523 FXUS63 KFGF 041457 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 957 AM CDT Fri Oct 4 2024 .KEY MESSAGES... - Frost and freeze impacts continue through 8 AM this morning. - Near critical fire weather conditions are expected in southeast ND this afternoon. - Strong winds develop Saturday along and west of the Red River Valley. The best chance for wind gusts to 60 mph will be in the Devils Lake Basin. && .UPDATE... Issued at 957 AM CDT Fri Oct 4 2024 Some cirrus are drifting east this morning across central North Dakota. Expect a nice day ahead of us, albeit dry. Temperatures in the 60s for highs today. Forecast remains on track. UPDATE Issued at 632 AM CDT Fri Oct 4 2024 Mid level clouds associated with elevated WAA aloft have almost completely clears most of our north. Winds still remain somewhat variable, but have decreased in most locations. Temperates outside of urban areas have continued to drop and in the north colder spots have dropped near to below freezing. While not all location are going to see frost/freeze impacts trends continue to support keeping the warning/advisory in place through expiration. && .DISCUSSION... Issued at 348 AM CDT Fri Oct 4 2024 ...Synopsis... A progressive pattern aloft remain in place, with the main active storm track north of the US/Canada border through this weekend. Surface high pressure is migrating east this morning and in response to the next mid/upper wave building into the Pacific NW lee troughing will help increase flow over the Northern Plains along with increasing temperatures. Very dry air remains in place, so while this wave passes Saturday into Sunday to the north any light showers that do develop will have a low chance for more than a few hundredths (less than 20% chance for 0.1" for most locations). As this wave departs broad ridging is shown by all ensembles to redevelop west to east across the northern US, resulting in dry conditions as any active jet stream is shunted north. Rising heights and eventually a shift to southwest flow will favor unstable warm back above 70 by the end of next week (nearing 80 for some locations). For reference climate normals tend to be near 60 during the second week of October for our region. ...Frost/Freeze impacts this morning... A subtle surface trough and frontal zone developed on the northwest side of the surface ridge this morning resulting in localized winds 10- 15 mph. In addition, a mid level cloud layer developed in proximity to this frontal zone which added additional complications to radiational trends. As a result temperatures are highly variable across our region with some trends near forecast temps and other locations much milder. As mid level clouds clear and we approach potential for brief steepening of the low level inversion near sunrise we have a window to see temps drop more considering Tds in the low to mid 30s. Confidence in a widespread frost/freeze even has decreased (much more localized than previously thought). Products out and a window for additional drops in temps is still there, the decision was made to hold things as they are and allow this to play out through 8am (scheduled expiration). ...Near critical fire weather conditions this afternoon... As with previous days lower mixed layer Tds will support the potential for RH values in the low to mid 20 percent range,with some increase in BL Tds in the northwest. Winds increase with southerly flow and a low level jet developing towards evening. Afternoon winds during peak mixing should gust 20-30 mph, with higher values in ND. Adjustments were made to reflect any recent biases in Tds/Wind and based on this the most likely locations for near critical fire weather conditions will be in southeast ND (wind gusts lower in MN and RH higher in northeast ND). ...Strong winds Saturday... Strong LLJ and tightening gradient across the Northern Plains develops in response to the deepening mid/upper low on the lee side of the Northern Rockies in southern Canada later tonight. The associated cold front with this wave is shown to pass through our region Saturday morning through the afternoon, and strong unidirectional westerly flow develops behind this front though the mixed layer supporting a period of stronger winds. 280-310 directions tend to favor the locations in our west along and west of the valley escarpment towards Devils Lake Basin. This is where NBM/LREF highlight probs in the 20-40% range for gusts greater than 60 mph. ECMWF EFI shift of tails also highlights similar areas for potential warning impacts. The top of the dry adiabatic mixed layer on soundings are close to warning criteria as well (46-52kt depending on model). Mid level clouds from showers in the north could complicate mixing potential, but elevated showers could also help provide an extra push through evaporative processes. Widespread warning impacts (gusts 58mph+) are uncertain, but there is enough of a signal that the decision was made to issue a High Wind Watch for the Devils Lake Basin Saturday. Advisory winds are more likely to the south and east of the current watch, but we will hold off on headline decisions elsewhere this morning. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 632 AM CDT Fri Oct 4 2024 VFR conditions should prevail across eastern ND and northwest MN through the TAF period. The main aviation concerns will be related to increasing southerly winds, along with low level wind shear later this evening and overnight as a low level jet (50-60kt) develops. Gusty winds develop as low level gradient increases west to east this afternoon, however the gradient only becomes stronger this evening and overnight so rather than following a typical diurnal cycle winds may actually continue to increase through the nighttime period. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...High Wind Watch from Saturday morning through Saturday evening for NDZ006-007-014-015-024-026-028-054. MN...None. && $$ UPDATE...AH/DJR DISCUSSION...DJR AVIATION...DJR