Weather Service Report

FXUS65 KFGZ 272221

Area Forecast Discussion
National Weather Service Flagstaff AZ
321 PM MST Thu Jul 27 2017

.SYNOPSIS...Expect daily chance for showers and thunderstorms as
an active monsoon pattern remains in place across northern Arizona
into next week.


.DISCUSSION...So far today, scattered showers and thunderstorms
have formed over much of the Mogollon Rim, White Mountains and
high terrain in far northeast Arizona. Subsequent outflow
boundaries have produced some isolated storms in portions of
Yavapai County and the Little Colorado River valley. These storms
are slow movers, and the primary hazards have been lightning and 
heavy rain. The latest hi-res model guidance suggests showers may 
continue across eastern portions of the area well into the 
overnight hours.

On Friday, most model guidance suggests slightly higher boundary
layer moisture. In addition, an inverted trough is forecast to 
move into southern Navajo and Apache Counties. Forcing from this 
feature is expected to make eastern portions of the area the most 
active, and a favorable location for MCS development. Elsewhere, 
another round of scattered storms are expected, but an extensive 
mid and upper level cloud deck may limit instability. Flow around 
the inverted trough will cause storm mostion to switch to a more 
northerly direction, but will remain quite light - generally 10 
knots or less. Given deep layer shear values of 20 knots or less
and slow storm movement, flash flooding remains the primary 
hazard from Friday's storms.

Over the weekend, The inverted trough to the south will turn the 
flow aloft to the southeast over the weekend. This will advect in 
more moisture over the region keeping good chances for storms in
the forecast. Latest model guidance suggest this pattern may 
persist into early next week.


.AVIATION...For theFor the 18Z package...Scattered showers will develop in 
the afternoon and evening. Best chances are expected across the 
mountains of east-central AZ, with MVFR/IFR conditions possible in 
the stronger storms. Aviation discussion not updated for TAF 
amendments. 00Z package...Showers and storms will continue this 
evening. MVFR/IFR conditions possible in the stronger storms. 
Clearing skies will develop this evening with another round of 
showers and thunderstorms Friday afternoon. Aviation discussion 
not updated for TAF amendments.


.FIRE WEATHER...Slow moving thunderstorms will continue to develop 
and move across the area today, Friday afternoon and evening. Some 
flash flood potential exists due to the high rainfall rates and slow 
movement of the storms.

Saturday through Monday...Moisture is forecast to increase across 
Arizona with a greater chance for showers and storms expected across 
the fire district. 






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