546
FXUS63 KFGF 102319
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
619 PM CDT Wed Jul 10 2024

.KEY MESSAGES...

- Risk for heat related impacts Friday through Sunday,
  especially for heat sensitive or vulnerable groups and anyone
  without effective cooling or hydration.

- Medium chance for thunderstorms Friday night and Saturday
  night, some may be severe.

&&

.DISCUSSION...
Issued at 247 PM CDT Wed Jul 10 2024

...Synopsis...

Ensemble guidance in decent agreement with evolution of the
larger scale pattern into early next week - depicting a
building western CONUS ridge with the main storm track across
Canada. Ensemble members diverge with the speed and track of
individual upper waves and how they will affect the ridging.
Uncertainty increases with the large scale pattern into the
middle of next week as ensemble members diverge and many
potential outcomes exist.

Surface ridging into Friday will lead to mostly quiet weather
with minimal impacts over the next couple days.

...Heat Impacts...

Convection this weekend would tend to limit overall heat
impacts, and the majority of ensemble membership produces
convection at some point. Of course, if capping holds (no
convection) heat impacts will be more severe. At this time most
likely outcome is for convection into the morning hours each
morning, which would limit the northern extend of the warmer
airmass. NBM MaxT 25-75 percentiles range from ~85F to ~95F
during this period (across the southern CWA at least, warmest
day Saturday). With crops nearing peak Evapotranspiration Td
each day should be ~70F. Heat index values would be >100F if the
temperatures were able to reach upper 90s, but that is a low
probability outcome. Even if advisory/warning heat criteria is
not reached, the new NWS heat risk product (which accounts for
duration of heat including both daytime and nighttime
temperatures as well as if those temperatures pose an elevated
risk of heat related impacts based on data from the CDC)
indicates at least a moderate risk of heat related impacts,
which would be mainly for heat sensitive or vulnerable groups
and anyone without effective cooling or hydration.

...Thunderstorms Friday night and Saturday night...

As noted in the heat impacts discussion, there is uncertainty
with convective initiation this weekend. There will be at least
moderate instability each day, with weak upper waves propagating
across southern Canada. This could be a "ridge rider" set up,
with overnight convection as clusters of storms move into the
instability from the north. Deep layer shear is weaker Friday
night, but much stronger Saturday night. Severe potential does
exist, although at this point there are still a lot of
questions.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 618 PM CDT Wed Jul 10 2024

VFR conditions prevail through the TAF period. Skies are clear
in eastern North Dakota, with FEW clouds in northwestern
Minnesota. Winds are light and variable overnight and into
tomorrow morning before turning southerly. Slight chance for
patchy fog in Minnesota overnight.

&&

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

&&

$$

DISCUSSION...TG
AVIATION...Spender