Area Forecast Discussion
Issued by NWS Pueblo, CO
Issued by NWS Pueblo, CO
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806 FXUS65 KPUB 211736 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 1136 AM MDT Fri Jun 21 2024 .KEY MESSAGES... - A Flash Flood Watch is in effect from Noon until Midnight tonight for the San Juan Mountains. - Thunderstorms increase in coverage and severity across the high country today, with main risks being flash flooding, damaging winds gusting to 60 mph, large hail to 1 inch diameter, and lightning. - Warming and drying trend into early next week, most notably across the southeast Plains, with temperatures some 10-15F above seasonal levels early next week. - An uptick in daily showers and storms for the middle and end of the next work week. && .SHORT TERM /THROUGH SATURDAY/... Issued at 343 AM MDT Fri Jun 21 2024 Currently.. A surface low is in place over Pueblo County, bringing gusty southwesterly winds to the southern I-25 corridor and our southwestern plains, and gusty southerlies to our far eastern plains. Trinidad recorded southwesterly winds gusting to 35mph at 130am and Lamar recorded southerly winds gusting to 30mph around the same timeframe. Temperatures are warm this morning, with most locations still in the mid to upper 60s across the I-25 corridor, and even some low 70s on the eastern plains as of 2am. Dewpoints are in the 50s and low 60s on the plains. Satellite and radar imagery show continued rain showers over the high country, where many locations have seen significant moisture over the past 24 hours. MRMS 3 hour precip totals are estimating portions of the San Juans at around 0.65 inches of rain between midnight and 3am this morning. With more rain and storm chances in store for today, our warm and moist airmass and previous rainfall will increase chances for excessive rainfall across the high country this afternoon and into this evening. Today.. Models bring a messy and weakening trough across Colorado throughout the day today. This feature will help to usher in even more moisture, and enough instability to increase our chances of seeing some strong to severe thunderstorms across the high country today. With both EPS and GEFS ensemble members showing PWATs in the 200- 220% of normal range over the high country today, along with steep lapse rates, our main risk with storms this afternoon and this evening will be excessive rainfall and flash flooding, especially for our burn scars and flood prone areas. Many of these areas saw rain yesterday and the day before as well, and will already be saturated before today`s storms begin to fire up over the area. The WPC has our San Juans and La Garitas outlooked for a slight risk for excessive rainfall, with the rest of our mountains in a marginal risk as well. The San Juans saw the most rain overnight, and have the highest forecast QPF amounts for today as well. Early in the afternoon, models paint enough instability over this area to indicate the potential for very heavy rainfall that could lead to flash flooding. For this reason, a Flash Flood Watch was issued for this afternoon, valid from Noon until midnight tonight. With decent shear and CAPE values of around 1200-1700 J/Kg over the high country and our mountain adjacent plains, large hail up to 1 inch diameter and damaging winds with gusts up to 60 mph can`t be ruled out with any stronger storms that develop as well. The SPC has the San Juans, the La Garitas, and Lake and Chaffee counties outlooked for a marginal risk for severe thunderstorms today, but one other area to watch closely will be Fremont and Teller counties, where higher shear and instability seem to overlap around max heating this afternoon. Other than our increased storm chances over and near the mountains, temperatures today will be around 3 to 6 degrees warmer than yesterday for most locations, with increasing cloud cover and breezy southwesterly winds. Tonight.. High res model guidance suggests that storms begin to die off quickly after sunset over the Pikes Peak region and the central mountains, but are likely to continue through the evening hours further south. Our far southeast mountains look to clear out latest, with all locations clear by around midnight tonight. With all the lingering moisture and overcast skies, overnight low temperatures look to stay in the mid to upper 60s for our plains as we head into Saturday morning, with 50s for mountain valleys and 40s for higher terrain locations. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Issued at 343 AM MDT Fri Jun 21 2024 Latest model data continues to indicate a warming and drying trend for the weekend, as drier air within modest west to northwest flow filters into the region. Ensemble data indicates pwats decreasing to at and below seasonal levels, most notably across southeast Colorado, with enough residual moisture across western and into south central Colorado, to support isolated to scattered afternoon showers and storms over and near the higher terrain through the weekend. Sounding data supports convection to be higher based with the main threats through the weekend being lightning and gusty outflow winds. With warming aloft and less expected convection, highs through the weekend will be above seasonal levels in upper 80s to upper 90s across the southeast Plains, and mainly in the 70s and 80s across the higher terrain, save for 50s and 60s at the peaks. Warming continues into early next week as upper level ridging builds across the Southern Rockies and into the Four Corners region by midweek. This will keep modest and fairly dry west to northwest flow aloft in place with temperatures areawide continuing to sizzle, especially across the plains with highs above the century mark and some 10 to 15 degrees above seasonal levels, with the potential for heat advisories across portions of southeast Colorado Monday and Tuesday. The upper high gets pushed south and east through the end of the next work week, leading to another influx of subtropical moisture within modest southwest flow aloft across the Central Rockies. This increase in available moisture, along with a surge of cooler air and low level moisture across the southeast plains from a passing High Plains front, will lead to increased coverage and intensity of diurnal convection areawide into the end of the next work week. The increased moisture and expected convection will also lead to slightly cooler temperatures into later next week. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1127 AM MDT Fri Jun 21 2024 Thunderstorms will develop over the mountains and move off into the lower elevations affecting the TAF sites after 22-23z. KALS will have the best chance for TSRA which could drop cigs into the MVFR to even high end IFR category with +RA if storms directly impact the terminal. Gusty outflow winds up to 50 kts and hail up to 1 inch will be possible across the San Luis Valley with the isolated stronger storms. Storms will become less energetic as the move into the I-25 corridor with KCOS having the greater likelihood for VCTS in the 23z-01z time period. Gusty erratic winds up to 40 kts will be possible. KPUB will have a lower chance so TAF will carry VCSH with a wind shift from the west due to convective outflows around 00z. Winds and convective cloud cover will diminish after 03z for KCOS and KPUB, but -SHRA could continue at KALS until 08z. There is the chance some fog could develop at KALS overnight if skies clear out quickly enough but some VFR cloudiness is more likely to prevent this from occuring. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... Flood Watch through this evening for COZ068. && $$ SHORT TERM...EHR LONG TERM...MW AVIATION...KT