textproduct: NWS Flagstaff

SYNOPSIS

Widespread rainfall continues to fall across northern Arizona. The heaviest rainfall is mainly along and south of the Mogollon Rim, but rain is spreading northward across the Navajo Nation and the Kaibab Plateau. There have been several reports of flooding/flash flooding, especially along and south of the rim, and will continue to be possible across the entire region through this afternoon. Rain should start to decrease this evening and through the overnight hours. This continues to be a serious situation. Stay away from waterways, and if you come to a flooded road, turn around, don't drown.

DISCUSSION

Since midnight, rain gauge and radar data suggest a widespread area 2 to 4 inches of rain have fallen across and south of the Mogollon Rim, with some stream gauges exceeding record stage heights. There have been several reports of flooding/flash flooding, especially along and south of the Rim. Rain has been spreading northward across the Navajo Nation and the Kaibab Plateau, and while rainfall totals are expected to be lower north of the Mogollon Rim, flooding/flash flooding is still possible through this afternoon. As a mid-level shortwave trough moves northeast into the Southwest, latest hi-res models and mesoanalysis suggest a transition from widespread rain, to more scattered showers and isolated thunderstorms pattern this afternoon by 3 to 4 pm, allowing for some breaks in rain, but keeping the risk for periods of heavy rainfall across northern Arizona through is afternoon and early evening hours. The risk for strong or severe thunderstorms is low due to limited instability and moisture helping to prevent low and mid-level lapse rates from steeping. However, cannot rule out some strong gusts near thunderstorms. After 8pm MST, shower and thunderstorm activity should be on the decrease as the mid-level trough starts to push off to the east and drier air follows in the wake of a frontal passage. The Flood Watch remains in effect through late tonight as water will continue to be draining through the washes, stream, and river basins, keeping waters levels high. River flooding may continue to be an issue through Monday and at least Tuesday.

A Wind Advisory remains in effect through 11 PM MST for the Little Colorado River Valley, Eastern Mogollon Rim, and White Mountains were gusts as high as 40-50 mph are possible. Peak wind gusts will decrease overnight, but gusts around 30 mph will be possible with the frontal passage after 11 pm Monday to 8am Tuesday. There is also potential for snow mostly above 7500-8000 ft elevation before things fully dry out on Sunday night. The main area of concern is the Kaibab Plateau where 1-2 inches of snow are possible. A dusting of snow will also be possible for the higher elevation locations around the Flagstaff area. Fully dry conditions are expected by Monday afternoon and through the week as ridging dominates. Another trough will brush past Arizona on Wednesday, but this looks to remain mostly dry at this time

There is also potential for snow mostly above 7200-7800 ft elevation before things fully dry out tonight. The main area of concern is the Kaibab Plateau where 1-2 inches of snow are possible. A dusting of snow will also be possible for the higher elevation locations around the Flagstaff area, with potentially around 1 inch near the top of the San Francisco Peaks. Fully dry conditions are expected by late Monday morning and through the week as ridging dominates. Another trough will brush past Arizona around Wednesday or early Thursday, but this looks to remain mostly dry at this time.

AVIATION...Monday 02/00Z through Tuesday 03/00Z

MVFR to IFR conditions continue across most of the region, though starting to see more break as widespread rainfall is transitioning to SCT SHRA with embedded ISOLD TSRA possible through 03-06Z. SHRA will start to decrease after the 06Z from west to east across northern AZ, but low CIGS, lingering mist, and potentially fog can affect some of the higher elevation airports through 17Z Monday, bringing bringing periods of MVFR, with ISOLD IFR. Winds will be SW 10-20 kts with gusts 35-45 kts through 06Z, turning W to NW and gradually diminishing to 10-20 kt by 17Z Monday with winds becoming NW-NE after 06Z Monday.

OUTLOOK...Tuesday 03/00Z through Thursday 05/00Z...VFR conditions. Winds are expected to be NW-NE and around 10-15 kt, becoming more variable and light 00Z Wednesday. Starting around 17Z Wednesday, winds will start become W around 5-10 kt, then shifting N by 00Z Thursday.

FIRE WEATHER...Sunday and Monday

Widespread rainfall will continue today, eventually decreasing in coverage by the late evening. A few embedded thunderstorms are possible. Heavy accumulations are expected especially along/south of the Rim. Threats of flooding and flash flooding will be exacerbated by the already very saturated ground conditions. Strong winds are also expected. Winds are southwest 15-25 mph gusting up to 30-40 mph this morning, then gusts as high as 50 mph possible across eastern AZ this afternoon. Winds turn more westerly and gradually diminish through Sunday night, becoming northwest 10-20 mph on Monday afternoon.

Tuesday through Thursday...A drier weather pattern is expected through this period, with lingering flooding impacts possible. Winds are easterly 5-15 mph on Tuesday, turning westerly 10-20 mph on Wednesday, then light and variable on Thursday. Minimum RH above 30- 50% through the period.

FGZ WATCHES/WARNINGS/ADVISORIES

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

Wind Advisory until 11 PM MST this evening for AZZ012>014-016- 017.