Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 171204
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
704 AM CDT Tue Oct 17 2017

.SHORT TERM...(Today and tonight)
Issued at 321 AM CDT Tue Oct 17 2017

How warm today is the question, as 850 temps warm some 5 deg C
from 00z Tue to 00z Wed. Southwest wind today in the 10-20 kt
range today along with plenty of sun should help boost temps a
good 4-5 degrees over Monday`s. Thus went with the warmer guidance
ideas for highs today, which push much of the Red River valley
into the 74-77 range. Clear sky tonight until very late when some
high level moisture increases into the DVL region ahd of the
front. 850 mb winds increase overnight with 40-50 kts at 850 mb
level, but inversion present near the sfc will keep these strong
winds from reaching the surface. Strong 850 mb thermal gradient
with vary warm airmass ahd of front with a good 10 deg fall in 850
mb temps behind it in a short time into DVL region close to 12z
Wed. The inversion just abv the sfc will shield the area from the
very warm and windy airmass just abv.

.LONG TERM...(Wednesday through Monday)
Issued at 321 AM CDT Tue Oct 17 2017

For Wednesday...how strong will the winds be. All models indicate
the max in 850 mb are in the 12-15z period as the front moves
through with 40-50kt. 925-850 mb wind decrease some by 18z into
the 30-40 kt range. GFS soundings show better mixing at 18z with
mixed layer to just above 800 mb in NE ND where winds of 45 kt
present. All signs point to advisory criteria winds in the DVL
basin,nrn RRV Wed midday-aftn with sustained values 25-30 kts and
gusts 45kts. Best drying aloft and best mixing and thus highest
risk of 50kt winds reaching the surface is a bit farther north
more over parts of southern Manitoba closer to the deep low in
northern Manitoba. So for this reason no high wind watches being
issued. Since advisory more likely will let dayshift monitor for
further updates/changes. Significantly cooler Wednesday with highs
upper 50s to lower 60s.

Thursday and Friday will be marked by a return to warm
temperatures and breezy southerly winds. Current guidance is in
reasonably good agreement of a warm, moist airmass being advected
from the central plains into the Red River Valley and surrounding
regions. This warm advection regime at the surface will aid in
building of the upper level ridge over the Plains and south
central Canada. Temperatures for Thursday and Friday are expected
to reach into the low to mid 70s for much of the Red River
Valley... eastern North Dakota... and west central Minnesota with
mid 60s expected for northwest Minnesota. Southerly winds at 15 to
20 mph with gusts to 25 mph are likely both days.

Meanwhile... a longwave trough is anticipated to begin moving into
the Pacific northwest region during this time period. Lee
cyclogenesis is expected over the norther plains on Saturday...
through model guidance differs on the placement of the surface low
as well as the speed and orientation of the upper level trough.
However... with sufficient moisture in place rain showers are
expected along a cold front during the day and into the evening on
Saturday. Though a few recent model runs have hinted at enough
instability for a few thunderstorms, confidence is not high enough
to keep thunderstorms in the forecast at this point. Scattered rain
chances will continue Sunday through Monday as some model guidance
suggests a secondary shortwave embedded in the northwesterly flow on
the backside of the longwave trough. This could allow for a few
showers across the region. Temperatures Saturday and Sunday should
cool to the low to mid 60s for much of the region. A return to
seasonal weather is expected for the start of the next work week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 702 AM CDT Tue Oct 17 2017

Winds today the main issue. A steady south-southwest wind will
increase in speed and be in the 15 to 25 kt range in E ND/RRV and
and more in the 10-15 kt range east of the RRV today. Skies
clear-FEW250. Low level wind shear tonight as winds at 2000ft agl
will be nr 40 kts while considerably less at the surface due to
inversion.

&&

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

$$

SHORT TERM...Riddle
LONG TERM...AM/Riddle
AVIATION...Riddle



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