Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 270945

Area Forecast Discussion
National Weather Service Phoenix AZ
245 AM MST Thu Jun 27 2019

A high pressure system centered over New Mexico will continue to be
a strong influence for weather in Arizona and southeast California
through next week. This will result in mostly near normal
temperatures across Arizona to slightly below normal readings
across southeast California. The dry weather also looks to persist
well into next week for the bulk of the region with high terrain
showers and thunderstorms relegated to far east central Arizona.


The subtropical high situated just to our southeast will shift
more into our region beginning Friday leading to warmer conditions
through early next week. Well to our northwest, a deep closed low
will remain nearly stationary through the weekend, keeping the
subtropical high from completely engulfing the Desert Southwest.
Stuck between the two upper level systems will result in increased
south to southwesterly flow aloft and continued breezy daytime
conditions for the bulk of the region. The slight northwestward
shift in the high will allow for a bump in temperatures starting
Friday with highs reaching between 106-110 degrees over the

The shift in the subtropical high will also likely open a small
window for some modest low and mid level moisture working into
extreme southeast and east-central Arizona beginning Friday. This
pattern looks to mainly stay the same into at least early next
week, but any shower and thunderstorms should be fairly limited
and remain over high terrain areas. Long range models continue to
show no realistic chance of any monsoonal moisture nearing the
lower deserts through next week.

Though it will not affect our region to a great degree, models are
still showing the mid and upper level remnants of Tropical Storm
Alvin moving north-northeastward centered over the Lower Colorado
River Valley on Saturday. This will bring a decent slug of
moisture above 15K feet through the region with the deepest
moisture likely coming up through southeast California and
southwest Arizona. The main impact will be mostly cloudy skies
Friday night and Saturday with high temperatures likely stunted
somewhat on Saturday, especially west of Phoenix. Some leftover
clouds on Sunday will likely thin enough to allow temperatures
to recover with highs Sunday approaching 110 degrees over the
bulk of the deserts. Slightly above normal temperatures should
persist through Monday before dropping back to around normal by
the middle of next as the subtropical high is forecast to weaken
and shift farther to the southeast.


.AVIATION...Updated at 0547 UTC.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:

Gusty winds will be the main aviation concern under clear skies.
The gusty westerly winds that have been affecting the Phoenix
sites over the past several hours should weaken below 10 knots
over the next hour, with easterly winds around 5 knots returning
later tonight. Southerly crosswinds are once expected to develop
late Thursday morning before veering toward the W-SW during the
afternoon. Gusts up to 20 knots are expected with both the
southerly crosswinds at KPHX and KDVT and gusty W-SW winds across
the entire Valley tomorrow afternoon. Stronger gusts are possible
if 25-35 knot S-SW winds at 700 mb mix to the surface, but hi-
res and MOS guidance have weaker winds than depicted in the TAFs.

Southeast California/Southwest Arizona including KIPL and KBLH:

Gusty winds tomorrow afternoon and early evening will be the
primary concern with clear skies and minimal aviation concerns
otherwise. East-southeast winds at KIPL and southerly winds at
KBLH should remain below 10 knots overnight into tomorrow morning
before winds increase during the afternoon hours with S-SW gusts
up to 25 knots at KBLH. Winds will remain southeasterly at KIPL
until downsloping W-SW 15-20 knots gusts move in late in the
afternoon through the evening hours.

Aviation Discussion not updated for amended TAFs.


Saturday through Wednesday:
Seasonably warm and mostly dry weather will persist over all the
districts through the middle of next week. However, a slight
increase in moisture could lead to an isolated, non-wetting
thunderstorm across the far eastern Arizona high terrain Saturday
afternoon/evening. Ridge top and gap winds will occasionally be
breezy during the afternoon hours with SW gusts around 25 mph
common. Minimum relative humidity values will mostly fall into a 10-
15% range with generally poor (locally fair) overnight recovery. The
winds and humidity combined with very dry fuels will frequently
result in elevated fire weather conditions during this period.


Spotter activation is not expected.




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