072 FXUS63 KFGF 200007 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 707 PM CDT Mon Aug 19 2019 .UPDATE... Issued at 654 PM CDT Mon Aug 19 2019 Still a bit of uncertainity how things will evolve tonight, esp in regards to strength (severity) of t-storms. The various short range models such as the RAP/HRRR indicate a weak low in NW ND moving east tonight along a northward moving low level moisture axis. Dew pts climbing to around 70 in SE ND and this moist airmass will push north tonight. Sfc low likely to move along this boundary from central into east central ND by late tonight then southeast Tuesday morning. Isold t-storms forming in far western ND at 00z, but the main action is expected to form closer to or just north of the sfc low in far north central ND closer to midnight and then spread east-southeast thru NE ND into NW MN overnight. Focus of stronger activity is in NW MN 08z-12z period as 500 mb short wave coming around the upper low in northern Manitoba moves into the area providing some upper level forcing. But late night storms likely more elevated vs sfc based but tstm action on nose of a 30 kt 850 mb jet spreading low level moisture into the storm development area. Net result may end up being heavy rain producing storms with marginal severe threat (hail, gusty winds). Before this an isolated shower did form in the CU field that was from near Bemidji to Detroit Lakes to Wahpeton..on leading edge of higher dew pts. This shower formed near Detroit Lakes and has been moving east and as of 00z is about dissipating and expect that trend to continue. && .SHORT TERM...(This evening through Tuesday night) Issued at 313 PM CDT Mon Aug 19 2019 Storms tonight will be the main challenge for the period. The moisture has arrived, at least in our southern CWA ahead of a weak trough axis. ML CAPE has reached 1000-1500 J/kg across our southwestern counties, and even higher surface based. There is some bubbly cumulus just east of Fargo, but so far not much taking off with no strong upper forcing and not enough convergence along the weak surface trough. However, there will continue to be moisture return into this evening as the surface trough gets going to the west and winds pick up out of the south. The models are still probably overdoing the dew points a bit, but think there should be some 60 dew points and over 2000 J/kg of MU CAPE pushing towards the international border later tonight. Deep layer bulk shear is around 40 kts, and forcing should come as a cold front moves from the Canadian border towards ND and MN. CAMs have been becoming more consistent with storms moving down into our northern counties overnight, with some pretty high updraft helicity values. Bumped up POPs for the 09Z to 18Z time frame, and included a mention of severe for at least part of the area. Any storms will be elevated so hail of quarters and winds of 60 mph will be the primary threat. The cold front will push further into the forecast area during the day on Tuesday, with most of the lingering precipitation exiting the eastern CWA by early afternoon. Temps and dew points will be lower behind the front, with highs in the 70s and breezy north winds. The dry air will help Tuesday night temps drop pretty low as skies clear and winds decrease, with readings down into the 40s and 50s. .LONG TERM...(Wednesday through Monday) Issued at 313 PM CDT Mon Aug 19 2019 Wednesday through Friday The pattern looks to be fairly settled for Wednesday as a ridge will be located to the west. Some lower 500mb heights following the passage of the cold front will keep temperatures slightly below average with highs generally 70 to 75 degrees. With mostly clear skies into the night, lows could drop into the mid 40s in some locations Wednesday night. Thursday looks to remain settled as well with similar temperatures. Thursday night into Friday morning is when the pattern is suggested to become active again. Though disagreement exists within the guidance, the ridge will be located over the area Thursday night and moving to the east. The GFS and Canadian-NH are both showing embedded shortwaves over the area by Friday morning continuing during the day, which will keep chances of showers and thunderstorms in the forecast. The ECMWF and Canadian-NH are both suggesting large troughing moving south from Canada by Friday night. Temperatures will remain in the 70s with seasonal lows Friday night. Saturday through Monday Much of the latter portion of the long term will be dominated by an active pattern. Small shortwaves are shown by all guidance on Saturday, keeping at least isolated chances of showers and thunderstorms in the forecast. Temperatures will likely remain mild. Saturday night to Monday will have chances for better coverage as the WPC is forecasting a cold front to progress across North Dakota with low pressure areas in Manitoba and South Dakota. The NAEFS Ensemble Situational Awareness Table is also suggesting PWAT values to be in the 90th percentile area-wide Saturday night into Sunday, meaning that isolated heavy rainfall within convection is possible. Rainfall totals Saturday night into Monday could be near or above an inch in many areas. Temperatures will remain seasonal during this active period. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 654 PM CDT Mon Aug 19 2019 VFR expected for most of the night but after 08z/10z period risk of t-storm activity increases near TAF sites with initial cloud bases in the 4000-7000 ft agl range. As cold front drops southeast behind low pressure Tuesday daytime..a period of MVFR cigs is psbl in the morning but confidence is low. Otherwise likely some CU develolpment in the afternoon Tuesday in the cold advection. North-northwest winds 10 to 20 kts daytime Tuesday. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Riddle SHORT TERM...JR LONG TERM...Wasilewski AVIATION...Riddle