Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 302041
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
341 PM CDT SAT JUL 30 2016

.SHORT TERM...(This evening through Sunday)
Issued at 341 PM CDT Sat Jul 30 2016

As the surface high pressure ridge slowly continues to move off to
our east, light south to southeast flow will persist tonight and
Sunday, and will result in a continued slow return of warmer air
and higher quality low level moisture to the region. Isolated
convection has persisted along the leading gradient of better
moisture in the 925-850 mb layer all day across the northwest CWA,
aided by weak FGEN forcing, and this process should slowly
diminish and translate into Ontario this evening. Other isolated
convection to the south and east of Duluth should also diminish
with the loss of daytime heating. This should give way to partly
cloudy skies with some left over convective debris clouds
overnight and light east/southeast winds. Once again, this should
support patchy fog in many of the favored low lying areas,
especially near rivers/streams and lakes.

Temps should warm a few more degrees in most areas on Sunday, with
a notable increase in humidity out west. We have also introduced
low chances for showers and TStorms across northern MN in
proximity to the leading moisture and thermal gradient below 800
mb, where weak ascent processes in the 925-700 mb layer should
allow for at least isolated convective development, somewhat
similar to what has occurred today, but spreading into areas
farther east into the Arrowhead and International Border regions.

.LONG TERM...(Sunday night through Saturday)
Issued at 341 PM CDT Sat Jul 30 2016

Models are trending toward a dry Sunday night. However, the GFS/NAM
brings a piece of short wave energy along the Canadian border. The
ECMWF is dry in the evening then brings some storms in late along the
western edge of the forecast area. Meanwhile, the upper ridge is
nearby and may eventually win out. Have some low pops along the
western edge of the area to account for this trend. The ECMWF is the
most bullish with QPF on Monday with rain everywhere. The GFS/NAM
are drier and keep the best rain chances along the Canadian border
south to the Brainerd Lakes. Will lean toward that solution which
has the upper ridging keeping the best forcing along the border.
Monday night finds the ECMWF driving a more robust short wave trof
through the area. The NAM/GFS have upper level/surface ridging
keeping most of the forcing along the international border over the
apex of the ridge. A blend was used for pops with highest north of
the Iron Range.

Tuesday finds this trof moving east of the region before slowing.
Vorticity maxes are pushing along the international border.
Highest chances will be along the border in the evening, with
lower chances farther south, then drying things out from west to
east late with high pressure building in. Lingered some pops over
northwest Wisconsin Tuesday night for any left over rain. Model
differences are large on Wednesday with he ECMWF dry with ridging
overhead. The GFS is suffering from convective feedback and trying
to drive a storm complex over northern Minnesota. Used a blend
which gives low pops over the northwest quad of the forecast area.
No change in model disagreement Wednesday night with the GFS
driving an MCS over northern Minnesota, while the ECMWF is mainly
dry. The blend of pops favored the GFS a bit more with highest
pops over the Chippewa National Forest area. Thursday the ECMWF
pushes a vigorous trof/cold front through the area, the GFS moves
the cold front through, but flattens the trof along the Canadian
border. Have pops along the cold front. Lingered pops over
northwest Wisconsin for any left over storms Thursday night. High
pressure prevails on Friday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1228 PM CDT Sat Jul 30 2016

VFR through the forecast. Models disagree on where and when
showers may develop at HYR and INL. Have a VCSH mention at each
terminal when confidence is at a point to see showers form. Some
patchy BR may affect DLH and HIB late tonight when clouds are
fewest. Cumulus cloud field should return and affect the terminals
Sunday morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
DLH  58  80  59  79 /  10  10  10  10
INL  58  85  63  82 /  10  20  20  40
BRD  60  81  64  82 /  10  10  10  20
HYR  57  81  59  82 /  10  10  10  10
ASX  58  82  59  82 /  10  10   0  10

&&

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

&&

$$


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