226
FXUS65 KFGZ 170848
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
150 AM MST Sat Aug 17 2024

.SYNOPSIS...Showers and thunderstorms return to northern Arizona
this weekend and continue into next week. Temperatures will fall a
bit as moisture increases, but will still remain around normal, or
even a bit above normal.

&&

.DISCUSSION...The Monsoon moisture boundary is pushing rapidly
north and west overnight. This rapid movement is being aided by 2
outflow boundaries, which originated from organized convection NE of
Tucson and over Apache County Friday evening.

The flow pattern is such that our entire CWA should be within the
Monsoon moisture boundary by daybreak, the last vestiges of dry air
are currently up around Page. The high has relocated to a favorable
position east of Arizona and has amplified a bit, coinciding with a
somewhat unseasonable and stable trough along the west coast.

This makes for an interesting dynamic scenario. where our eastern
zones are a bit on the stable side, but moist and our western zones
are unstable, with shear, but fighting drier air over Nevada. Kind
of a "sweet spot", where the moisture and enhanced instability/shear
meet, will be over northwestern Arizona for next few days. For this
reason, a FFA is in effect.

We are not really looking at singular, intense, and heavy rain
producing storms. More so that briefly intense, but fast-moving and
perhaps severe storms, are likely to to move over the same location
several times each afternoon.

This is basically the pattern we are in for the remainder of the
forecast package. There will be convection every day, not really
widespread, but dynamically driven lines of storms are likely over
western and central Arizona each day. There will be dry incursions
from time to time over the northwest and the eastern zones will heat
up and have days that are almost too stable, but generally, we will
remain active through next week.

&&

.AVIATION...Saturday 17/06Z through Sunday 18/06Z...Mainly VFR
conditions will prevail. Until 12Z, look for isolated SHRA/TSRA
east of a KPGA-KPAN line. After 12Z, isolated SHRA are forecast
to develop along and west of the KPGA-KPAN line becoming numerous
and mixing in with TSRA after 18Z. East of this line, isolated
activity will continue. Storms gradually dissipating Saturday
evening. Brief MVFR to IFR conditions and gusty winds in stronger
storm cells. Winds outside of any storms, southwest at 5-15 kts,
becoming light after 02Z.

OUTLOOK...Sunday 18/06Z through Tuesday 20/06Z...Scattered
SHRA/TSRA each afternoon/evening with coverage favoring areas from
KPRC-KFLG-KPGA westward. Brief MVFR to IFR conditions and gusty
winds in stronger storm cells. Away from storms, expect southerly
winds 10-20 kts during the daytime.

&&

.FIRE WEATHER...Today and Sunday...Moisture and thunderstorm
chances increase through the weekend. Storm coverage and the best
chances for wetting rain will favor northwestern Arizona. Outside of
thunderstorm outflow winds, expect southerly winds 5 to 15 mph.

Monday through Wednesday...Expect daily chances for showers and
thunderstorms to continue. Winds will be southwest around 10 mph or
less, away from any thunderstorms and/or outflows.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...

Flood Watch from 5 AM MST /6 AM MDT/ this morning through 9 PM MST
/10 PM MDT/ this evening for AZZ004>007.

&&

$$

PUBLIC...Peterson
AVIATION...McCollum
FIRE WEATHER...MAS

For Northern Arizona weather information visit
weather.gov/flagstaff