Flash Flood Warning 218, NWS Flagstaff, AZ

Area Forecast Discussion
National Weather Service Flagstaff AZ
249 AM MST Mon Aug 15 2022

.SYNOPSIS...An active monsoon pattern will continue across
northern and central Arizona through the upcoming week. Heavy
rainfall leading to flash flooding will continue to remain a
threat.

&&

.DISCUSSION...An active monsoon pattern will continue through the
next week across the forecast area. Showers and isolated
thunderstorms continue to develop across western Yavapai county
along the southern edge of a decaying MCV.

Today looks to be like a fairly active day and with the very wet
conditions in place due to the rain we have seen over the past week,
flash flooding remains a big concern. PWATs remain around 1-1.25"
and some of the hi-res guidance shows decent rainfall across parts
of the area. However, the aforementioned decaying MCV has been
crossing the region through the early morning hours and we have had
considerable cloud cover across the state. This feature is pushing
off towards the north-northwest but there is concern that the cloud
cover will not erode early enough to allow for widespread convection
to develop. Will we have enough energy to allow for convection after
such an active day yesterday? Models show that instability will
increase as we head into the afternoon with perhaps a later start
time for storms than the past several days. So, we do expect
storms to develop but just how widespread they will be is not as
clear.

With all that said, thoughts were given to having another Flash
Flood Watch today. Uncertainty remains as to where the greatest
threat lies and in the end, we opted to forgo the watch due to
lower confidence and just continue to message the flash flood
threat, which will exist for much of the week. As a reminder, be
sure to avoid flood prone areas (recent burn scars, slot canyons,
and low- water crossings). If you come across flooded
roadways...turn around, don't drown.

As we head into Tuesday and Wednesday, we may start to see a
slightly less active monsoon across the desert southwest. This
doesn't mean that we will be free of storms but just that there may
be less coverage. Any storms that do develop will still have heavy
rainfall and flash flooding will remain a concern.

Things start to turn more active as we head into Thursday and
through the weekend. A system will move from the Gulf of Mexico
across northern Mexico and into Sonora over the next several days,
which should start to bring more moisture into Arizona once again.
Another uptick in convection is expected across the region with the
flash flood threat continuing.

&&

AVIATION...For the 12Z TAF package...Light to calm winds under
scattered high clouds with a few isolated rain showers lingering
this morning. Localized patchy fog and mist will be possible until
just after sunrise. Showers and storms are forecast to begin by 19z
over high terrain, becoming more widespread from 20Z through 03Z.
VFR conditions through the day as surface winds remain light away
from storms. Aviation discussion not updated for TAF amendments.

&&

FIRE WEATHER...Widespread showers and storms in the afternoon today
and Tuesday with some activity lasting into the evening. Expect
gusty, erratic winds near thunderstorms. Flash flooding remains
possible. Light winds with minimal fluctuation in the forecast.

Wednesday through Friday...Monsoon moisture will remain in place
with showers and thunderstorm each day. Slightly less coverage
Wednesday before widespread activity returns to end the week.

&&

&&

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

&&

PUBLIC...Meola
AVIATION...JM
FIRE WEATHER...JM

For Northern Arizona weather information visit
weather.gov/flagstaff