430
FXUS63 KFGF 150553
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1253 AM CDT Wed May 15 2024

.KEY MESSAGES...

- On and off showers through at least the next week.

- Thunderstorm chances increasing over the next few days. A low
  probability scenario exists which would include a few strong
  thunderstorms on Friday.

&&

.UPDATE...
Issued at 1253 AM CDT Wed May 15 2024

The forecast remains on track this morning, with light shower
activity working very slowly eastward across the Devils Lake
basin. Temperatures range from the upper 40s near the
International Border to the low 60s in the southern Red River
Valley.


&&

.DISCUSSION...
Issued at 230 PM CDT Tue May 14 2024

...Synopsis...

Water vapor imagery indicates zonal flow aloft with several upstream
shortwaves meandering toward the region. Ensemble guidance in good
agreement with the general zonal flow pattern, but differ with
timing, strength, and location of individual shortwaves. All in
all anticipate on and off showers through at least the next
week with possibly a stronger thunderstorm. Through the next
week, the 25-75 percentile range for rainfall amounts across the
majority of the forecast area is 0.50-1.50 inches.

...On and Off Showers...

Water vapor indicates immediate subsidence through the late
afternoon behind the departing wave, but many more waves
approaching. HRRR indicates a few storms initiating across
north central ND this afternoon moving into the Devils Lake
basin this evening. This scenario seems plausible given the
current plume of instabilty ahead of the surface
convergence/low pressure. Any storms that do develop would
quickly dissipate this evening as they depart from the
instability.

Next wave of concern is currently across Idaho, with another
lead wave across southwest South Dakota. Ensemble guidance in
good agreement indicating these features will slowly propagate
through the region on Wednesday, with rain chance increasing
especially Wednesday afternoon and into the evening.

Beyond Wednesday, timing and location of waves uncertain.

...Severe Storm Potential...

There is a stronger wave that will be approaching from the
northwest by Friday, and ensemble guidance shows many different
scenarios with how this system will develop across southern
Canada. Location of this feature by Friday into Saturday will be
important, as stronger and further west would lead to increased
moisture return along with warmer temperatures and greater
instability, with the potential for strong to severe storms. In
fact, the CU machine learning indicates a low chance for severe
storms Friday and Saturday. Of course, a weaker and further east
system would not allow for moisture return or warmer
temperatures thus limiting instabilty. At this point each
scenario has an equal chance of happening.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1152 PM CDT Tue May 14 2024

VFR conditions should continue during the early TAF period
across eastern ND and northwest MN, with a few light showers at
KDVL. MVFR stratus arrives by 12Z at KDVL and eventually MVFR
(possible IFR) overspreads the region Wednesday as a low
pressure system is bringing a period of rain to all TAF sites
through Wednesday afternoon/evening. Winds will tend to vary
from the east to southeast 8-13kt, becoming more light and
variable near the low center Wednesday then shift to the north-
northwest 8-11kt at KDVL Wednesday evening as the low shifts
east.

&&

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

&&

$$

UPDATE...Lynch
DISCUSSION...TG
AVIATION...DJR