textproduct: Salt Lake City

KEY MESSAGES

- Critical fire weather conditions continue across central and southern UT tomorrow, lasting through at least Wednesday as forecast confidence continues regarding gusty conditions with low relative humidity each afternoon.

- The threat for isolated to scattered dry thunderstorms capable of strong to severe wind gusts and isolated lightning exists tomorrow across central UT and southeasternmost portions of northern UT. This will result in a conditional fire weather risk across the aforementioned areas with the dry lightning threat.

- Given preceding dry and gusty conditions, blowing dust is expected once again across much of UT and southwest WY tomorrow afternoon. This threat may be locally enhanced from thunderstorm outflow.

DISCUSSION

Tomorrow, the fire weather threat continues across much of central and southern UT, though the most favorable overlap for critical fire weather conditions exists across southern and southeast UT. This is due to a cold front currently progressing through the area tonight which will serve to mitigate afternoon mixing, keeping winds more moderated with northern extent. This will be most pronounced across northern UT, though west-central UT may see slightly lower gusts tomorrow afternoon compared to today. Regardless, high confidence exists in gusts greater than 30mph with humidities in the single digits to low teens across central and southern UT resulting in critical fire weather conditions once again. Additionally, the cold front will bring temperatures closer to seasonal normals tomorrow

Across central and far eastern portions of northern UT, there is at least some potential for isolated scattered dry thunderstorms with attendant strong to severe microbursts tomorrow afternoon. Modest height falls will continue overspreading the region as a midlevel trough ejects across ID/MT. With various shortwave perturbations traversing central UT along the aforementioned frontal boundary serving as a forcing mechanism at the surface, scattered dry thunderstorm development appears likely tomorrow afternoon. Inverted- V soundings are abundant given notable dewpoint depressions across the area of interest with modest flow aloft, suggesting that any shower or storm that forms will be capable of strong to severe wind gusts (greater than 58mph). Lightning is also possible with these storms in the presence of some instability aloft, potentially yielding a more localized fire weather threat across central UT.

Monday and Tuesday continue to remain quite favorable for continued critical fire weather conditions across central and southern UT. While humidities may rebound somewhat into the low teens, a more widespread wind threat looks to develop with very high confidence for wind gusts greater than 30mph (generally 60-90%+). Additionally, the signal for gusts greater than 40mph remains quite widespread this forecast cycle, ranging from 40-60% and increasing somewhat with eastern extent. Lastly, there is also some signal for dry thunderstorms once again on Tuesday as a frontal boundary may stall or slowly progress south across central UT with time, though exact location is extremely uncertain at this time.

Wednesday will bring another round of fire weather conditions to central and southern UT, though uncertainty remains regarding the northern extent of the critical fire weather conditions due to frontal boundary placement. There is some potential that near- critical fire weather conditions extend past Wednesday, though high uncertainty surrounds this.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions will prevail across the region under increasing mid-level cloud cover. Winds will remain elevated during the overnight hours near significant terrain features in the central and southern area, as well as a portion of the northeastern area, potentially gusting upwards of 25-30kts. Gusty southwest winds continue across much of the area on Sunday, primarily over the eastern area, with gusts upwards of 25-30kts. Additionally, high-based showers are also expected to develop across central Utah on Sunday afternoon, bringing potential for gusty and erratic outflows in excess of 40kts.

FIRE WEATHER

There is a conditional fire weather threat across portions of far northern Utah late this afternoon and evening as there is potential for isolated to scattered dry thunderstorms across the area. Storms will be capable of producing dry lightning as well as gusty and erratic outflow winds to 50 mph, which could lead to rapid fire spread given a spark. Otherwise, widespread critical fire weather conditions are expected across central and southern Utah as wind gusts 30-40 mph continue through this evening. Winds remain elevated in some locations overnight, with poor overnight recoveries. While winds taper slightly on Sunday, widespread gusts 25-30 mph will keep critical fire weather conditions in place through the evening. Overnight RH recoveries improve Sunday into Monday morning behind the front, but very efficient mixing ahead of another system moving into the region will result in critically dry RH and widespread wind gusts 30-40 mph again across southern Utah beginning Monday afternoon. Widespread critical conditions remain through Tuesday before becoming more localized Wednesday into Thursday.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Red Flag Warning until 10 PM MDT Sunday for UTZ484-489-492>498.

Fire Weather Watch from Sunday evening through Wednesday evening for UTZ484-489-492>498.

WY...None.