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000
FXUS65 KPSR 141145
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
445 AM MST Sun Apr 14 2024

.UPDATE...Updated Aviation Discussion.

&&

.SYNOPSIS...
A weather disturbance moving through northern Arizona and southern
Utah will result in locally windy conditions and temperatures
retreating closer to the seasonal normal the next couple days.
However, strong high pressure building into the region later this
week will allow temperatures to warm rapidly with some lower desert
communities possibly approaching close to the 100 degree mark late
in the week.

&&

.DISCUSSION...
A well defined negative PV anomaly continues to propagate southeast
along the central California coast, however satellite imagery
depicts the first signs that subtropical jet energy was influencing
the circulation towards an eastward turn. As a result, the central
cold core and more pronounced height falls will translate inland
towards southern UT over the next 36 hours. Nevertheless, increased
pressure packing along a decaying cold front crossing the coast
range will support enhanced winds descending into lower elevations
of Imperial County again this afternoon and evening. While not the
optimal scenario for strong mountain rotors, deep mechanical
transport of higher momentum air will support a brief period of
advisory level winds. By Monday, the greatest combination of jet
energy, midlevel height falls, and tightened pressure gradient will
have shifted into New Mexico though a few stronger ridge top gusts
across Gila County may be common.

Operational and ensemble members continue to consolidate on a
singular solution later this week featuring mean troughing shifting
into the Upper Midwest/Great Lakes and dampened ridging building
over the SW Conus. Trends among NAEFS membership show less support
for higher amplitude riding, but rather H5 heights becoming
sequestered around 582dm due to low amplitude perturbations being
pulled eastward in an active subtropical jet. As a result, NBM
probabilities of lower elevation communities reaching 100F this week
have dropped considerably below 25%. Regardless, forecast confidence
is excellent that temperatures will hover 5F-10F above normal during
the latter half of the week with numerical guidance spreads
narrowing significantly. This pattern of quasi-zonal, dry westerly
flow should persist into the weekend yielding an extended period of
widespread minor HeatRisk, but nothing terribly unusual for mid/late
April.

&&

.AVIATION...Updated at 1144Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Gusty winds will be the primary aviation weather concern through
the TAF period, while dry conditions persist. Light easterly winds
are favored to persist into the mid morning hours before veering
toward a southerly component around 16-17Z and then WSW around
20-21Z. Breezy conditions will increase heading into the afternoon
hours with gusts climbing upwards of 20-25 kts. Gusts subside
later in the evening while directions maintain a westerly
component into the overnight hours. A diurnal easterly switch is
not expected during the overnight hours. Mostly clear skies will
persist.

Southeast California/Southwest Arizona including KIPL and KBLH:
Strong winds will be the primary aviation weather concern during
the TAF period while dry conditions persist. Gusty westerly winds
will increase through the afternoon before peaking this evening at
KIPL. Gusts at KIPL may climb to or in excess of 35 kts at times
this evening, which could potentially lead to some visibility
restrictions due to blowing dust. At KBLH, winds won`t be quite as
strong, though SW gusts upwards of 25-30 kts will be possible
this afternoon and evening. Winds weaken at the terminals later
tonight into the overnight hours. Mostly clear skies will
continue.

&&

.FIRE WEATHER...
With dry weather prevailing, near normal temperatures early this
week will rapidly warm back into an above normal category during the
latter half of the week. Very breezy afternoon conditions will be
common through Monday, especially across western districts today and
eastern district ridge tops Monday. As minimum afternoon humidity
levels fall into a 10-25% range, a locally elevated fire danger will
exist. With warmer temperatures later in the week, minimum humidity
levels will dry further into a 10-20% range with single digits
common across lower desert locations. Overnight recovery will turn
poor to fair in a 20-40% range. However, lighter wind speeds will
preclude a greater fire danger and provide an excellent opportunity
for prescribed burning during the middle of the week.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 6 AM PDT Monday for CAZ562.

     Wind Advisory from 3 PM this afternoon to 11 PM PDT this evening
     for CAZ563-566-567.

&&

$$

DISCUSSION...18
AVIATION...Smith
FIRE WEATHER...18