640 
FXUS63 KFGF 251803
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
103 PM CDT Tue Jun 25 2019

.UPDATE...
Issued at 1259 PM CDT Tue Jun 25 2019

Additional adjustments to PoP/sky to reflect ongoing shower 
coverage and trends in CAMs. Axis of 500 J/KG ML CAPE developing 
in region of clearing (MUCAPE ~1000 J/KG). This ha support a few 
weaker storms developing, though over the next few hours 
additional destabilization will support a few stronger updrafts. 
A few CAMs (including HRRR) still indicating potential for 
stronger updrafts before 2PM closer to the Red River Valley, but 
main focus before 4PM is still further east based on timing of 
shortwave trough. 

UPDATE Issued at 1010 AM CDT Tue Jun 25 2019

Showers still tracking across northeast ND and northwest MN
(mainly north of Hwy 2). Increased coverage to reflect current 
radar trends. Otherwise we are still looking and the activity to 
continue to transition east through the afternoon. Narrow window 
for severe still can't be ruled out in NW MN midday through the 
early afternoon, but CAMs indicating threat may be further east
this afternoon. Before that there could also be funnel potential
with high vorticity associated with mid level circulation/cold 
pool transitioning over our northern CWA. Will have to monitor as 
instability is just recently beginning to increase. 

UPDATE Issued at 636 AM CDT Tue Jun 25 2019

Showers will continue along and north of Hwy 2 this morning with 
a few claps of thunder along the international border. Upper wave
continue to progress east slowly with coverage expected to expand
across NW MN around the lunch hour. 

&&

.SHORT TERM...(Today through Wednesday)
Issued at 353 AM CDT Tue Jun 25 2019

Showers continue across the north this morning and will do so as
upper wave tracks along the international border. As instability
increases with daytime heating shower and thunderstorm coverage
will expand across NW MN under the upper forcing. An isolated
severe storm is possible early this afternoon as 0 to 3km MU CAPE
up to 1500J/kg of instability develops. With the instability and
steep lapse rates will see the possibility of 1 inch hail and
severe down burst winds up to 60mph with any stronger low topped
convection. This potential exists across the Lake of the Woods
southward to the Bemidji area. 

Temperatures today will be coolest across the cloudier areas of NW MN
with low to mid 70s and upper 70s to near 80 across the west and 
Red River Valley with breezy west winds. Showers and thunderstorm
chances will begin overnight across the southern valley as the
northern portion of a convective complex may brush the southern
valley. Placement and cloud cover impacts for Wednesday temps
still to be determined however thinking that temps will begin
their upward climb with highs topping out in the low to mid 80s. 

.LONG TERM...(Wednesday night through Monday)
Issued at 353 AM CDT Tue Jun 25 2019

The main focus for the extended period is above-normal 
temperatures and increasing thunderstorm chances. 

Wednesday night through Thursday...

By Wednesday night a northwest to southeast upper level ridge is 
expected to be in place from northern MT into the central Plains. 
Under this ridge, a poleward flux of higher quality boundary layer 
moisture characterized by dewpoints in the low to mid 60s is 
expected to reach northward up to the I-94 corridor. Despite 
nocturnal cooling, this increased boundary layer moisture will help 
promote moderate instability across southern ND overnight Wednesday 
through Thursday morning. Although forcing for ascent will be 
minimal for much of Wednesday night, several deterministic models 
suggest a weak upper level impulse will orbit around the upper level 
ridge and into southern ND early Thursday morning. This will provide 
forcing for ascent that may be able to realize the instability in 
place across the region. Deep layer shear values of 30-45 knots out 
of the west will promote organized, and possibly severe, storm 
propagation from central ND towards the eastern half of the state 
between early Thursday morning into Thursday afternoon. Although 
confidence in exact timing is low, the most likely location for 
severe weather will be along and south of the highway 200 corridor 
where greater moisture/instability will be in place.  At this time, 
the most likely threat appears to be strong winds, but the severe 
threat will be conditional on storm evolution as the system moves 
into the region. 

Friday through Sunday...

Continued lee troughing across MT/WY will continue to promote a 
northward flux of warm/moist air into the region and help maintain 
instability across the region. This will also help shift the upper 
level ridge to the east through the day on Friday and introduce 
southwesterly flow over ND by Friday night. An upper level impulse 
propagating through this southwesterly flow is expected to help 
eject the lee low into the Dakotas and MN Friday afternoon through 
Saturday afternoon. Some guidance suggests showers/thunderstorms 
will be possible across the region along the warm front on Friday 
afternoon, but confidence in these storm chances is low. 

Thunderstorms will be more likely along a surface trough/weak cold 
front Saturday afternoon as the surface low moves into eastern 
ND/northwest MN. The instability/shear parameter space described by 
both deterministic and ensemble guidance suggests organized severe 
convection will be possible Saturday afternoon. However, confidence 
in exact timing and location of the severe risk is low at this time 
due to model spread. 

Also worth noting is the warm temperatures on Saturday. With 
afternoon high temperatures expected to reach into the low 90s with 
dewpoints in the upper 60s to low 70s, heat indicies may reach to or 
above 100 across portions of the region, particularly across the 
southern Red River Valley/Fargo area where higher dewpoints and 
temperatures are expected. 

Sunday night through Monday...

A gradual pattern change is expected for Sunday through Monday as 
upper level flow becomes more zonal to northwesterly as the upper 
level ridge over the central CONUS begins to deamplify. Most 
guidance is in fairly good agreement with this pattern change and 
with a weak upper level low moving through the region sometime late 
Sunday into Monday morning. Scattered showers and thunderstorms will 
once again be possible as this system moves through, but the severe 
potential will be conditional on favorable timing of diurnal heating 
and the passage of the upper level wave and associated surface 
trough. 

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1259 PM CDT Tue Jun 25 2019

MVFR ceilings lingering at KBJI, but should improve early in the
TAF period. VFR expected to prevail elsewhere in eastern ND and
northwest MN, though brief drops to 2500-3000 KFT AGL with
showers/storms can't be ruled out this afternoon (before 22Z). 
Any shower/storm activity should transition east of our terminals 
after 22Z. Wind gusts this afternoon in eastern ND and KTVF
(west-northwest) will occasionally reach 20-22kt range. Winds
should decrease and shift to the west-southwest 5-7kt this 
evening.

&&

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

$$

UPDATE...DJR
SHORT TERM...JK
LONG TERM...AM
AVIATION...DJR