Scientific Forecaster Discussion
fxus65 kfgz 140427
Area forecast discussion
National Weather Service Flagstaff Arizona
927 PM MST Wed Dec 13 2017
Synopsis...a series of weather disturbances will brush northern
Arizona over the coming days. A cold front moving through Thursday
will bring breezy and colder weather. For Friday, temperatures
will warm some before yet another cold front Ushers in windy and
colder weather later on Saturday through Monday.
Update...at 915 PM, an area of mid-level clouds was moving into
northeastern Arizona, ahead of a trough diving south through Utah.
There are some light radar echoes developing across southern Utah
and far northern Arizona. While the vast majority of any precip is
likely to evaporate before reaching the ground, we threw in a
slight chance of a sprinkle or flurry over portions of the Black
Mesa and chuska mtns overnight. Otherwise, the forecast for gusty
northeast wind and colder temperatures is still on track for
Previous discussion /348 PM MST/...a trough of low pressure will move
across the western US Thursday bringing a dry cold frontal
boundary across northern Arizona. This frontal boundary passage
will bring a return of gusty northeast winds. Winds will remain
gusty into Thursday evening along and south of the Mogollon Rim. A
few areas could see some advisory level gusts briefly. High
temperatures will cool to near or slightly above normal for
Friday through Sunday...by Friday, calmer winds and weather return
as a ridge of high pressure builds back across the area into
Saturday. Temperatures will cool slightly into Saturday hovering
around 5-10 degrees above normal for most areas. By Sunday, a
deeper trough of low pressure will move south over the area with
the passage of another cold frontal boundary and a return of
breezy conditions. Temperatures will cool noticeably to around or
slightly below normal values for Sunday.
Model trends have been to indicate the increased possibility of
precipitation across southern Coconino, Apache, and Navajo
counties on Sunday. As a result, increased pops to include slight
chance for showers and snow showers through the day Sunday.
Models are still somewhat inconsistent on amounts at this point so
we will continue to watch this in the coming days.
Monday through Thursday...after the passage of the Sunday system,
a return to more benign weather as ridging builds back in from
the west. This will bring a gradual warm up to above normal
temperatures around 10 degrees above normal by Wednesday.
Aviation...for the 06z package...VFR conditions expected over the
next 24 hours. A fast moving trough will brush The Four Corners area
late tonight and through the day Thursday. Localized ceilings in the 5-
7kft agl range are possible east of a kov7-ksjn through around 00z.
Surface winds variable to 10 knots through 12z...then becoming northeast
and increasing. Winds along and south of the Mogollon Rim/White
Mountains could become NE 20g30kt or higher Thursday afternoon and
evening. Aviation discussion not updated for taf amendments.
Fire weather...a cold front will sweep southward through northern
Arizona on Thursday. Strong northeast winds will develop Thursday
afternoon and continue overnight across areas along and south of the
Mogollon Rim. Northeast winds are expected to diminish on Friday.
Saturday through Monday... another dry front will move through from
north to south over the weekend. Cooler temperatures are possible,
especially across northeast Arizona. A few showers are possible
south and east of Clints Well. Clear weather should return on