917
FXUS65 KFGZ 190522
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
1022 PM MST Tue Jun 18 2024

.SYNOPSIS...Seasonal temperatures with typical afternoon winds are
expected for the remainder of the week. Chances for showers and
thunderstorms return on Thursday and continue each day through
this weekend as moisture increases from the southeast.

&&

.UPDATE...Mostly clear conditions noted across our CWA this
evening, minus a few areas of high clouds towards the AZ/UT
border. Calm and cool conditions are expected overnight with
seasonable temperature returning tomorrow afternoon. The forecast
is still in good shape with the increasing moisture Thursday
through the weekend. Only minor updates were made this evening.
Check out the previous discussion for more details.

&&

.PREV DISCUSSION /422 PM MST/...Lighter southwest winds are taking place this
afternoon compared to yesterday as a low pressure trough lifts
towards the north and west. However, conditions remain dry with
much of northern Arizona near the critical 15% humidity mark.
Temperatures are on the "cooler" side than they have been lately,
currently near average for this time of year. Winds should calm
down just before sunset with near average temperatures and mostly
clear skies overnight.

For Wednesday, anticipate another hot and dry day with typical
afternoon southwest breezes as the trough retrogrades westward
allowing a strengthening high pressure system towards the east to
migrate westward. Both ensemble and deterministic model guidance
continues to show this synoptic progression resulting in enhanced
southeasterly flow into the Southwest by Thursday. Along with
being on the western fringes of this high pressure system,
tropical moisture from a potential tropical storm in southern
Texas looks to make its way northeastward during this time. Both
the GEFS and EPS suggest an increasing trend in surface dewpoints
and the current NBM is on board as well. Because of these trends
and agreement in model guidance, confidence has increased in the
potential for more moisture resulting in greater chances for
showers and thunderstorms to develop each day beginning on
Thursday and lasting through the weekend.

Thursday looks to have isolated to scattered coverage focused
across northeastern Arizona. For Friday and through the weekend,
thunderstorms become more scattered and spread westward across
much of northern Arizona. Because PWATs and surface dewpoints look
to increase significantly during this time (forecast dewpoints in
the 50s-60s) the threat for dry lightning has decreased. Even
though geopotential heights increase as the high pressure system
towards the east strengthens, temperatures look to remain near
average for the most part with most locations within the 5 degree
range of average for this time of year mainly due to the presence
of additional moisture, clouds, and storms. With that said,
southeast winds are forecast to increase on Thursday with gusts of
25-35 mph likely at this time. Even with the increase in moisture
on Thursday, there could be some areas of near critical fire
weather conditions given how dry fuels are right now. Southerly
winds remain enhanced on Friday, however, much of northern Arizona
should be above 20% humidity in the afternoon with scattered storm
coverage.

As we head into the weekend, lighter west-southwesterly flow
returns as the high pressure system elongates across much of the
southern half of the country. Long range ensemble guidance along
with WPC`s Days 4-9 Cluster Tool indicate high pressure building
and then strengthening over the Southwest by next week. Temperatures
look to increase, however, chances for showers and thunderstorms
remain in the forecast each day. There are some discrepancies in
regards to the model guidance, for example the overall positioning
of this high, the strength of the high, and moisture availability,
so make sure to keep up to date with the forecast as things
evolve.

&&

.AVIATION...Wednesday 19/06Z through Thursday 20/06Z...VFR
conditions will persist through the TAF period. Look for light and
variable winds through 18Z. SW winds 10-15 kts return throughout
the afternoon before becoming light and variable near 06Z.

OUTLOOK...Thursday 20/06Z through Saturday 22/06Z...VFR conditions
will prevail through 18Z before brief periods of MVFR conditions
due to increasing SHRA/TSRA. The potential for showers and
thunderstorms will continue through the outlook period where
gusty/erratic winds will be possible near storm development.
Outside of storm development, expect S-SW winds 10-25 kts in the
afternoons becoming light and variable overnight.

&&

.FIRE WEATHER...Wednesday and Thursday...Dry and breezy Wednesday
with southwest winds 15 to 25 mph. A bit warmer on Thursday, with
increasing clouds and chances for showers and thunderstorms moving
in from the east. RH values increase substantially for Thursday.
South/southwest winds Thursday, 15 to 25 mph, with gusts as high as
35 mph.

Friday through Sunday...Warm, daily chances for showers and
thunderstorms. South/southwest winds 15 to 25 mph, with gusts as
high as 30 mph Friday, lighter Saturday and Sunday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

PUBLIC...Konieczny/LaGuardia
AVIATION...Konieczny
FIRE WEATHER...Peterson

For Northern Arizona weather information visit
weather.gov/flagstaff