Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 10/31/23

Area Forecast Discussion

National Weather Service Phoenix AZ

 452 PM MST Mon Oct 30 2023

.UPDATE...Updated 00z Aviation Discussion...

&&

.SYNOPSIS...
Cool high pressure will moderate the next several days as near to
below normal temperatures steadily warm into an above normal
category. Occasionally breezy conditions will be common through the
midweek period across south-central Arizona. Otherwise, chances of
rain area essentially zero through at least early next week.

&&

.DISCUSSION...
Latest surface analysis reveals an anomalous surface high across
the southern Rockies, with a cold air mass plunging southward into
Texas. Further west across the Desert Southwest, conditions are
not quite as chilly, however cool and dry conditions predominate
with afternoon temperatures generally in the upper 70s and lower
80s across the lower deserts. Morning ACARS soundings measured
PWATs near a quarter of an inch, while at the surface, dewpoints
in the teens and twenties are prevalent.

RAP streamline analysis indicates a pronounced northwesterly flow
in the upper levels. A weak short wave trough is also evident on
water vapor imagery east of the Four Corners, which brought a
reinforcing shot of cool air to the region this morning and
produced wind gusts up to 35 mph, particularly across the
foothills east of Phoenix. Winds earlier this morning were also
strong enough to generate areas of blowing dust across portions of
Pinal County, which briefly resulted in reduced visibilities near
the intersection of I-8 and I-10.

Latest HREF indicates winds will subside this afternoon, however
ECMWF EFIs above 70 percent suggest another period of windy
conditions is likely tonight and Tuesday morning as another
surface high drops southward into the Plains. The strongest winds
are again expected in the same spots east of Phoenix, mainly in
the foothills and along ridge tops in the Superstitions. HREF
median/mean gusts were considerably stronger than what was
observed this morning. Nevertheless, even the 25th percentile
suggests occasional breeziness across the Valley tomorrow.

Some of the coldest temperatures of the fall are expected
overnight in the sheltered areas outside of Phoenix where light
winds and radiational cooling can be maintained. There is a 60
percent chance temperatures will drop into the 40s near Deer
Valley and portions of the West Valley. At Sky Harbor Airport, the
NBM forecast low temperature is 55 degrees, which would make it
the coolest temperature observed since early April.

Model ensembles are in good agreement and indicate the ridge
across the western CONUS will persist through at least early next
week, initially oriented meridionally across the Great Basin
before shifting into the eastern Pacific and extending eastward
with a zonal ridge axis. Positive height anomalies are expected to
increase, which will translate into a gradual warming trend and a
return to above normal temperatures by the middle of the week.
Model clusters are also exhibiting little variability and with
PWATs likely remaining below normal, the pattern will remain
unfavorable for any precipitation across the Desert Southwest.

&&

.AVIATION...Updated at 2350Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Easterly winds will prevail throughout the period. Light winds aob
10 kts expected through early Tuesday morning. Winds will pick up
during the mid to late morning hours with occasional gusts as
high as 20-25 kts before subsiding to aob 10 kts by the mid to
late afternoon hours. Skies will remain mostly clear.

Southeast California/Southwest Arizona including KIPL and KBLH:
At KIPL, winds will fluctuate between the northwest and north with
speeds aob 10 kts. At KBLH, winds will favor a northerly component
with moderate speeds through this evening fluctuating between
10-15 kts before becoming light aob 8 kts through the rest of the
period. Skies will remain mostly clear.

&&

.FIRE WEATHER...
Very dry conditions with no chance of rain will continue through the
week as temperatures gradually warm back above the seasonal normal.
Minimum afternoon humidity levels will generally fall into the teens
with somewhat higher values over mountain areas of eastern
districts. Overnight recovery will only be poor to fair in a 15-40%
range. Wind speeds will remain somewhat enhanced into the middle of
the week favoring an east or north component before weakening
substantially later in the week. Ridge tops and terrain gaps of
eastern districts should experience the strongest gusts above 20 mph
creating periods of elevated fire danger.

&&

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

$$

DISCUSSION...Hirsch
AVIATION...Lojero
FIRE WEATHER...Young/18