textproduct: Salt Lake City

KEY MESSAGES

- Critical fire weather conditions are increasing in likelihood for the latter half of the week across southern and central Utah. - As temperatures warm, the chance of Moderate HeatRisk increases to above 50% across the Wasatch Front and northwest Utah by the end of the week.

DISCUSSION

A west to southwesterly flow aloft is in place over Utah currently while the storm track remains active to the north. The previous storm system continues to lift into the northern high plains while a weak trailing disturbance is grazing northern Utah currently. A third trough is noted over the PacNW. The weak disturbance grazing northern Utah today was responsible for some weak high-based showers/virga that were noted over central Utah overnight and this morning. These showers will focus more across the Uinta Basin and adjacent mountains for the rest of the afternoon. Cannot rule out a thunderstorm or two with afternoon heating, otherwise the showers are expected to generally remain on the weaker side. Temperatures areawide will trend warmer for today while still remaining slightly below normal.

The trough over the PacNW will take its turn grazing northern Utah tomorrow. As such, expect a similar trend, with weak high-based showers/virga overnight (but focused more over northern Utah), with some additional showers and perhaps a thunderstorm or two across northeast Utah and southwest Wyoming tomorrow afternoon. The flow will turn more southwesterly tomorrow, and as a result, temperatures will continue to trend warmer to slightly above normal readings.

The next trough is expected to graze the area Wednesday night through Thursday. Again, can expect some high-based showers across portions of northern Utah. However, there is some model spread regarding the amplification of this trough. The stronger solutions will bring enough southwesterly winds to pose a concern for critical fire weather conditions in southern Utah. However, based on cluster analysis of ensemble members, the stronger solutions are currently in the minority with around 40% of members compared to 60% for the less-amplified solutions with weaker winds.

There is better model consensus on a stronger trough moving onto the West Coast next weekend. The potential for critical fire weather conditions increase across southern and central Utah given stronger forecast winds ahead of this storm combined with a dry airmass. Additionally, as temperatures continue to trend warmer through the week, reaching into the 90s in many valleys by the end of the week, HeatRisk will increase. On Saturday, there is widespread 50% chance or greater of Moderate HeatRisk across the Wasatch Front and Great Salt Lake Deserts, and 30% chance or greater in the eastern Utah Valleys.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions will persist for the entire airspace through the period. Dry and stable conditions with a few high clouds will continue with winds light and diurnally driven.

FIRE WEATHER

Utah will mostly remain under a drier and warmer west to southwesterly flow aloft through the week while the storm track to the north remains active. Weather disturbances grazing northern Utah will allow for isolated to widely scattered high- based showers and very isolated diurnal thunderstorms to develop over portions of mainly northern Utah through Tuesday. Storms during the latter half of the week look to be a bit deeper, which could drive stronger southerly winds resulting in an increasing threat of critical fire weather conditions for southern Utah. Otherwise, temperatures will trend slightly above normal areawide tomorrow, then rise to 5-15 degrees above normal by the end of the week. Relative humidities will fall below 15% in most valleys by Tuesday, trending more into the single digits across much of southern and central Utah during the latter half of the week when poor overnight recoveries can also be expected.

SLC WATCHES/WARNINGS/ADVISORIES

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