Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 240038
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
638 PM CST Thu Nov 23 2017

.UPDATE...
Issued at 638 PM CST Thu Nov 23 2017

Updated sky and temps in the latest forecast. Will be watching to
see how road temps do as warm air moves in. All indications are
that roads will be above freezing by the time the rain comes
tonight. Right now, the only ND road ob that is below freezing is
near Pembina, while most of the NW MN roads north of highway 2
are below freezing. Still...believe roads will warm as temps rise
into the upper 30s to low 40s tonight. Could be close in some
areas, however.

&&

.SHORT TERM...(This evening through Friday)
Issued at 311 PM CST Thu Nov 23 2017

Key forecast challenges will be a non-diurnal temperature curve
overnight tonight, a potential for record warm low temperatures
for tomorrow, and windy conditions across portions of eastern
North Dakota and the southern Red River Valley on Friday.

A surface low will move across southern Canada this evening ahead
of an upper wave that will move across the region Friday morning.
A very warm H925-H850 layer will move across the region from early
this evening through mid-day Friday...with the H850 thermal ridge
over the valley at roughly 03Z this evening and breaking down by
15Z Friday. This will result in WAA beginning early in the tonight
period and overnight lows occuring over much of the area early this
evening...then remaining steady or rising overnight. The question
on whether or not Nov 24 record warm minimum temps occurs will be
how quick temps drop off late Friday evening, with coldest Friday
temps likely being just prior to midnight Saturday. An area of
rain showers will move across the north and northeast from late
tonight through early Fri aftn.

A sharp pressure rise will then follow as surface low moves into
Ontario, and NAMnest is indicating an area of advisory level winds
punching into the Devils Lake basin around 15Z...moving
southeast...and exiting Grant County MN early Fri aftn. This will
result in a 4 to 6 hour window where advisory level winds of 30
to 45 mph may occur from mid-morning to early afternoon. Will hold
off on issuing headlines at this time as impacts are still 18 hrs
out with some question on timing/exact location of highest winds.

.LONG TERM...(Friday night through Thursday)
Issued at 311 PM CST Thu Nov 23 2017

Mostly dry conditions are expected by Friday evening as surface high
pressure builds back into the Northern Plains and a surface low
moves off into the Great Lakes region. The NAM does suggests a few
lingering snow showers are possible in the Lake of the Woods region
into Friday night, though confidence is relatively low. Breezy
northwesterly winds will subside overnight into Saturday. Upper
level ridging will allow for overall calm conditions for Saturday
and Sunday with afternoon temperatures reaching into the low 40s for
southeastern North Dakota, cooling to the low 30s in northwest
Minnesota. Winds are expected to become more southerly late on
Sunday, allowing for warm return flow and slightly warmer
temperatures for Monday. Another clipper low embedded in a weak
upper level trough is expected to progress across southern Canada
Monday, bringing rain/snow chances Monday afternoon into early
Tuesday along the international border.

After Monday, models have been showing notable divergence and
ensemble spread with regards to the mid-week forecast. Most models
agree on the breakdown up the upper level ridging regime that has
been in place over the western U.S., favoring a series of less
amplified shortwave troughs after Monday. The main differences arise
in timing of these systems and progression/strength of attendant
surface features. Because of this, sticking with lower chances of
precipitation overall through Thursday with the best chances coming
in during the Wednesday/Thursday time frame.

A cool down back into the mid 30s is likely for Tuesday with the
passage of a cold front associated with the Monday night clipper.
Temperatures during the mid week period are expected to be slightly
above seasonal average with highs the mid 30s and overnight lows
dropping to the mid 20s. Any precipitation that may occur towards
the end of the forecast period may fall as snow along the
international border, but temperatures above freezing will likely
result in rain further south.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 527 PM CST Thu Nov 23 2017

Aviation-wise, there is the potential for some low level wind
shear across the region this evening. The best chances appear to
be in the DVL and BJI areas where, after the inversion sets in,
we`ll likely see 45-50 kts just off the surface at 2000 ft or so.
Also...with the cold front coming in late tonight/tomorrow
morning, some light rain and MVFR cigs are possible. There are
some hints at IFR cigs, but believe MVFR is more likely. Also...if
cigs do drop, it`ll likely only be for 2-3 hrs or so. Will be
watching low level temps closely to see if freezing rain is a
possibility. Based on latest temp forecast, think TAF sites are
OK. Winds with the front look strong and gusty tomorrow morning
and continue into the afternoon.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&

$$

UPDATE...Knutsvig
SHORT TERM...Speicher
LONG TERM...Moore
AVIATION...Knutsvig



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