az discuss
Office: PSR
FXUS65 KPSR 250008
AFDPSR
Area Forecast Discussion
National Weather Service Phoenix AZ
508 PM MST Wed Apr 24 2024
.UPDATE...Updated 00Z Aviation Discussion.
&&
.SYNOPSIS...
Two weather systems moving through the region over the next few
days will lead to much cooler temperatures with desert highs in
the low to mid 80s Thursday through Saturday. There will also be a
significant uptrend in windiness. The strongest winds will be over
southeast California tonight and again Friday. Precipitation
chances over the forecast area will be limited mainly to La Paz
County very late tonight and then south-central Arizona late
Friday night and Saturday morning. A warming trend begins Sunday
with desert highs climbing well into the 90s by Monday and
flirting with 100 Tuesday and Wednesday.
&&
.DISCUSSION...
A pattern change has begun with the high pressure ridge moving
eastward as an upper low (centered off the SoCal coast) advances
eastward. That system moves across our forecast area tonight and
during the day Thursday. The system will have to overcome a warm
and dry airmass and moisture advection looks to be modest.
However, there will be a cool front along with some dynamical
forcing to try to overcome the limitations. To varying degrees,
deterministic CAMs are showing a batch of showers starting up over
La Paz County late tonight and tracking northeastward brushing
northern portions of Maricopa County as well. Some subtle upward
adjustments were made to the NBM PoPs to increase the area with
slight chances. The shower activity increases just north over the
FGZ forecast area during the day Thursday due to a combination of
more orographic lift and destabilization (anticipate some
thunderstorms in the mix there as well).
The next system to affect the forecast area will be a
strengthening short wave originating from the Pacific Northwest.
The overland trajectory isn't ideal for moisture advection but the
models have trended stronger with this feature and moisture
availability trends up a little bit. Plus, there will be some
preconditioning of the atmosphere from the previous system leading
to more widespread PoPs over AZ. However, those PoPs will still be
mainly limited to northern AZ but more of south-central AZ
(including portions of Greater Phoenix) will now have at least a
slight chance for precipitation - mainly late Friday night and
Saturday morning.
With the passage of these systems, a significant uptrend in
breeziness/windiness can be expected. As is often the case, the
strongest winds for our forecast area will be over southeast CA. A
Wind Advisory is in effect there tonight with a new Advisory there
for Friday afternoon and evening. A new Advisory has also been
issued for portions of southern Gila County for the same time
frame. The southwest corner of Imperial County continues to have
a longer lived Advisory in effect tonight through Friday evening.
Though there are any Advisories for Thursday, it will still be at
least breezy; likewise with Saturday.
After highs in the 80s Thursday through Saturday, a warming trend
begins Sunday with desert highs climbing well into the 90s by
Monday and flirting with 100 Tuesday and Wednesday.
&&
.AVIATION...Updated at 0008Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Southwesterly winds with occasional gusts up to 20-25 kts continue
through sunset. Surface decoupling should allow winds shift back
to an E to SE component, however it may be brief and winds may
veer back S-SW with a weather system moving through. There is a
low chance (5-10%) for some showers to sneak into Phoenix Thursday
morning between 12-17Z. Most activity will pass to the north,
where a few thunderstorms may also develop. FEW to SCT high clouds
are exiting with clear skies returning through the overnight hours.
Then FEW, to briefly SCT, clouds as low as 5-6K ft may develop
Thursday morning and then rise to 10-12K ft during the day.
Southeast California/Southwest Arizona including KIPL and KBLH:
Very breezy to windy conditions are expected at both terminals
through most of the TAF period. Winds will be strongest this
evening, with westerly gusts peaking up to 35-40 kts at KIPL and
southwesterly gusts peaking up to 25-30 kts at KBLH. Some reprieve
from the gustiness is anticipated overnight, but sustained speeds
will likely remain elevated in the 10-20 kt range. The strong
winds will be capable of kicking up dust, but the wind direction
at KIPL is not ideal for significantly reduced visibility (MVFR or
lower). There is a low chance (10%) for a high-based shower to
develop near KBLH between 7-10Z before quickly moving off to the
east. SCT mid-level clouds will develop Thursday morning and clear
by the afternoon.
&&
.FIRE WEATHER...
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Wind Advisory from 2 PM Friday to midnight MST Friday night for
AZZ557-558.
CA...Wind Advisory from 2 PM Friday to midnight PDT Friday night for
CAZ560-563-565>567.
Wind Advisory until 3 AM PDT Thursday for CAZ560-563-565>567.
Wind Advisory until midnight PDT Friday night for CAZ562.
&&
$$
DISCUSSION...AJ
AVIATION...Berislavich/Benedict
FIRE WEATHER...AJ
Office: TWC
FXUS65 KTWC 241943
AFDTWC
Area Forecast Discussion
National Weather Service Tucson AZ
1243 PM MST Wed Apr 24 2024
.SYNOPSIS...Weather systems passing north of our area will bring
strong gusty winds the last half of the week. Precip chances
should generally stay north of the area, but temperatures will
fall below average Thursday into Saturday. High pressure with a
rapid warming trend will push temperatures back to well above
average again by Monday and Tuesday.
&&
.DISCUSSION...Winds starting to increase this afternoon ahead of a
storm system near the southern California coast. Stronger tomorrow
afternoon with cooler air filtering in under the low as
temperatures drop 10+ degrees Thursday. Any precip chances should
remain north of our area.
The first system will quickly shear into the central and northern
Plains states as a stronger low digs down through the Pacific
Northwest and into the Great Basin over the weekend. Probably
windier Saturday with several more degrees of cooling. Best precip
chances will again be north of us, but a few showers are possible
mainly near the mountains. We'll need to watch for isolated
lighting strikes in the east central mountains of Graham and
Greenlee counties for potential wildfire starts.
Weak residual troughiness sagging back over the area Sunday, but
after a cooler morning we'll already be seeing a quick warmup
underway. Broad low amplitude high pressure will push
temperatures back to around 10 degrees above climo by Tuesday.
&&
.AVIATION...Valid through 26/00Z.
BKN-OVC clouds AOA 20k ft AGL thru 24/01Z, then clearing from the
west. SLY/SWLY SFC wind at 12-18 kts with gusts to 22-28 kts
until 25/02Z, then diminishing in the evening hours. Winds
increasing again from the west after 25/17Z, Aviation discussion
not updated for TAF amendments.
&&
.FIRE WEATHER...A weather system will move north of the area on
Thursday, dropping temperatures below normal and increasing wind
speeds. Wind speeds will be near critical levels over portions of
Cochise, Graham and Greenlee counties, however min RH levels will
increase as well. Another weather system will move across the
area Friday night and Saturday, resulting in even cooler
temperatures and highs 5-10 degrees below normal, as well as
strong winds areawide. This system will also bring a chance of
showers mainly north/northeast of Tucson Saturday (maybe a few
lighting strikes Saturday afternoon). Min RH values in the
valleys will increase to 12-20 percent Thursday through Saturday,
increasing to 25-50 percent in the mountains. Drier conditions
return to start the new week.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
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Office: FGZ
FXUS65 KFGZ 242334
AFDFGZ
Area Forecast Discussion
National Weather Service Flagstaff AZ
434 PM MST Wed Apr 24 2024
.SYNOPSIS...Slightly cooler and windy conditions today will give way
to cooler and unsettled conditions for the second half of the week.
Chance for showers arrive Thursday and again by late Friday and into
Saturday.
&&
.DISCUSSION...Low pressure off the Pacific coast is upping the
winds this afternoon and increasing moisture in the SW. This can
be noted with the growing cumulus cloud deck over the Kaibab.
Moisture will continue to increase over the coming hours ahead of
the systems arrival.
Tonight into early tomorrow morning, CAMs are in good agreement
that as the low traverses the SW, a band of showers and storms
will develop and move across Yavapai county, heading northeast to
the Mogollon Rim. Because of the agreement, thunderstorm chances
were hand forced upward as larger scale and blended models are not
handling this well.
After tomorrow morning, the remainder of Thursday will feature
more widely scattered shower and thunderstorm activity generally
along and north of the Whites/Mogollon Rim, and Kaibab. Still
overall moisture availability remains low with this first system
and most will see a tenth of an inch or less in liquid
precipitation.
Friday will be mostly dry as we briefly get sandwiched between
the departing first system and another trough starts to dive south
into the region. This will keep the winds elevated during the day
and could pose a limited fire weather concern closer to the White
Mountains Region: green-up conditions will largely limit fuels
from being available though.
Friday night into early Saturday morning the trough will traverse
the area, bringing widespread rain chances to the region. Snow
levels still remain elevated, only dipping down to around 7000
feet for a few hours Saturday AM before climbing again. Thus,
accumulating snowfall will be limited to elevations of 8000 feet
and above. As the trough moves east, instability and lingering
moisture will help drive additional showers and storms Saturday
afternoon. Greater coverage and confidence in them occurring will
be along the higher terrain where orographic influence will aid
in development. Greater moisture availability and dynamics with
the second system will help contribute greater precipitation
amounts:
most in Northern Arizona will at least receive a wetting rainfall,
with high confidence in many higher elevation locations
receiving-2 tenths of an inch in liquid precipitation.
After Saturday, zonal flow sets up over the region and
temperatures will be moderating with lighter winds. By Tuesday
next week temperatures will start to run almost 10 degrees above
normal.
&&
.AVIATION...Thursday 25/00Z through Friday 26/00Z...Mainly VFR
conditions expected. MVFR conditions continue near KPAN due to
FU/HZ. ISO -SHRA/-TSRA increase from west to east after 15Z, with
localized MVFR possible. S-SW winds 10-20 kts, gusting up to 35
kts, becoming 10 kts or less after 03Z. SW winds increase to
15-25 kts after 15Z/Thu with gusts up to 40 kts.
OUTLOOK...Friday 26/00Z through Sunday 28/00Z...ISO -SHRA/-TSRA
through 00Z/Thu. Additional showers expected after 18Z/Fri,
increasing from NW to SE. Gusty SW winds expected Friday.
&&
.FIRE WEATHER...Thursday and Friday...Isolated showers and
thunderstorms are expected to begin early Thursday, with drier
conditions forecast overnight. More widespread storms will pick up
late Friday. Look for southwest winds 15-25 mph, gusting 30-40 mph
each afternoon.
Saturday through Monday...Isolated to scattered
showers/thunderstorms will continue through Saturday, with warmer
and drier weather returning by Sunday. Expect west winds 15-25 mph
on Saturday, west winds 5-15 mph on Sunday and light southwest winds
on Monday.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
PUBLIC...RKR
AVIATION...Meola
FIRE WEATHER...Konieczny
For Northern Arizona weather information visit
weather.gov/flagstaff
