Flash Flood Warning 12, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
209 PM MST Mon Jul 27 2020

.SYNOPSIS...Scattered thunderstorms will continue to develop this
afternoon, and will develop again Tuesday afternoon, with the
best chances east of I-17 and Highway 89.

High pressure will then build over the desert southwest by
Wednesday and will bring much warmer temperatures and a downturn
in monsoon activity through the end of the week.

&&

.DISCUSSION...Scattered thunderstorms are currently developing
along the higher terrain of northern Arizona as of this writing.
The strongest storms are currently over the Kaibab Plateau and
near Navajo Mountain, where the deepest shear is located.
Thunderstorm activity should begin to wane later this afternoon
and evening with the loss of daytime heating.

By Tuesday, lingering moisture and instability should allow for
low-end thunderstorm chances during the afternoon hours across
the eastern Mogollon Rim into the White Mountains. Slight chances
for afternoon thunderstorms will also exist across the Black Mesa
and Chuska Mountains, with dry conditions expected elsewhere.

Wednesday through Saturday, expect mainly dry and warming
conditions through the period as high pressure builds over
Arizona. Record heat will be possible Friday. The current
excessive heat watch looks good, so will keep it going for now.

Sunday and Monday, medium range models begin to break down the
ridge a little bit allowing for some moisture and instability to
re-enter the region. This will allow for at least low-end chance
precipitation chances along the Mogollon Rim Sunday and Monday.

&&

.AVIATION...For the 00Z package... A drier air mass will move across
Arizona overnight and on Tuesday. Shower and thunderstorm activity
will come to an end overnight with development on Tuesday mainly
along and east of a Payson to Four Corners line. Light winds, except
gusty near any stronger storms. Aviation discussion not updated for
amendments.

&&

.FIRE WEATHER...A warming and drying trend will deliver a
significant decrease in shower and thunderstorm activity on Tuesday
and Wednesday. Storm activity Tuesday will be mainly limited to the
area east of a Payson to Four Corners line with even lower chances
on Wednesday. Expect light winds and increasing Haines Indices.

Thursday through Saturday...Expect abnormally hot and dry
conditions. Shower and thunderstorm activity is unlikely through
Friday with only a slight increase in the threat on Saturday.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...Excessive Heat Watch from Thursday morning through Saturday
evening FOR AZZ006-037-038.

&&

PUBLIC...TM
AVIATION...McCollum
FIRE WEATHER...McCollum

For Northern Arizona weather information visit
weather.gov/flagstaff

Special Weather Statement
National Weather Service Flagstaff AZ
343 PM MDT Mon Jul 27 2020

AZZ005-009-272215-
Marble and Glen Canyons-Northeast Plateaus and Mesas Hwy 264
Northward-
343 PM MDT Mon Jul 27 2020

...SIGNIFICANT WEATHER ADVISORY FOR COCONINO COUNTY NEAR PAGE
AND SOUTH END OF LAKE POWELL UNTIL 415 PM MDT/315 PM MST/...

At 341 PM MDT/241 PM MST/, Doppler radar was tracking a strong
thunderstorm near Antelope Canyon on State Route 98, or 7 miles
northeast of Page, moving north at 35 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Page, Big Five, Wahweap, Antelope Canyon, Antelope Creek Basin and
Lake Powell.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If on or near Lake Powell, get out of the water and move indoors or
inside a vehicle. Remember, lightning can strike out to 10 miles
from the parent thunderstorm. If you can hear thunder, you are close
enough to be struck by lightning. Move to safe shelter now! Do not
be caught on the water in a thunderstorm.

&&

LAT...LON 3685 11119 3687 11152 3700 11150 3700 11116
TIME...MOT...LOC 2141Z 188DEG 28KT 3695 11134

JJ