Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 132132

Area Forecast Discussion
National Weather Service Grand Forks ND
332 PM CST Mon Nov 13 2017

.SHORT TERM...(This evening through Tuesday)
Issued at 320 PM CST Mon Nov 13 2017

Issue tonight is low cloud and/or fog formation. Uncertainity
abounds in the exact trends, but given warmer and more moist
airmass moving in, some snow melt conditions should favor fog
formation over much of eastern ND. HRRR-TLE and NSSL WRF indicate
best fog development RRV and west tonight into mid morning
tuesday. Farther east low clouds a bit better bet with some fog as
well. Though how dense is questionable due to likely clouds. One
batch of clouds moving up north this aftn reaching nr CKN-BJI at
20z. This batch may clear a bit from the west this evening before
more develops overnight. Ceilings likely to lower into IFR range,
esp higher terrain around BJI/PKD. Overall clouds with patchy fog
east and areas of fog west seems reasonable. At the present time
models indicate best bet for any drizzle to be east of our fcst
area more from SW MN into the Duluth-Brainerd area.

Frontal system will move through Tuesday aftn/eve. Ahead of front
mild with likely lower clouds lingering. At the present time the
chance for any precipitation has diminished and no longer
mentioned daytime Tuesday.

.LONG TERM...(Tuesday night through Monday)
Issued at 320 PM CST Mon Nov 13 2017

A clipper moves across southern Canada towards the upper Great Lakes
region Wednesday with a cold front moving through from the west late
Tuesday into early Wednesday. This will increase precipitation
chances in the form of mainly light snow Wednesday. Model guidance
varies on the degree of precipitation being realized Wednesday as
well as the type of precipitation falling. Most guidance suggests
the region will be in the dry slot of this clipper ridding the moist
column of seeders hinting at some chance of freezing liquid. However
with the strong cold air advection expected behind the cold front as
well as northwest winds uncharacteristic of typical freezing liquid
for the region, this leads me to believe the dominant type will be
mostly snow with the forecast reflecting this. Best chances for snow
resides in northwestern Minnesota and very near the international
border. Accumulations are expected to be generally light, however
would like to see better agreement between global versus regional
models. The next precipitation chances come Thursday, Friday, and
into Saturday as a deepening low develops within Canada and it`s
cold front passes through the region around Friday. Snow is expected
to be the dominant type with some chances of rain or wintry mix
associated with strong warm air advection ahead of the cold front.

Another factor to this week`s weather will be the noticeable increase
in winds. A tightened gradient behind the cold front Wednesday will
yield winds gusts into the lower 30s mph, then followed by return
flow Thursday into Friday will increase winds, possibly with wind
gusts into the upper 30s/lower 40s mph within the return flow
Thursday afternoon.

Temperatures will continue to roller coaster with periods of well
below normal behind the aforementioned cold fronts Thursday and this
weekend, and closer to normal within return flow Thursday and Friday.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1220 PM CST Mon Nov 13 2017

Issue will be fog chances and low clouds overnight. Low cloud
threat appears more in a SW to NE fashion from E SD into north
central MN (BJI) area. Now west of there enough clear sky this
evening and moisture added to the air due to snow melt (in those
areas with snow) so that even with a bit of south wind some fog
development is likely. Combo of radiational and due to low level
moisture advection. Used the conshort idea of fog/clouds for the
TAF which does bring many areas into IFR range overnight. But
confidence on exact visibilities are rather low.




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