textproduct: Salt Lake City

KEY MESSAGES

- Ridging continues through Monday bringing warm and dry conditions to the forecast area.

- A pattern shift is expected to develop Tuesday bringing wetter and cooler temperatures to the forecast area through at least Thursday with valley rain and mountain snow. Additionally, gusty winds will develop Thursday ahead of and near a cold front.

DISCUSSION

A weak shortwave disturbance continues to ripple through central Utah this evening and will exit the area overnight. Some high-based showers associated with this disturbance produced a few wind gusts over 45 mph across central Utah, but with the loss of daytime heating, these showers have trended weaker and will continue to diminish tonight. Although shower activity will decrease for Sunday, lingering midlevel moisture and very weak instability could still produce a few diurnal high-based showers, mainly over the higher terrain. Temperatures on Sunday are expected to be similar to, or just slightly warmer than, today.

On Monday, westerly to southwesterly flow will increase as a low- amplitude trough moves across the PacNW and into Montana. A cold front associated with the trough is expected to enter northern Utah Monday night before weakening over central Utah Tuesday morning. Warm and generally dry conditions will continue Monday ahead of this cold front. Behind the cold front, afternoon max temperatures on Tuesday are expected to fall 9-13 degrees from Monday's highs across northern Utah and southwest Wyoming and around 4-8 degrees across southern Utah. Similar to recent cold fronts, however, this will largely fail to bring temperatures down below climatological normals. As far as precipitation, models are not terribly enthusiastic, with generally light amounts of precipitation behind the front late Monday night into Tuesday focused mainly across the northern half of the forecast area.

The next trough arriving for late Tuesday into Wednesday currently looks more promising in terms of precipitation, as it will be associated with increased moisture transport especially into southern Utah. Expect more widespread precipitation beginning Tuesday night and continuing through much of Wednesday afternoon. The airmass is expected to cool enough to allow for accumulating snow at the higher elevations, as H7 temperatures fall to between -2 to -3C across northern Utah and 0 to -2C across the south. This would equate to snow levels down to 7.5-8kft across northern Utah and around 8.5-9kft across southern Utah. As such, mountains should be able to receive much-needed snowfall, even though amounts will not be very significant.

A potentially stronger trough is still on tap for Thursday. Breezy conditions are expected to precede the front which looks to arrive into northern Utah Thursday before midday. Currently, model consensus shows H7 temperatures cooling to -10C across northern Utah Thursday night which could bring snow down to the valley floors. However, precipitation may be winding down by that point. Additionally, there remains a subset (~17%) of ensemble members that depict a less amplified, and thus warmer and weaker, trough. In short, while the potential is there for light valley snow (40-55% chance for 0.1 inches or greater along the Wasatch Front and Cache Valley) and some of our coldest temperatures since briefly during the middle of the month, there is still some uncertainty this far out.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions will prevail through the TAF period. Winds will generally remain terrain driven through midday Sunday. By Sunday afternoon winds will have a light northerly component across northern TAF sites, while southwesterly winds prevail across southern Utah.

SLC WATCHES/WARNINGS/ADVISORIES

UT...None. WY...Red Flag Warning until 9 PM MDT Monday for WYZ277.