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Area forecast discussion 
National Weather Service Grand Forks ND
1133 PM CDT Friday Jul 3 2015

Update...
issued at 1130 PM CDT Friday Jul 3 2015

Forecast on track so no update needed.

Update issued at 930 PM CDT Friday Jul 3 2015

No update necessary.

Update issued at 630 PM CDT Friday Jul 3 2015

No changes this update period.

&&

Short term...(this evening through Saturday night)
issued at 245 PM CDT Friday Jul 3 2015

Forecast challenges for the short term will be smoke...fog
potential and timing onset of precipitation tomorrow night.
Overall models in general agreement with slight differences in
timing of a cold front that will move through the region from late
tomorrow night through Sunday evening. Will therefore use forecast
blend (superblend) for timing front end of convection (main event
will be early in the long term period...see below).

Tonight...ridge of high pressure and clam winds over central ND will
shift east and bring generally light winds to the region. This
will continue to trap smoke that subsidence has forced to the surface.
Another night of hazy and smoky conds will continue. Question is
whether or not fog will form as well. Fog tool did not produce
much significant fog tonight despite dew points in the middle 60s
and light winds...so will hold off and let evening shift monitor.

Fourth of July...skies will continue to appear cloudy as elevated
smoke lingers. The smoke should continue over the area until the
Sat night/Sunday cold front scours out the atmosphere. Late in the
day or early evening sky cover will begin to increase in the far
northwest...even sooner if any ts blowoff moves in from ts that
will develop in southern Canada. For the most part...however...most of
the day will be clear with the smoke filtering the sun as it has
much of the week. An open Golf will help pump increased moisture
into the region during the day.

Tomorrow night...main surface boundary will move into County Warning Area around 06z
and into the northern valley by about 12z. Convection ahead of the
boundary could begin spreading northwest to southeast across the region as early
as 06z to 09z...depending on timing and deep layer moisture. Deep
layer shear will remain only 15 knots to 25 kts...and the main severe
threat will be across western and central ND...lining up with Storm Prediction Center
marginal risk area. GFS and NAM are similar in solutions for 06z
to 12z and have used superblend for guidance.

Long term...(sunday through friday)
issued at 245 PM CDT Friday Jul 3 2015

Sunday into Sunday evening...main surface boundary should move into
northwest Minnesota during peak heating hours Sun afternoon. Models have
been fairly consistent with the best deep layer shear being behind
the front...only 25 knots to 35 knots in the area of very high convective available potential energy on
the order of 2k to 3k j/kg (possible) depending on dew points. The
NAM has been a bit more bullish with dew point values. Today dew
points are in the middle 60s h850 flow from the Southern Plains
should tap into Gulf moisture...so realizing these cape values
does not seem out of the question nor do the higher NAM dew point
values. The biggest factor will be the shear...where the GFS is a
bit more bullish. Should higher shear move ahead of the surface boundary
Sun afternoon...more organized severe is quite possible.

Sun night into Monday...front will move across Minnesota with Post
frontal showers and storms lingering in the east through early Monday
morning. A much cooler Canadian airmass will sink into the
northern tier of the Continental U.S. And bring daytime highs well below
seasonal norms to the region on Monday. Unfortunately...upper
level winds will reset to northwest flow pattern and cold bring back
smoke from upstream fires in northern sask/Alberta.

Monday night through Friday...medium range models are in pretty good
agreement on starting out the period with dry conditions and below
average temperatures as high pressure builds down into the northern
plains. The next shortwave trough should start to move into the
northern plains by middle week...and there are differences in the exact
timing of the system with the European model (ecmwf) a bit faster than the other
deterministic models. Blended solution has fairly high probability of precipitation Tuesday
night through Wednesday and that seems reasonable at this point.
West to northwesterly flow aloft sets up by the end of the period
and as expected models are struggling with the timing of various
weak shortwaves coming through. Will keep chance probability of precipitation going with a
return to temperatures near seasonal averages.

&&

Aviation...(for the 06z tafs through 06z Saturday night)
issued at 1130 PM CDT Friday Jul 3 2015

Maintained haze through the overnight for all but bji. Could see
some improvement towards morning but more likely will be middle
morning when mixing increases. Some potential for rain showers/thunderstorms and rain
tomorrow afternoon across eastern ND but coverage likely to be
spotty so left out of tafs at this point.

&&

Fgf watches/warnings/advisories...
ND...none.
Minnesota...none.
&&

$$

Update...voelker
short term...speicher
long term...Jr/speicher
aviation...voelker

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