Area Forecast Discussion
Issued by NWS Phoenix, AZ
FXUS65 KPSR 231019 AAA
Area Forecast Discussion...updated.
National Weather Service Phoenix AZ
320 AM MST SAT JUL 23 2016
.UPDATE...Updated aviation and fire weather discussions.
Excessively hot temperatures will last for one more day before some
relief is seen starting Sunday. Though temperatures will moderate
slightly, they will still remain fairly hot through next week while
thunderstorm chances increase. Thunderstorm chances for next week
look fairly typical for monsoon with better chances over high terrain
areas and mainly just slight chances over the deserts.
Current moisture levels remain on the low side with PWATS around 1.25
inches while warmer than normal conditions aloft continue to keep
monsoon activity somewhat dampened. These conditions will last
through today with monsoon storms confined to higher terrain
locations. The Excessive Heat Warning remains in effect through the
rest of today, but increasing moisture and slightly lower heights
aloft will bring temperatures below criteria starting Sunday.
A more favorable monsoon flow is in the process of setting up and
will allow PWATS to increase to closer to 1.50 inches for Sunday. As
the sub-tropical high sets up to our north or northeast through much
of the coming week, moisture levels should remain high enough to
promote fairly typical monsoon thunderstorm activity. Storms on
Sunday will still mostly be limited to higher terrain locations, but
we should see at least a few isolated storms into the deserts. As
moisture spreads further west and deepens into Monday, chances for
afternoon and evening thunderstorms will increase slightly while
even extending into portions of southeast California. Due to the lack
of any significant distinct inverted troughs and the good possibility
of more extensive cloudiness from quite high mid level RHs, PoPs are
mainly broad-brushed and still in the slight chance to chance
category through Wednesday. Winds aloft, including steering flow for
this period will be rather weak, so not anticipating much of a
threat for severe thunderstorms.
Overall it seems the coming week will be a fairly typical monsoon
thunderstorm week with a couple more active days and a couple less
active days. It does seem models are pulling back on the moisture
levels somewhat, especially for the middle of the week. Because of
this, I noticeably lowered PoPs on Thursday as both the GFS and
European temporarily lowers moisture levels. This drying likely
won`t last long as a more favorable moisture flow is indicated going
into next weekend. Temperatures through the coming week should be
near seasonal normals to a couple degrees warmer as there is no clear
indication of any cooler days from widespread rain or cloud cover.
South-Central Arizona Including KPHX, KIWA, and KSDL: A quiet period
weatherwise can be expected through the taf period as somewhat drier
air aloft and a more stable airmass keeps convective active well off
to the east of the Greater Phoenix area. Winds to mainly follow
typical diurnal trends, with little chance of any outflows from
distant thunderstorms affecting the terminals. Few-sct clouds layers
to remain mainly aoa 12k feet.
Southeast California/Southwest Arizona including KIPL and KBLH:
Little to no aviation impacts through the taf period under mostly
clear skies. Sfc winds to favor a southerly direction at KBLH and
southeasterly direction at KIPL, with the strongest winds during the
afternoon and early evening hours.
Aviation Discussion not updated for amended TAFs.
Monday through Friday... Monsoon moisture working its way back into
the region will bring chances for afternoon and evening
thunderstorms each day from Monday into Thursday. The best chances
for wetting rains will be over the higher terrain east of Phoenix,
will lesser chances over the lower deserts of South-Central and
southwest Arizona, and only slight chances over southeast
California. Some increase in convective activity is expected on
Friday, as deeper moisture begins to move into the region.
Temperatures to remain slightly above normal through the entire
forecast period. Minimum humidities in the 15-30 percent range
Monday-Thursday to rise into the 20-35 percent range on Friday.
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.
AZ...Excessive Heat Warning until midnight MST tonight for AZZ020>023-
CA...Excessive Heat Warning until midnight PDT tonight for CAZ031>033.
Visit us on Facebook...Twitter...and at weather.gov/phoenix