659
FXUS65 KPSR 291750
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1050 AM MST Sun Mar 29 2026

.UPDATE...Updated 18Z Aviation Discussion.

&&

.KEY MESSAGES...

- Unseasonably hot temperatures will continue to challenge daily
  records through Monday before noticeable cooling occurs during
  the middle of the week.

- Isolated showers and potentially a few thunderstorms will be
  possible over portions of southcentral and southeastern Arizona
  this afternoon and Monday. Any storm that develops could
  produce gusty outflow winds.

&&

.SHORT TERM /TODAY THROUGH MONDAY/...
A slow pattern change is underway with the strong ridge that has
brought record temperatures gradually weakening and shifting
farther to the east. The repositioning of the ridge has also
allowed for some moisture to pool across northwest Mexico where
convection has developed over the last couple of days. This
moisture is expected to advect northward into far southeast
California and southern Arizona today before spreading through the
rest of southern and central Arizona tonight into Monday. The
south southwesterly flow today will also continue to feed higher
level moisture and clouds into the area, but highs this afternoon
will again reach well into the 90s across the lower deserts.

The increasing moisture today may be enough to spark off some
high-based showers and potentially a thunderstorm or two, focused
south of the Phoenix metro. Portions of southern Maricopa county
and Pinal county could see some of this activity with gusty
downdraft winds possible due to the boundary layer still being
quite dry. Also can`t rule out outflow winds extending northward
into the Phoenix area during the first part of the evening.
Localized wind gusts of 35-45 mph will be possible closer to the
convection with the stronger wind gust potential diminishing into
the Phoenix area. Little if any rainfall is expected with this
activity as most will fall as virga.

Better moisture in the lower levels will advect into the area
tonight through Monday morning with surface dew points briefly
reaching into the lower 60s in southwest Arizona to the mid 50s
elsewhere. However, this moisture will be very shallow with drier
air aloft quickly eroding the surface moisture Monday afternoon
pushing dew points back into the 40s. Isolated afternoon and early
convection will again be possible on Monday, but with basically no
support aloft and limited moisture the convection should be very
sparse and weak. Best chances are likely to be focused over higher
terrain areas south and east of Phoenix Monday with PoPs mostly
between 10-25%.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
A mostly zonal westerly flow pattern will set up into mid week
with a weak shortwave trough tracking across central California
before moving through our region on Wednesday. Drying conditions
will continue during this time with low level mixing ratios
dropping from the 5-7 g/kg on Monday to 3-5 g/kg starting Tuesday.
Conditions on Tuesday present virtually no chance of any shower
activity, but with the passing shortwave on Wednesday some high
terrain showers may develop. NBM PoPs still seem too high for
Wednesday, so we have lowered chances more into the 5-10% range
for the lower deserts and 10-20% for the higher terrain.

Temperatures will also finally cool off during the middle of the
week with highs falling into the lower 90s Tuesday and into the
mid 80s Wednesday. Once the shortwave trough moves to the east of
the region Wednesday night, even more dry air will filter in from
the northwest. Dry conditions with temperatures on average 3-6
degrees above normal are expected late in the week as a another
Pacific trough passes well to our north. Ensemble guidance then
mostly agrees a modest ridge is likely to develop off the West
Coast late in the week before moving into our region next
weekend. This should produce another warming trend with NBM
forecast highs back into the 90s by around next Sunday.

&&

.AVIATION...Updated at 1750Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The main aviation concern this TAF period will be strong S-SW
winds associated with an outflow boundary emanating from distant
storms south of the Phoenix Metro this evening. Until then, east
to southeasterly winds are expected to shift out of the west at
all terminals by 20-21Z this afternoon. Speeds should remain
around 10 kt or less through the afternoon. Showers and storms are
expected to develop well south of Phoenix later this afternoon
and will be capable of pushing outflow boundaries into Phoenix by
the evening, likely between 02Z-03Z, with around a 10-20% chance
for gusts to exceed 30 kts. TEMPO groups were added to all
terminals to account for the southerly wind shift. There is also
at least a low chance (10-30%) that weak showers associated with
the outflow boundary could develop over the southern fringes of
the metro area, thus VCSH was also added to this TAF package.
Confidence is low whether blowing dust will accompany the outflow,
however there may be a 1-2 hour period where vsby could fall to
around 5-6 SM. Skies will remain SCT to BKN with mid to high
clouds staying around 10-15 kft AGL this evening.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major weather issues will exist through the TAF period under
persistent mid/high cloud decks. Winds will remain predominantly
southeasterly at KIPL and southerly at KBLH through tonight. Wind
speeds will generally be around 10 kt or less, but some occasional
gusts into the teens will be possible this afternoon and evening.

&&

.FIRE WEATHER...
Unseasonably hot temperatures with mostly dry conditions can be
anticipated through this weekend, however a gradual cooling trend
will transpire by early next week. MinRH values will increase
from 10-20% today up to 15-20% Sunday and Monday, while MaxRHs
will also increase from 20-40% tonight to 40-70% Sunday night. Due
to the increase in low-level moisture, there will be at slight
chance for rain (10-30%) across southcentral AZ Sunday and Monday,
but the CWR will remain under 10%. Any storms that do develop
will be capable of producing gusty and erratic outflow winds and
dry lightning, which could lead to new fire starts. Winds will
continue to taper off below 15 mph through this afternoon and
remain out of the E-SE overnight. Winds will resume a diurnal
pattern on Sunday with afternoon upslope breeziness expected to
increase early next week.

&&

.CLIMATE...

Daily record highs:

Date      Phoenix         Yuma         El Centro
----      -------         ----         ---------
3/29     97 in 2015    100 in 1897     97 in 1969
3/30     97 in 2004     99 in 1934    101 in 1934

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

$$

SHORT TERM...Kuhlman
LONG TERM...Kuhlman
AVIATION...Salerno
FIRE WEATHER...Salerno/Kuhlman
CLIMATE...Kuhlman

NWS Phoenix (PSR) Office