Area Forecast Discussion
Issued by NWS Flagstaff, AZ

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS65 KFGZ 271643

Area Forecast Discussion
National Weather Service Flagstaff AZ
943 AM MST Thu Jul 27 2017

.SYNOPSIS...A significant decrease in storm coverage will continue
today and Friday. A return to more active monsoon conditions is
expected this weekend and into early next week.


.DISCUSSION...Observations reveal dew points in the 50`s to low
60`s across northern Arizona this morning, with precipitable water
of 0.91 inches recorded in the upper-air sounding from near
Flagstaff. Modified and forecast soundings indicate 300 to 600
J/Kg of mixed layer cape across much of the area today. Relatively
light winds associated with an upper-level ridge will result in
weak wind shear, with values ranging from 5 knots in Yavapai and
northern Gila Counties to 20 knots along the Arizona/Utah border.
0-6 km mean wind is expected to be from the southwest at 5 knots
or less.

With decent moisture, climatologically weak to moderate
instability and light steering flow, isolated to scattered showers
and thunderstorms are expected across the area. The primary
threat from today`s storms look to be flash flooding, sub-severe
wind gusts and frequent lightning.


.PREV DISCUSSION /348 AM MST/...Some mid and high level clouds are
streaming northward across northern Arizona this morning.
Otherwise, the weather is quiet. Thursday is expected to be
another below normal monsoon day in terms of convective activity.
However, we are expecting a bit more shower and thunderstorm
development than yesterday. Storms will develop first across the
higher terrain with the steering flow generally taking storms to
the north and east. The area with the best chance to see showers
and storms today will be in the eastern portion of the area
including the White Mountains. Similar conditions are anticipated
on Friday with scattered showers and thunderstorms, favored over
the eastern portion of the area.

The presence of an 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 with an increase in shower and
thunderstorm activity expected. Latest model guidance suggest this
pattern may persist into early next week.


.AVIATION...For 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


.FIRE WEATHER...Typical late morning to early evening thunderstorms
are expected today and Friday, though overall coverage may be a bit
below monsoonal normals.

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






For Northern Arizona weather information visit is the U.S. government's official web portal to all federal, state and local government web resources and services.