textproduct: Salt Lake City

KEY MESSAGES

- A monsoon surge will continue to bring the threat of thunderstorms with heavy rainfall, with the highest threat across southern Utah through the weekend and into at least early next week. - A Flood Watch for flash flooding is in effect for southern Utah through this evening.

- A new Flood Watch for flash flooding was issued for Friday afternoon and evening for southwest and south central Utah. Additional Flood Watches may be needed for Saturday in this area.

DISCUSSION

As an active monsoon surge continues across the region for the entire forecast period, the weather each day across the southern half of Utah will be focused on afternoon and evening convection. Precipitable water values have already exceeded the 98th percentile across many locations of southern Utah and extended ensemble modeling suggests PWs will remain above 90th percentile through at least next Thursday.

While there is no obvious source of lift today in regards to a shortwave trough, convection will continue to develop across the higher terrain through early afternoon. With most parameters at or more preferential for cold pool/shear balance, expect slow moving convection with very heavy rainfall to gradually shift into adjacent valleys with higher available instability. A Flood Watch remains in effect across much of southern Utah this afternoon and evening.

It'll feel a bit like rinse and repeat for southwest and south central Utah Friday afternoon and evening. Little change in the environmental conditions will yield another round of higher probabilities of flash flooding for these areas. A Flood Watch for flash flooding was issued for southwest and south central Utah with this package.

Not seeing much change in relation to the monsoon into the weekend...so future shifts will continue to monitor for expansion of the flood watches into the weekend. This is not the time for outdoor recreationists to plan hikes into/near slot canyons, normally dry washes, slick rock areas. Additionally, those near recent burn scars such as Cottonwood, Monroe Canyon, France Canyon, and Forsyth should continue to monitor for potential warnings and have a plan if a warning is issued.

AVIATION...KSLC

Overall VFR conditions are expected at the terminal today and tonight. Showers and thunderstorms will develop over the surrounding high terrain to the south by late this afternoon, bringing increasing potential for gusty outflow winds by this evening. With storms generally residing to the south of the terminal, would expect these winds to have a southerly component. There will be a 10 to 20% chance for showers to move over the terminal itself this evening between 0Z and 3Z.

REST OF UTAH AND SOUTHWEST WYOMING...Showers and thunderstorms are expected to develop again over the high terrain features across a majority of Utah (lower coverage north of I-80). Showers and thunderstorms are expected to begin drifting off terrain features into adjacent valleys after 20Z, bringing potential reductions in visibility due to moderate to heavy rainfall along with gusty and erratic outflow winds in excess of 30 kts.

FIRE WEATHER

An ongoing monsoon surge will continue to bring the threat of heavy rainfall to much of southern and portions of eastern Utah through at least the weekend, and potentially into early next week. For areas more removed from this surge across northern and west central Utah, coverage of any thunderstorms will be less across valley locations. Humidities in the 20-30% range across the northern and western valleys will further increase this weekend to around 30-40%.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Flood Watch through this evening for UTZ121>131.

Flood Watch from Friday afternoon through Friday evening for UTZ122>128.

WY...None.