Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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202 FXUS65 KBOU 142049 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 249 PM MDT Tue May 14 2024 .KEY MESSAGES... - Scattered showers/thunderstorms through early eyeing, most numerous along/south of I-70 where a few could be strong and produce hefty outflow winds. - Additional showers and isolated storms expected late this evening and overnight mainly across northern Colorado. - Front brings cooler and wetter weather on Wednesday. Light snow for elevations mainly above 10,000 feet. - Warmer and generally drier starting Thursday, with lesser but at least isolated daily afternoon showers/thunderstorm coverage, highest for the mountains. - A return to more active weather early next week with a better chance for afternoon and evening showers and storms. && .SHORT TERM /Through Wednesday/... Issued at 247 PM MDT Tue May 14 2024 West-northwest winds have develop over the northern part of the Front Range. The drying and subsidence associated with this has kept showers and storms from forming. We are seeing scattered showers and isolated storms develop else where. A severe wind gust or two to 60 mph will be possible with this activity, but most will see a quick weak moving shower/storm this afternoon with gusty winds. Better chance for precipitation will come mid evening through the overnight hours behind a cold front that will bring northeast upslope winds. A jet streak and lift from the upper level trough over northern Colorado may also provide lift for showers and isolated thunderstorms through tonight. Upper level trough will be over Wyoming and northern Colorado through Wednesday. A wave dives down the backside of the trough late tonight and tomorrow morning while the rest of the system progresses eastward. This will shear the trough apart. However, there should be plenty of cold air aloft to produce steep lapse rates leading to scattered to numerous showers and storms. ML CAPE up to 700 J/kg will prevail mainly over the Denver area and south. Here, the stronger storms may produce hail up to penny size with 40 mph winds. In addition to seeing the best instability, the foothills and Palmer Divide will see northeast upslope flow, which is expected to help showers and storms develop. && .LONG TERM /Wednesday night through Tuesday/... Issued at 247 PM MDT Tue May 14 2024 Wednesday night and Thursday, a split upper trough will stretch from the upper Midwest into the Southwestern States. The main piece of energy will be over the Arizona and New Mexico, with a secondary branch over the Northern Great Plains States. Colorado will in-between the main troughs under the influence of a weak to moderate westerly flow aloft. Models are showing another cold front sliding south across the Northeastern Plains late Wednesday afternoon or early evening hours with some upslope flow behind it. This combined with some lift from a 50Kt upper jet should keep showers and a few storms continuing across the forecast area into the evening hours. At this time, it appears the best chance for measurable QPF will across the foothills and western sections of the Palmer Divide with lesser amounts the further north and east you go. The far Northeastern Plains may see little to no precipitation with this system. Warmer temperatures and decreased precipitation chances are expected on Thursday as the upslope flow diminishes. However, there should be enough lingering moisture combined with daytime heating to produce isolated to scattered afternoon and evening showers and storms, mainly over the higher terrain. Dry and warmer conditons are expected on Friday as some upper level ridging takes place over Colorado. With some downsloping flow east the mountains, temperatures across most plains are expected to climb into the lower to mid 80s. An upper level storm system is progged to move across the Northern Rockies and Northern Plains States Friday night and Saturday. Breezy to windy conditons may develop across far Northeastern Colorado on Saturday as the upper shortwave and surface low pressure pass to the north of Colorado. Temperatures once again are expected to be quite warm on the plains with readings climbing into the lower to mid 80s with temperatures approaching the 90 degree mark across Southern Lincoln County. The warm, dry and breezy conditions may lead to increasing fire danger across the northern sections of the plains along and near the Wyoming border both Friday and Saturday afternoon. Cooler temperatures are expected late Saturday and Sunday behind the passage of a cold front. We may also see a return to isolated to scattered afternoon and evening showers and storms in response to a 90KT upper jet moving across Southern Colorado. Looking further ahead, it looks a little more active early next as upper level troughiness develops across the Western U.S. With occasional upper level shortwaves and jet streaks moving across the region , there is the potential for some severe weather both Monday and Tuesday across the plains. && .AVIATION /18Z TAFS through 18Z Wednesday/... Issued at 1147 AM MDT Tue May 14 2024 West-northwest winds will continue to spread east off the foothills, bring gusts to 25 knots and drier air. Satellite showing some cumulus clouds forming, indicating we are starting to reach our convective temperature. The question...is there enough moisture for showers and storms? Model trends are leaning towards no in the DEN area and likely in the APA area. May be able to remove the VCTS from the DEN TAF in the next couple hours if the drying trend pans out. Still may see a gusty outflow the convection to the south of DEN. Cold front will bring northeast to north winds mid evening, around 03Z. Will see an improved chance for showers with a slight chance (20%) for a thunderstorm behind the cold front. The airmass moistens up and low clouds are expected to form 09-12Z with ceilings of 2000-4000 feet. The clouds slowly rise Wednesday morning and afternoon, but expect ceilings to stay below 6000 feet. Scattered showers and thunderstorms are expected to form after 20Z Wednesday. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Meier LONG TERM...JK AVIATION...Meier