textproduct: NWS Flagstaff

SYNOPSIS

A Flash Flood Watch kicks in today for all our CWA, so anticipate persistent showers and thunderstorms for the next 24-36 hours. Although heavy rain leading to flash flooding will be one of the main concerns, some storms will be stronger in nature and could also produce gusty/erratic winds and hail. Activity will decrease through the end of the week and over the weekend, although a stray shower or two across higher terrain is not out of the question. Seasonable temperatures and breezy southwest winds are also expected.

DISCUSSION

The conversation of overnight activity has come to fruition, as showers and thunderstorms propagate northward through Yavapai County. Storms are moving quickly and there doesn't appear to be much in the way of training thunderstorms, so we aren't overly concerned with any flash flooding at the moment. For now, the main impact looks to be a few folks being woken up by some thunder. However, we do have a Flash Flood Watch in effect starting at midnight and continuing through 5 AM MST Thursday.

Model guidance hasn't been our best friend the last several days, but from what I've seen recently, all models seem to agree today (Wednesday) will be the most active in terms of showers and thunderstorms. Where models quickly disagree is the timing. Some models suggests the worst of it will be overnight tonight/early Wednesday morning, others suggest Wednesday afternoon/evening getting the bulk of the activity. With how radar is looking right now, I'd put more weight on the solutions suggesting this afternoon/evening being the busiest. WPC also has much of Arizona in a Slight Risk for excessive rainfall and also a section of the state (Tucson to Payson roughly) in a Moderate Risk. So there is confidence in continuous showers and thunderstorms throughout the day, with our southern zones likely having the greatest coverage. While any location will be susceptible to flash flooding, recent burn scars will be even more prone to flooding concerns. With that being said, be sure to have a way to receive warnings and never drive into a flooded roadway!

This active pattern is due to a large area of low pressure positioned across the Pacific Northwest. This pattern will shift by the end of the week and over the weekend as the low lifts more inland and a high pressure system moves towards the West Coast. This will bring drier conditions across the state Saturday and Sunday, but this drier trend looks to be short-lived with another disturbance potentially moving in early next week. Stay tuned for more details.

AVIATION...Wednesday 16/12Z through Thursday 17/12Z

Look for isolated -SHRA/-TSRA through 17Z. After 17Z, expect numerous SHRA/TSRA and ISOLD +TSRA across northern Arizona for the remainder of the period. Storm activity will result in areas of MVFR/IFR conditions due to low clouds and TSRA. Away from thunderstorm outflows, winds S at 5-15 kts gusting 15-25 kts.

OUTLOOK...Thursday 17/12Z through Saturday 19/12Z...Expect scattered to numerous SHRA/TSRA and ISOLD +TSRA until 00Z Friday, with areas of MVFR/IFR conditions due to low clouds and TSRA. After 00Z Friday, storm activity is forecast to decrease, with the best chances for storms over higher terrain in Navajo and Apache counties. Outside of gusty/erratic thunderstorm outflows, winds generally south to southwest at 5-15 kts.

FIRE WEATHER...Today and Thursday

Widespread showers and thunderstorms are forecast through Thursday morning, bringing wetting rain to the region. There is an elevated risk of flash flooding, especially over recent burn scars. A few isolated severe storms are also possible. Outside of storm activity, expect near to below average temperatures and south to southwest winds 10-15 mph gusting up to 25 mph. Expect gusty and erratic winds in/near storms.

Friday through Sunday...A drying trend will lead to decreasing storm coverage over the weekend. Temperatures will remain near average with south to southwest winds around 10 mph during the daytime hours, becoming light overnight.

FGZ WATCHES/WARNINGS/ADVISORIES

Flood Watch through late tonight for AZZ004>018-037>040.