Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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198 FXUS63 KFGF 141832 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 132 PM CDT Fri Jun 14 2024 .KEY MESSAGES... - General rain with limited chances for severe weather this weekend - More notable chances for severe weather for the first half of the week. && .UPDATE... Issued at 1259 PM CDT Fri Jun 14 2024 Fair weather cumulus continues to increase in coverage within the northern Red River Valley into Minnesota. Higher clouds should start to creep in from the west this afternoon. UPDATE Issued at 1026 AM CDT Fri Jun 14 2024 Any lingering patchy fog has since diminished. Satellite reveals mostly clear skies across much of the Dakotas into Minnesota under the influence of surface high pressure and ridging aloft. Fair weather cumulus is starting to develop in lakes country of Minnesota, which will likely continue to spread in coverage through the morning into this afternoon. Getting into this evening, morning guidance still suggests thunderstorms develop in central North Dakota spreading eastward tonight as upper ridging shifts east allowing troughing in the PacNW to impinge upon the northern High Plains, along with moisture/instability return to feed convection. At this time, the chance for severe weather is low (less than 10%) with this activity due to marginal available instability, however shear is strong. Should storms this evening find better available instability (potentially through via steeper than forecast lapse rates aloft), hail would become possible. UPDATE Issued at 627 AM CDT Fri Jun 14 2024 Satellite and webcams show a few spots this morning with patchy ground fog, with otherwise clear skies across the area. Winds remain calm with temperatures in the 50s. && .DISCUSSION... Issued at 300 AM CDT Fri Jun 14 2024 ...Synopsis... Low amplitude ridging centered from northern Mexico to the Central Plains will shift east over the next few days and deepen, blocking western flow and allowing southwest flow to amplify over the Northern Plains. This will see increased chances for widespread rain and numerous chances for severe weather in the Northern Plains through Wednesday when the stubborn eastern CONUS ridging gives way and allows for more zonal flow to wrap up next week. Currently sfc high pressure can be noted shifting east across the Dakotas and Minnesota with wind becoming light and variable. A lack of cold air advection or DNVA will likely limit fog formation without the support of widespread subsidence from aloft but wouldn`t be surprised to see some localized pockets of fog either. Regardless low impacts from any fog that does develop with clearing shortly after sunrise. This evening weak theta-e advection will be the focus for elevated convection. MUCAPE of 500 j/kg or less will likely only yield a lightning threat with rain totals being highly variable and generally under a quarter inch per HREF PMM. ...Weekend Appetizer... 850mb ridge then shifts east into the Great Lakes by Saturday with an upper trough moving into British Columbia. At the same time a cold front sweeping through Montana into North Dakota will become the focus for isolated to scattered thunderstorms Saturday afternoon reaching eastern North Dakota overnight. Early indications show a primary wind threat especially as convection trudges east. A combination of CSU MLP and CWASP paints the highest severe risk across the Devils Lake basin for our domain aligning well with the SPC day 2 outlook. MUCAPE of 1000-2000 J/kg and limited bulk shear atop a nocturnal LLJ aligns well with this picture of upscale linear growth through the night. ...Severe Threat Continues... Unfortunately this will likely only be an appetizer as the upper trough shifts east into the northern Rockies with the stationary eastern ridging locking us into southwest flow aloft. While guidance does not show any well defined individual waves moving through the area to increase confidence on the overall severe threat any given day the overall pattern of veering winds, gulf moisture, and a plume of steep mid level lapse rates should point to a continued severe threat of which the severity will maintain a lower predictability horizon relying of location of sfc fronts and other mesoscale details. Currently a marginal risk of severe storms Sunday across the tri state SD/ND/MN and point east roughly along the remnants of saturdays cold front. Then a more well defined wave Monday with better overall thermodynamic and kinematic support to warrant a 15% from SPC though areal changes are likely this far as guidance gets a better handle on the pertinent shortwave, a reminder that the parent trough is still over the Pacific currently where models have minimal data to ingest and improve the forecast confidence. While the shiny object in the forecast is likely the severe threat for most repeated convective rainfall will also yield a flooding threat. Despite the plethora of rain received in the past 60 days (2 to 4" above average regionally) soils have continued to show at least some capacity to absorb more moisture which was evidenced in the blowing dust last week. Thus at least antecedent conditions will likely limit the overall flooding threat but increased water in fields and local stream rises appear likely as soils saturate. Confidence continues to grow for hydro related impacts as ensembles depict a stalling sfc front in the Northern Plains early next week with the aforementioned upstream dynamics providing ample support for heavy rainfall across the region (convective or not). && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1259 PM CDT Fri Jun 14 2024 VFR conditions are forecast through 12Z. There is a low-medium chance for scattered thunderstorms to develop in eastern North Dakota into Minnesota between 04Z-16Z, although confidence remains low enough to keep out of TAFs for now. Will include in later issuances if confidence increases enough in TS impacting a TAF site. At around 12Z, the chance for MVFR CIGs increases within eastern North Dakota, spreading eastward into Minnesota after around 15Z. Winds will also be increasing out of the south around 20kt around 15Z. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...CJ/Lynch DISCUSSION...TT AVIATION...CJ