Sunrise 5:42 AM   Sunset 8:33 PM Moonrise 4:23 AM   Moonset 7:37 PM

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FXUS63 KFGF 071432 AFDFGF

Area Forecast Discussion National Weather Service Grand Forks ND 932 AM CDT Tue May 7 2024

KEY MESSAGES

- Isolated thunderstorms mainly this afternoon over northeast North Dakota and northwestern Minnesota.

UPDATE
Issued at 932 AM CDT Tue May 7 2024

Forecast remains on track with rain through the early afternoon in the north before the dry slot moves in from the south. A few shallow top thunderstorms will likely form along a differential heating boundary propagating north through the dry slot along the backside of the cloud cover. Would expect main hazards to be lightning and gusty to winds to 40mph. Timing of these thunderstorms would be roughly 2pm to 8pm Along and north of I-94.

UPDATE Issued at 714 AM CDT Tue May 7 2024

Rain band filled in the past 2 hours with light rain now from NE ND southeast into central MN, moving NW. This aligns pretty good with pops and will see the higher precip chances gradually lift north this morning...with high pops remaining NE ND and parts of NW MN thru the day. Showers will come to an end in SE ND and WC MN as the band shifts north.

DISCUSSION
Issued at 317 AM CDT Tue May 7 2024

500 mb low at 08z as over northwest South Dakota. Moisture feed around this system is from northern Arkansas to central Minnesota then back west-northwest across parts of North Dakota and into southern Saskatchewan and Alberta. What has been noticed is that moisture from the south as been weakening the past 6 hours, perhaps due to convection from Iowa to northern Arkansas. The trends in radar with showers moving NNW from central MN is for diminishing returns as they move toward the RRV. Thunderstorm chances have dropped greatly since 06z and likely to remain thru 16z based off of SPC HRRR Calibrated Thunder fcst and HRRR lightning prog via DESI. So through 16z shower activity looks to be on the light side moving NNW thru MN into eastern ND.

This afternoon will see upper low move a tad east to west of Bismarck with sfc low drifting a bit NNE into southwest ND near Hettinger. A trough rotating around this upper low/sfc low will move into NE SD midday and then into SE ND mid to late aftn with a subtle wind shift from southeast to south. Also drier airmass moves in. Clearing chances appear limited and in this area of SE ND/far WC MN (Valley city-Fargo-Fergus Falls-Wadena)
chances for afternoon showers or t-storms is quite low.

Farther north, north of the boundary 0-6 km shear is quite strong near 40 kts due to stronger 850 mb winds but by 20z 850 mb winds are in the 35-40 kt range vs 50-55 kt currently. So some shear exists but instability looks very weak...barely 100-250 j/kg and no sfc heating is anticipated with aftn temps in the low 60s. With upper low sufficiently far enough west and colder 500 mb temps wrapping around the system and more into Nebraska thinking is that some t-storms will form in a narrow axis from near DVL-GFK-BJI area mid aftn and move north, but lack of instability, lack of cold air aloft, will prevent much development. Bufkit soundings for GFK show a nearly vertical temperature column from sfc to 500 mb with very limited CAPE (50-100 j/kg). This is from both NAM and GFS models. So net result is thinking any chance of a stronger storm is very low (5 pct).

Chance for showers Wednesday as upper system drops south but drier air also moves back in from the north. Instability is focused in southern MN, so covearge of showers look scattered.
Clearing Wed night into Thursday.

GFS/ECMWF ensembles show 500 mb ridging into Alberta and Saskatchewan Thu-Fri period and enough to height falls over the Great Lakes for an upper level wave to drop south-southeast into Minnesota Friday. This will give chances for showers, and with some colder air aloft with wave several hundred CAPE and a chance for a few t-storms mainly in northern or central MN.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
Issued at 714 AM CDT Tue May 7 2024

East or east-southeast winds today gusty at times in the 20-27kt range. Rain showers most widespread thru the morning and into the aftn NE ND and into NW MN. Ceilings within rain area may lower into MVFR range. Tonight faces uncertainty as lower clouds may linger in the north vs in the south higher chance of VFR conditions.

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

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