270
FXUS65 KFGZ 131051
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
351 AM MST Thu Jun 13 2024

.SYNOPSIS...Expect another round of abnormally warm temperatures
today, even in the face of increasing cloud cover and some
isolated, light rain showers. From this evening through Friday, a
passing low pressure system will bring more scattered shower
activity, and a slight chance for thunderstorms. Dry, warm, and
breezy conditions return by the weekend, with a slight cooling
trend early next week.

&&

.DISCUSSION...Current satellite and upper-air analysis shows a 500
mb low centered off the west coast of northern Baja and a 500 mb
ridge over northern Mexico. A southerly flow between these
features has transported moisture into southern Arizona. For
example, the dew point in Yuma, AZ is currently sitting around 50
degrees, which is about 5-10 degrees higher than this time
yesterday morning.

Moist air will continue to spread northward across the state
today, bringing with it increasing cloud cover and chances
(10-30%) for light rain showers. While this moisture will keep
high temperatures a couple of degrees cooler than yesterday,
abnormally warm conditions will persist and an Excessive Heat
Warning remains in effect below 4000 feet within the Grand Canyon
and lower deserts of Yavapai County through 8 pm MST. Otherwise,
most locations will see a round of south-southwest winds, with
gusts in the 20-30 mph range during the afternoon hours.

From this evening through Friday, the aforementioned low will
move across the state resulting in higher chances (20-50%) for
showers, and a slight chance (10-15%) of thunderstorms and dry
lightning. While rainfall amounts are expected to be meager, a
few pockets of rainfall in the 0.2-0.4 inch range may occur,
especially across northeast Arizona. As you would expect with the
cloudy and unsettled weather forecast for Friday, daytime
temperatures will dip a few degrees resulting in an end to the
excessive heat.

On Saturday, dry weather returns to Arizona as the low pressure
system slides across the central United States. At the same time,
the general model consensus predicts a long wave trough over the
western United States will deepen keeping Arizona under the
influence of a dry southwest flow aloft through at least mid-
week. High temperatures may quickly rebound again on Saturday,
with temperatures approaching excessive heat levels once again.
This increase in temperature may be short-lived though, with a
slow but steady cooling trend likely after that.

Forecast uncertainty is high beyond Sunday. Model disagreements
hinge on the strength of the developing longwave trough, as well
as the timing of shortwaves traversing the general flow. Overall,
the main hazard in the extended forecast is for critical fire
weather. The majority of longer range models highlight Sunday and
Monday as the period with the best combination of low relative
humidity and strong surface winds.

&&

.AVIATION...Thursday 13/12Z through Friday 14/12Z...Expect
increasing mid-level cloud cover. Light and variable winds
through 16Z-17Z, then south-southwest wind gusts 15-25 kts.
Isolated -SHRA after 18Z, increasing after 00Z mainly along and
east of KGCN-KFLG-KSOW line. Periods of MVFR visibilities
possible under the heaviest showers.

OUTLOOK...Friday 14/12Z through Sunday 16/12Z...Isolated to
scattered -SHRA with isolated TS, mainly east of a KPGA-KINW-
KSOW line through 00Z Saturday. Brief MVFR visibilities or lower
possible under the heaviest showers. West-southwest winds gusting
10-20 kts Friday, becoming southwest with gusts 15-25 kts
Saturday.

&&

.FIRE WEATHER...Today and Friday...Hot temperatures will continue
today before slightly cooling off on Friday. Chances for
light rain showers Thursday afternoon across Yavapai and Coconino
counties become more focused across eastern Arizona on Friday.
Slight chances for thunderstorms are forecast from late tonight
through Friday. The main hazards from these storms will be dry
lightning and strong/erratic outflow winds. Southwest wind gusts
20-30 mph on Thursday will become more westerly 10-20 mph on
Friday.

Saturday through Monday...Above normal temperature return over the
weekend, before cooling Monday. Mainly dry conditions with gusty,
southwest winds and afternoon RH values 5-15% daily. Wind and
humidity may approach critical fire weather thresholds on Sunday
and/or Monday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 8 PM MST /9 PM MDT/ this evening
for AZZ005-006-037.

&&

$$

PUBLIC...RR
AVIATION...RR
FIRE WEATHER...RR

For Northern Arizona weather information visit
weather.gov/flagstaff