textproduct: Salt Lake City

KEY MESSAGES

- Critical fire weather conditions will persist across much of central and southern Utah today, with the threat becoming focused over southeast Utah on Wednesday. - Showers and thunderstorms will persist over Utah and southwest Wyoming through the afternoon. Coverage will generally decrease, but any storms that develop will be capable of producing strong to severe wind gusts with a low chance of large hail.

- Confidence is high in dry conditions through the upcoming weekend, with high temperatures at least 5F above seasonal normals developing by Friday.

DISCUSSION

A Pacific Northwest trough is making its way across northern Utah and southwest Wyoming this morning with the associated cold front currently near a KELY-KSLC line. Showers were widespread across northern Utah, primarily along and behind the front, earlier, with coverage becoming more focused from Weber county into the Cache Valley as of this writing. Overall, coverage will tend to decrease as the leading edge of shortwave energy and associated moisture lift into Idaho and Wyoming. Still, with cloud cover also decreasing and additional instability to be provide as daytime heating increases, will continue to see at least isolated coverage of showers this afternoon, particularly for areas near the Utah/Idaho border.

For the storms that do develop, the position of the jet will provide favorable dynamics in the from of CAPE in excess of 500 J/kg and 35 kts or more of shear per the latest RAP, enough to bring a chance of strong to severe convection into play. Given the relative dryness of the airmass, particularly at low levels, primary threat with the storms will be gusty downburst winds. However, the ingredients do exist to produce enough organization to bring a small threat of large hail.

Winds will be generally on the decrease this afternoon over northern Utah and southwest Wyoming behind the front. However, this feature should stall and wash out over the next few hours, keeping southerly winds gusty over the southern two-thirds of Utah. Combined with the very dry airmass, confidence is high in another round of fairly widespread critical fire weather conditions.

The main trough is expected to move east of the area by Wednesday, though shortwave energy will linger north of the area over Idaho throughout Wednesday. The dry airmass over the area should limit convective initiation over northern Utah, however. Though northern Utah maxes should return to values near seasonal normals Wednesday afternoon, an associated reinforcing dry front Wednesday night into early Thursday will drop maxes by about 5F for much of the area Thursday afternoon.

With the second shortwave exiting, the most likely scenario for the forecast area is a dry and increasingly warm zonal flow setting up Friday through Saturday with a broad ridge spinning off the Pacific coast. Maxes are expected to peak Saturday with highs averaging 10F above climo. Most guidance continues to show a solution where a trough moves over the top of the ridge during the day Sunday, skirting northeast Utah and southwest Wyoming, bringing in a weak and mostly dry front to knock temperatures down by a few degrees Sunday afternoon. A return to zonal flow and increasingly warm temperatures is then expected for day 7 and beyond.

REST OF UTAH AND SOUTHWEST WYOMING

A line of showers with a few lightning strikes will continue to push across northern UT/southwest WY, resulting in some squirrelly winds and low (10-20%) chance of MVFR VIS. A few stronger storms along the UT-ID border could produce small hail this afternoon. These showers will largely end by 22z, with skies clearing for the rest of the valid TAF period. Gusty southwesterly winds around 25-35kts will persist ahead of a diffuse cold front currently draped over roughly KDTA-KPVU. Winds have shifted to northwesterly behind this front, gusting to around 20-30kts behind it.

FIRE WEATHER

A cold front has moved through northern Utah and will stall and continue to weaken during the early afternoon. Ahead of this front, gusty southerly winds will persist for the southern two-thirds of the state, combining with the continued very dry conditions to produce fairly widespread critical fire weather conditions through Tuesday evening. Some showers and thunderstorms will continue over northern Utah into the early evening, particularly near the Utah/Idaho border, and any storms that develop with have the potential to produce gusty and erratic winds. As the trough moves east of the area Wednesday, winds will decrease some over western Utah, but winds will be breezy enough to keep critical fire weather conditions going over southeast Utah. Conditions will continue to be quite dry across the area through at least early next week, but winds are expected to remain on the light side through Saturday. Another northern Utah cold front on Sunday could bring a return to stronger winds, bringing the potential for areas of critical fire weather conditions.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Red Flag Warning until 10 PM MDT this evening for UTZ492-495-497.

Red Flag Warning until 10 PM MDT Wednesday for UTZ484-489-493- 494-496-498.

WY...None.