036
FXUS63 KFGF 221746
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1246 PM CDT Fri Sep 22 2017

.UPDATE...
Issued at 1240 PM CDT Fri Sep 22 2017

Weak returns just starting to get going over the DVL basin the
last few scans. Cams have been overdoing shower development on
cold side of boundary so far today. Continued to delay development
with pops the remainder of the mid afternoon. All cams in
agreement in keeping warm sector dry so will continue trend.
Adjusted cloud cover some but remainder of forecast ok.

UPDATE Issued at 946 AM CDT Fri Sep 22 2017

Showers have yet to develop over the Devils Lake basin so delayed
pops.  Otherwise no changes.

UPDATE Issued at 649 AM CDT Fri Sep 22 2017

Made a few tweaks to POPs this morning as thunderstorms in west
central MN pull off to the east. A few tiny isolated showers have
tried to develop near the Red River, but have dissipated again so
will keep low POPs on the MN for a few more hours. More showers
will move into the west later this morning.

&&

.SHORT TERM...(Today and tonight)
Issued at 310 AM CDT Fri Sep 22 2017

Thunderstorm chances and severity will be the main challenge for
the period.

Water vapor loop shows an amplified pattern with a strong upper
low over the Intermountain West. This set up will continue for the
next few days with southwesterly flow aloft bringing several weak
shortwaves up into our area. Surface frontal boundary has set up
from Aberdeen, SD to Fargo and up towards the Roseau area. This
front will remain nearly stationary today, with a low pressure
center moving up from SD into western MN during the day. One weak
shortwave moving through this morning could bring some elevated
hailers to our far southern CWA, although there has been a
weakening trend as storms move north so far. Will continue to keep
an eye on storms forming along the nose of the low level jet.

The first round of morning convection across our south and east
should exit the area by mid morning at the latest, and there will
be a brief period with not much going on before showers get going
behind the cold front across the north and western counties. In
the warm sector of the low across our southeast, models have some
very high CAPE values near 4000 J/kg. However, the 700 mb temps
are above 12 C and even with highs reaching into the 80s the cap
may hold over the southeastern CWA. The best chance for some
severe weather will be along or just behind the frontal boundary
from the northern Red River Valley towards Lake of the Woods,
where some of the CAMs are showing some intense development by
afternoon. With storms likely elevated hail will be the biggest
threat.

Tonight, the surface trough axis and frontal boundary will slide
slightly further south and east. Convection across the
northeastern CWA will move off to the east overnight, leaving
mostly lingering showers behind the cold front. However, a few of
the models including the Canadian and some of the high resolution
runs like the NSSL-WRF, bring another round of convection into the
southern CWA out of SD by the early morning hours Saturday. Have
some higher POPs in that area after midnight.

.LONG TERM...(Saturday through Thursday)
Issued at 310 AM CDT Fri Sep 22 2017

Saturday and Sunday...The active pattern will continue with
southwesterly flow aloft and the surface trough axis and frontal
boundary just to our south and east. Exact timing of precip rounds
is hard to tell at this point with the timing of minor shortwaves,
but will continue to keep high POPs over the southeastern counties
nearest the front, with more widespread chances late Saturday
night and into Sunday morning as the global models are in decent
agreement with another shortwave coming out at this time and some
high QPF values over much of the CWA. With much of our area behind
the front and in rain cooled air the highs over the weekend will
be stuck in the 50s to low 60s for the most part.

Monday through Thursday...The start of the new work week will keep
the area in southwest flow aloft with an upper low out across the
Wyoming/Colorado area. A few weak waves will allow precipitation
chances to linger (mainly across the eastern half of the area)
until the low finally exits the region by midweek. Drier northwest
flow aloft and surface ridging should bring quieter conditions
for the Wednesday/Thursday time period. The latest GFS introduces
another upper low swinging through the Plains states late in the
week but is an outlier at this time compared to the other models.

Cool and cloudy conditions will keep high temperatures in the 50s
for Monday and Tuesday before warming a bit by midweek.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1240 PM CDT Fri Sep 22 2017

Cigs quite variable between low VFR and MVFR where there are
clouds. CIGS and shra/tsra potential will continue to be a
challenge the remainder of the period. With uncertainty on
coverage was pretty selective on mentioning pcpn as model guidance
so far has been too aggressive in bringing pcpn into the area.
Coverage of T also in question however with degree of shear and
some cape will keep some potential for T.

&&

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

$$

UPDATE...Voelker
SHORT TERM...JR
LONG TERM...JR/Lee
AVIATION...Voelker