Scientific Forecaster Discussion
fxus65 kpsr 172200
Area forecast discussion
National Weather Service Phoenix Arizona
300 PM MST Thu Oct 17 2019
dry and sunny to mostly sunny conditions will persist across the
region through next week. High temperatures will remain above
normal today reaching the low to mid 90s as a dry weather system
also brings breezy conditions to the area. Additional dry weather
disturbances will cool the area down to near seasonal norms from
Friday through early next week. A warming trend can be expected
again by Tuesday next week as highs climb back into the low to mid
today's satellite imagery depicts mostly clear skies across the
region with just a few fair weather cu popping up over eastern parts
of the County Warning Area and Southeast Arizona. The upper air pattern shows an upper
level trough over southeast California associated with a dry weather system with
a southwesterly mid to upper jet Max extending from south-southwest to NE Arizona.
The dry and warm airmass that gave Phoenix a high of 98 degrees
yesterday is still in place ahead of the encroaching system and
promises to deliver another day of above normal highs mostly in
the mid 90s all across the region today. Tightened gradients with
today's dry system is producing strong gusty advisory level
westerly winds in SW Imperial County and other southeast California locales such
as Joshua Tree np. Wind gusts of 35 to 50 mph are expected into
tonight and tomorrow morning in some places with wind advisories
currently in effect. Patchy areas of blowing dust in southeast California can
also be expected with today's system as well as breezy conditions
spreading into SW and S-central Arizona this afternoon and evening.
Today's fast-moving dry weather system is the first in a series of
progressive fast-moving dry disturbance weather systems that will
move across the region through this weekend. Today's system, another
one tonight and early Friday, and a third one on Saturday afternoon
and Sunday night further to the north will drop regional
temperatures to near normal, in the mid to upper 80s, beginning
tomorrow and lasting through this weekend as well as on Monday. In
addition to some relief from the recent period of very warm above
normal temperatures expect lingering breezy winds tomorrow with
periodic breezy conditions lasting into the weekend, and
again/especially on Sunday afternoon.
By Monday afternoon high pressure will build in from the northwest
and bring a regional warmup with highs returning to the low to mid
90s by Tuesday and lasting well into next week.
Aviation...updated at 1759z
South-central Arizona including kphx, kiwa, ksdl, and kdvt:
An upper-level disturbance moving through the region will cause a
brief period of southerlies through 20z before west-SW winds gusting
up to 20 knots affect the Phoenix terminals this afternoon. Any
southerly Crosswinds that occur at kphx and kdvt over the next
couple of hours should generally stay below 10 knots with brief
gusts above that, with some variability in the winds expected from
southeast to S-SW before permanently switching to west-SW after 20z. Winds
should quickly subside below 10 knots after sunset with light and
variable or easterly winds returning late in the overnight and
morning hours. Westerly winds should return late Friday morning as
the base of the upper-level trough moves through the region.
Southeast California/southwest Arizona including kipl and kblh:
An upper-level disturbance moving through the region will cause
gusty winds up to 30 knots this afternoon and evening. Winds at
kipl will generally be out of the west which will enhance the
downsloping component to the flow, causing sustained winds around
20 knots with gusts to 30 knots. Winds will be a little lighter at
kblh where more southwesterly winds sustained at 15-20 knots will
gust to 25-30 knots. Winds will subside below 15-20 knots shortly
after sunset at kblh, but may remain elevated through the evening
hours at kipl before decreasing below 15-20 knots overnight.
Aviation discussion not updated for amended tafs.
Sunday through thursday:
a dry weather pattern with a developing warming trend is expected
during the period. Expect near normal high temperatures in the upper
80s through Monday to warm to above normal by Tuesday with highs
reaching the low to mid 90s. Breezy northerly to northwesterly winds
on Sunday with a dry weather system will begin in southeast California and spread
east into remaining areas by the late afternoon with gusts of 20-25
mph. Breezes will linger on Monday with mostly light winds expected
thereafter. Expect min relative humidity values to stay mainly in the 7-12 percent
range across the lower deserts. Fair overnight recoveries through
Wednesday night will fall to poor by Thursday night.
Spotter information statement...
spotters should follow Standard reporting procedures.
California...Wind Advisory until 3 am PDT Friday for caz562-566.
Wind Advisory until 10 am PDT Friday for caz560.