Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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FXUS65 KFGZ 171537

Area Forecast Discussion
National Weather Service Flagstaff AZ
837 AM MST SUN JUL 17 2016

.SYNOPSIS...Monsoon moisture will return over the coming week with
the potential for showers and thunderstorms each day. Erratic
gusty winds will be the main threats today.


.DISCUSSION...Monsoon moisture will continue to surge northward
today as we transition from a dry to wet Monsoon weather pattern.
One of the threats today will be from erratic gusty winds near
thunderstorms and showers. The best chances for shower activity
today will be along and south of the Mogollon Rim region. The
boundary between the dry and moist airmass this morning, as shown
by precipitable water is over Munds Park 10 miles south of


.PREV DISCUSSION /302 AM MST/...High pressure aloft is in the
process of shifting to a position over the central United States.
Models show the high center then remaining in place into next
weekend. The main impact of this shift will be the development of
southerly flow with an increase in moisture and monsoon activity.

For Today...A large organized thunderstorms complex failed to form
over northwest Mexico over the past 24 hours with no significant
push of low level moisture anticipated. What northern Arizona will
see is an increase in mid to upper level moisture, the remnants of
weaker storms that have been forming over Mexico. The moisture
aloft and a lack of low level moisture will combine for a weakly
unstable environment. The best chance for showers and storms will
be over the eastern Mogollon Rim and White Mountains region where
the deepest moisture resides. Elsewhere, only a slight chance of
showers and storms. Cloud bases will be relatively high so expect
gusty winds of 30 to 45 mph in the vicinity of any storms that do

The remainder of the week...Moisture will continue to creep in
from the south but the amount will be dependent on the level of
thunderstorm activity over northwest Mexico. At this time, the
overall pattern does not favor the development of a large
thunderstorm complex over Mexico which is critical for significant
moisture surges. In addition, models are consistently showing mid
to upper level cloudiness day and night early in the week which
normally puts a damper on instability and convective activity.
Later in the week, intrusions of drier low level air from the west
will become an issue. The net result will be generally low grade
monsoon activity with the best chance for wetter storms extending
from the White Mountains and eastern Mogollon Rim to the Chuska


.AVIATION...For the 18Z package...Expect VFR conditions over the
next 24 hours for most of the area. After 17z through the the
afternoon hours scattered to numerous showers and thunderstorms in
and around the White mtns with brief intrusions into MVFR conditions
near storms. Elsewhere scattered high based storms are possible with
wind gusts to 40kt.

Surface winds SW 15-25 kts this afternoon. Aviation discussion not
updated for TAF amendments.


.FIRE WEATHER...Monsoon moisture is slowly increasing
from south to north this morning, the leading edge along a line from
Chinle to Valle at 3 am. North of this line the dry southwest flow
experienced by all the past several days is weakening. For this
afternoon, the White mountains area should see scattered
thunderstorms and the best chance for wetting rain amounts.
Elsewhere only isolated high based storm coverage is forecast,
though afternoon cloud cover should be greater than the past several
days. Gusty outflow winds are probable from any storms or showers
this afternoon and evening.

Monday through Thursday...Moisture to slowly increase across
northern Arizona, with shower and thunderstorm chances each day.
Winds may become erratic and gusty near thunderstorms.






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