Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Grand Forks ND
648 PM CST Sat Feb 13 2016

issued at 647 PM CST Sat Feb 13 2016

Early finger of light snow if approaching James River Valley and
should be to Valley City in the 7 PM to 8 PM timeframe...however
this light snow if moving into drier air mass that will have some
impact. While I did not remove probability of precipitation...did delay categorical probability of precipitation
for the early evening hours and removed blowing snow through 9 PM
as there will be very little accumulation to blow around. Bis only
received one half an inch so far. No other changes to 7 PM update
at this time.


Short term...(this evening through Sunday night)
issued at 320 PM CST Sat Feb 13 2016

The main challenge will be snow event and wind tonight into
Sunday. Models have come into good agreement with this system and
confidence is increasing with evolution of event. The GFS has been
consistent along with the NAM so will utilize a blend.

For tonight...snow will develop in the western forecast area in the 00-03z
timeframe then slowly move east overnight. Southerly winds will
also continue to blow around 20-23kt along and west of the when snow is falling expect some blowing snow. Winds
will slowly subside after 9z. The best lift per q vector fields
does move into the southern forecast area later tonight with mainly
warm/moist advection ahead of the shortwave. There should be a
band of 2-5 inches in the south and west overnight...along with
the wind. The Winter Weather Advisory may need to be expanded into
the northern valley if snow moves in faster tonight and is heavier
than expected. It will take quite some time to saturate to the
east though with a very dry airmass in place...but we will
monitor. Temperatures will slowly rise tonight with continued warm air advection.

On Sunday...the main band of light snow should be moving into the
valley early then shifting east through the day with the
shortwave. Some minor accumulations around an inch...perhaps up to
2 inches are possible. Winds will be much lighter though with no
blowing snow threat after 15z or so.

For Sunday night...any light snow chances will be in the far east
with all other areas dry. Temperatures should be fairly mild with some
clouds expected with not much clearing behind shortwave and
minimal cold air advection.

Long term...(monday through saturday)
issued at 320 PM CST Sat Feb 13 2016

For Monday...expect a dry day with temperatures above normal. Northwest flow
will persist with clouds increasing during the afternoon ahead of
the next shortwave.

For Monday night...another chance of light snow with a fast moving
shortwave will spread northwest to southeast. Quantitative precipitation forecast amounts should be on the light
side but can/T rule out an inch or so...mainly in the southern 1/3
of the region near better lift.

On Tuesday...weak high pressure builds in with some cold air advection so temperatures
will be a bit cooler than Monday.

For Wednesday through Sat...high pressure will be retreating to the
east as the extended period begins Tuesday evening to be followed
by a couple of mainly dry days. Guidance in good agreement with
return southerly surface flow and zonal aloft encouraging surface
temperature rises to above average values as 850 mb readings stay above
freezing a good part of the time. Shortwave traversing
international border Thursday night/Friday is reflected weakly at surface
but with temperature profiles as they are anything or everything from
snow/ra/fzra will be possible to end the week.


Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 647 PM CST Sat Feb 13 2016

Main issue this forecast period is timing of snow and vsby/cigs. Still lots
of uncertainty regarding when snow will push east into the Red
River valley and northwest Minnesota and how intense it will be. Did slow down
timing a tad from previous forecast mainly due to dry airmass in place
and a bit slower movement of system overall. Winds will pick up
overnight into Sunday morning with surface winds in the 15 to 25 knots
range with higher gusts in the Red River valley...especially Fargo. Did
bring ceilings down into the MVFR range with the snow with vsbyspredominately
in the IFR range 1-3sm.


Fgf watches/warnings/advisories...
ND...Winter Weather Advisory until noon CST Sunday for ndz006-014-015-

Minnesota...Winter Weather Advisory until noon CST Sunday for mnz003-029-030-



long term...wjb/dk

National Weather Service Glossary of Abbreviations