Area Forecast Discussion
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
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711 FXUS65 KBOU 301812 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 1212 PM MDT Thu May 30 2024 .KEY MESSAGES... - Scattered afternoon showers and thunderstorms today and Friday. A few could be severe across the plains, and even portions of the I-25 Corridor for Friday. - Warmer and drier beginning Saturday, but a couple strong to severe storms still possible on the plains. - Hottest temperatures of the year so far Sunday into early next week. && .UPDATE... Issued at 1033 AM MDT Thu May 30 2024 No changes to the overall forecast today. Tonight, there is some uncertainty about the severe threat of overnight thunderstorms developing north of I-76. Will continue to monitor the next few model runs. && .SHORT TERM /Through tonight/... Issued at 425 AM MDT Thu May 30 2024 A weak cold front will drop across the northeast plains this morning. A preliminary ripple came down into Denver, but a deeper surge of north winds will come by mid morning. This will result in some stabilization of the atmosphere across most of our area today, and some drying aloft will help as well as deep mixing occurs later today. For the most part, we`re expecting weak convection without much precipitation over the northern and western parts of our area most of the afternoon, maybe nothing in the northern half. A little cooling around 700 mb along with some moistening at the surface should bring an increase in convection and scattered thunderstorms late in the day. Further south, generally south of I-70 on the plains, there will be a bit more instability as there should be less cooling and drying. So the storms may form a bit earlier there and be stronger. There may still be CAPEs up to 1000 J/kg in Lincoln county with a small severe threat, mainly hail. With fairly light winds aloft, whatever convection we get could be slow to move east, and there will be moist surface winds providing convergence to keep them going. So we`ll have PoPs over the eastern part of the plains into the early morning hours. There`s another surge of north to northwest winds late tonight along with some QG lift from a better shortwave trough passing north of us. Models vary on the strength of the surface boundary and whether there will be a band of showers or thunderstorms with it. But this threat is mainly over the northeast corner. If this feature is strong enough and generates a decent batch of showers, it could produce an area of stratus that pushes back to Denver at the end of the night. Only minor adjustments to forecast temperatures, the previous forecast looks pretty good and is near guidance with highs about 5 degrees cooler today. && .LONG TERM /Friday through Wednesday/... Issued at 425 AM MDT Thu May 30 2024 Moist easterly low level flow combined with moderate flow aloft and steep mid level lapse rates will bring a greater threat of severe storms on Friday. However, that will be conditional on whether or not we see enough surface heating and breaking of the cap. The low levels will also be initially cool and areas of stratus across the plains Friday morning. That will likely delay the destabilization, but there is some broad scale lift in the form of QG and right rear entrance region of a jet max to our north that would potentially weaken the cap. Ingredients would be favorable for a few severe storms late in the afternoon and evening, including MLCAPE of 1200-1800 J/kg with mid 70s/~50 T/Td, and 0-6km bulk shear of 40+ kts. Given the surface pressure pattern, we believe the low level moisture actually has a decent chance of holding in the I-25 Corridor, so the threat of a couple severe storms could be as far west as Denver and Fort Collins. Again, that`s dependent on stratus and surface heating, so unfortunately we may not have any "clearer" answers until tomorrow. Moving onto Saturday, we`ll start to see flat ridging arrive, leading to the beginning of true summer warmth. We are expected to dry out along the Front Range with less and only high based convection, while a dryline/lee trough pushes east across the plains. A couple strong to severe storms will be possible east of the dryline - right now we think that would mainly be along/east of a Sterling to Limon line. Sunday will bring on full summer warmth, with high temperatures likely reaching 90F over most of the plains and I-25 Corridor. There is now very good agreement in ensembles regarding this heat and drier weather, which will likely last through at least Tuesday. Ensemble averages only nudge down slightly (1-3 degrees on average) toward the end of next week, but overall summer warmth appears to be here to stay. && .AVIATION /18Z TAFS through 18Z Friday/... Issued at 1211 AM MDT Thu May 30 2024 VFR conditions will continue through tonight. There is a possibility of low clouds overnight due to scattered thunderstorms developing north of all terminals but will keep the TEMPO group for this outcome. This afternoon through early evening, thunderstorms will occur bringing variable winds gusting to 30kts. It is possible winds will shift south then westerly by tonight. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...AD SHORT TERM...Gimmestad LONG TERM...Barjenbruch AVIATION...AD