Area Forecast Discussion
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
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422 FXUS65 KPUB 090949 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 349 AM MDT Sun Jun 9 2024 .KEY MESSAGES... - Showers and thunderstorms are expected today, some strong to severe, over the mountains and adjacent plains. - Strong thunderstorms possible Monday with the primary risk evolving towards slow moving heavy rain producing thunderstorms capable of localized flash flooding. && .SHORT TERM /THROUGH TONIGHT/... Issued at 341 AM MDT Sun Jun 9 2024 An upper-level ridge will begin to build in today, with weakening flow aloft that will give us an overall less active pattern than yesterday. However, lingering moisture and instability, along with easterly upslope at the surface, will give us another day of showers and thunderstorms across parts of our area. Thanks to the upsloping surface winds, most of the active weather will be tied to the southeast mountains and the I-25 corridor. Models noticeably differ on the amount and extent of afternoon-evening convection today, likely due to differences in stability and mixing at the low levels. The HRRR, which tends to be more aggressive in boundary layer mixing, ingests more unstable air into the mountains/plains interface and produces widespread showers and storms across southern I-25 and Pueblo County. Meanwhile, other models such as the NAM Nest show much more isolated convective showers, mostly tied to the mountains with very little hitting the lower terrain. Though a good chunk of the model output from this evening shows modest severe parameters (700-1200 J/kg CAPE and 20-30 knots of shear) this afternoon, stability will still be the main factor in how much QPF the plains see. Looking through some of the ensemble members, the majority of guidance today is keeping most of the precip over the mountains until after sunset, after which some showers will move east and onto I-25. Main impact concerns today will be heavy rainfall and flash flooding, especially over more vulnerable areas, along with gusty outflow winds and some hail. Thanks to the cloud cover and lingering moisture, high temperatures today will be much cooler than the previous several days, with 70s- 80s across most of the area. Later tonight, precipitation will dissipate across the plains while still lingering in the mountains as we move into the work week. && .LONG TERM /MONDAY THROUGH SATURDAY/... Issued at 341 AM MDT Sun Jun 9 2024 Remnants of the Pacific trough across the Desert Southwest will propagate through the upper ridge across southern CO on Monday. Showers and isolated thunderstorms will be ongoing across southern areas in the morning. Dew points are likely to maintain in the 50s across the I-25 corridor and southeast plains with 40s across the mountain valleys in the afternoon. With afternoon heating/increasing instability, thunderstorms will blossom again across the mountains with a better chance of a few spilling out into the adjacent plains during the evening before weakening as they push eastward. HREF mean CAPE still shows up to 1500 J/kg across the southeast mountains and adjacent plains though deep layer shears will be weak given light flow aloft within the remnant upper circulation cutting through the ridge. A strong storm or two will be possible which could briefly support hail up to 1 inch in diameter and wind gusts near 60 mph, but risks will transition more towards heavy rainfall given deep layer shears 20 kts or less. So as organized severe thunderstorm risk decreases, risk for flash flooding on burn scars and urban areas will increase. Tuesday is the beginning of the drying and warming trend as the upper trough shifts eastward and ridging returns across the southwest U.S. Sufficient remnant moisture lingers for scattered afternoon thunderstorms but these will be more high based with gusty outflow winds and brief rainfall the primary risks. Pops continue to decrease for Wednesday and Thursday as the upper ridge builds over the southern Rockies. Temperatures are likely to hit 100 across portions of the plains one or both days with 70s and 80s for the valley and mountain communities. This will ramp up snow melt again across the high country. Another Pacific trough approaches the 4 corners region on Friday spreading increasing moisture and increasing thunderstorm chances across the mountains and plains as southerly low level flow advects higher dew points northward into the plains. Another active day for thunderstorms can be expected though details on storm strengths are still to be determined. Conceptually gusty downburst winds will be possible over the mountains/valleys and adjacent plains where DCAPE is likely to be greatest, with stronger storms near the KS border if southerly return flow can bring sufficient low level moisture/CAPE northward in time. These details will have to be resolved as we get closer to the event, but for now Pops will increase into the scattered to likely range for most of the area on Friday. It will dry out and heat up again next weekend. -KT && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 341 AM MDT Sun Jun 9 2024 KALS: Winds will turn southwest this afternoon, gusting 25-35 knots as cloud cover increases. Showers and thunderstorms will form over the nearby mountains and drift into the valley, which should have impacts on the terminal after about 22Z this afternoon. Passing showers will produce gusty outflow winds, brief periods of reduced visibility, and cigs down into the low VFR, high-MVFR range. KCOS and KPUB: Winds will generally be from the southeast today, increasing this afternoon with gusts to around 30 knots. Showers and thunderstorms will form over the higher terrain this afternoon, after about 20Z, with some scattered activity expected to drift close to the terminal late this afternoon into early evening. If showers do manage to move overhead, expect briefly limited visibility and MVFR cloud ceilings. Winds near thunderstorms will also become gusty and erratic, gusting close to 40 knots. Precipitation will dissipate overnight across the area, though some showers may linger over the mountains into tomorrow. && .HYDROLOGY... Issued at 341 AM MDT Sun Jun 9 2024 Rapid snow melt continues, leading to elevated flows along the Arkansas River from Leadville to Avondale through at least Monday, along with smaller creeks and streams close to the mountains. While water levels are generally expected to stay within their banks, fast flows can still be dangerous. Heavy rainfall today and tomorrow could increase flash flood potential for the southeast mountains and eastern plains, especially for waters with already elevated flows. && .PUB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...GARBEROGLIO LONG TERM...KT AVIATION...GARBEROGLIO HYDROLOGY...GARBEROGLIO