Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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FXUS65 KFGZ 291018

Area Forecast Discussion
National Weather Service Flagstaff AZ
318 AM MST Mon May 29 2017

.SYNOPSIS...An increase in moisture will result in a chance of
afternoon showers and thunderstorms over the mountains of eastern
Arizona today into Wednesday with just a slight chance elsewhere.
A more stable air mass will move over the state starting Thursday
with the threat for thunderstorms generally ending. Otherwise,
seasonable temperatures will continue with some increase in
afternoon winds on Wednesday and Thursday.


.DISCUSSION...High pressure will continue to move across the southwest
United States and Arizona into Tuesday with weak troughing then
becoming more dominant toward the end of the week. The troughing
will help to strengthen southwest flow aloft on Wednesday and
Thursday with gusty afternoon winds developing both days.
Otherwise, temperatures will continue to hover around seasonable

More importantly, a push of moisture from New Mexico associated
with a very weak boundary/front will enhance the chances for
afternoon showers and thunderstorms today, primarily over the
mountains of eastern Arizona. Moisture will continue to ebb into
Arizona on Tuesday and Wednesday primarily from thunderstorm
outflow boundaries in the vicinity of the Arizona/New Mexico
border and to some degree low-level flow from over the Gulf of
California. Generally, just enough moisture to support a slight
chance of high based showers and storms area wide. The deepest
moisture will be that which moves in from New Mexico. As a result,
the best chance for decent rainfall accumulations will be
over the White Mountains region of eastern Arizona. Troughing
that will begin to develop over Arizona from late Wednesday into
Thursday will introduce a warmer air mass in the mid to upper
levels. Precipitable water values don`t drop off appreciably but
the warm air aloft looks to stabilize the atmosphere over Arizona
with the thunderstorm threat mostly ending heading into the

Nothing unusual about any of this. Very typical for the pre-
monsoon period.


.AVIATION...For the 12Z package...VFR conditions will continue over
northern Arizona for the next 24 hours. Moisture increasing from the
southeast will bring isolated -SHRA/-TSRA south of a KPAN-KRQE line
18-02Z. Aviation discussion not updated for TAF amendments.


.FIRE WEATHER...Moisture increasing from the southeast will bring
isolated showers and thunderstorms south of a Payson-Window Rock
line this afternoon and evening.  On Tuesday, chances for showers
and thunderstorms will spread northwest--mainly south of a Prescott-
Page line. Strong outflow winds are possible in the vicinity of
storms, otherwise winds will be light.

Wednesday through Friday...Expect a cooling trend and a slight
chance for showers and thunderstorms on Wednesday and Thursday.






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