Scientific Forecaster Discussion
fxus65 kabq 170008 aaa
Area forecast discussion...updated
National Weather Service Albuquerque nm
508 PM MST Sat Dec 16 2017
18z taf cycle
lowering of VFR cigs is forecast tonight as an upper level low
approaches from northern baja. Rain and mountain snow from this
system will begin across southwest nm after 12z Sunday, spreading
north and northeast to near I-40 by 21z Sunday. Majority of taf sites
will remain precipitation-free but cannot rule out a stray shower or
two at/near kgup, kaeg, kabq and krow Sunday afternoon. South of
I-40, sct-num rain and mountain snow showers are expected btwn 12z
sun and 00z Mon with Mt obscurations, MVFR/IFR cigs and vsbys likely.
Previous discussion...308 PM MST Sat Dec 16 2017...
clouds will continue to thicken tonight ahead of a low pressure
system organizing over Southern California. Rain and snow showers
will develop over the high terrain of southern New Mexico Sunday
morning then expand northward toward the Interstate 40 corridor
through Sunday night. Snowfall totals of 2 to 5 inches are expected
above 7000 feet within Catron and Lincoln counties. A trace to one
inch of snow is possible in a few other areas as low as 5,000 feet by
Monday morning. Rain and snow showers will linger Monday and Monday
night around central and southeastern New Mexico before clearing
develops Tuesday. Temperatures will warm back above normal Tuesday
and Wednesday before a significant change to much colder weather
the latest forecast guidance improved confidence on the evolution of
the upcoming storm system through Monday morning. A Winter Weather
Advisory will be issued for the southwest mts and the sacs/capitans
of Lincoln County. High temps were also lowered for Sunday with cold
advection, thick cloud cover, and wet-bulb effects in place.
Water vapor imagery shows the center of the upper low just west of
San Diego and a tap of mid/upper level moisture streaming northward
into Arizona. Model guidance is in good agreement on the placement
of the 500 mb low center over Southeast Arizona thru 12z Monday, however the
details of the quantitative precipitation forecast pattern are still somewhat in question. The first
impulse of rain/snow will develop over Southeast Arizona tonight as a 95
kt subtropical jet ejects northeast ahead of the main low center.
Precip then spreads into the southwest mts and higher terrain of
Socorro and Lincoln counties thru Sunday afternoon. The focus for
snowfall accums will be near or above 7,000 feet during the daytime
period. It is Sunday night when guidance diverges on how rain/snow
evolves while moving north toward the I-40 corridor. The Storm Prediction Center-WRF and
GFS indicate deformation increasing along the northern/western edge
of the upper low as it shears and fills eastward Monday morning. For
now, raised pops slightly and expanded northward during this period.
It would not be surprising to see snow showers around the abq Metro
area Monday morning.
Most guidance then shows the upper wave filling and moving eastward
into West Texas thru Tuesday. However, the 15z sref and 12z Canadian
indicate the system lingering, or even spreading more qpf, across
southeast portions of the area into Monday night and Tuesday. As a
result, raised pops slightly and lowered temps a few degrees during
this period to reflect potential for a more slow departure.
Temps will trend above normal Wednesday as upper level flow shifts
more zonal. Downslope flow over eastern nm will warm temps into the
mid 60s. A major change to much colder weather is still advertised
from extended guidance with a high amplitude pattern beginning
moisture advection ahead of an approaching upper low will result in
improved humidity through Monday, especially across southern
portions of the area closer to the track of the low center. Chances
for wetting precipitation will be on the uptrend Sunday into Sunday
night and will favor the southern higher terrain. Look for vent
rates to remain a mix of poor to fair through Monday.
A warming trend is in play going into midweek, with daytime
temperatures back above normal areawide by Wednesday. Vent rates
will continue to be poor to fair on Tuesday in the wake of the
departing upper low, but will improve significantly by Thursday as a
potent upper level low and a strong backdoor cold front impact the
state. Vent rates will take a dip and be mostly poor by Friday
behind the cold front. High forecast confidence on a significant
drop in temperatures late Thursday through the Holiday weekend, but
lower forecast confidence on wetting precipitation potential due to
significant differences in the 12z medium range model solutions
with regard to the progression of thursday's upper level low.
Winter Weather Advisory from 6 am Sunday to 11 am MST Monday for
the following zones... nmz508.
Winter Weather Advisory from noon Sunday to 11 am MST Monday for
the following zones... nmz526.