Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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371 FXUS65 KBOU 230956 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 356 AM MDT Thu May 23 2024 .KEY MESSAGES... - Warm, dry, & breezy today, with elevated fire weather conditions across the urban corridor and plains - A cold front tonight should bring some snow showers to the mountains with light accumulations possible. - Showers expected to impact the region for parts of the end of the week and weekend. - Summer-like temperatures for next week && .SHORT TERM /Through tonight/... Issued at 229 AM MDT Thu May 23 2024 Warm and windy is the theme of the day today. A closed 500mb low is spinning across southern Idaho this morning and should race across Wyoming into the northern Great Plains by tonight. The mid/upper level flow is expected to strengthen to the south of this feature, leading to fairly strong downslope flow across the forecast area by this afternoon. The main forecast questions today are "how warm?" and "how much wind?" - as minimal moisture will keep just some scattered cloud cover and fairly low chances of any precipitation for most of the day. In terms of wind, deep mixing should allow for gusts up into the 25-35 mph range across the lower elevations, with stronger gusts in the high country where mid-level flow is more impressive. Most guidance keeps PBL/mixing heights just below the strongest flow at 500mb, but it`s possible we see a few stronger gusts than what the grids have at this point. In terms of temperatures... model guidance is in fairly good agreement that we`ll see upper 70s to low 80s across the I-25 corridor into the eastern plains. As the trough advances, a cold front is expected to drop into the region this evening into the overnight hours. Cross-sections show enough moisture in the high country for a band of rain/snow showers with light accumulations. Can`t rule out a few showers or a storm in the plains, but chances are we`ll simply be too dry for much activity here. Instead, the main impacts for the lower elevations will likely be another burst of wind along the front, followed by cooler temperatures for tonight into tomorrow. && .LONG TERM /Friday through Wednesday/... Issued at 229 AM MDT Thu May 23 2024 As the shortwave trough exits the northern Rockies and heads eastward into the northern Plains, its associated cold front will be the cause of cooler temperatures for Friday across the forecast area. Temperatures will likely be in the upper 50s to upper 60s across the plains and foothills and 40s to 50s for the mountains, which will be roughly 5- 10 degrees below the norm for this time of year. Cross sections show mid and upper level moisture increasing throughout the afternoon and evening ahead of the next approaching trough to the west. Instability looks to increase throughout the day as well, with forecast soundings indicating nearly DALR Friday afternoon. A few afternoon/evening thunderstorms and scattered showers can`t be ruled out with a chance of snow showers for the overnight hours for elevations above roughly 10,000 ft. For the holiday weekend, guidance indicates heightened chances for widespread precipitation as a shortwave trough and cold front bring enhanced forcings to the region. Daily chances for rain showers are possible across the area with snow showers likely for the higher elevations. Forecast soundings show modest CAPE values (between 300- 600 J/kg), which would support a slight chance for some isolated thunderstorms to develop across the entire forecast area on Saturday and Sunday. Temperatures will be warmest on Saturday with widespread upper 70s forecast for the plains with a few locations topping 80 degrees. The foothills are forecast to be in the 60s, and the mountains high 50s to low 60s for elevations below 9000 feet. Sunday`s high temps will be slightly cooler behind the cold front, but still likely manage to make it to the 60s for the plains, and 50s for the foothills and mountains below 9000 feet. The beginning of next week will bring warmer and drier conditions to the CWA as models agree on a decent ridge building over the western CONUS. This looks to be the warmest period seen so far this year with consecutive days of 80 degrees plus possible across the plains, bringing us back to above normal temps through mid-week. && .AVIATION /06Z TAFS through 06Z Friday/... Issued at 1135 PM MDT Wed May 22 2024 VFR through the TAF period. Drainage flow is slowly establishing and should continue overnight. Less certainty in the wind forecast Thursday as winds gradually turn to the west through the morning hours, with a second wind shift to more of a WNW later in the afternoon or evening. Could see a few gusts to 25kt during the evening hours as well. Beyond that, a cold front is expected to push towards the terminals close to 06z with another wind shift to the north/northeast, but with lighter speeds. No ceiling or visibility concerns are anticipated. && .FIRE WEATHER... Issued at 229 AM MDT Thu May 23 2024 Dry and windy conditions are forecast today, with minimum RH values near 10-15% across the lower elevations. Wind gusts will pick up through the day with gusts to 35 mph likely for the plains with higher gusts across the foothills. Though we are technically near or at criteria across several zones, we`ll hold off on any highlights given current fuels status. RAWS-based ERC values are near or below normal for this time of year with 100/1000-hour fuel moisture running above normal across most of our region. Still, today is not a great day to be doing outdoor burning! && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Hiris LONG TERM...Bonner AVIATION...Hiris FIRE WEATHER...Hiris