FXUS63 KFGF 300809
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
309 AM CDT Tue May 30 2023

.SHORT TERM...(Today through Wednesday)
Issued at 307 AM CDT Tue May 30 2023

Key Messages:

-Showers and thunderstorms are possible once more this afternoon, 
and again on Wednesday. 

-Conditional chances for strong to severe thunderstorms remain in 
place, especially for the southern Red River Valley and west central 
Minnesota.

-Best case scenario brings scattered non-severe to marginally strong 
thunderstorms into the area today and Wednesday; this is the most 
likely scenario.

-Worse case scenario allows storm-scale modification of the 
environment in the presence of thunderstorm activity, which would 
support isolated severe thunderstorm impacts.

Discussion:

Synoptic pattern remains rather amplified across the CONUS, with a 
deep trough, to our west, extending southward into the Four Corners 
region, and an H5 ridge, to our east, extending northward into 
western portions of the Hudson Bay region. 

For the Northern Plains and Upper Midwest, we will see shortwaves 
propagate northward into the area, bringing showers and 
thunderstorms during periods of peak heating. CAPE values remain in 
the 1500 to 2500 J/Kg range today and Wednesday, with minimal deep 
layer shear. Thunderstorms that form will do so in response to waves 
of energy pushing northward into this pool of instability. 

A few stronger storms are possible, and severe thunderstorm 
potential highly conditional both today and Wednesday. Any severe 
potential will be in response to storm-scale shear enhancements. 
Currently, several CAMs actually show this taking place in portions 
of the southern Red River Valley and west-central Minnesota this 
afternoon, but with very low confidence. The most likely scenario 
would be isolated marginally strong thunderstorms capable of small 
hail; however, In a storm-scale modified environment, the same 
storms could produce larger hail up to 1 inch and 60 mph wind gusts.

.LONG TERM...(Wednesday night through Monday)
Issued at 307 AM CDT Tue May 30 2023

Key Messages:

-A gradual warming trend will result in persistent well above normal 
temperatures throughout the long term period.

-Periodic chances for scattered showers and weak thunderstorms will 
be possible through the end of the week and into the weekend.

Discussion...

An unsettled weather pattern looks to persist through the end of 
the week. Southwesterly flow aloft looks to remain in place on 
Thursday, with transient shortwaves progged to travel through the 
flow pattern. Given the overall weak nature of these shortwaves, 
widespread organized severe is not anticipated. Rather, with modest 
instability from warm temperatures and persistent moisture 
advection, scattered showers and weak thunderstorms are the 
expectation. Still, a few stronger storms capable of gusty winds and 
small hail cannot be completely ruled out, but should remain sub-
severe. These scattered showers and thunderstorms will be possible 
both Wednesday evening and Thursday afternoon and evening as this 
activity will be more diurnally driven. Exact QPF amounts will be 
tough to nail down as these showers and storms will be spotty in 
nature. Regardless, any thunderstorms that do develop will have the 
potential for higher rainfall amounts. 

Moving toward the weekend, synoptic forcing from these periodic 
shortwaves will become much more limited as ridging aloft begins to 
back build into the Plains. Initially, southerly flow on Friday may 
still be able to introduce a shortwave to the region. As a result, 
some chance (30-40%) will remain for showers and thunderstorms 
across the region, with the same caveats regarding rainfall amounts 
as earlier in the week. Moving into the weekend, the ridge axis 
looks to become centered over the Plains. While large scale 
subsidence aloft will generally work in favor of keeping things dry, 
a few diurnally driven pop up showers or storms cannot quite be 
ruled out. Especially given strong daytime heating and persistent 
moisture advection into the region at the surface. Otherwise, 
temperatures look to continue a warming trend from Friday into the 
weekend. Highs in the 80s to low 90s will be likely, with even a few 
mid 90s readings not entirely out of the question. As the ridge 
aloft continues to retrograde, the northern Plains looks to fall 
underneath north-northwesterly flow aloft moving toward the early 
week period. This will result in a slight cool down (although still 
above normal temperatures) and potential for increasing chances for 
precipitation with any ridge riding shortwaves that develop. 
Confidence in precipitation at this time is low, but will bear 
monitoring moving forward.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1146 PM CDT Mon May 29 2023

Convection continues to be the main challenge with fairly random
thunderstorms going in and out of the TAF sites. Mostly VCTS for a
while longer tonight, but should start to see a decrease in
activity towards morning. Still some indication of MVFR ceilings
at our MN airports, so kept some lower ceilings for a while
towards morning. Ceilings will lift and all sites should be VFR by
late morning, with some clearing late in the day. Winds will shift
around from the south to southwest, then become light and variable
by the end of the period. 

&&

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

$$

SHORT TERM...Lynch
LONG TERM...Rick
AVIATION...JR