198
FXUS65 KFGZ 041712
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1012 AM MST Tue Jun 4 2024

.SYNOPSIS...Hotter temperatures and mainly dry conditions are
expected this week as high pressure builds over the Southwest.
Temperatures begin to cool gradually for this weekend with the
potential for a few showers and thunderstorms.

&&

.UPDATE...The drying and warming trend develops today as high
pressure builds and strengthens over the Southwest. Very warm to
hot afternoon temperatures are expected for the remainder of the
week, with forecast record temps on Thursday and Friday. PWATs
remain near 0.50" from this morning`s sounding with dry conditions
at the surface. By Thursday, the ridge of high pressure looks to
migrate slowly eastward as southerly flow returns to Arizona.
With the enhanced daytime heating and additional moisture, slight
chances for isolated showers and thunderstorms remain in the
forecast for Thursday afternoon, mainly confined to the high
terrain...from the Kaibab Plateau/Grand Canyon, along the Mogollon
Rim, and into the White Mountains. For this afternoon, anticipate
scattered cloud cover and west-northwest winds, 10-20 mph, with
cool, but above average temperatures overnight.

&&

.PREV DISCUSSION /421 AM MST/...Mid and high level clouds continue
to rotate southward into our region around the developing high
off the west coast. Expect to see these clouds off and on through
most of the day before clearing out this evening. Temperatures
will be a few degrees warmer than Monday topping out 3-7 degrees
above average for early June. Daytime temperatures will continue
to heat up Wednesday through Friday as the high shifts eastward
over Arizona and New Mexico. The hottest days still look like
Thursday and Friday when highs are 10-15 degrees above average.
Forecasts highs are 105-111 below 4000 feet for the Grand Canyon,
Marble/Glen Canyons, and Yavapai County/Verde Valley. An Excessive
Heat Warning remains in effect Thu/Fri in these areas. It will be
hot elsewhere too, near 90 along the Mogollon Rim/Flagstaff,
upper 90s for Prescott/Payson, to 100-104 in the Little Colorado
River Valley including Winslow. If Flagstaff reaches the forecast
high of 90 on Thursday, it will tie for the earliest occurrence of
90 degrees on record (June 6, 2010). One factor that could
possibly keep high country temperatures from reaching the full
potential beginning Thursday is some increased moisture leading to
cumulus cloud cover during peak heating hours. The moisture is
being drawn northward around the high center that will be just to
our east. We added a slight chance for a high-based (mainly dry)
thunderstorm to the forecast for the White Mtns and rim country up
to Grand Canyon for Thursday afternoon. Again, gusty winds could
accompany any showers/storms but any rainfall would be very light.
This continues Friday but should shift to mainly eastern Arizona.
By the weekend - heights are forecast to drop slightly as a weak
low drifts northward from Mexico. Temperatures come down a few
degrees each day. Right now the plan is to end the Excessive Heat
Warning on Friday evening but we will need to monitor the northern
zones that are included (Grand/Marble/Glen Canyons) as there is a
chance these would need extended to Saturday. Otherwise, limited
moisture lingers over the weekend into Monday, with low chances
for a shower or thunderstorm (10-20%).

&&

.AVIATION...Tuesday 04/18Z through Wednesday 05/18Z...VFR
conditions persist. Generally W-NW winds 5-15 kts, though some
variability in direction expected. Light and variable winds
forecast to return around 03Z.

OUTLOOK...Wednesday 05/18Z through Friday 07/18Z...VFR conditions
continue to persist. Light and variable winds generally 10 kts or
less forecast for much of Wednesday, becoming W-SW 5-15 kts
Thursday afternoon. Isolated TS/-TSRA possible Thursday along a
KGCN-KFLG-KJTC line between 18Z Thursday - 06Z Friday.

&&

.FIRE WEATHER...Today and Wednesday...Warming temperatures and
mostly dry conditions expected to continue. Minimum RH values
forecast between 5-20% each afternoon, with overnight recoveries
varying between 25-60%. Look for west-northwest 5-15 mph today,
becoming variable around 10 mph or less on Wednesday.

Thursday through Saturday...Hot temperatures and mostly dry
conditions will continue, except for a slight potential for dry
thunderstorms. Minimum RH values generally 15% or less, with
overnight recoveries around 25-50%. Expect west-southwest winds 5-15
mph each afternoon.

&&

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

&&

$$

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

For Northern Arizona weather information visit
weather.gov/flagstaff