Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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539 FXUS65 KBOU 012032 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 232 PM MDT Mon Jul 1 2024 .KEY MESSAGES... - Isolated to scattered showers and thunderstorms expected today. A couple of stronger storms possible in far northeast Colorado this afternoon and evening. - Downward trend in showers and storms beyond Wednesday. && .SHORT TERM /Through Tuesday/... Issued at 1246 PM MDT Mon Jul 1 2024 Satellite imagery shows cumulus developing across areas that got a break from the mid-level clouds across the high country and east plains and Lincoln County. These will be the more likely areas to develop scattered thunderstorms this afternoon. Instability has been low across the urban corridor and plains resulting in scattered showers/convective showers rather than thunderstorms. For the remainder of the afternoon and evening, expect scattered showers and some thunderstorms. Elevated moisture and marginal instability will warrant monitoring over the burn areas for any training showers/storms. The better environment for stronger storms was in the northeast corner, but may not be as favorable with showers having gone through today. Overnight, scattered, lower coverage showers are possible. A weak cold front moves through early Tuesday morning with potential for development of low stratus behind it. HREF guidance lacks agreement on how much moisture will stick around overnight resulting in lower confidence in the stratus chances. Tuesday, the upper level trough remains over the region. An upper level jet max positions to the north, increasing flow aloft over Colorado. A weak upper level shortwave trough moves through the flow. Moisture will be less than Monday, but will be sufficient to support a low chance (< 25%) isolated showers and thunderstorms in the afternoon. Marginal instability will also help keep chances and coverage low with MLCAPE values > 500 j/kg and will keep the "higher" chances confined to the southern Foothills, Palmer Divide, and far east plains. A weak frontal passage and cloud cover will keep temperatures cooler Tuesday with highs in the 80s on the plains. && .LONG TERM /Tuesday night through Monday/... Issued at 1246 PM MDT Mon Jul 1 2024 West to northwest flow aloft is expected for the middle part of the week. An upper level disturbance moves into the Wyoming Wednesday and then into the upper Midwest by Friday. With the upper level disturbance moving to our north Wednesday, southerly surface winds increase across the eastern plains. While low level moisture is limited for the western portion of the area, the plains will see enough moisture for scattered thunderstorms to develop. A few strong to severe thunderstorms are possible in the northeast corner of the state. For the higher elevations, with dry and breezy conditions, could have some areas with near critical fire weather conditions. Currently looks like Fire Weather zone 214 (Park County) may be the area of greatest concern. The cold front moves into the northeast plains late Wednesday night and pushes south across the plains Thursday morning. A breezy day is expected Thursday with cooler temperatures and drier air in place. Pops are very lows for the plains Thursday, meaning very low chances for any thunderstorms or precipitation. Thursday will also be the coolest day of the week with highs in the 70s and lower 80s. Fire Weather zone 214 again looks like it will flirt with critical fire weather conditions, but the dry and breezy weather across the CWA will mean that caution should be exercised with outdoor burning and fireworks. For Friday through Monday...the upper high remains over California with northwest flow aloft continuing across the CWA during this time. Generally dry conditions are expected through the weekend with an isolated shower or thunderstorm producing only gusty winds and very little rainfall. High temperatures on Friday will be slightly below normal, but warmer temperatures return Saturday through Monday with highs at the lower elevations in the low to mid 90s. && .AVIATION /18Z TAFS through 18Z Tuesday/... Issued at 1220 PM MDT Mon Jul 1 2024 Westerly component winds this afternoon at 08-13 kts. Gusts up to 25 kts are possible through 19/20Z as a result of a weak mountain wave that extended off the Foothills this morning. Showers this early this afternoon with scattered thunderstorms possible after 20Z. Brief variable outflow gusts are possible in any nearby/passing storms with gusts up to 30 kts. Low coverage showers possible tonight. A weak cold front moves through early Tuesday morning. Timeframe is low confidence as this front is weak with no defined boundary/push of northerly winds. Within in the 08-12Z timeframe, winds transition to north at 07-10 kts. There is potential for low stratus to develop post-front (10-13Z). Confidence is still on the lower end with models unsure of how much low level moisture will be available. For now, messaging this in the TAF as SCT015 until confidence increases. Tuesday, light winds turn to the WNW in the afternoon. There is a low chance for isolated showers/storms in the afternoon, mainly for APA. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Mensch LONG TERM...Stark AVIATION...Mensch