SHORT TERM /THROUGH SATURDAY/
Issued at 212 PM MDT Fri Jul 26 2024

We continue to anticipate scattered convection across much of the forecast area this afternoon and evening as monsoonal moisture interacts with pulses of shortwave energy advecting through the southwesterly flow aloft. Dew point temperatures this morning were in the 50s area wide, but it became apparent that most of the CAMs were underdoing dew point temperatures. For example, the HRRR has dew points upwards of 10 degrees too cool compared to ground observations. The NAM Nest seems to be the most representative at this time. With satellite imagery showing sufficient clearing after a cloudy start to the day, convection this afternoon will likely realize forecasted mixed-layer CAPE values of 500-1200 J/kg. Deep- layer shear on the order of 15-25 knots could support a few isolated severe storms, but organized severe convection is not likely with limited shear in place. Gusty outflow winds up to 50 mph and hail up to 1" in diameter are the primary threats. Localized heavy rainfall is also on the table. CIN increases quickly after sunset but a few showers and storms may continue into the evening.

A similar story again tomorrow afternoon and evening with the biggest difference being increased shear with an upper-level jet moving in overhead. The biggest forecast uncertainty is how quickly monsoonal moisture will begin to erode. All of the hi-res models show decreasing PWATs late tonight into tomorrow, but given that they are struggling with the moisture currently available and that the models are usually too quick to clear the monsoonal moisture from the region, we cannot rule out scattered convection similar to what we will see today. If the mositure does decrease, the coverage of convection will also decrease. A drier atmosphere could also lead to elevated fire weather conditions in parts of eastern Utah tomorrow afternoon with surface winds gusting up to 25 mph, but given our lower confidence in mositure clearing by tomorrow afternoon we opted against fire weather headlines at this time.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/
Issued at 212 PM MDT Fri Jul 26 2024

On Sunday a trough tracks from the Great Basin to the Northern Rockies bringing a midlevel dry punch into the region from the southwest. Guidance remains aggressive in scouring out moisture from west to east by Sunday morning, dropping PWATs down to near 50 percent of normal that afternoon. It is always a bit tricky to get rid of residual moisture post-monsoonal surge, so can't rule out a few storms over the mountains Sunday afternoon. If conditions dry out as anticipated, the potential for near critical fire weather conditions will be possible. This will be due to the presence of a 60 to 70 kt jet overhead across much of eastern Utah and western Colorado, resulting in surface gusts right around 25 mph. The gradient relaxes on Monday which would lead to more localized near critical fire weather conditions. Continued warm southwest flow aloft will bring about a warming trend into the midweek point with temperatures returning to several degrees above normal and even back to the low triple digits for some of the lower valleys. Early next week will also see the next trough of low pressure begin to dig into the Pacific Northwest. Its progression east on Tuesday will usher the Subtropical High closer towards the Southern Plains, allowing for monsoon moisture to slowly trickle back into the Four Corners region on Tuesday and Wednesday. That might be short lived as the trough to the north suppresses the moisture back to the south.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
Issued at 1117 AM MDT Fri Jul 26 2024

With the clearing taking place storms should develop soon.
Expect gusty outflow winds, small hail, and some heavy rain under the strongest cells. Included VCTS for almost all TAF sites with TEMPO groups for -TSRA on station as well. Brief MVFR will be possible under and near the strongest storms but did not include those conditions for TAF sites. Some overnight convection will be possible though coverage should be less than seen last night.

GJT WATCHES/WARNINGS/ADVISORIES

CO...None.
UT...None.