Area Forecast Discussion
Issued by NWS Grand Forks, ND

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615
FXUS63 KFGF 172347
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
647 PM CDT Thu Aug 17 2017

.UPDATE...
Issued at 647 PM CDT Thu Aug 17 2017

Made some updates to PoPs to slow down the arrival of any
precipitation to the forecast area. Not a whole lot of activity
yet out in western North Dakota so will continue to watch timing
and coverage. Otherwise, the rest of the forecast looks good.

&&

.SHORT TERM...(This evening through Friday)
Issued at 208 PM CDT Thu Aug 17 2017

Rain chances through the short term will be the main
challenges/impacts. Next short wave in Montana will slide through
the fa later tonight into Friday with associated surface low
propagating from west central nd to any wheres from se ND to east
central SD tomorrow morning. Upstream cloud trends and model
guidance indicating that initially this system will be lacking
deeper layered RH with precipitable h2o values from .75 to an inch
and upstream dew points in the 40s. Convective parameters also
limited with 250-500j/kg mu cape and lifted/showalter indices
around zero with minimal shear. Low level convergence weak but
there is a modest 25-30kt low level jet focused to n ND so will
have higher chc pops this area. Based on current dewpoints minimum
temperatures will generally range in the 50s to around 60.

Based on track of sfc low appears best rain potential tomorrow
will shift from nw-se across the fa and adjusted pops accordingly.
Some differences continue between models on actual low track so
for now maintained just chance pops. Clouds will again keep
temperatures blo average.

.LONG TERM...(Friday night through Thursday)
Issued at 208 PM CDT Thu Aug 17 2017

For Friday night and Saturday, an upper ridge builds through and
brings mostly sunny, dry, and warm conditions with highs in the 80s
for much of the area. Depending on how strong the return flow and
ridge build in Saturday, highs could reach the upper 80s to near 90
degrees.

Late Saturday afternoon through early Sunday, a cold front pushes
across the area from west to east. This looks to be a drier frontal
passage with such brief duration of the return flow. Still may see a
isolated storms in the area, but the models suggest that weak upper
level forcing, lack of deep layer moisture, and time of day greatly
limit potential for severe storms. After this system rushes through,
Sunday will be generally dry with near normal temperatures, before a
weak shortwave aloft bring small chances for showers to the Devils
Lake region and southeast ND Sunday night.

Early next week, zonal flow aloft yields an active weather pattern
with near normal temperatures. For Monday and Tuesday, increased
cloud cover and small chances for showers and storms continue on and
off as a low pressure system cuts through the Central Plains and
weak shortwave disturbances pass through the Northern Plains. Model
confidence weakens considerably after the aforementioned system
moves through, but there is a signal for a period of high pressure
and drier weather during the Tuesday night to Wednesday night time
frame.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 647 PM CDT Thu Aug 17 2017

VFR conditions expected throughout the period. Cloud cover will
increase across eastern North Dakota late this evening/early
overnight and spread eastward. However, ceilings should remain
VFR. Showers/thunder to also spread eastward but coverage
potentially too spotty to mention yet. Lastly, fog at KBJI isn`t
out of the question towards morning but guidance keeps it just
east of there for now.

&&

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

$$

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



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