142
FXUS63 KFGF 170857
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
357 AM CDT Sat Aug 17 2024

.KEY MESSAGES...

- Wildfire smoke may impact sensitive groups within northwest
  Minnesota and eastern North Dakota this weekend.

&&

.DISCUSSION...
Issued at 344 AM CDT Sat Aug 17 2024

...Synopsis...

Areas of smoke, haze, fog cover the area. Pockets of dense fog
are forming in central ND in area of clear sky and light winds.
For today, expect likely some residual smoke/haze but just how
thick it is is highly uncertain as RAP/HRRR surface smoke
numbers fall below 10 ug/m3 today. Extensive collaboration was
done with BIS/ABR to come up with a unified approach and net
result was to stick to 7-10 ug/m3 concentrations for our smoke
grids and then blend as needed to avoid small patches of smoke
which wouldnt make sense. Overall with lower concenterations
once you get past 15z there is little to no smoke in the grids
today and beyond.

Did keep the 20 pop for shra/tsra in NW MN this aftn per prev
fcst. MUCAPE does reach around 1000 j/kg in the area and
convective temps in mid 70s, which will be reached. CAMs are not
producing much in the way of precip but certainly think that
keeping a chance is warranted based on CAPE values and any
potential short wave or weak covergence on backside of upper low
and east side of upper ridge/sfc high building in.

Dry tonight into Sunday. A little warmer Sunday with mostly low
80s.

Theme of having highs in the low-mid 80s continue next week as
500 mb ridge builds into the northern high plains and spreads
east. 500 mb flow becomes more zonal mid to late week as 500 mb
high shifts back from 4 corners region into the mid Mississippi
valley. Couple short waves will move along the US/Canadian
border, one Tuesday/Tuesday night which has been well
advertised. This one is associated with MUCAPE potential values
in the 1500-2000 j/kg range. In fact Tues-Thu afternoons will
see high CAPE values with probability of sfc CAPEs above 2000
j/kg in the 50 pct range in central ND. Thus Tues-Fri period
has chances for thunder in the fcst (except for Thu). This may
help set the stage for additional strong to perhaps severe
convection, although confidence in strength of storms is quite
low given uncertainties into the degree of unstable air mass as
well as details revolving around potential forcing and moisture.



&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1016 PM CDT Fri Aug 16 2024

Smoke will be the primary impact for the TAF period. MVFR
visibility will result from smoke for the entire TAF period,
with shifts to VFR also expected. No other aviation impacts are
anticipated for the TAF period.

&&

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

&&

$$

DISCUSSION...Riddle
AVIATION...Perroux