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