366
FXUS65 KFGZ 120503
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1003 PM MST Tue Jun 11 2024

.SYNOPSIS...Expect hot temperatures for the next couple of days,
with brief cooling on Friday from the onset of a low pressure
system. Slight chances for showers/thunderstorms return on
Thursday and Friday, followed by dry, warm, and breezy conditions
for the weekend and into next week.

&&

.UPDATE...Clouds have cleared this evening across northern Arizona
as drier air moves in from the southwest. Expect cool, near
average temperatures tonight with little to no wind. Daytime
temperatures will continue their increasing trend for Wednesday
and Thursday with most locations likely to experience the warmest
temperatures of the week on Wednesday. The Excessive Heat Warning
remains in effect for Wednesday and Thursday for our lower
valley/canyon locations.

An upper-level low, currently off of the southern California/northern
Baja coast, will eventually move inland on Thursday, resulting in
isolated to scattered showers and thunderstorms across northern
Arizona. As this low makes landfall and treks across Arizona
Thursday into Friday, it will most likely become a weaker, open
wave/trough with limited moisture availability. The potential for
dry lightning and gusty outflows are the main threats. Southwest
winds do look to increase for this weekend, with gusts of 25-35
mph likely, continuing into Monday. This would increase the
potential for critical fire weather conditions, especially after a
few days of high-based storms. The forecast remains on track with
no changes needed at this time.

&&

.PREV DISCUSSION /356 PM MST/...An area of high pressure will
continue to bring hot temperatures this week, with daytime highs
averaging 5-10 degrees above normal. As a result of the increasing
temperatures, the Excessive Heat Warning for many areas below
4000` remains valid for Wednesday 10 AM MST through Thursday 8 PM
MST. It`s highly encouraged to avoid strenuous activity during the
hottest part of the day (~10AM-8PM) and stay hydrated.

Relief from the heat is likely in store for much of northern
Arizona late Thursday through Friday as a low pressure system
moves inland from off the southern California Coast. There is not
an abundant amount of moisture associated with this disturbance,
but there looks to be enough forcing to get a few isolated to
scattered showers going. The U of A WRF model shows precipitation
chances increase west to east across our CWA as early as Thursday
morning and lasting through Friday. Which brings up the potential
for temperatures to not get as warm on Thursday, but that will
all depend on exact timing/moisture availability/and location of
precipitation. If temperatures do not have the opportunity to
reach the highs we are projecting, the Excessive Heat Warning
could be expired early.

Outside of precipitation associated with the incoming low,
increased winds are also expected. Although winds are below any
product threshold/criteria, there will be continued elevated fire
weather concerns. Ideally, relative humidities will increase
enough with the slight up-tick in moisture, but fuels are fairly
dry across northern Arizona and any storm with enough instability
could produce lightning - potentially leading to a natural fire
start.

Warm temperatures will quickly return over the weekend, but a
cooler/zonal looks to return over much of the Southwest by Monday.
This will keep daytime highs near normal for this time of year,
and winds on the breezy side.

&&

.AVIATION...Wednesday 12/06Z through Thursday 13/06Z...VFR
conditions persist through the period. Light and variable winds
overnight, becoming W/SW 10-15 kts gusting 20-30kts after 16Z and
until ~02Z Thursday.

OUTLOOK...Thursday 13/06Z through Saturday 15/06Z...VFR conditions,
outside of brief periods of MVFR in -SHRA/-TSRA after 00Z Friday,
but could be earlier Thursday depending on how models continue to
trend with moisture. Gusty, erratic winds possible near
thunderstorms. Winds west/southwest 10-20 kts with gusts 20-30
kts each afternoon.

&&

.FIRE WEATHER...Wednesday and Thursday...Expect dry and hot weather,
with afternoon RH values from 5-15%. West/southwest wind gusts 15-25
mph on Wednesday, increasing to 20-30 mph on Thursday. Chances (10-
30%) for isolated, showers and thunderstorms begin late Thursday.

Friday through Sunday...On Friday, a passing low pressure system
will bring slightly cooler and more cloudy weather, but afternoon
humidity will remain in the 8-16% range at most places. Chances (20-
50%) for showers, and a slight chance of thunderstorms, are forecast
primarily along and north of the Mogollon Rim. Winds will shift to
the west/northwest, expect in the vicinity of storms where erratic
outflow winds are possible. Dry and warmer weather, along with
breezy southwest winds return Saturday and Sunday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from 10 AM MST /11 AM MDT/ Wednesday to 8
PM MST /9 PM MDT/ Thursday for AZZ005-006-037.

&&

$$

PUBLIC...LaGuardia/Konieczny
AVIATION...RKR
FIRE WEATHER...RR

For Northern Arizona weather information visit
weather.gov/flagstaff