Area Forecast Discussion
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FXUS65 KPSR 232121
Area Forecast Discussion
National Weather Service Phoenix AZ
222 PM MST Thu Feb 23 2017
Dry weather with below normal temperatures will continue through
Saturday. However, two fast moving weather disturbances are forecast
to move into the region Sunday and again Monday night. The weather
system Monday night will have better potential for spreading rain
showers across the region. Drier and eventually warmer weather will
return to the area by the middle of next week.
Tonight through Saturday...
In the wake of a dry cold front last night, a cooler airmass will
continue to settle over the region through Saturday. Under mostly
clear skies and much lower dewpoints, temperatures will be much
cooler than normal, but a little warmer on Saturday. Light winds.
Sunday through Tuesday...
A couple of Pacific storms are still forecast to move into the
region this period, generally one Sunday and another Monday night.
However, a very complex Rex Block pattern continues over the eastern
Pacific, so daily model run solutions for Sunday and Monday night
continue to waver slightly, with adjustments to timing, intensity
and precipitation amounts. For example, the European model is now
much wetter than the GFS for Monday night in south central AZ,
including Phoenix. And, what complicates precip forecasts in south
central AZ is the increasingly moist southern branch jet stream,
from just north of Hawaii, that is forecast to merge with the
northern branch jetstream over the area.
For now the Sunday system will be relatively dry, but a good chance
of showers will continue generally from the Colorado River Valley
eastward on Monday night.
Wednesday and Thursday...
Dry weather with near normal temperatures are forecast this period.
South-Central Arizona including KPHX, KIWA,and KSDL:
High-Res model output continues to show isolated-scattered
showers/thunderstorms developing over the eastern portions of the
Greater Phoenix area through about mid-morning today as the upper
low that has brought the moisture to the region moves off to the
south and east. However, confidence on any shower activity actually
affecting a particular terminal is not high enough at this time to
include anything more than VCSH in the TAFs. Cigs could briefly dip
as low as 8k feet in any showers that do develop, but should remain,
for the most part, aoa 10k feet. Cigs/shower chances to lift/end
this afternoon and evening as the upper low moves off well to the
east. Winds to remain easterly until late afternoon, then briefly
shift to light westerly to northwesterly during the late
afternoon/early evening hours before reverting back to easterly
direction during the mid-late evening hours.
Southeast California/Southwest Arizona including KIPL and KBLH:
High pressure building into the region to bring mainly clear skies
to both KIPL and KBLH through most of the taf period, with perhaps a
bit of high cirrus moving into the region late tonight. Winds to
remain mainly out of a westerly to northwesterly direction at KIPL
and out of a northerly direction at KBLH through the taf period,
with speeds mainly aob 12 kts.
Aviation Discussion not updated for amended TAFs.
Saturday through Wednesday...
Dry conditions, but increasing clouds are expected for most areas
through early Sunday as a mostly dry weather system passes by to
the north. A second weather system is likely for Monday into
Tuesday with better chances of wetting rains, especially across
the high terrain of Arizona. Below normal temperatures are
expected through the entire period. Breezy conditions early Sunday
and again on Monday are expected in most areas with breezy
conditions persisting down the Lower Colorado River each afternoon
through Wednesday. Humidities will start out dry on Saturday, but
improve through early next week with minimum readings as high 35
to 40% on Monday. Gradual drying thereafter will lead to afternoon
readings closer to 20% on Wednesday.
.SPOTTER INFORMATION STATEMENT...
Spotter reports will not be needed through the weekend.
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