Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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FXUS65 KFGZ 281646
AFDFGZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
946 AM MST TUE JUN 28 2016

.SYNOPSIS...Monsoon activity will be on the increase over the next
few days as a moist southerly flow develops across Arizona. Look
for showers and thunderstorms each day with the best potential for
heavy rain arriving on Thursday and Friday.

&&

.DISCUSSION...This morning`s sounding from near Flagstaff, AZ
reveals precipitable water is up a bit as compared to this time
yesterday. In addition, surface dew points are up a few degrees
at most places. With that said, forecast soundings indicate that a
mid-level stable layer may develop later today in the wake of
passing shortwave trough skirting northwestern Arizona. Will need
to monitor this feature as it would aid in suppressing convection
later this afternoon.

With that said, today`s storm motion will generally be from the
southeast to northwest. The high based nature of today`s storms
will make strong outflow winds in the 30 to 50 mph range the
primary threat, followed by brief/localized downpours under the
stronger cells.

In terms of forecast updates, made a couple short-term grid
updates to account for a line of showers over central Coconino
County. These showers are associated with the previously mentioned
shortwave trough, which is due to exit the region around noon or
so.

&&

.PREV DISCUSSION /241 AM MST/...For Wednesday through
Friday...The high center gradually shifts to a position over Texas
with southerly flow developing across Arizona. The southerly flow
pattern will be favorable for deep moisture over Northwest Mexico
and the Gulf of California to move northward. In addition, there
will be a good chance for a convective blow-up in Mexico (known as
a mesoscale convective complex) which could induce a Gulf of
California surge pushing additional moisture into the state. We`ll
be keeping and eye on Thursday and Friday because those two days
show the best potential for storms producing extremely rain.

From Saturday onward...The flow becomes more westerly with origins
from over the eastern Pacific Ocean. Under this regime look for a
bit of drying and stabilization with a downturn in thunderstorm
activity anticipated.

&&

.AVIATION...For the 18Z Package...An area of mainly light rain and
isolated thunderstorms will affect the KGCN TAF site and points NW
through 19z. Otherwise, expect sct-numrs shra/tsra and isold +tsra
from 19z-02z today. Coverage becmg isold aft 02z. The strongest
storms may produce mvfr conditions with heavy rain, small hail and
wind gusts to 45kts. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...An active monsoon pattern is now in place across the
district. This means daily shower and thunderstorm activity. Storm
motion will be from southeast to northwest today, then becoming
nearly stationary and terrain driven by Wednesday. Expect erratic
and gusty winds near showers and storms.

Thursday through Saturday...Expect active monsoon weather with
scattered showers and thunderstorms each day. Temperatures will be
right around seasonal averages.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

PUBLIC...RR/McCollum
AVIATION...Peterson
FIRE WEATHER...MCS


For Northern Arizona weather information visit
weather.gov/flagstaff


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