Scientific Forecaster Discussion
fxus65 kfgz 222209
Area forecast discussion
National Weather Service Flagstaff Arizona
309 PM MST Thu Jun 22 2017
Synopsis...hot conditions will persist through the weekend.
Temperatures will begin to slowly trend downward over the weekend
and into next week. The chance for afternoon showers and
thunderstorms will increase again Sunday into early next week
mainly for Apache and southern Navajo counties.
Discussion...prominent high pressure is keeping the southwest hot
and dry and will continue to do so through the upcoming weekend. A
weak trough passing to the north through Utah has resulted in
breezy winds this afternoon and we've seen several areas gusting
from 30 to near 40 miles per hour. These winds will persist through around
sunset before decreasing. In addition, a few instability showers
managed to form over the White Mountains and have updated the
forecast to reflect these. Little if any rain is expected, with
gusty winds the main concern.
The excessive heat warnings and advisories will expire this
evening for most areas. Regardless, it will remain hot over the
weekend and those with outdoor plans should prepare for unusually
hot temperatures during the daytime. The exception is the lowest
elevation areas of northern Arizona that will continue to see
dangerously hot temperatures over the weekend and heat warnings
remain in effect for these areas through Sunday. Outdoor
activities in these areas should be avoided if possible during the
heat of the day.
The ridge of high pressure makes very little movement next week,
but it looks like some moisture will move in from the southeast
bringing a return of thunderstorm chances to mainly Apache and
Navajo counties early in the week. It looks like by late in the
week, any increased moisture will be fighting with drier westerly
flow developing over the region. At this time, it doesn't look
like any significant monsoon moisture through next week but things
can change rather quickly this time of year. Stay tuned.
Aviation...for the 00z package...VFR conditions are expected for
the 24 hour forecast period. SW-west winds at 15-25kts will subside
this evening and will remain quiet on Friday. Areas of smoke from
area wildfires may affect flight paths through the period. Aviation
discussion not updated for taf amendments.
Fire weather...gusty west through southwest winds will decrease
this evening. Warm and mainly dry conditons will continue Friday and
Saturday, with a very slight chance of high-based convection near
the White Mountains. Winds will be light and generally southwesterly
on both Friday and Saturday.
Sunday through Tuesday...despite a small cooling trend, above normal
temperatures will continue. Winds will remain generally light from
the west through southwest. Increasing mid-level moisture will bring
a modest increase in high-based shower and thunderstorm coverage to
the eastern and central zones. The best chance remains over the
Fgz watches/warnings/advisories...heat advisory until 8 PM MST
this evening for azz004-007>017-039-040.
Excessive heat warning until 8 PM MST this evening for azz018-
Excessive heat warning until 9 PM MST Sunday for azz005-006-037.