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578
FXUS65 KPSR 162102
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
202 PM MST Thu May 16 2024

.UPDATE...Updated 18Z Aviation Discussion.

&&

.SYNOPSIS...
Above normal temperatures will continue through the weekend with
lower desert highs warming a few more degrees before peaking at
just over 100 degrees on Friday and Saturday. Isolated shower and
thunderstorm activity can be expected again today over the
eastern Arizona high country, which could cause some erratic
gusty winds reaching the lower deserts of south-central Arizona.
A slight cooling trend and continued dry conditions are forecast
for the first half of next week with temperatures likely falling
back to near normal.

&&

.DISCUSSION...
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Latest satellite imagery and local area radars indicate residual
showers left over from early morning convection are now progressing
into southern AZ. New convection is now firing over the Mogollon Rim
indicated by a large cu field on visible satellite. These showers
are associated with a weak shortwave/mesovortex which is embedded in
northerly flow on the back side of a larger scale trough. Steering
flow at 500 mb is still out of the N-NW which will allow showers to
drift southward into E Maricopa and S Gila County this afternoon and
early evening. Mid-level lapse rates are still rather steep around 8
deg C/km with MU CAPE values up to 250 J/kg across southcentral AZ
which could result in a few stronger cells capable of producing
gusty outflow winds over 30 mph and pea sized hail. Chances are
low (10-30%) for an outflow boundary to reach Phoenix this evening
and any realistic rain chances will be confined to S Gila County
where PoPs range from 15-25%. As we lose daytime heating,
shower/storm activity will diminish around sunset. A quiet night
is expected across the region with lows in the mid 60s to lower
70s.

Heading into this weekend, 500 mb hghts are expected to rise to
around 582-585 dam Friday and Saturday which will result in
temperatures pushing 6 to 8 degrees above normal. Highs both days
will reach the upper 90s to triple digits across the lower deserts,
resulting in areas of Moderate HeatRisk. The hottest day looks to be
Saturday with a forecast high of 103 degrees in Phoenix. If you have
any outdoor plans, please limit time in the sun and drink plenty of
water. On Sunday, model guidance suggest a large trough is expected
move into the Pacific Northwest, helping to suppress the ridge
over our region. Temperatures will decrease slightly Sunday
afternoon, but will still remain around 3 to 5 degrees above
normal in the upper 90s to near 100 degrees.

From Monday into early next week, most ensemble members continue
to show another upper level trough digging southward through the
Pacific Northwest into the Great Basin and absorbing a weak low
off the coast of Baja California. This pattern will result in a
decrease in hghts aloft and lower temperatures across the Desert
Southwest. By Monday afternoon, we will see highs back around
normal in the mid to upper 90s and near normal temperatures will
likely carry into mid- week as an overall troughing pattern
remains in place. There could be increased breeziness early next
week, however gusts will likely remain aob 20 kts each afternoon.
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&&

.AVIATION...Updated at 1725Z.

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

No major aviation concerns are expected during the TAF period.
Winds will follow diurnal trends with gusts this afternoon around
20 kts. Hi-res guidance does hint at some more isolated shower
activity this afternoon and early evening, but the majority of
rainfall activity should remain primarily to the N and E of the
Phoenix metro, with chances for rain over terminal locations only
around 10%. These distant showers will create the potential for a
strong outflow (gusts >30 kts) to traverse the metro area, but
chances for these enhanced winds are also only around 10%. SCT
mid-level clouds will prevail over the region with lower bases
associated with any potential VCSH. Skies will clear out
overnight.

Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation concerns are expected during the TAF period. VRB winds
at IPL will become established out of the W this evening, with
perhaps a few gusts around 20 kts around sunset. At BLH, winds
will be out of the S through much of the period with elevated
sustained speeds this evening around 15 kts. Speeds the remainder
of the period will be aob 10 kts. Skies will be clear through
tomorrow morning.

&&

.FIRE WEATHER...
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Another round of high-based afternoon showers and isolated storms
will be possible, mainly across the higher terrain areas of Maricopa
and S Gila Counties. The main impacts with any storm that develops
will be gusty, erratic winds and dry lightning. Much warmer and
drier conditions are expected this weekend with highs topping out
around 6 to 8 degrees above average. Breezy to locally windy
conditions will develop this weekend, especially on Sunday where
winds may gust as high as 25-35 mph across the lower deserts and up
around 40 mph in the higher terrain. A dry weather system will
arrive early next week, resulting in slightly cooler temperatures
and continued breezy conditions. Minimum relative humidity values
will range from 8-20% each day. Moisture recovery will range from
poor to fair each night, or around 25-50%.
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&&

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

$$

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