####018006024#### FXUS63 KGLD 040925 AFDGLD Area Forecast Discussion National Weather Service Goodland KS 325 AM MDT Sat May 4 2024 .KEY MESSAGES... - Monday has a chance for high winds (mainly gusts above 60+ mph), blowing dust, and severe storms. However, there is still a fair amount of uncertainty with the placement/timing of the system so all listed hazards currently have less than a 50% chance of occurrence. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 320 AM MDT Sat May 4 2024 Overview: A potent upper level low moving ashore the Pacific Coast today will progress eastward across the Intermountain West (tonight-Sunday) and 4-Corners (Sunday night). Today-Tonight: Expect a continued clearing trend with sunny skies by late morning and early afternoon -- in assoc/w synoptic subsidence and surface pressure rises in the wake of shortwave energy lifting northeastward through the Dakotas -- along with light winds and slightly below average temperatures. Near average overnight lows will follow, tonight. Sun-Sun night: A southerly return flow regime will ensue, on Sunday, as the MSLP-H85 height gradient reorients and tightens in response to renewed surface pressure falls in the lee of the central Rockies -- via height falls /increasingly cyclonic flow aloft/ attendant the aforementioned upper level low approaching from the west. Expect strengthening (25-40 mph) southerly winds and a warming trend.. with highs ranging from the upper 60s to mid 70s, warmest in eastern Colorado. Low-level flow will back to the SSE and further strengthen Sunday evening -- on the eastern periphery of an intensifying lee cyclone in Colorado. Forecast soundings indicate 40-50 knot SSE flow 'off-the-deck' within a shallow mixed layer in eastern CO and adjacent KS border areas Sunday evening into Sunday night -- after sunset, ~02-03Z -- suggesting a potential for strong winds (30-45 mph G 55 mph), though.. confidence is low with regard to whether or not mixing will be sufficient to transport said flow to the surface / penetrate a near-surface nocturnal inversion. && .LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 238 AM MDT Sat May 4 2024 For Monday, there are still a lot of potential hazards that are unclear if they'll happen as there is still a sizable spread in 500mb low track and surface low setups. Compared to prior forecasts, there is more consensus on the upper trough swinging more into the Northern Rockies and Plains. In this scenario, the deeper part of the low pressure would be well north into the Dakotas, Montana, or even Southern Canada. With it, the rest of the lower pressure and potential front would swing through the area during the day Monday and bring dry air across most of the area. With this, the severe weather threat would be limited to Highway 83 and east or maybe even completely out of the area. The main hazard would be the potential for high winds (namely gusts to 60mph+) as long as the upper low swings near the area. Blowing dust across the area and critical fire weather conditions south of I-70 would also be possible with the strong winds and dry conditions (though the dust could be hampered by recent moisture). There are still some scenarios that keep the low closer to the area with dryline closer to the Colorado border (instead of Central KS/NE). While scenarios like this now have a 25% chance, it is worth mentioning that this scenario would bring the same threat for high winds, but the severe threat would be much greater with all hazards possible. Critical fire weather would be more limited to parts of Eastern Colorado and the dust threat would likely decrease as we would have stratus which would weaken low level lapse rates. Tuesday, the upper trough is forecasted to spin over the Northern Rockies and Plains which will keep the area in roughly westerly flow aloft and relatively low pressure at the surface. The main thing to watch will be for a potential smaller wave to move around the larger low and generate lower pressure near the area. That could strengthen the winds a bit and maybe wrap some more precipitation into the area, though severe weather looks to be unlikely at this time. A small disturbance could also weaken/disrupt the height gradients which would lower the chance for strong/high winds. Temperatures would likely be similar to Monday in the 70's. Critical fire weather conditions would be possible again along and south of I-70 depending on how dry the air gets during the afternoon. The rest of the week looks to have troughing or laminar flow above the area as a cut-off low is forecast to try and split off from the main flow and shift off to the west coast. This would likely give us average temperatures in the 60's and 70's with daily chances for precipitation if smaller disturbances move through the flow and across the area. Hazardous weather looks to be unlikely for this time period except for the possibility of lows dropping into the mid to low 30's if enough cold air advects into the area and little to no moisture returns. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 320 AM MDT Sat May 4 2024 VFR conditions will rule through the TAF period at both terminals. NNW winds at 10-15 knots will weaken and become variable early this afternoon.. as surface high pressure in Nebraska extends southward over northwest Kansas. Winds will shift to the SSE-SE and increase to 10-15 knots this evening (GLD) and Sunday morning (MCK).. as high pressure shifts east of the region and a surface trough develops in the lee of the Rockies. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...Vincent LONG TERM...KAK AVIATION...Vincent ####018002655#### FXUS65 KMSO 040927 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 327 AM MDT Sat May 4 2024 .DISCUSSION...Today should be the warmest day of the week even though high to mid level clouds will be steadily increasing. Temperatures are still anticipated to be 5 to 10 degrees above seasonal averages. A significant low pressure system will move on shore near the California/Oregon border and track across southern Idaho Saturday night into Sunday night. Cooler temperatures and widespread shower activity is expected over the Northern Rockies during this time frame. Then the low starts to track to the northeast across southwest Montana into eastern Montana on Monday. This path appears to enhance the precipitation across Lemhi county into southwest Montana. Snow levels will be lowering to around 5000 feet by Monday morning, causing accumulating snow on Lost Trail, Homestake and MacDonald Passes along with Gilmore Summit and Georgetown Lake. These locations have a 50 to 80% chance of receiving over 2 inches of snow by Monday morning. The low appears to settle along the Montana and North Dakota border and intensify Tuesday into Wednesday. This amplification of the low will create north to northeasterly flow over the Northern Rockies. This flow pattern is conducive to upslope flow along the Continental Divide, especially around Glacier National Park. Marias pass has a 90% chance of receiving over 2 inches of new snow Tuesday into Wednesday and even a 60% chance for greater than 4 inches. The bulk of the low pressure system will move off to the east while a portion of energy drifts back to the Great Basin region during the latter part of the work week. This pattern shift will leave the Northern Rockies in a weak northerly to easterly upper level flow Wednesday through Friday. Temperatures will gradually warm, but still remain below seasonal averages. Shower activity is expected to decrease in coverage and intensity each day. A ridge of high pressure is still expected to build over the region during the weekend causing a warming and drying trend. && .AVIATION...A ridge of high pressure will be the dominant feature over the region today, but high level clouds will be steadily increase as the next system approaches the region. Precipitation is expected to start moving into north central Idaho and Lemhi county this evening with rain showers potentially impacting KSMN after 05/03z. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$