Scientific Forecaster Discussion
fxus65 kfgz 211125
Area forecast discussion
National Weather Service Flagstaff Arizona
425 am MST Mon Oct 21 2019
Synopsis...the start of the work week will be cool this morning
with warming temperatures through Wednesday. Another dry cold
front will cool temperatures again Thursday. Northwesterly to
northeasterly surface winds will continue through the end of the
Discussion...the longwave pattern with ridging off the Pacific
coast and troughing over the plains states will keep northern
Arizona in a northwesterly flow through the coming week. Some
scattered high clouds are spilling over the ridge and moving
southeast out of Nevada into the area. They will have little
effect on the morning low temperatures, as many areas have already
cooled to their low ahead of the clouds. The cold dry air over
The Four Corners area will modify today under mostly clear skies.
Look for a warming trend through Wednesday with the ridge building
in from the west. A shortwave trough will pass to the northeast
Thursday morning returning cooler temperatures briefly to the
northern Arizona, especially in The Four Corners area.
Temperatures will warm again going into the weekend with the high
pressure continuing to build in from the west. Models somewhat
agree on a deep cold core low moving into the Pacific northwest
this weekend bringing a possible change to the longwave weather
pattern, but timing, location and impacts from this system vary
widely among the several models. At this time confidence is low on
what changes this system may bring to northern Arizona other than
the typical stronger southwest winds Sunday afternoon and likely
cooler temperatures going into next week.
Aviation...for the 12z package...expect VFR conditions and mostly
clear skies through the taf period. Sfc winds becmg NW-ne5-15g20kts
from 17z-01z. Aviation discussion not updated for taf amendments.
Fire weather...fair, dry and warmer conditions are expected Monday
and Tuesday, with generally light northwest through northeast winds.
Wednesday through Friday...warm weather continues Wednesday, with
light winds. Another dry cold front will bring some cooling to the
district Thursday and Friday, along with increasing northerly winds.
Very dry surface conditions will continue.