Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Grand Forks ND
944 am CST Sat Feb 6 2016
issued at 943 am CST Sat Feb 6 2016
Expanded very low probability of precipitation to the far northwest forecast area remainder of the morning.
No other changes.
Update issued at 632 am CST Sat Feb 6 2016
Not much reaching the ground from radar echos over Montana or southern
Canada...so bumped probability of precipitation down but continued to keep a slight chance in
the north later today. With extensive cloud cover and the short
range blend trending a bit cooler...have highs in the southwest
just a few degrees cooler than original forecast but still well
Short term...(today through sunday)
issued at 358 am CST Sat Feb 6 2016
The possibility of blizzard conditions late tonight and Sunday
continues to be the main forecast concern.
Upper trough currently moving through the Pacific northwest will quickly
move east and enter the northern plains by late today. Surface low
pressure will move into southern Manitoba and winds should pick up
and shift to a more southwest or westerly direction by afternoon.
With the warm tongue at 925 and 850mb right over the Red River
valley at peak heating...we should have no problems seeing very
warm readings this afternoon with the west hitting the low 40s
with cooler temperatures in the east. The NAM and some of the short range
models break out some precipitation in the warm air advection coming
through...starting in the Red River valley middle day and moving off
towards the Lake of The Woods area by evening. Current radar
returns over the northern County Warning Area not showing much...but most models
have some intensification over the northern counties as the main
upper low approaches. Will continue to keep some low probability of precipitation in the
north...and some mixed precipitation is not out of the question with warm
air hanging around. Think that any amounts will be light...with
the main show on the backside of the upper system.
By tonight...the upper low begins dig into Minnesota as a large ridge
builds over the western Continental U.S....and a reinforcing shortwave comes
down the backside of the system late tonight and into tomorrow.
The second shortwave should help bring some fairly strong cold air
advection down the backside of the system by tomorrow...which will
help with mixing. 850mb winds are near 50 kts and even 925mb which
is more reachable are in the 35 to 40 knots range. BUFKIT model
soundings have strong winds mixing down starting during the early
morning hours at kdvl and spreading south and east throughout the
day. The main question is will there be enough snow to blow. The
models are in somewhat good agreement on some larger quantitative precipitation forecast values
for just east of the Red River as the upper system wraps up over
Minnesota. Further south and west it is less certain...with sref plumes
showing snow amounts at Devils Lake mostly clustered below one
inch...but quite a few member in the 2 to 3 inch range. With the
uncertainties of snow amounts and the fact that worst conditions
are still more than 24 hours out...will keep the blizzard watch
Long term...(sunday night through friday)
issued at 358 am CST Sat Feb 6 2016
Sunday night through Monday night...snow will begin to taper off
Sunday night although the tight pressure gradient remains. Much
more quiet for Monday as winds start to decrease...although temperatures
will be colder behind the departing system with highs mostly in
the teens with low 20s west. The colder air will linger over our
northeastern counties into Monday night although clouds will keep
temperatures in the west above zero. The GFS and NAM put out some very
light precipitation for Monday night as a weak shortwave comes down the
northwest flow but will keep probability of precipitation out for now.
Tuesday through Friday...long wave pattern Delaware-amplifies toward
the end of the period. Long wave ridge remains over western North
America while long wave trough remains over eastern North America
for the extended period.
The European model (ecmwf) was a farther east solution than the GFS early in the
period. The GFS becomes the farther east solution on day 7 and day
8. The European model (ecmwf) was trending farther east while the GFS was trending
farther west over the last few runs. Will blend the two models.
High temperatures were decreased one to three degrees for
Tuesday...decreased four or five degrees on Wednesday...decreased one to six
degrees on Friday. Little change was made on Thursday.
Aviation...(for the 12z tafs through 12z Sunday morning)
issued at 632 am CST Sat Feb 6 2016
High clouds will increase this morning...with some middle level
clouds around 5000-8000 feet moving in later in the afternoon and
evening. Some MVFR ceilings will be possible after 06z tonight. Winds
will shift around to the southwest and pick up by this
afternoon...then become breezy from the west to northwest during
the evening with gusts in the 20 to 25 knots range. By the end of the
period...it will be downright windy with gusts 30kts or above.
With increasing winds and snow moving into the region...kdvl and
kgfk could see some significantly reduced visibilities with
falling and blowing snow late in the period. Just included 2sm for
now but may be down even lower beyond into Sunday morning.
ND...blizzard watch from Sunday morning through late Sunday night for
Blizzard watch from late tonight through late Sunday night for
Minnesota...blizzard watch from Sunday morning through late Sunday night for
Winter Storm Watch from Sunday morning through late Sunday night