Area Forecast Discussion
Issued by NWS Flagstaff, AZ
FXUS65 KFGZ 181700
Area Forecast Discussion
National Weather Service Flagstaff AZ
959 AM MST THU AUG 18 2016
.SYNOPSIS...Thunderstorm chances will remain in the forecast for
the next seven days. Temperatures will generally be near normal
through the period.
The forecast for this morning was updated to add showers and
increase cloud cover across central AZ.
.PREV DISCUSSION /346 AM MST/... A weak flow pattern aloft will
allow for monsoonal moisture to linger over the region bringing
chances of showers and thunderstorms...mainly in the late morning
through afternoon time frame each day throughout the period. A
dispersed upper level low pressure system will start out over the
intermountain region of California and Nevada today giving Arizona
moist southerly flow responsible for shower and thunderstorm
activity again today. A weak disturbance in the flow has allowed
for some showers to remain active into the early morning
hours...however most of the activity is expected to remain in
Southern and Central Arizona.
A large scale trough will dip into the northern United States
along the eastern side of the Rocky Mountains, this will push the
low pressure system responsible for the southerly flow westward
and effectively limit broadscale support for the moist airmass by
Saturday...however weak forcing will still remain over the area
and convective activity will still be possible, although a little
more widespread and not as active as Thursday and Friday.
With the large scale trough pushing eastward early next week the
low off the California coast will begin to integrate into the
zonal flow and will allow for southwesterly winds to once again
develop over the region and enhance atmospheric moisture and
convective thunderstorm chances going into next work week.
Confidence out in the later half of the work week drops off as
some forecast solutions are calling for a continuation of the
monsoonal pattern, while others begin to transition into a drier
more zonal flow. Have kept conditions near seasonal values at this
time knowing that conditions may change either towards drier or
wetter weather by this time next week.
.AVIATION...For the 18Z package...Scattered showers and
thunderstorms will develop this afternoon...most numerous over the
higher terrain. Expect isolated MVFR/VFR conditions in the strongest
storms. SCT -SHRA will persist aft 02Z. Aviation discussion not
updated for TAF amendments.
PUBLIC...41 / Suk
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