015
FXUS63 KFGF 140911
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
407 AM CDT Wed Aug 14 2024

.KEY MESSAGES...

-Showers and thunderstorms will increase in coverage today and
 last into Thursday. Heavy rain and lightning are the main
 impacts.

&&

.DISCUSSION...
Issued at 351 AM CDT Wed Aug 14 2024

...Synopsis...

500 mb low moving slowly east/northeast thru west
central/central Saskatchewan with one area of concentrated
t-storms in that area. In our region though a second weaker
upper low is over partrs of Oregon/Idaha with a broad 500 mb
ridge into Minnesota. This puts our area in southwest flow aloft
and within this flow there are numerous short waves seen on
water vapor this early morning. How these short waves move and
bring development of showers/t-storms is the main forecast
challenge. PWATS are near 2 inches in a zone over central SD/ND
and this ribbon of deeper moisture slides slowly east today but
basically remains in the Devils Lake-Jamestown-Bismarck region
thru this evening.

Thunderstorm/heavy rainfall situation today remains typically
uncertain. HREF and various CAM guidance highlight what is the
most likely scenario which is t-storms from NW SD or SE MT
moving northeast and developing within this deeper moisture area
toward Devils Lake during the course of the day. Latest HRRR
backs off on timing and focuses it more into DVL region midday
vs WPC/HREF had higher precipitation 12z-18z today. At this
point and time, either scenario is just as likely. Not much
development in central ND at 08z but as short wave from NW SD/NE
MT moves northeast rapid development of t-storms may occur and
bring the heavier rainfall this morning or wave is slower to
move and slower to develop t-storms and main rain is midday or
afternoon into Devils Lake area.

Either way...idea is for the concentrated area of showers and
t-storms in central ND into Devils Lake area to advance east in
time into the Red River valley late today/this evening and into
NW MN tonight...though with lower intensity rainfall.

With high PWATS localized rain amounts 2-3+ inches are possible
in the zone thru central ND into Devils Lake basin. Uncertainity
is high enough though and also past 7 day NDAWN precipitation
for the area shows little to no precipitation for most of the Devils
Lake area. Thus feel going with a flood watch before storms form is
not quite the way to go due to prior conditions have been mainly dry
weather.

Thursday will see 500 mb trough to our west slide over eastern
Dakotas/Minnesota with Global Canadian and ECMWF developing a
closed low aloft vs GFS is more progressive. 00z ECMWF remains
more consistent from run to run and at this time favored in
developing area of rain around the upper low into parts of E
ND/RRV and much of northwest MN Thursday on backside of the
upper low. Not a heavy rainfall but a general rain area. If more
progressive GFS is right then rain area Thursday is less and
ends as system moves east.

Weekend into early next week shows an upper level ridge building
into south central Canada and northern Plains. 00z operational
GFS is a complete outlier compared to the 00z GFS ensemble and
discounted at this time. It has an upper low in NW Ontario into
Manitoba vs a ridge. Net weather result with a ridge would be
temps more into the low 80s. Some risk of a shower/t-storm early
and mid next week due to short waves moving.




&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 1020 PM CDT Tue Aug 13 2024

Showers will impact GFK, FAR, and DVL within the TAF period,
with showers eventually impacting TVF and BJI towards the end of
the TAF period to after the TAF period. Lightning probabilities
are low, so for now will be keeping -SHRA and -RA, but lightning
may arise at FAR. Winds will increase in magnitude but will
remain primarily from the southeast for a majority of the TAF
period.

&&

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

&&

$$

DISCUSSION...Riddle
AVIATION...Perroux