textproduct: NWS Flagstaff

SYNOPSIS

Showers and thunderstorms will continue through Tuesday as an upper level low moves through the region. Expect cooler and windier conditions to continue through the rest of week.

DISCUSSION

The remnants of Tropical Storm Rachel continue to lift north, while a strong upper level low digs down through the Great Basin. Showers and thunderstorms continue to move northward through central Arizona overnight, with additional storms expected through this afternoon.

Model soundings show PWATs dropping off quite a bit from previous days but still remaining near or above the 75 percentile. Heavy rain will still be a threat but with dry air pushing in aloft and moisture being largely confined to the lower levels, it may not be as widespread as it was over the weekend. Hi-res models still show the potential for heavy rain across western Arizona, mainly Yavapai and Coconino counties through this morning, with areas across the higher terrain continuing to see potential for showers and thunderstorms through this afternoon and early evening. With the low crossing the region on Tuesday, we will likely continue to see scattered showers and thunderstorms continue, especially across the higher terrain, through Tuesday evening, tapering off Tuesday night into early Wednesday.

Rainfall amounts across the region over the past couple of days have ranged between 1-3", with a few locally higher amounts. While coverage of storms may end up being more scattered than numerous through this afternoon, the wet antecedent conditions mean any storm with decent rainfall rates could lead to flooding. With that in mind, the Flood Watch has been extended and remains in effect through 5 PM for areas along and south of the Mogollon Rim up through the Kaibab Plateau.

With the low digging down, we don't see the pressure gradient relax all that much, which will leave us with continued gusty winds through the day. Strongest winds will be downwind of the higher terrain and through the Little Colorado River Valley, where gusts to 40-50 mph will be possible. Coverage of the higher winds looks to be more limited than they were on Sunday and therefore no Wind Advisory has been issued.

The low slowly moves to the east Wednesday before becoming cut off from the main jet and settling over the southwest through the end of the week. Dry air will get pulled into the region and we should see chances for showers and thunderstorms dwindle with dry conditions expected through Thursday. The low slides to the southwest and moisture starts to creep back in on the eastern edge, which may allow for showers to return for Friday through the weekend. Expect cooler temperatures to continue with gusty northeast to east winds.

AVIATION...Monday 12/12Z through Tuesday 13/12Z

VFR/MVFR conditions expected through the TAF period. SCT -SHRA/-TSRA will continue today. Brief IFR conditions possible in +RA and low CIGS. S-SW winds 10-20 kts with gusts 20-30 kts, increasing to 15-25 kts with gusts 30-35 kts after 15-18Z.

OUTLOOK...Tuesday 13/12Z through Thursday 15/12Z...VFR/MVFR conditions with ISO/SCT -SHRA/-TSRA through 00Z/Wed. Expect clearing late Tuesday through early Wednesday. S-SW winds 15-25 kts, with gusts near 30-35 kts on Tuesday, becoming light and variable on Wednesday.

FIRE WEATHER...Today and Tuesday

Scattered to numerous showers and thunderstorms are expected each day. Periods of heavy rain are possible each day, with the potential for flooding. Showers will end from west to east Tuesday night into Wednesday morning. South to southwest winds 15-25 mph with gusts 30-40 mph today, shifting to the west-southwest on Tuesday.

Wednesday through Friday...Mainly dry conditions are expected through the end of the week, with a slight chance of showers and thunderstorms over the higher terrain on Friday. West to northwest winds 5-15 mph on Wednesday, becoming north to northeast 10-20 mph on Thursday, then shifting to the east to southeast 10-25 mph on Friday.

FGZ WATCHES/WARNINGS/ADVISORIES

Flood Watch through this afternoon for AZZ004>008-015-016-018- 037-038.