Area Forecast Discussion
Issued by NWS Grand Forks, ND
Issued by NWS Grand Forks, ND
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163 FXUS63 KFGF 111836 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 136 PM CDT Sat May 11 2024 .KEY MESSAGES... - Near critical fire weather is expected today across much of the region as RH values fall into the 20 to 30 percent range along with wind gusts up to 25 mph. - Widely scattered showers and isolated thunderstorms are possible late this afternoon and early evening for portions of far northeast ND and northwest Minnesota. A few storms could produce damaging wind gusts to 60 mph. && .UPDATE... Issued at 136 PM CDT Sat May 11 2024 RH values fell a bit faster than forecast, however Tds are now increasing across our west (with BL moisture spreading east). We may see RH values level off soon in MN (or increase a bit in our west despite additional warming). We are seeing gusts generally around 20 mph (isolated gusts 25-30 mph mainly along/west of the RRV) and messaging of near critical fire weather conditions seems to me on point. Main adjustments were to better capture Td/T trends. Other concern will be the potential for isolated strong to severe thunderstorms later this afternoon and early evening. Forecast instability profiles are marginal, but high mixed layers in inverted-V type environment does raise the potential for isolated marginally severe gusts (to 60 mph). Forcing will be there with the weak shortwave and eventual cold front passage, but the depth of the dry layer aloft does lower confidence in coverage or even wetting rains (dry thunderstorms may be more common). UPDATE Issued at 1012 AM CDT Sat May 11 2024 We are starting to see an increasing trend with Td`s in our west that better matches guidance, while lower Tds/RH are still lingering in our east. Earlier adjustments generally reflect these trends and while clouds/high based weaker shower/storm may still complicate Td/RH trends in some areas we should see many locations see min RH around 25% with better potential to drop below that in our MN counties. Based on these trends I went ahead and reissued the SPS in MN for near critical fire weather conditions through 02Z/9PM CDT. UPDATE Issued at 655 AM CDT Sat May 11 2024 The forecast remains mostly on track this morning. Currently watching dew point observations against forecast values as the air mass is a bit drier than most guidance. A few high clouds are working across the Lake of the Woods region, along with weak radar returns. Upstream observations remain dry this morning, but will continue to monitor PoPs. Soundings remain rather dry at the surface, which will serve to inhibit precipitation with weaker showers and thunderstorms. && .DISCUSSION... Issued at 403 AM CDT Sat May 11 2024 Weak shortwave ridging traverses the region today, with a strong response in temperatures this afternoon. Look for highs in the low 80s across much of the area; there is a 30% chance to reach 85 degrees in the northern Red River Valley. With low dew points already in place, this will create a scenario for very low RH values as low as 20 percent. Winds will not be as strong as yesterday; however, we could still see a few gusts to 25 mph. For the late afternoon and into the overnight period, shortwave troughing moves progressively from northwest to southeast in response to an H5 upper low moving across northern Manitoba. This should provide an axis of instability and forcing starting late this afternoon across portions of northwest Minnesota. Soundings indicate an environment somewhat supportive of strong wind gusts where high based thunderstorms are able to form. While SBCAPE looks to be minimal, MUCAPE supports elevated thunderstorm development and will be in the range of 800-1200 J/Kg. DCAPE is quite high as is expected with the very dry air mass at the surface, and soundings show a range of 900-1500 J/Kg. As such, any strong storm that develops would most likely produce strong wind gusts, with lower chances for hail. Heading into Sunday and Monday, impact potential looks minimal in as ridging builds into the Northern Plains. Highs will be in the 70s on Sunday, with 60s to low 70s Monday. For Tuesday and Wednesday, another H5 low pressure system brings rain chances back into the area. Guidance has hinted at a deeper low in the past several runs, which could slow the system and increase the potential for higher rainfall amounts. Currently, amounts look rather light, with a 70 percent chance for 0.10 inch and a 30 percent chance for 0.50 inch for the period covering late Tuesday through early Thursday. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 630 AM CDT Sat May 11 2024 VFR conditions prevail at all TAF sites through the period. Look for an increase in winds heading into the afternoon hours, with gusts to near 20 knots possible. These higher winds are expected to diminish later in the afternoon into the early evening. For KBJI, there is a low chance for showers and isolated thunderstorms this afternoon. A few stronger storms could produce brief gusty winds. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Lynch/DJR DISCUSSION...Lynch AVIATION...Lynch