Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
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842 FXUS65 KCYS 070449 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 1049 PM MDT Mon May 6 2024 .KEY MESSAGES... - Strong winds today for southeast Wyoming and western Nebraska with a prolonged period of elevated winds continuing through midweek. Wind gusts of 70-80 mph are possible for wind-prone locations the rest of today into Tuesday. - Cool and unsettled weather continues for Wednesday through Friday with a chance of late day showers and thunderstorms. && .SHORT TERM /THROUGH WEDNESDAY/... Issued at 330 PM MDT Mon May 6 2024 Cold front currently pushing into central Nebraska this afternoon with a surface low analyzed near Sturgis in western South Dakota. Anticipated strong winds have developed over much of southeast Wyoming with mid 70 mph gusts widespread. Current Craig to Casper 850/700mb height gradients running in the low to mid 90 mtr range. Current wind headlines looking good and no changes can be expected to whats already out. As for the winter headlines...area SNOTELS are really ramping up on precipitation in Mesowest. Most SNOTELS in the Sierra Madre have reported 24 hour precipitation in excess of 1 inch on Mesowest and the Snowy Range reporting 24 hour precipitation between .5 and .8 inches. The north Laramie Range SNOTELs are about the same as the Snowy Range...so will keep the Winter Storm Warning and Winter Weather Advisories going as they are through expiration times. We remain in strong winds tonight into Tuesday as in house WRKHGT and Random Forest guidance continue to show gradients over 75mtrs and high wind probabilities over 80 percent at least through the day Tuesday. May need to keep an eye on the rest of the Panhandle though tonight into Tuesday morning as GFS 800/850mb winds forecast at 45-55kts mainly from 06Z through 12Z tonight. May need to expand the wind headlines further east with these stronger winds. Stacked vertical low finally moves into central North Dakota Tuesday afternoon with wrap around moisture ending in our northern zones and winds easing slowly across southeast Wyoming. GFS does retrograde the low back into eastern Montana Tuesday night into Wednesday morning and we get another secondary vort max that swings through the CWA Wednesday afternoon. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Issued at 330 PM MDT Mon May 6 2024 We will gradually break out of the cool and windy pattern with a warming trend carrying us through the weekend. Chances for light precipitation will be frequent through this period. The potent upper level closed low responsible for the extended period of strong winds across the area through mid-week will split Wednesday or Wednesday night, finally bringing down wind speeds. One piece of the closed low will retrograde into the southwest, while the other will clear out to the east. Expect the flow aloft to turn more northerly to northeasterly as this occurs. A surface high sliding down the east side of the Rockies will also shut off the cross-barrier pressure gradient. While the winds will be coming down, we`ll remain unsettled into Thursday as the retrograding low moves through. Weak upslope flow and isentropic lift will keep scattered rain and snow showers around the area through the day. We could see a few rumbles of thunder during the afternoon and evening hours. Temperatures will remain on the cold side Thursday, still stuck in the upper 40s to 50s across the area as 700-mb temperature remain in the -2 to -4C range. The closed low will get pushed further south on Friday, but there is still some uncertainty on how quickly this will happen which will impact how quickly skies clear and precipitation fades away to the south. Regardless, expect a gradual warming trend to begin Friday with 700-mb temperatures creeping back up to around 0 to -2C. Temperatures will still likely be a few degrees cooler than average for this time of year. Nicer weather is likely for the upcoming weekend as the cutoff low dissipates to our south and a broad ridge over the western US expands eastward across the Rockies. 700-mb temperatures will climb to around +4 to +6C Saturday, and then towards +5 to +7C Sunday. Most of the area should see highs near normal to perhaps a few degrees above normal. This ridge won`t be totally dry though. Precipitable water values are expected to be near normal Saturday. Then beyond that, ensemble means show values creeping just slightly above normal for Sunday and Monday. As temperatures warm, we may have enough moisture and instability to return convection and thunderstorms to the forecast. This should be mostly confined to the higher terrain (where it may be snow) Saturday, then expanding in coverage Sunday and Monday. The next shortwave may arrive as early as Monday, but some models also delay it until closer to the middle of next week. This may manage to add some extra lift and precipitation if it passes close enough to the area. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 1048 PM MDT Mon May 6 2024 Strong winds remain the primary concern across southeast Wyoming and western Nebraska. Strong winds are expected to remain overnight, but may decrease 5-10kts for a few hours before strengthing again. Showers will linger across southeast Wyoming and western Nebraska tomorrow afternoon, with showers ongoing at KCDR at this time. Ceilings at KCDR are above MVFR criteria, but ceilings could drop into the MVFR category as heavier rain showers move into this terminal. Additionally, low-level wind shear will be a threat overnight as surface winds decrease slightly, but strong winds remain aloft. Expect low-level wind shear at KCYS, KLAR, KBFF, KSNY, and KAIA overnight. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...High Wind Warning until 9 PM MDT Tuesday for WYZ103>105- 107>109-115-117>119. High Wind Warning until 6 PM MDT Wednesday for WYZ106-110-116. NE...High Wind Warning until 6 AM MDT Tuesday for NEZ019-020-054. && $$ SHORT TERM...GCC LONG TERM...MN AVIATION...AM