Area Forecast Discussion
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
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923 FXUS65 KPUB 292124 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 324 PM MDT Sat Jun 29 2024 .KEY MESSAGES... - Thunderstorm chances increase this evening/tonight, along with the risk for severe storms and heavy rainfall with flash flooding. Flash Flood Watch in effect for the far southeast plains. - Thunderstorm chances along with the risk of severe storms and heavy rainfall with flash flooding return on Sunday. - Thunderstorms decrease in coverage and intensity for the Monday through Wednesday timeframe. - Dry conditions return for Fourth of July, which will mean less thunderstorm coverage for many, but marginal fire danger for some. && .SHORT TERM /THROUGH SUNDAY/... Issued at 322 PM MDT Sat Jun 29 2024 Relatively quiet this afternoon, with latest radar imagery showing only isolated shower and thunderstorm development across primarily the Continental Divide. Meanwhile, post frontal air and early morning cloud cover has supported relatively cooler temperatures this afternoon. For the remainder of the afternoon, expect isolated to widely scattered showers and thunderstorms to continue over and near the higher terrain, where slightly better moisture and instability reside. While can`t rule out an isolated stronger storm this afternoon and potentially a severe storm, think this risk is low given overall low values of moisture and instability. If a stronger storm or even severe storm were to occur, think wind gusts up to 60 mph would be the main risk. By this evening, will see the mid level energy which is moving overhead right now, continue to push across the region. This will support lee troughing in the lower and mid levels this evening. Higher moisture along with higher instability, that is to the southeast, finally returns in this setup. Will likely see the risk of scattered strong to severe storms spread into the I-25 corridor, with hail to the size of quarters and wind gusts up to 60 possible with any severe storm. This risk looks to continue through mid evening, and possibly shifting to the east of the I-25 corridor but attention quickly turns to the far southeast plains by mid to late evening. In this area, instability and moisture will be the highest with CAPE values of 1000-2000 j/kg in place, surface dew points in the low to mid 60s, and PWATs approaching 1.75 to 2.00 inches. Additionally, bulk shear with be in the 40-50 range. This is concerning because focus for ascent really ramps up during this time across the far southeast plains. Will see the lingering boundary and surface trough in place, as southerly 700mb flow ramps up over head. This increase in likely persistent focus/forcing will support an increasing risk for severe storms with hail up to 1.50 inches in diameter and wind gusts up to around 60 mph possible. Additionally, given the setup and potential for training thunderstorms, have issued a Flash Flood Watch for the far southern tier of counties across the far southeast plains. While forecast amounts are in the 1- 3 inch range, locally higher, some model raw output is showing localize amounts up to around 5 inches. Once again, the moisture, instability, and setup could support these higher amounts. Will need to monitor for a slight shift north in the development with time during the over night hours, and the possibility of expanding the Flash Flood Watch. Showers and thunderstorms will likely continue for most of the night, but should see the severe risk lessen during the overnight into the early morning hours as instability diminishes. General drying trend is expected through the morning hours on Sunday, though some lingering showers may persist across the far southeast plains as well as a few showers and thunderstorms over the southwest mountains. Ridge in place on Sunday, though will see a continued stream of mid level energy along with additional lee troughing. While this is expected, there is some uncertainty as to where this will occur. This will not only factor on focus for thunderstorm development, but will play into the extent of the westward movement of the higher moisture and instability. Given some likely steady east/southeast flow at the surface dew points could easily exceed 60 degrees across the plains, while CAPE meets or exceeds 2000 j/kg and while bulk shear increases. Will need to monitor where this sets up and once again, how likely capping in place will factor into development. Nonetheless, a severe risk is in place on Sunday, with all hazards possible. Meanwhile, will see increasing moisture and focus across the Continental Divide that will likely support periodic shower and thunderstorm development. Can`t rule out a strong to severe storm, but think the risk of heavy rainfall and possible flash flooding will be the main threat. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... Issued at 322 PM MDT Sat Jun 29 2024 For Monday and Tuesday, we will see warming and drying, as a trough tries to pass to our north and our flow aloft remains weak and southwesterly. This will keep afternoon and evening showers and thunderstorms in our forecast, especially over and near the mountains, though coverage and intensity will decrease from this weekend`s activity. Temperatures both days will be just a few degrees above normal for most locations, and critical fire weather looks to be unlikely due to weak winds, though we will be fairly dry by Tuesday with humidity values falling down into the 17-22% range over portions of the Arkansas River Valley that afternoon. Models bring a cold front across the plains Tuesday night, which will cool things off for our Wednesday, leading to increased rain and thunderstorm chances for much of the area, along with near or just below normal temperatures for many locations. Fourth of July and Onwards.. Ensembles bring quieter and more northwesterly flow aloft towards our region by Thursday behind the passing trough to our north, which should lead to at least a day or two of very sparse thunderstorm chances, and warmer temperatures for Thursday and Friday. One concern with our Fourth of July forecast is that our relative humidity values look to fall down into the low to mid teens in a few places, including the upper and middle Arkansas River Valley to include the Pueblo area, along with northern Teller County, which could lead to dangerously dry conditions for Holiday activities. For most areas, winds look to remain below critical fire weather thresholds, but the overall dryness could end up being something that needs to be monitored as the Holiday approaches. Models bring a cold front across our plains sometime in the Thursday night or Friday morning timeframe, which should help to increase our humidity values and decrease our temperatures for Friday and Saturday, but will also increase our chances for showers and thunderstorms for both days as well. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1135 AM MDT Sat Jun 29 2024 For KCOS and KPUB..VFR conditions are expected for the next few hours early this afternoon, before showers and thunderstorms begin to push off the terrain and near or over both stations after 23Z this afternoon. MVFR conditions during thunderstorms will be possible, along with gusty and erratic thunderstorm winds from around 00Z through 06Z this evening. MVFR and IFR ceilings and visibilities are also expected from 06Z through around 14-16Z tomorrow morning due to stratus and upslope conditions, and could persist longer at KCOS. For KALS..VFR conditions are expected for the next 24 hours, with a slight chance for vicinity showers and weak thunderstorms this afternoon, mainly from 23Z until 03Z. Winds are expected to be mostly light today, but could be gusty and variable near thunderstorm activity later this evening. && .PUB WATCHES/WARNINGS/ADVISORIES... Flood Watch through late tonight for COZ088-094-099. && $$ SHORT TERM...RODRIGUEZ LONG TERM...EHR AVIATION...EHR