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fxus65 kpsr 112318 
afdpsr

Area forecast discussion
National Weather Service Phoenix Arizona
418 PM MST Wed Dec 11 2019

Update...
aviation section updated

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Synopsis...
high pressure under mostly clear skies will bring slightly warmer
daytime temperatures through Saturday as highs climb to around 70
degrees each day. A weak but mostly dry weather system for Sunday
into Monday should bring cooler temperatures into early next week
with readings closer to seasonal normals.

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Discussion...
thick high clouds have been pushed off to our east, as a weak
shortwave quickly moves across the eastern half of Arizona. High
pressure will continue to build into the region in the wake of
this shortwave and result in a warming trend through the first
half of the weekend, with highs in the low 70s forecast on Friday
and Saturday.

For the remainder of today, expect mostly clear skies during the
daylight hours with temperatures across the lower deserts rising
into the upper 60s. After sunset, another batch of high clouds
will move into the area from west to east, and remain in place
through much of the day tomorrow before clearer skies take over
Friday.

The second weather system will move across the region Saturday
night through Sunday and bring slightly elevated rain chances back
to the forecast, especially across the western portions of jtnp
Saturday night/Sunday morning and across southern Gila County
Sunday afternoon. Still looks unlikely that the lower deserts
will see any rain from this system, but a light shower and/or
virga cannot be ruled out and gefs plumes continue to indicate
that Sky Harbor could see up to a hundredth of an inch of rain
Sunday. Impacts with this system should be minimal and the most
noticeable outcome will be the lowering of temperatures Sunday
and even more so on Monday. It looks like high pressure will once
again build into the region in the wake of this weather system,
resulting in a slight warming trend as we head into the middle of
next week.

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Aviation...updated at 2320z.

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

No aviation concerns through the taf period. Mostly clear skies
will transition to scattered coverage as another batch of thicker
high clouds aoa 20 kft moves into the region overnight. Wind
speeds will be very light and directions will favor typical
diurnal tendencies but with long periods when the direction will
be variable.

Southeast California/southwest Arizona including kipl and kblh:

No aviation concerns through the taf period. Mostly clear skies
will transition to scattered-to-broken coverage as another batch
of thicker high clouds aoa 20 kft moves into the region overnight.
Look for very light winds over the next 24 hours at kipl and kblh.



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Fire weather...
Friday through tuesday: dry conditions under increasing high
pressure aloft will prevail through Saturday before a weak low
pressure system affects the region Sunday into Monday. Moisture
levels with the late weekend system should be rather dry, hindering
precipitation chances although there is a slight chance of rain or
high elevation snow Sunday afternoon and overnight Sunday night over
high terrain east of Phoenix. Above normal high temperatures Friday
and Saturday give way to somewhat cooler conditions Sunday into
early next week as highs fall slightly below normal by Monday.
Minimum humidity levels initially should stick around 25-35% much of
the period, potentially lowering slightly into early next week.
Winds will stay light through Saturday before some breezy conditions
move in for Sunday and Monday. Light winds return again Tuesday as
weak high pressure aloft returns to the area.

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

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

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