Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Albuquerque nm
500 am MST Thursday Dec 12 2013
12z taf cycle
rain and high terrain snow will move into the area from the south
today as an upper level low pressure system approaches from the
SW. Tonight...models depict the initial wave of precipitation
shifting east of New Mexico with more activity in the form of
mainly snow shifting into central and western areas from the west
with the weakening upper level storm system and a Pacific cold
front. A few inches of snow accumulation will be possible in the
western mountains overnight with lighter amounts at lower
elevations along and west of the central Montana chain. MVFR conditions
should be common with the precipitation as it starts today...then
periods of IFR conditions are expected across much of
western...central and southeast portions of the forecast area
tonight. Models suggest fog and low clouds could produce LIFR
conditions late tonight in Roswell. Flight category restrictions
are expected to linger in many locations well into Friday as the
Baja California system gradually exits and another weaker upper trough moves
in from the northwest keeping showers active. Northwest winds will also
strengthen Friday...especially east of the central mts.
Previous discussion...303 am MST Thursday Dec 12 2013...
with the exception of a brief bout of rain/snow today/tonight across
central and western nm the overall pattern will remain relatively
tranquil through the next 7 days. Currently a deep fetch of subtropical
moisture surging NE out of the equatorial Pacific will slide over
southern nm ahead of a weak upper low over soca. The latest hrrr
and RUC solutions slow down timing of precipitation for today so lowered
probability of precipitation substantially this morning. The wpc probabilistic quantitative precipitation forecast (pqpf)
indicates the best shot for measurable in the southeast will be noon to
early evening. 700mb warm advection with this fetch will raise
snow levels to above 9000 feet. Temperatures expected to warm above freezing
by the time precipitation arrives over the area thus snow accums will be
Made some notable changes to pop distribution for central/western
nm late today and tonight. Trended toward sref/gefs and wpc pqpf...
which focuses greatest chances along the continue dvd tonight then the
central Montana chain/abq metropolitan area early Friday. Cold advection with
the upper cold core will allow for rain to snow...however quantitative precipitation forecast is
light...so expect highest snow amounts over highest terrain. Will
issue Special Weather Statement again since confidence on timing/location of cold air
and precipitation is too low for any advisories. Accums look marginal too
even if best precipitation coincides with cold air and instability.
After this quick hit of rain/snow colder temperatures will again slide over
the state this weekend with a series of weak waves in northwest flow.
Otherwise it will remain quiet through next week as temperatures moderate back
near to slightly above normal. Periodic gusty breezes in northwest flow are
likely along wind prone areas east of the central Montana chain.
poor ventilation is expected areawide today as a low pressure system
that has been stalled off the upper Baja California coast begins to shift
northeastward toward nm. The bulk of the moisture with the system
will be associated with the subtropical jet...which will shift
eastward across southern nm today. Models and our forecast grids
have slowed the arrival of this moisture...with rain and very High
Mountain snows favoring locations along and south of Highway 60 this
afternoon. Instability looks sufficient for a few thunderstorms to
develop over the SW mountains this afternoon...too. The upper level
low and a Pacific cold front are then prognosticated to bring modest
moisture and colder temperatures to western areas...and to a lesser
extent central and southern areas...tonight. The Baja California system will
exit eastward during the afternoon Friday...but a secondary upper
low right on its heels will cross the area from the northwest...
keeping showers in the forecast for central and western areas Friday
and Friday night. By late Friday...a few inches of snow accumulation
will be possible in the western mountains...with lighter amounts
across the remainder of the high terrain. From Thursday through
Friday night...liquid and liquid equivalent precipitation should
total around a quarter inch across southern parts of the fire
weather forecast area...with a tenth of an inch possible in
locations as far north as the Chuska Mountains and Albuquerque. A
few hundredths of an inch will be possible from Farmington to Santa
Fe and Portales.
In the wake of the Pacific cold front...west and northwest winds will pick up
Friday as a speed maximum in the polar jet rounds the base of the
secondary upper trough and crosses southern nm. Meanwhile...a
surface low will shift southeastward from southeast Colorado over the Texas
Panhandle keeping the surface pressure gradient tight across the
plains. The strongest northwest winds should be found along and south of
I-40...with gusts from 40 to perhaps 50 miles per hour east of the
Sandia/Manzano and Gallinas Mountains to the Pecos River. Breezy
conditions will extend east of there to the Texas border.
Fortunately...humidities will remain above critical thresholds.
Because of the stronger winds...there will be some ventilation
improvement Friday along and south of I-40...with poor ventilation
lingering across much of the north.
One last weak and dry upper trough will dive southeastward across
the forecast area Saturday...promptly behind fridays secondary
system. This third trough will keep cold air advection in place for
one last day. High temperatures are expected to bottom out Saturday
around 3 to 10 degrees below normal. Ventilation will be poor
areawide...except for some improvement across the far eastern plains
due to gusty north winds lingering behind a back door cold front
that will sink southward through the plains Friday night.
Dry northwest flow aloft will persist through the middle of the coming
week. Weather systems will pass far enough north to keep
precipitation out of the forecast for northern and central nm. A
warming trend will develop Sunday through Tuesday with high
temperatures reaching above normal in most locations as early as
Monday. A back door cold front should then drop southward through
the plains Tuesday night cooling temperatures across the east for
Wednesday. Otherwise...ventilation will generally be poor...except
for periods of improvement across the east Central Plains.