textproduct: Salt Lake City

KEY MESSAGES

- A dry and mild airmass will boost temperatures 10 to 15 degrees above normal on Friday.

- A cold front will cross northern Utah Saturday afternoon and evening bringing a slight chance for thunderstorms. Strong west winds will accompany this front across the northern Wasatch Mountains, western Uinta Mountains, western Uinta Basin and Castle Country.

- Anomalously strong high pressure will build into the West for much of next week, with temperatures averaging near 20 to 30 degrees above normal during the latter half of the week. High temperatures will challenge all time monthly records for March beginning Thursday.

DISCUSSION

Evening satellite imagery and objective analysis show a strong zonal flow across much of the Pacific Northwest/northern Rockies, with a very mild airmass in place to the south of this jet across much of the Great Basin and Colorado Plateau region. This airmass allowed temperatures to run 10-15 degrees above climo across much of the forecast area, with KSLC reaching the 70F mark. This stronger flow was noted across the northern Wasatch Range as well as into Uinta County WY, where gusts sporadically reached the 60 mph range earlier. These winds began to taper off shortly before sunset, and the wind headlines were dropped accordingly.

A low amplitude shortwave ridge will temporarily build across the region Friday, allowing for another very mild afternoon with temps again running 10-15F above climo. Gusty afternoon winds will once again develop across favored areas such as the Bear River Valley, Uinta County WY, and the western Uinta Basin, however these speeds should remain below the Advisory threshold and no headlines are planned.

A shortwave trough is forecast to dig through the northern Rockies Saturday, pushing a fairly strong cold front into far northern UTah Saturday morning, then through the remainder of the forecast area Saturday afternoon into early evening. Some spread remains between models regarding how far west this trough digs, which will have a big impact on precipitation across northern Utah. A deeper and further west solution would bring better upper dynamics and colder air aloft into northern Utah, favoring a heavier band of precipitation. In this scenario a more robust convective line with heavier precipitation (0.10-0.25 most likely) with some snow accumulation above roughly 9000 feet would affect northern Utah Saturday afternoon, with a chance of precipitation extending into the higher terrain of central Utah. A weaker, brush-by solution would push a more shallow frontal boundary through the state, accompanied by a band of lighter, more scattered precipitation. Regardless, strong post-frontal winds exceeding 45 mph are expected across favored downslope areas including the Bear River Valley/Uinta County WY, the western Uinta Basin and Castle Country with a chance these gusts extend east into the San Rafael Swell.

Much cooler air will follow this front, knocking max temperatures Sunday below normal across the forecast area, with daytime temps remaining in the 40s across northern valleys including the Cache Valley and Wasatch Front, and low 50s across central/southwestern valleys including Richfield, Delta and Cedar City, while St George/Zion Canyon remain around 70F Sunday afternoon.

Confidence remains high in the long term forecast for next week, as an anomalously strong ridge builds across the West. Temperatures will tend considerably warmer (6-10F each day) beginning Monday, and continuing through midweek. By Thursday, max temperatures will be challenging not just daily, but monthly temperature records across the forecast area. This record warmth will continue through at least next weekend.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions will prevail through the TAF period at all terminals. Winds will remain generally terrain driven, with the exception of KEVW where gusty west winds will redevelop after 16Z Friday, with gusts in excess of 25 KTS possible.

SLC WATCHES/WARNINGS/ADVISORIES

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