455
FXUS65 KFGZ 122254
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
354 PM MST Wed Jun 12 2024

.SYNOPSIS...Hot temperatures, even for June, are in the forecast
the next couple of days. Some relief from the heat arrives Thursday
evening into Friday along with a chance for light rain showers
and a few thunderstorms. Precipitation amounts will be minimal
with dry lightning possible. Dry, warm, and breezy conditions
return by the weekend, with a slight cooling trend early next week.

&&

.DISCUSSION...Hot temperatures continue today with strong high
pressure in place (500mb height 593-595 dam). Highs today are
going to top out at 10-15 degrees above mid-June averages. An
Excessive Heat Warning is in effect below 4000 feet in Coconino
and Yavapai counties. A closed low centered off the coast of San
Diego is moving slowly eastward. Pressure gradients between these
2 systems are tightening, and breezy southwest winds are the
result. Gusts in the 20-30 mph range are being observed at 1 PM.

Thursday and Friday - the closed low will move into southern
California by Thursday afternoon and western Arizona by sunrise
Friday. The low will open up and move into Colorado by Friday
afternoon. We will see some increasing mid and high level
cloudiness as early as sunrise Thursday, continuing to increase
through the day. There will be a chance of virga/sprinkles from
around Flagstaff westward through the afternoon, but forecast CAPE
values are very low so the risk of thunderstorms should be
minimal until the low pressure center moves closer to the area.
The extra clouds could knock temperatures down a bit and allow for
an early end to the Excessive Heat Warning, but will make that
call tomorrow. The best lift and slightly deeper moisture move up
across Yavapai/Coconino counties Thursday night with precip
chances 30-40%. Only very light amounts of less than 0.10" are
anticipated. Lightning chances go up slightly due to cooling
aloft, but without daytime heating the instability and lightning
risk remain low overnight. On Friday - the higher rain chances
(30-60%) shift into northeast Arizona. With daytime heating, the
chance of lightning goes up which poses a threat of new wildfire
starts, again mainly in northeast Arizona. Rain chances end Friday
evening near the four corners.

Saturday through Tuesday - temperatures rebound briefly on
Saturday as the low departs eastward. Highs will be 7-12 degrees
above normal. From Sunday onward, models are in agreement that a
large trough will set up over the northwest US, pushing the ridge
well south of our area. This will bring a gradual cooling trend to
the region, with highs possibly even a few degrees cooler than
normal by early next week. Unfortunately, we will be on the windy
southern end of the trough with gusts in the 30-40 mph range in
the forecast Sunday and Monday - possibly leading to a period of
critical fire weather so stay tuned.

&&

.AVIATION...Thursday 13/00Z through Friday 14/00Z...VFR conditions
with clear skies continue through 06Z tonight. Cloud cover will
increase to SCT-BKN above 10,000 feet AGL thereafter. Expect the
southwest winds to decrease in intensity by 01Z/02Z this evening,
becoming light and variable thereafter. Northeast winds of 10 kts
are likely at KSEZ overnight. South-southwest winds increase to
15-25 kts after 17Z.

OUTLOOK...Friday 14/00Z through Sunday 16/00Z...Chances for
isolated -SHRA/-TSRA increase after 00Z Friday and continue
through Friday afternoon. Greatest chances will be along and east
of a KGCN-KFLG-KSOW line, shifting east of a KPGA-KINW-KSOW line
by 12Z Friday. BKN-OVC skies are expected during this time with
brief periods of MVFR conditions possible in heavier showers.
Conditions improve to VFR as showers clear out for this weekend.
Anticipate west-southwest winds, 10-20 kts, for Friday afternoon,
followed by southwest winds, 20-25 kts, on Saturday.

&&

.FIRE WEATHER...Thursday and Friday...Hot temperatures will continue
Thursday before slightly cooling off on Friday. Look for rain/storm
potential to begin Thursday afternoon across Yavapai & Coconino
Counties, becoming more focused in NE Arizona on Friday. Dry
lightning and gusty/erratic possible throughout the period. Outside
of storm-driven winds, look for southwest winds 15-25 mph on
Thursday and west winds 10-20 mph on Friday.

Saturday through Monday...Above normal temperature will continue
through Sunday, with cooler conditions returning by Monday. Expect
mostly dry conditions (minimum RH values 5-15%) and gusty southwest
winds. Near critical fire weather conditions likely over the
weekend/into next week.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...

Excessive Heat Warning until 8 PM MST /9 PM MDT/ Thursday for
AZZ005-006-037.

&&

$$

PUBLIC...JJ
AVIATION...LaGuardia
FIRE WEATHER...Konieczny

For Northern Arizona weather information visit
weather.gov/flagstaff