Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Phoenix Arizona
145 PM MST sun Mar 9 2014
Update...updated fire weather discussion...
mostly dry weather will continue over the southeast California and
southwest Arizona deserts over this week. A weak front will move
through the region Tuesday and Wednesday but little to no
precipitation is expected. Temperatures will remain slightly above
normal through the end of the week with highs in the lower 80s
across the deserts. Even warmer temperatures are expected Friday
into the weekend.
aside from occasional easterly winds around 20 kts...conditions
across the region have been pretty quiet today as a dirty upper
ridge sets up across the area. High clouds continue to approach the
Desert Southwest this afternoon...but the leading edge continues to
erode and the more substantial cloud cover remains over Nevada and
central California. Clouds will eventually fill in...but not until
The forecast through Tuesday will be one of mostly sunny skies and
above normal temperatures as a series of weak dry shortwaves move
through The Four Corners area. Could be some breeziness down the
lower Colorado River valley on Tuesday but winds should remain below
Wind Advisory levels. Meanwhile...afternoon temperatures will generally
stay in the lower 80s...although the normally warmer spots could
touch the middle 80s.
A weak shortwave over northern Arizona on Tuesday will retrograde
and stall over the area on Wednesday/Thursday. The exact position of
the stalled upper trough varies among the GFS/ec/naefs solutions but
they all agree that precipitable waters will remain around 0.3 inches or less.
GFS/ec point soundings reveal the majority of that moisture is
confined to the upper levels of the atmosphere while the best
/albeit weak/ isentropic lift is confined to the 305-310k surfaces.
Hard to imagine much of a precipitation threat with such limited moisture
and aside from an increase in cloud cover and perhaps some
cumulus/isolated showers east of Phoenix...this looks like a minimal
impact event for the region. Probability of precipitation were already in the upper single
digits east of Phoenix and this still looks reasonable based on
today\s 12z models.
The trough doesn\t stick around for long...as it ejects into New
Mexico on Friday followed by increasing heights Saturday and Sunday.
The European and GFS both advertise 500 mb heights at or above 580dm
next weekend and not surprisingly...consensus guidance is showing
hints of highs in the 90s in Phoenix and the middle 90s around Yuma/el
centro. Not ready to jump on board with 90s in Phoenix quite yet but
upper 80s is definitely looking like a solid bet. 90s do seem
reasonable across Yuma/southeast California however and temperatures were nudged upward
south-central Arizona including kphx...kiwa...and ksdl...and
southeast California and southwest Arizona including kipl and kblh...
No aviation impacts are expected through Monday. Mainly clear
skies...with just a few patches of high clouds passing overhead from
time-to-time tonight and on Monday. Surface winds to remain mainly on
the light side...at or below 8kts...and generally follow the typical diurnal
Aviation discussion not updated for amended tafs.
Wednesday through Sunday...
a weather disturbance that will be moving very slowly into...and
across northern Arizona on Wednesday and Thursday is expected to
bring locally gusty winds and slightly cooler temperatures to the
region...but little or no rainfall. High pressure building eastward
into the Desert Southwest will then bring a warming trend to the
region from Friday into the upcoming weekend...with temperatures
approaching 90 at a few Lower Desert locations by Sunday. Minimum
humidities are expected to fall into the upper single digits and
teens each afternoon...with fair to good overnight recoveries.
Arizona...Fire Weather Watch from Tuesday morning through Tuesday evening
California...Fire Weather Watch from Tuesday morning through Tuesday evening
Visit US on facebook...twitter...and at weather.Gov/Phoenix