Scientific Forecaster Discussion
fxus65 kfgz 172201
Area forecast discussion
National Weather Service Flagstaff Arizona
301 PM MST sun may 17 2020
Synopsis...a strong, late season low pressure system will bring
windy conditions to Arizona Sunday through Tuesday. The strongest
winds will likely be on Tuesday. A brief cool down will also
occur on Tuesday and Wednesday, before warmer weather and less
wind develops Wednesday and Thursday. Windy weather is expected
again late in the week and into next weekend.
Discussion...a strong area of low pressure off the West Coast
began to bring increasing southwest winds over northern Arizona
This area of low pressure will move southeast toward Arizona
through Tuesday with increasing southwest winds. A dry cold front
will then move across the state Tuesday night.
Expect southwest winds ranging from 10 to 20 mph, with gusts
around 30 mph this afternoon into this evening.
Expect southwest winds ranging from 15 to 25 mph, with gusts
around 45 mph by Monday afternoon.
Expect southwest winds ranging from 20 to 30 mph, with gusts from
35 to 50 mph by Tuesday afternoon.
A dry boundary layer Monday will also contribute to areas of critical
fire weather conditons. A red flag warning has been issued for
portions of northern Arizona on Monday. Relative humidity values will likely be
higher on Tuesday over much of western Coconino County due to the
arrival of colder air. However, dry air may remain over eastern
portions of our area where a Fire Weather Watch is in effect for
The wind will much lighter on Wednesday with a slow warming trend
through Thursday. Another trough enters the Great Basin late in
the week and next weekend, bringing more wind and some cooling.
Aviation...for the 00z package...VFR conditions will prevail for
the next 24 hours. Breezy southwest winds at 10-20g20-30 kts this
afternoon will decrease to around 5-10 kts after 02z. Winds will
begin to increase again after 16z. Daytime winds on Monday will be
around 12-22g25-38 kts. Expect periods of low level wind shear
tonight after 03z at high country terminals. Aviation discussion not
updated for taf amendments.
Fire weather...a dry cold front will produce low relative
humidity values and strong southwesterly winds. A red flag warning
has been issued from 11 am - 8 PM MST Monday for critical fire
weather conditions. Cooler temperatures in western zones on Tuesday
will increase relative humidity values for some high terrain areas.
Although, continued strong winds and low relative humidity in
eastern Arizona will create near-critical to critical fire weather
conditions. A Fire Weather Watch has been issued for northeastern
Arizona on Tuesday from 11 am - 7 PM MST.
Wednesday through Friday...winds will be much lighter Wednesday
with cooler temperatures. Temperatures will warm slightly each day
through Friday with continued dry conditions.
Fgz watches/warnings/advisories...red flag warning from 11 am to 8 PM
MST Monday for azz104-106- 107-109-112-113-139-140.
Fire Weather Watch from Tuesday morning through Tuesday evening
Wind Advisory from 1 PM to 5 PM MST Monday for azz007-009-012-