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Area forecast discussion 
National Weather Service Grand Forks ND
1143 PM CDT Tuesday Jul 22 2014

issued at 1142 PM CDT Tuesday Jul 22 2014

Light winds were across the area. Plenty of rain fell over the
northern Red River valley yesterday. Will add patchy fog in the
north/northeast zones for late Tuesday night. No other changes made.

Update issued at 932 PM CDT Tuesday Jul 22 2014

Fog loop indicated clouds have dissipated. However with storm in
western ND, blow off should move into the southern zones for at
least part of the night. Dewpoints expected to drop off a bit
overnight. Will lower temperatures tonight a degree or two with high
pressure moving in.

Update issued at 656 PM CDT Tuesday Jul 22 2014

Northwest flow aloft over the area tonight becomes more so as ridge
and trough amplifies a bit. Cooler tonight with low in the fifties.
Surface dewpoints also in the fifties. Will look at temperatures at next
update. Tweaked winds up a bit for tonight but still light with high
pressure to move overhead by morning.


Short term...(this evening through Wednesday night)
issued at 240 PM CDT Tuesday Jul 22 2014

Challenges for the next few days will be temperatures and clouds as surface
high pressure tracks southeast across the area through Wednesday night.

Surface high pressure building into the forecast area
overnight...current thinking is that with little mixing and good
clearing will see efficient radiative cooling overnight. Center of
the high remains in S Manitoba so some mixing exists and will not
mention any fog in the grids...even with the heavy rain amounts
from last nights storm but pass along the potential for the next

Surface high with light winds and a relatively dry air mass fewer cumulus
than today with maximum temperatures in the upper 70s to low 80s for
Wednesday a near perfect northern plains Summer day.

Long term...(thursday through tuesday)
issued at 240 PM CDT Tuesday Jul 22 2014

Will continue to see increasing pop chances Thursday into Friday
across western forecast area as precipitable waters /instability advect in with 500mb
ridging ahead of the western ridge flattening potent short wave.
Instability remains highest in western Dakotas as upper low
pinwheels above the Alberta Saskatchewan border through Friday.

Friday night through Tuesday...the models are actually in better
agreement at the end of the period rather than at the beginning as
the pattern begins to shift once more to an amplified trough over
the eastern Continental U.S.. deterministic models differ on the timing of the
upper low over the weekend...with the GFS a bit faster than the
European model (ecmwf) and the Gem in between. With a fairly high amount of
uncertainty...kept some 20-40 probability of precipitation going through much of the weekend
before tapering them off late Sunday as even the slower European model (ecmwf) has
the upper low coming through. Temperatures by Sunday will be a bit cooler
than Saturday on the backside of the upper low and temperatures into early
next week should continue to be just slightly below seasonal
averages as we settle into northwesterly flow aloft.


Aviation...(for the 06z tafs through 06z Wednesday night)
issued at 1142 PM CDT Tuesday Jul 22 2014

Generally VFR conditions expected overnight and Wednesday with light winds.
However fog loop indicated some clouds developing south and west of
dvl. Will add scattered clouds around 4 thousand feet at dvl. Also
will add some patchy fog in the northeast/east zones late Tuesday night.


Fgf watches/warnings/advisories...


short term...jk
long term...jk/Jr

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