textproduct: NWS Flagstaff

SYNOPSIS

Showers and thunderstorms will continue through the day due to tropical moisture being pulled into Arizona as the remnants of Tropical Storm Rachel move northward. Expect cooler, windier, and wetter conditions to continue through at least the first half of the week.

DISCUSSION

After making landfall earlier this evening, the remnants of Tropical Storm Rachel are moving towards the north- northeast early this morning before exiting into Utah this afternoon. Associated showers and thunderstorms continue to move quickly northward through the region, remaining fairly scattered across our area. With a continued strong southerly flow, moisture has continued to advect into the region and have left ripe conditions with the potential for heavy rain through today. Models continue to highlight areas across central/western Arizona as being at the greatest risk for flash flooding. Model soundings show PWATs that are near or above the daily max. QPF amounts will vary widely as we see more of a convective element to the precipitation vs a widespread stratiform event. Rainfall amounts between 1-3" still seem reasonable with locally higher amounts possible. The Flood Watch remains in effect for areas along and south of the Mogollon Rim up through the Kaibab Plateau.

Storms should be moving pretty quickly as current RAP 0-6 km winds are around 40-50 kts. The speed of the storms may help to limit some of the flash flood potential, though some training of storms may occur. As far as a severe component goes, there is a small amount of instability that may increase slightly today if the sun is able to peek out for a bit. Shear is deep and strong though appears to be largely unidirectional through the low and mid levels on model soundings. There will be potential for some strong storms to develop with mainly a damaging wind threat with the threat for a tornado remaining pretty low but not zero.

Increasing south to southwest will occur through the day today as the gradient remains tight and upper jet moves overhead. For today, winds will be south to southwest 25-35 mph with gusts 40-50 mph and some locally higher gusts possible. Winds remain strong on Monday and Tuesday, mainly across the higher terrain but really begin to taper off later Tuesday. A Wind Advisory remains in effect through this evening.

The remnant circulation pushes off to the north as a trough deepens across the western states. Dry air gets pulled into the mid-levels along the eastern side of the trough and helps to dry us out as we head towards mid-week. However, with moisture remaining in the low levels, expect scattered showers and thunderstorms to continue through at least Tuesday before ramping down in coverage Tuesday afternoon/evening. By Wednesday, conditions start to dry out and are expected to continue into Thursday.

Beyond Wednesday, there remains uncertainty as to how the pattern will evolve through the rest of the week. The trough looks to become cut off from the main flow, lingering near the Four Corners region through much of the week. Models continue to disagree on how fast this low will move to the east which leaves us with low confidence for the extended forecast.

AVIATION...Sunday 11/12Z through Monday 12/12Z

Mainly MVFR conditions in SHRA/TSRA through the period. Periods of IFR or lower possible in +RA and low CIGs. Strong S-SW winds 15-30 kts gusting 40-50 kts, especially after 16Z.

OUTLOOK...Monday 12/12Z through Wednesday 14/12Z...Mainly MVFR conditions in SHRA/TSRA through the period. Periods of IFR possible through Sunday in +RA and low CIGS. Expect gradual clearing late Tuesday/early Wednesday. S-SW winds 15-25 kts with gusts 25-35 kts on Monday, decreasing to 10-20 kts with gusts to 20-30 kts on Tuesday.

FIRE WEATHER...Today and Monday

Numerous to widespread showers and thunderstorms are expected today, becoming scattered to numerous on Monday. Periods of heavy rain are possible each day, with the potential for flooding. South to southwest winds 25-35 mph with gusts 40-50 mph today, decreasing to 15-25 mph with gusts 30-40 mph on Monday.

Tuesday through Thursday...Scattered showers and thunderstorms continue Tuesday, ending west to east Tuesday night into Wednesday morning. Drier conditions are expected for Wednesday and Thursday. South to southwest winds 15-25 mph with gusts 30-40 mph on Tuesday, becoming west to northwest 5-15 mph Wednesday, then shifting to the north to northeast 10-20 mph on Thursday.

FGZ WATCHES/WARNINGS/ADVISORIES

Flood Watch through late tonight for AZZ004>008-015-016-018-037- 038.

Wind Advisory from 8 AM MST /9 AM MDT/ this morning to 8 PM MST /9 PM MDT/ this evening for AZZ004>018-037>040.