607
FXUS65 KPSR 131728
AFDPSR
Area Forecast Discussion
National Weather Service Phoenix AZ
1028 AM MST Fri Mar 13 2026
.UPDATE...Updated 18Z Aviation Discussion.
&&
.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.
- Widespread Minor Heat Risk is expected through the weekend
before increasing to Moderate HeatRisk by the middle of next
week.
&&
.SHORT TERM /TODAY THROUGH SUNDAY/...
An unseasonably strong high pressure ridge continues to impact our
region with the center of the ridge situated just west of northern
Baja. H5 heights over our region peaked yesterday between
586-588dm and have started to fall as the ridge slides farther to
the south. However, this will not curtail our temperatures today
as the unseasonably warm air mass remains in place allowing for
lower desert highs to top out in the lower 90s in the Phoenix area
to as warm as the mid 90s across southeast California and
southwest Arizona.
By tonight, a very weak and subtle shortwave trough will be
reaching the central California coast with a more significant
trough entering the Pacific Northwest from the northwest. The weak
shortwave will enter our region by later Saturday afternoon,
further suppressing heights across our region into Saturday
night. Higher level clouds will accompany this weak disturbance
making Friday night through much of Saturday partly cloudy.
Despite the presence of the higher clouds and the slightly lower
heights, high temperatures Saturday may only drop a degree from
Friday`s. The lower heights (578-582dm) will be quite brief and
mainly focused late Saturday into early Sunday before the next
ridge quickly begins to raise heights from west to east by Sunday
afternoon. NBM forecast highs for Sunday are nearly identical to
Saturday with highs mainly between 90-93 degrees in the Phoenix
area to 91-95 degrees across southeast California and southwest
Arizona.
The passing disturbance this weekend will also lead to an increase
in winds with areawide gusts up to around 20 mph on Saturday
before becoming focused across the Lower CO River for Sunday and
Monday with gusts as high as 25-30 mph.
&&
.LONG TERM /MONDAY THROUGH NEXT SATURDAY/...
The forecast and forecast thinking for next week has barely
changed with Moderate HeatRisk becoming widespread by the middle
of the week and localized Major HeatRisk possible for next Friday
and Saturday. The majority of the area will experience summer-
like temperatures for a few days with highs potentially as hot as
110 degrees for next Thursday-Saturday. Please see our previous
discussion for more detailed information.
&&
.PREVIOUS DISCUSSION...
Issued at 324 AM MST Thu Mar 12 2026
An unprecedented heat wave for mid March is expected next week
across the Western U.S. with widespread temperature anomalies of
20-30F. Model guidance continues to show remarkable 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 Monday and lasting into next weekend.
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.
By late Saturday, the next high pressure ridge will be developing
well off the coast of California, quickly reaching record
strength for this time of year on Sunday. Large negative height
anomalies developing across the Eastern U.S. will also help drive
an increasing amplitudinal pattern, quickly expanding the ridge
over the Western U.S. by Monday.
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, to put this in
better prospective 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.
Record temperatures are forecast for the majority of next week,
particularly from Tuesday-Saturday. 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 which would easily break the earliest
100 degree day on record (currently March 26, 1988).
Forecast H8, H7, and H5 temperatures are all at record levels for
Wednesday through next Saturday. It is not a question of whether
we will get record temperatures next week, the question should be
by how much will they be broken. Highs are nearly certain to top
100 degrees each day during the latter half of next week with the
hottest readings even topping 105 degrees at some point next
Thursday-Saturday. NBM 75th percentile temperatures continue to
show potential for some spots to even hit 110 degrees late next
week. The earliest ever 105 degree day in Phoenix is April 20th
and the earliest 106 degree day is May 2.
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. However, the large diurnal swings may keep this from
occurring. Forecast lows are still shown to dip into the 60s for
the majority of the area during the entire event which only puts
the lows in the Minor category, affecting the calculation of the
overall HeatRisk. Either way, this event should easily bring high-
end Moderate HeatRisk for several days.
&&
.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...None.
CA...None.
&&
$$
SHORT TERM...Kuhlman
LONG TERM...Kuhlman
AVIATION...Berislavich/RW
FIRE WEATHER...Kuhlman
CLIMATE...18/Kuhlman
NWS Phoenix Office
Tucson, AZ 
