Fountain Hills, Arizona 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

156
FXUS65 KPSR 231110
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
410 AM MST Sat Nov 23 2024

.Update...Updated Aviation Discussion

&&

.SYNOPSIS...
A pattern shift will take place over the weekend as riding aloft
begins to flatten allowing Pacific moisture and abundant clouds to
stream into the region. Temperatures will remain well above average
today, but are expected to fall to near normal beginning Sunday when
thick cloud cover arrives. A weak shortwave trough will pass
north of the area by the middle of next week, however any
precipitation chances are expected to remain confined to the
higher terrain of Northern Arizona.

&&

.DISCUSSION...
Latest mid-lvl wv imagery and 500 mb streamline analysis reveals a
deep cutoff low situated off the Pacific NW coastline along with an
associated IVT plume impacting NorCal. A multi-day AR event will
continue through this weekend, bringing soaking rainfall to much of
inland CA. Closer to home in AZ and SE CA, a ridge of high pressure
remains the predominate feature, resulting in dry and tranquil
weather. 500 mb hghts are expected to lower slightly today as
ridging aloft begins to weaken, however positive hght anomalies
still anticipated over our region. Highs will once again top out in
the upper 70s to lower 80s across the lower deserts under mostly
clear skies. Effective radiational cooling will allow lows to fall
into the upper 40s to lower 50s across much of the area tonight.

A pattern change is anticipated on Sunday when ridging over the
Desert Southwest will transition to zonal flow in response to the
deepening trough over the West Coast. As this occurs, Pacific
moisture aloft will begin to overspread the forecast area. Latest
GFS bufr soundings for KPHX and KYUM still indicate near saturation
above the 500 mb layer which is indicative of a thick mid-lvl cloud
deck. The widespread cloud cover on Sunday should preclude
insolation enough to allow temperatures to be much closer to normal
with highs in the low to mid 70s across the lower deserts. Thick
cloud cover is expected to persist into Monday which will result in
warmer morning low temperatures mainly in the 50s across the lower
deserts. Highs will be very similar on Monday afternoon, reaching
the low to mid 70s in most locations.

Ensemble cluster analysis continues to show the deep cutoff low over
the Pac NW transitioning to an open wave and eventually swinging
through the Intermountain West Tuesday into Wednesday. The track of
this system is still projected to remain well north of our region
and thus the best moisture and lift should remain focused over the
Arizona high terrain. Therefore, PoPs are expected to be <10% for
the entire forecast region. The shortwave trough will bring a dry
cold front through the area late Wednesday, which will only serve to
lower temperatures by a few degrees. There may be some post frontal
breeziness across SE CA, however gusts are not expected to exceed 25
mph at this time. After the shortwave passes through, dry NW flow
aloft will keep temperatures near or slightly above average through
the remainder of next week.

&&

.AVIATION...Updated at 1110Z.

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

No aviation weather concerns are expected through Sunday morning
with increasing cloud cover through the course of the TAF period.
Light winds, AOB 8 kt, with extended periods of variability and
even calm conditions, will be common. More traditional diurnal
tendencies across the Phoenix sites are anticipated through
tonight.

&&

.FIRE WEATHER...
Warm and dry conditions will prevail today with highs around 5 to 8
degrees above average. Increasing cloud cover will result in slightly
cooler temperatures beginning Sunday and persisting through early
next week. Relative humidity is expected to fall below 15% across
the entire area this afternoon, but is expected to rise to around
20-35% regionwide on Sunday. Overnight recovery will range from
poor to fair across the lower deserts tonight and increase to
widespread fair to good on Sunday night. Overall light winds will
continue with only some periodic light breezes over the higher
terrain in the afternoon and early evening.

&&

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

$$

DISCUSSION...Salerno
AVIATION...Young/RW
FIRE WEATHER...Salerno