Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 280330
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
830 PM MST FRI MAY 27 2016

.SYNOPSIS...
A broad area of low pressure will persist over the western United
States through the beginning of next week yielding somewhat cooler
than normal temperatures and dry conditions. Strengthening high
pressure much of next week will bring a warming trend with high
temperatures in the lower deserts pushing near 100 degrees by the
middle of the week.

&&

.DISCUSSION...
Clear skies under dry westerly flow is present this evening, but
temperatures got a boost over the past 24 hours. Evening temperatures
are running roughly five degrees warmer than yesterday at this time
and this will be a common theme for next week. Once a weak but dry
shortwave trough passes through the region on Sunday, temperatures
will start climbing again with a good likelihood of seeing highs
north of 105 by late next week. In the short term there is little to
worry about, just continued dry conditions and near normal
temperatures. No updates are needed to the current forecast.

&&

.PREVIOUS DISCUSSION...
Low amplitude broad troughing remains splayed across the SW Conus as
the primary PV anomaly lifts into SW KS this afternoon. Substantial
warming aloft has occurred in the past 24 hours with H5 temperatures
spiking 5C-8C throughout Arizona. Warming in the lower levels has
been far more muted, however afternoon readings were trending 5F-10F
warmer than Thursday. Similarly for tonight, temperatures will hover
several degrees above what had been experienced Thursday evening
yielding a delightfully comfortable late May evening to start off
the holiday weekend.

No monumental surprises for the entire long weekend despite a more
defined sharp trough slowly edging through Arizona. This system will
be completely moisture starved to the point where only flat mountain
CU would be the highlight of its existence. Regardless, H5 heights
will remain nearly steady state around 576dm while 1000-850mb
thicknesses only peak about 142dm. Numerical guidance spread from
raw and post-processed sources remains extremely narrow and highs
only a couple degrees below average appears a near guarantee.

Precipitation chances remain negligible through next week, except
with the far eastern sections of southern Gila county. Some timing
differences are evident between the ECMWF and GFS and their
respective ensembles, though there is some remote potential for
showers or thunderstorms across the higher terrain associated with
the compact upper low moving through AZ Tuesday/Wednesday. In all
likelihood, any shower activity would be relegated to the White
mountains and New Mexico. Otherwise, heights and thicknesses will
intensify further beyond the middle of next week such that a more
prolonged period of highs breaching the 100F threshold appears very
likely. This may especially become the case if the North American
flow pattern become blocked again as many ensemble members suggest
for the end of next week.

&&

.AVIATION...
South-Central Arizona Including KPHX, KIWA, and KSDL and
Southeast California/Southwest Arizona Including KIPL and KBLH

Clear skies to persist through Saturday under a light wind regime.
May have some occasional gusts during the afternoon hours Saturday,
but less than 20 kts. Wind directions for the Phoenix terminals will
follow typical diurnal tendencies and generally follow a southerly
component for KIPL and KBLH. No aviation impacts through the period.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
Monday through Friday...
A hot and dry weather pattern will dominate the week including a
strong high pressure ridge that will build over the region from
Wednesday through Friday. Hot and near normal daytime high
temperatures reaching as high as the lower triple digits through
Wednesday are expected to increase to 100 to 106 degrees beginning
Thursday. In addition, minimum relative humidities of 8 to 15
percent will dry to the 7 to 11 percent range by Friday.
Breezy southerly to southwesterly winds with gusts of 15 to 20 mph
are forecast for Wednesday afternoon and evening.

&&

.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected.

&&

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

$$

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DISCUSSION...Kuhlman
PREVIOUS DISCUSSION...MO/Hirsch
AVIATION...Kuhlman
FIRE WEATHER...Sawtelle


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