely be suppressed by the lack of
deep-layer wind shear, stifling the potential for storm
organization and updraft persistence. The more sufficient wind
shear will be trailing behind the cold front, while the convection
is expected to occur ahead and near the cold front. However, GFS
and NAM model soundings of CAPE profiles suggest there could be
isolated storms capable of brief small hail. Brief heavy rain is
also possible considering the precipitable water values around 1.5
inches.

Later tonight...the models suggest shower and storm coverage will
become more spotty as the cold front works its way into the
Northland. However, some models (such as the regional Canadian)
warrant increasing chances across parts of northwest Wisconsin
because of the potential for a shortwave trough lifting through
the Upper Midwest (southern Minnesota and Wisconsin) to spark a
cluster/complex of showers and storms that could move through
northwest Wisconsin late tonight. Overnight lows will be
bolstered by the cloud cover and breezy southerly flow, so leaned
on the warmer model guidance, such as the ECMWF, regional
Canadian, and SREF. Lows should primarily be in the middle 60s.

Wednesday...the cold front will continue moving through the
Northland, from west to east, until exiting to the east during the
afternoon. There will be some chances of showers and storms,
ahead of the cold front, primarily during the morning, but also
lingering across the far eastern forecast area into the middle
afternoon. Sufficiently dry air will be moving into the region
behind the front, amidst the breezy westerly flow, to stave off
much cumulus. Even the 4 km NAM, which tends to due well showing
cumulus when other models do not, has little cloud cover. Even
though cooler weather will be moving into the region, the warm
temperatures to start the morning, sunny skies, and dry flow will
help temperatures climb to the upper 70s and low 80s. There should
be afternoon wind gusts around 15 mph, but may need to increase
the forecast to closer to 20 mph when the timeframe comes in range
of more high resolution model guidance.

.LONG TERM...(Wednesday night through Monday)
Issued at 341 AM CDT Tue Aug 23 2016

Wednesday night and Thursday we will be on the back side of the
storm system that moves through our area tonight and Tuesday, with
cooler and drier conditions in west-northwest flow. Steep low
level lapse rates should produce showers and isolated
thunderstorms, mainly during the day on Thursday along the
Canadian border region. High temperatures Thursday will only be in
the mid 60s to low 70s. We can also expect another chilly night
Thursday night with a surface ridge building into the area and the
cooler airmass in place. Currently have min temps in the mid 40s
to low 50s, but some upper 30s are possible if we get good
radiational cooling conditions.

Warm air advection sets in again for Friday, which should bring
temperatures back into the 70s for most areas. Our next
significant storm system is a large shortwave that moves across
the Upper Midwest into the Great Lakes in the Friday night through
Saturday night time frame. Models are still showing some
differences in timing and placement of best potential for showers
and thunderstorms, but for now have placed highest pops on
Saturday night, though the entire weekend has some potential for
rainfall.

The models are showing large differences for early next week with
several weak shortwaves in the upper level southwesterly flow over
the CONUS which could affect the Northland. In general it looks
like warmer temperatures are heading our way once again, with
small chances for showers and thunderstorms each day. Have kept to
the model consensus for now.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1240 AM CDT Tue Aug 23 2016

VFR through the forecast. Expect some LLWS at all sites but INL
until 12Z as a low level jet affects MN. Thunderstorms have
developed over eastern North Dakota within the low level jet which
may also spread east to affect KBRD and KINL generally in the
09z- 14z time range, but confidence in their arrival is not high
enough and have left out for now. After 14z Gusty surface winds
will develop. A cold front will reach northwest MN toward the end
of the forecast period. Have a VCSH mention at INL at 02Z to
account for any activity that forms ahead of the front.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  85  66  78  54 /   0  30  30   0
INL  88  63  77  53 /  20  60  20  10
BRD  86  64  79  54 /   0  30  10   0
HYR  83  66  78  54 /   0  40  40   0
ASX  85  67  82  57 /   0  30  40   0

&&

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

$$

SHORT TERM...Grochocinski
LONG TERM...LE
AVIATION...LE


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