textproduct: Salt Lake City

KEY MESSAGES

- Generally mild, stable and dry conditions persist through much of the work week. Redeveloping valley inversions may result in areas of valley haze.

- The next potential system looks most likely to move through in the Friday to Saturday time frame, bringing modest precipitation chances in addition to some light northern mountain snow, though uncertainty in details remains high.

DISCUSSION

Morning water vapor loop shows an extensive ridge parked over the Pacific Northwest. Deep north to northwesterly flow extends from the eastern periphery of this ridge down into the Intermountain West. Given the largely dry continental nature to the advecting airmass, much of the local forecast region remains stable, with nighttime microphysics RGB showing some mid/high clouds across southern Utah and a small amount of fog/low stratus trying to creep in across the Idaho border near the Raft River Mountains. Overall though, another night with fairly little of note.

From Monday on through the middle portion of the week the pattern will only slowly and gradually shift. Deep flow over the area will shift slightly more zonal as a Pacific trough starts to push towards/into the blocking ridge. In turn the low level temperatures of the air mass will tend to moderate back upwards day to day, likely peaking by midweek while remaining dry with the exception of some mid/upper level moisture and associated cloud cover. Afternoon highs are largely expected to follow a similar trend and remain above seasonal normal, though the continued stable conditions and mild lower levels will support the redevelopment of valley inversions. Areas where strong inversions and associated haze develop may struggle to see temperatures increase as much. Like much of the prior week, this will also result in potential for some localized overnight fog to develop... Though the airmass does appear quite dry. Not much else of impact though to note through midweek, with the exception of some modestly gusty (~20-40 mph) gap winds in portions of SW UT Monday.

The aforementioned Pacific trough looks mostly favored to cut off and push inland from around central to southern California, though a good deal of model uncertainty is noted (unsurprising with most cutoff systems). Timing wise, any local impacts currently look to fall roughly in the Friday/Saturday time range, though again with the cutoff nature there is uncertainty there. Given questions on available moisture (and cold air), forecast water amounts have a good bit of spread. 25th percentile amounts across the forecast region are more or less nothing, while even 75th percentile amounts only bring a general 0.10" to 0.20" of water to the high terrain. Still, there is some ensemble membership on the higher end (with a more appreciable shot of moisture noted in the 90th percentile amounts), so will be worth watching the trends since it's at least something. If nothing else, it could help provide better ventilation to valleys and in turn relief to inversions.

REST OF UTAH AND SOUTHWEST WYOMING

Light winds and clear skies will result in VFR conditions prevailing for all regional terminals today, outside of a low-end (15%) chance for MVFR vis for terminals across the Wasatch Front as the inversion persists.

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SLC WATCHES/WARNINGS/ADVISORIES

UT...None. WY...None.