144
FXUS65 KPSR 132050
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
150 PM MST Fri Mar 13 2026

.KEY MESSAGES...

- Strong high pressure has settled over the region with near
  record temperatures expected today and Saturday.

- An unprecedented heat wave for March is expected for next week
  with highs topping 100 degrees by Wednesday and 105 degrees by
  next Friday, shattering daily records by as much as 10 degrees.

- Extreme Heat Watch issued starting Wednesday morning for SE CA,
  expanding Thursday morning into SE and S.Central AZ.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...
Unseasonably strong high pressure continues to impact the region
today, with afternoon highs in the low to mid 90s across the lower
deserts. The center of this ridge is currently positioned over the
Northwestern coast of Baja Peninsula, but will begin to migrate
further south into Mexico over the weekend. H5 heights however will
remain elevated between 579-585 resulting in afternoon highs to stay
well above normal, in the low 90s. Throughout the weekend a very
weak shortwave trough will also be reaching the central California
coast, causing widespread windy conditions starting Saturday
afternoon, with gusts mostly between 10-15 mph. Then as the
shortwave passes, gusts will primarily impact the areas along the
CO. River, with gust speeds up to 25-30 mph Sunday and Monday
evening.

&&

.LONG TERM /MONDAY THROUGH NEXT SATURDAY/...
Moderate HeatRisk across much of the region will common as early as
Thursday with localized pockets of Major by Friday. This is an
unprecedented heat wave for mid March, with widespread temperature
anomalies of 20-30F across the Western U.S. Model guidance continues
to show agreement through all of next week with model trends over
the past couple of days suggesting an even stronger record breaking
ridge settling over the Western U.S. by early next week and lasting
into next weekend. However, models have been slowing down the incoming
ridge slightly, potentially pushing the main timeframe of peak temperatures
by roughly a day. Still, this event is likely to break daily records
by as much as 10+ degrees for many areas and all time March temperature
records, especially across the Southwestern U.S. where the largest
positive height anomalies are anticipated.

To put it into perspective, the climatological record H2 heights are
projected over the entire West Coast and into the Western U.S. by
early next week before slowly shifting eastward throughout the rest
of next week. A large area of record H5 heights focused across the
Southwestern U.S. is also expected to develop by mid week and last
through at least next Thursday or Friday. Ensemble mean H5 heights
of 588-592dm are shown across the Desert Southwest by early
Wednesday before peaking as high as 594-596dm on or around next
Thursday. For reference, sounding climatology data for Las Vegas,
Flagstaff, and Tucson all show record H5 heights for March are
around 590dm and April 591dm, 593dm, and 592dm respectively. So, the
ridge for next week is forecast to be as strong if not a little bit
stronger than any ridge this region has ever seen in March or April.
Guidance does start to show some weakening of the ridge by next
weekend, but that is where model uncertainty increases with some
members hanging onto the ridge a bit longer. Until then, forecast
H8, H7, and H5 temperatures are forecasted to remain above record
levels for Wednesday through next Saturday.

Record temperatures are forecast for the majority of next week,
particularly from Tuesday-Saturday so, the main question will be by
how much will record high temperatures be broken. Throughout next
week as the ridge begins to move into the region on Monday, highs
should warm more into the mid 90s at least across the western
deserts. The first 100 degree temperatures are likely to be seen by
Tuesday with NBM forecast highs of 99-102 degrees across much of
southeast California and southwest Arizona. Phoenix will most likely
have to wait until Wednesday to hit 100 degrees. This would easily
break the earliest 100 degree day on record (currently March 26,
1988). Additional records likely to be met or broken late next week
could be the earliest ever 105 degree day in Phoenix, which
currently is April 20th and the earliest 106 degree day which
currently is May 2.

As mentioned earlier widespread Moderate HeatRisk will affect the
area during the latter half of next week with at least some
potential for localized areas of Major HeatRisk developing across
the lower deserts. Due to this, an Extreme Heat Watch has been
issued starting Wednesday morning for Southeastern California and
expanding into Southwestern and South Central Arizona by Thursday
morning, both lasting through next weekend.

&&

.AVIATION...Updated at 1730Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT;
Southeast California/Southwest Arizona including KIPL and KBLH: :

No aviation concerns are expected during the TAF period. Winds
will once again follow diurnal trends with windows of VRB to calm
conditions during the overnight and in between directional shifts.
Increasing high clouds are expected through the TAF period.

&&

.FIRE WEATHER...
High pressure will dominate across the region through next week
with temperatures around 15 degrees above normal through the
weekend before heating up even further (20-30 above normal) later
next week. Dry conditions will also prevail with MinRHs at or
just below 10% and persisting through next week. Overnight
recoveries will be poor to fair, mostly between 25-40% each night.
Winds will remain light today before becoming increasingly breezy
this weekend. Elevated fire danger is likely to become a problem
this weekend into early next week, focused more across the Lower
CO River Valley.

&&

CLIMATE...

Daily record highs through next weekend:

Date      Phoenix         Yuma         El Centro
----      -------         ----         ---------
3/13     92 in 2017     95 in 2017     95 in 2017
3/14     95 in 2013     96 in 2017     97 in 2017
3/15     92 in 2013     98 in 1934    100 in 1934
3/16     99 in 2007     99 in 2007    100 in 2007
3/17     99 in 2007    101 in 2007    101 in 2007
3/18     95 in 2017     96 in 2017     95 in 2007
3/19     96 in 2017     98 in 2017     96 in 2017
3/20     96 in 2017     99 in 2004     98 in 2004
3/21     97 in 2004    102 in 2004    100 in 2004
3/22     94 in 1990     98 in 2004     96 in 2004

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Watch from Wednesday morning through Sunday evening
     for AZZ530.

     Extreme Heat Watch from Thursday morning through Sunday evening
     for AZZ531>544-546-548>551-553>555-559.

CA...Extreme Heat Watch from Wednesday morning through Sunday evening
     for CAZ561>570.

&&

$$

SHORT TERM...Ryan
LONG TERM...Kuhlman/Ryan
AVIATION...Berislavich/RW
FIRE WEATHER...Kuhlman/Ryan
CLIMATE...18/Kuhlman

NWS Phoenix (PSR) Office