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903
FXUS65 KPSR 261119
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
419 AM MST Sun May 26 2024

.UPDATE...
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Updated 12z Aviation Discussion.
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&&

.SYNOPSIS...
Another day of near to slightly below normal temperatures is
anticipated before hotter conditions arrive on Memorial Day.
Temperatures across the lower deserts will peak in the high 90s to
lower 100s, or around 5 degrees above average through the rest of
the workweek. Skies will remain mostly clear with dry conditions
prevailing. Winds should not be as strong through the upcoming week
with the exception of typical afternoon breeziness.

&&

.DISCUSSION...
A trough of low pressure which brought breezy conditions and cooler
temperature to our region over the past few days is now exiting into
the Central Plains. Near zonal flow will overspread the southwest
U.S. this afternoon with a slight bump in overall hghts aloft.
Expect highs to top out right around normal in the mid to upper 90s
across the lower deserts this afternoon under clear skies and much
lighter winds. Heading into Memorial Day, a ridge of high pressure
centered over N Mexico will become more amplified, allowing for
rising hghts/thicknesses across AZ and southeast CA. Highs are
expected to push into the triple digits for most locations in
southcentral AZ including the Phoenix Metro area Monday afternoon.
Therefore, it is important to take extra heat precautions if you
have any outdoor plans during Memorial Day.

Ridging aloft will continue to build over the forecast area through
the middle of this week with 500 mb hghts increasing to around 584-
586 dam. These increasing hghts will bring further warming to the
region with highs topping out around 5 degrees above normal each
afternoon. Phoenix will have about a 60% chance of reaching 105
degrees by Tuesday, making it the hottest day of the year thus far.
These above normal temperatures will result in areas (30-50%
coverage) of Moderate HeatRisk by Tuesday across the lower deserts.
The Phoenix Metro area could see the Moderate HeatRisk extend into
Wednesday with similar temperatures expected. Enhanced breeziness
can be anticipated by mid-week due to an tightening 500 mb hght
gradient between the high pressure ridge to the south and shortwave
troughing over the Pac NW. However, gusts will likely remain below
30 mph in most locations with the exception of western Imperial
County.

Heading into the end of this week and into next weekend, ensembles
and cluster analysis indicate that ridging will continue to be the
predominate feature over Western U.S. The magnitude of the ridge is
still uncertain, however there are good indications that we will
continue to see above average temperatures lingering into next
weekend. The average high temperature in Phoenix reaches the century
mark by Thursday and therefore 100+ degree temps will become more
common heading through the end of this month and into early June.

&&

.AVIATION...
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Updated at 1120Z.

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

Winds will follow their typical diurnal patterns with speeds
mostly aob 7 kt. Extended periods of light and variable winds are
expected, especially at KSDL, KDVT, and during direction
switches. Skies will remain clear through the TAF period aside
from FEW passing high clouds on Monday (mainly beyond the current
period).

Southeast California/Southwest Arizona including KIPL and KBLH:

Winds will exhibit extended periods of very light speeds (aob 5
kt) and variable directions before favoring S to SW at KBLH this
afternoon and W at KIPL by this evening. Speeds will peak late
this afternoon and into this evening at both terminals but mostly
remain aob 9 kt sustained through the TAF period. Confidence is
moderate that W`rly gusts into the upper teens could develop this
evening at KIPL. Skies will remain clear through Sunday night.
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&&

.FIRE WEATHER...
Hot and dry weather will persist through this week with temperatures
topping out around 5 degrees above average. Daily highs will reach
the century mark in most lower desert locations starting on Monday
and readings will generally top out between 100-105 through the
remainder of the week. MinRH values will range between 10-15% today
before falling to 10% or less across the central and western deserts
from Monday onwards. Overnight recoveries will continue to range
from poor to fair at around 25-40%. Winds are expected to be lighter
over the next several days besides typical afternoon breeziness each
afternoon.

&&

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

$$

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