094
FXUS65 KFGZ 040509
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1009 PM MST Mon Jun 3 2024

.SYNOPSIS...Much warmer temperatures and 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...Northern Arizona will see variable high cloudiness
through the night along with fairly mild temperatures. The most
important message is the hottest temperatures of the year are on
the way for Wednesday through Friday. Plan your outdoor activities
accordingly. All this is well handled in the current forecast
package with no evening update.

&&

.PREV DISCUSSION /335 PM MST/...Breezy southwest winds with
scattered to broken mid to upper-level clouds and near average
temperatures are taking place this afternoon across much of
northern Arizona. Conditions remain dry with current humidity at
or below 15% across the region. Cloud cover will continue from
north to south through this evening as a storm system makes its
way through the Pacific Northwest. Expect cool, near average
temperatures overnight with light and variable winds.

The forecast remains on track with a high pressure ridge building
over the Southwest beginning on Tuesday. From then through Friday,
anticipate a warming and drying trend to persist with daytime high
temperatures peaking on Thursday and into Friday, roughly 10-15
degrees above average for this time of year. These forecast high
temperatures are flirting with record highs on Thursday and Friday
as heights maximize. Confidence has grown in the potential for
this early season heat to develop which is why the Excessive Heat
Watches have been upgraded to Heat Warnings, mainly focused on
the lower valleys of Yavapai County and the Grand Canyon to Page
from Thursday through Friday. The heat is on and can be dangerous
for most. Don`t be a jabroni!

With potentially record heat during the day, the question
is...will we see any relief at night? Even though overnight lows
through the remainder of the week will also be 10-15 degrees above
average, given how early it is in the heat season and with dry
conditions present, expect a cool down into the low 50s/60s with
the warmest low temperatures in the low 70s for our lower valley
locations.

Besides for temperatures, expect mostly dry conditions to persist
with west-northwest breezes, 10-20 mph, for Tuesday and
Wednesday, followed by a return of west-southwest winds, 15-25
mph, for Thursday and Friday.

As for precipitation chances through this week, things look glum
at this time. Both GEFS and EPS ensemble guidances have PWAT
values gradually increasing each afternoon this week with even the
slightest chance of a shower/thunderstorm to develop along the
high terrain on Thursday as the ridge axis begins to shift
eastward, allowing more of a southerly flow. Confidence remains
very low in regards to any precipitation during this time as
conditions at the surface will remain quite dry (i.e. virga
showers). Ensemble guidance does continue to suggest additional
shower and thunderstorm chances for this weekend and into next
week, however moisture looks to be limited with any storms being
high-based, hybrid type storms with little rainfall (<0.10") and
the chance for dry lightning and gusty outflow winds. Will have
to keep our eye on the potential for a pesky, cut-off low to form
off the Baja coast later this week and into the weekend, which
could influence moisture availability in a positive way. However,
this will all depend on the overall strength of the already in
place ridge.

&&

.AVIATION...Tuesday 04/06Z through Wednesday 05/06Z...VFR conditions
with W/NW winds 10-15 kts with gusts to around 20 kts during
daylight hours, becoming light and variable for the overnight.

OUTLOOK...Wednesday 05/06Z through Friday 07/06Z...VFR conditions
with winds generally 10 kts or less.

&&

.FIRE WEATHER...Tuesday and Wednesday...Warming temperatures and dry
conditions. Minimum afternoon RH 10-20%, with overnight recoveries to
around 30-60%. Winds West/northwest 10-20 mph, becoming variable
around 10 mph or less on Wednesday.

Thursday through Saturday...Hot and mainly dry conditions continue,
outside of the potential for a few dry thunderstorms over the White
Mountains each afternoon. Southwest winds 10-20 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...McCollum/LaGuardia
AVIATION...Humphreys
FIRE WEATHER...Humphreys

For Northern Arizona weather information visit
weather.gov/flagstaff