Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus65 kpsr 161159 
afdpsr

Area forecast discussion
National Weather Service Phoenix Arizona
459 am MST sun Jun 16 2019

Update...
updated 12z aviation discussion.

&&

Synopsis...
the weather pattern will remain warm and dry with mainly clear
skies through the next seven days. Temperatures will be near
seasonal normals, with the warmest readings coming Thursday and
Friday but still typical for mid June. Typical afternoon breezes
can be expected.

&&

Discussion...
as the first full day of the monsoon closed out, the weather
pattern was about what we would typically expect for mid June -
hot and dry. Early morning GOES-17 water vapor channels depict an
upper level ridge axis pushing into eastern Arizona with a modest
southwesterly flow behind. The low level water vapor also caught
the late (saturday) evening "sea breeze" emanating northward from
the northern edges of the Gulf of California. This feature,
fairly typical during the Summer, brought an enhanced
southwesterly flow to lower elevations and a brief up-tick in
surface dew points. Area 16.00z raobs showed very dry air in
place, with ktus observing a precipitable water of 0.4". Raobs further north
though did pick up enough moisture in the deep boundary layer to
yield some saturation at mid levels.

Today through Tuesday, weak upper level troughing will remain in
place with the low/trough axis centered over Southern California.
This will induce a slight increase in typical afternoon upslope
winds across the region and keep temperatures at or just slightly
below normal. A slight uptick in heights midweek will result in a
modest bump in afternoon temperatures. Heights will dip again late
in the week as a rather deep upper level low moves across the
northern tier states, suppressing heights even this far south.
Overall, heatrisk will remain in the low to moderate range through
the 7-day forecast period. With this flow pattern, no notable
intrusions of moisture are noted or expected. However, we will see
typical diurnal increases and decreases of surface moisture in
the Imperial Valley. The waters in the Gulf of California are
around 76-80f, and nearby shoreline surface obs show dew points in
the 70s. Not out of the question that we see those high dew
points move northward at some point into the Yuma and el centro
areas.

Regarding The Woodbury fire, adjusted current forecast to try and
account a bit better anticipated smoke trends. GOES-17 blue
visible (ch1) showed fairly decent coverage broadening out from
the fire Saturday evening, thus spread the smoke out a bit more
this morning. With a near full moon, the viirs night time visible
will be interesting to look at when it comes in. Some slight
adjustments may be made once that happens in the next hour or two.
Based on current GOES-17 shortwave infrared (ch7), fire activity
appears to be rather minimal this morning, thus will keep smoke
close to the fire during the late morning/early afternoon. Once
the typical increase in fire activity happens in the afternoon,
will spread more smoke outward and downwind (to the northeast).
Repeating this pattern into Monday as well, but this is all highly
dependent on suppression activity and fire behavior.

&&

Aviation...updated at 1159 UTC.

South-central Arizona including kphx, kiwa, ksdl, and kdvt; and
southeast California/southwest Arizona including kipl and kblh:

Diurnal 5-10 knot winds will generally continue at the Phoenix
terminals through the taf period with light and variable winds
possible from 16-19z before the west-SW switch. Although gusts are
not expected this afternoon, another moisture surge tonight may
briefly cause 15-20 knot gusts. Winds will quickly subside and
become easterly overnight, with scattered 25 kft cloud decks
moving in as another weak trough approaches from the west. Smoke
from The Woodbury fire may cause some slantwise visibility issues
this morning at kphx, but confidence of this occurring is low with
VFR conditions expected otherwise. Winds in southeast California
will favor a southerly headings with a period 20-25 knot gusts
this afternoon at kipl and kblh and a brief period of southwest
winds at kipl this evening.



Aviation discussion not updated for amended tafs.

&&

Fire weather...
Tuesday through saturday:

Typical mid June weather can be expected as the overall pattern
remains steady the next week. Afternoon temperatures will show a
slight upward trend, peaking just a handful of degrees above
normal Thursday and Friday. Afternoon humidity values will remain
very low. Overnight recovery will generally be poor, though will
be notably better in the Imperial Valley and higher elevations of
far eastern Gila County. Typical afternoon breezes can be
expected.

&&

Spotter information statement...
spotter activation is not expected.

&&

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

National Weather Service Glossary of Abbreviations