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fxus65 kpsr 190202 aaa 
afdpsr

Area forecast discussion
National Weather Service Phoenix Arizona
702 PM MST Fri Oct 18 2019

Updated 00z aviation discussion.

Synopsis...
dry and generally sunny conditions will persist across
the region through next week. A passing low pressure system and cold
front will drop temperatures today close to seasonal norms with
highs reaching the mid to upper 80s across the area. There will
also be lingering breezy conditions especially from southeast
California to the deserts west of Phoenix. More dry weather
disturbances later this weekend will help keep temperatures near
seasonal norms through early next week. A warmup can be expected
again by Tuesday next week as highs climb back into the low to mid
90s.

&&

Discussion...
an upper level open wave trough axis associated with a very
progressive low pressure system and cold front had already moved
over far east Arizona and nm border area by the late morning as it begins
to exit the region. This system managed to trigger an area of
small showers and isolated thunderstorms this morning in the
higher terrain well east of Phoenix and northeast of Tucson where
where sufficient bl moisture that had been drawn up in advance of
the system was encountered. The shower/storm activity had largely
tapered off and moved east by late morning and will continued to
do so into the early afternoon. This system is also producing
lingering breezy to occasionally very breezy northwesterly winds
especially from southeast California to SW Arizona and the deserts west of Phoenix, as
well as high terrain areas through late today. The cold air with
this system had resulted in early afternoon temperatures that were
running 8 to 13 degrees lower than yesterday at the same time. As
a result expect near to slightly below normal highs today in the
mid to upper 80s.

This morning's dry weather system was the second in a series of
progressive fast-moving dry disturbance weather systems that
continue to move across the region through this weekend. The next
one is a very weak disturbance that will move through tonight and
Saturday. A fourth one then moves through the region on Saturday
night and Sunday. Associated with a stronger system skirting by to
the north this system will feature another cold front with a
reinforcing shot of cold air advection into the region. As a result the region will
continue to enjoy near normal highs in the mid to upper 80s through
Monday under sunny to mostly sunny skies. This "fourth" system will
also bring breezy northerly winds moving into southeast California and SW Arizona for
Sunday.

By Monday evening high pressure will begin to build in from the
northwest and bring a regional warmup with highs returning to the
low to mid 90s by Tuesday and then settling into the low 90s well
into next week. By Thursday operational models and ensembles
indicate a weak, dry cold front diving into the region from the
northwest resulting in another round of breezy northerly winds
spreading from west to east across the region. However, there is
still significant model spread and uncertainty on how much cold
air this system may bring. But for now expect highs cooling to
the mid to upper 80s across the region again by Friday.

&&

Aviation...updated at 0202z

South-central Arizona including kphx, kiwa, ksdl, and kdvt:

No significant aviation weather concerns are expected through
Saturday as high pressure aloft and weak sfc pressure gradients keep
skies mainly clear and allow winds to primarily follow typical diurnal
trends through the taf period. Wind speeds to remain mainly aob 10
kts.

Southeast California/southwest Arizona including kipl and kblh:

No significant aviation weather concerns are expected through
Saturday as high pressure aloft and weak sfc pressure gradients keep
skies mainly clear and allow winds to primarily remain westerly to
northwesterly through the taf period. Wind speeds to remain mainly
aob 10 kts.

Aviation discussion not updated for amended tafs.

&&

Fire weather...
Monday through friday:
continued dry conditions with an early period warmup can be
expected through the period. A weak, dry weather system is also
expected to move across the region beginning Thursday. Near normal
highs in the upper 80s on Monday will warm to above normal by
Tuesday with highs reaching the low to mid 90s before settling in
the low 90s for the remainder of the week. Northerly breezes will
linger on Monday with mostly light winds expected through
Wednesday. Then expect breezy northerly to northeasterly winds on
Friday after another weak, dry weather system with gusts of 20-25
mph. Expect min relative humidity values to stay mainly in the 7-12 percent
range across the lower deserts. Mostly fair overnight recoveries
through Wednesday night will fall to mostly poor by Thursday
night.

&&

Spotter information statement...
spotters should follow Standard reporting procedures.

&&

Psr watches/warnings/advisories...
Arizona...none.
California...none.
&&

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