Plaster City, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

975
FXUS65 KPSR 180822
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
120 AM MST Sat Jan 18 2025

.SYNOPSIS...
A quiet weather pattern will prevail across the region through the
middle of next week with high temperatures mostly hovering near
normal levels. Morning low temperatures will remain somewhat cooler
than normal with some of the typical sheltered lower desert valleys
reaching freezing. Precipitation chances continue near zero through
next week.

&&

.DISCUSSION...
Early morning WV imagery depicts high amplitude ridging building
across the East Pacific while a series of shortwaves were
consolidating downstream into an expansive, deep negative height
anomaly covering the central and eastern Conus. This pattern
configuration will force strong surface pressure rises over central
Canada/northern plains (sfc high pressure in excess of 1050mb)
dislodging a bitter cold airmass throughout the eastern portions of
the United States over the next 36 hours. The intensity and depth of
this cold airmass will allow some modified cooler air to bleed over
higher terrain into the Southwest through early next week. While
midlevel heights will not be particularly low across the forecast
area, this synoptic setup will result in sustenance of near normal
temperatures over the region with narrow guidance spread yielding
excellent forecast confidence.

Early next week, models are in good agreement showing a sheared
vorticity center and associated jet streak carving out the western
periphery of the eastern Conus longwave trough. This vorticity
center should dive through the Great Basin Monday forming a
positivity tilted trough axis propagating through the SW Conus.
Evidence is growing suggesting a more defined vorticity lobe
progressing through the CWA resulting in modest height falls
juxtaposed with an intensifying pressure field aided by a heightened
thermal gradient. Thus, probabilities are increasing that this
scenario will be supportive for locally gusty north winds funneling
down the Colorado River valley Monday late afternoon and evening
producing gusts 30-40 mph over parts of SE California. Otherwise, a
resurgent cooler, dry continental airmass will filter south behind
the trough passage during the middle of the week with a brief period
of below normal temperatures. The coldest conditions will occur
Wednesday morning with the typical non-urban sheltered valleys
falling below freezing, albeit with limited impacts given most of
these locations have recently experienced multiple days of sub-
freezing temperatures already.

Ensemble guidance during the latter half of next week is actually
showing greater spread than previous iterations with the GEFS
membership more dispersive, and a distinct subset of members now
siding with a solution more common in CMC and EPS output previous
days. While some measure of height rises and warming from East
Pacific ridging edging inland is still likely, a larger percentage
of ensemble members are showing more dampened height rises and
shortwave energy helping limit ridge amplitude. Nevertheless,
temperatures should easily rebound back closer to the seasonal
normal into the weekend. Thereafter, GEFS members are still more
conservative than the CMC and EPS suites, but at least are hinting
at further longwave retrogression where stronger negative height
anomalies settle somewhere over the western Conus while displacing
high pressure further west. This would be a natural and expected
pattern evolution for this time of year, and causation for more
unsettled weather across the Southwest towards the end of the month.

&&

.AVIATION...Updated at 0510Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Winds will tend to follow their typical diurnal tendencies. Wind
speeds will generally be aob 6-7 kt with some periods of light and
variable winds. Clear skies are expected through the TAF period.


Southeast California/Southwest Arizona including KIPL and KBLH:
Wind speeds will generally be aob 8kt through the TAF period. Winds
at KIPL will favor a westerly component. Current southerly winds at
KBLH will eventually shift to the north by late Saturday morning
with an extended period of variable winds in between. Clear skies
are expected through the TAF period.

&&

.FIRE WEATHER...
Temperatures should hover close to the seasonal normal through the
middle of next week with expansive dry air in place resulting in
essentially no chance of wetting rainfall. Minimum afternoon
humidity levels will settle in a 15-25% range through this weekend,
then closer to a 5-15% range next week with a renewed surge of drier
air. Weekend fair to good overnight recovery of 30-60% will
deteriorate towards poor recovery of only 15-30% next week. While
some gusty north winds resulting in a period of elevated fire danger
will exist across western districts early next week, light winds
will be more common over the remainder of the region.

&&

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

&&

$$

DISCUSSION...18
AVIATION...Estupinan/Berislavich
FIRE WEATHER...18