Area Forecast Discussion
Issued by NWS Grand Forks, ND

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538
FXUS63 KFGF 200544
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1144 PM CST Thu Jan 19 2017

.UPDATE... Issued at 1144 PM CST Thu Jan 19 2017

No final update needed this evening as the ongoing forecast
appears to still be on track.

UPDATE Issued at 950 PM CST Thu Jan 19 2017

Fog has stayed in check thus far this evening with visibilities
staying around one half mile, or even improving some. Even with
plenty low enough dew point depressions, it looks like winds have
stayed up just enough to inhibit any dense fog formation. Will
continue to monitor.

Additionally, bumped temperatures down a handful of degrees or so
across the far northwest where clouds haven`t quite reached yet
and readings dropped into the mid teens. Clouds are close now,
though, so don`t anticipate much more of a drop.

UPDATE Issued at 659 PM CST Thu Jan 19 2017

Main concern this evening will continue to be fog. One area of
fog/low clouds continues to impact the far northern Red River
Valley, through Grand Forks, then expanding to the southwest
through the Cooperstown, Valley City, Gwinner, etc. areas of
southeast North Dakota. Will continue to monitor the extent of
this area of fog, in addition to a larger area advecting
northward out of South Dakota and west central Minnesota. Short
term/hi-res models continue to depict reduced visibilities across
pretty much the entire forecast area late this evening and
overnight, except for maybe near the Devils Lake basin.

As of now, the worst visibilities are hovering around 1/2 mile
but will continue to monitor throughout the evening for any
widespread areas below that for Dense Fog Advisory consideration.
The threat for any drizzle/freezing drizzle will also continue to
be watched. Current LAPS soundings show the low level saturated
layer is fairly shallow at around only 1 kft but model soundings
do show this layer expanding as the evening goes on.

&&

.SHORT TERM...(This evening through Friday)

Issued at 300 PM CST Thu Jan 19 2017

Fog/drizzle/mist potential will be the main impacts for tonight
continuing into tomorrow. For the most part skies have cleared and
visibility has lifted except for a narrow ribbon from Hallock
through Grand Forks and Valley City. Farther south a larger area
of stratus and fog over E South Dakota will work northward tonight
as moist low level southerly flow continues. Areas of visibility
blo a half mile so will have to monitor and would not be surprised
if dense fog advisory may be needed later this evening. Always
possible to see some zl/mist in denser fog however there is
minimal isentropic lift and moist layer very shallow so feel any
pcpn would be pretty spotty but again will need to monitor. With
higher dewpoints moving in some areas over the se half of the fa
may not drop blo freezing with coolest temperatures over the far
nw.

Lower condensation pressure deficits and isentropic lift clip the
far east tomorrow so this area may see more of a wintry mix than
just drizzle like farther west. Fog likely will also be around at
least for the am. Temperatures will remain mild although not a
great deal of recovery with clouds.

.LONG TERM...(Friday night through Thursday)

Issued at 300 PM CST Thu Jan 19 2017

Upper level low and lower level saturated layer to provide clouds to
the northern plains through the weekend and into early next week.
Only light accumulations are expected with primary ptype to be
liquid, rain or drizzle, across the valley and NW MN as thermal
profile remains unseasonably warm. 925mb temps and even SFC
dewpoints above freezing to persist into Sunday when blyr winds turn
to the west northwest. Devils Lake Basin will remain a bit colder
with a freezing drizzle or -sn threat Saturday into Saturday night.
Minimal diurnal temperature changes with the low level clouds,
highs and lows at most 5 degrees apart.

By Monday upper level low and associated weak lift move north of the
FA and the next area of concern begins to organize across the
central high plains. Model guidance with this system keeps the track
of the snow band across southern MN and Iowa Tuesday and Wednesday.
Will maintain some slight -sn chances in the far south during this
time. Thermal profile will gradually lower with highs steadily
decreasing from low 30s to mid 20s by the end of the period and lows
falling from 20s to teens, still above normal for the end of
January.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)

Issued at 1144 PM CST Thu Jan 19 2017

Low clouds/fog has finally spread to all TAF sites across the area
with LIFR ceilings and generally IFR visibilities. Expect
these conditions to continue through at least Friday morning along
with southerly flow of 10 kts or so. Small chance for some
improvement by Friday afternoon before mixed precipitation chances
begin to move into the area.

&&

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

$$

UPDATE...Lee
SHORT TERM...Voelker
LONG TERM...JK
AVIATION...Lee



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