Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Albuquerque nm
446 am MST Thursday Dec 18 2014
12z taf cycle
localized MVFR ceilings/visible will be found across northwest/NC portions of the
forecast area through 16z to 18z. This includes impacts to fmn/gup. LIFR
conditions will occur across far eastern areas...particularly
impacting tcc through middle/late morning. Pacific wave will spread
middle level cloud cover across most of the area as the day
progresses. Sh chances mainly relegated to western/southern areas.
Perhaps some terminal impacts to gup but most probable impacts
come tonight at row. Skies will clear for a bit behind the wave
passage and could lead to fog/br development at many
locations...especially locations that have some residual wet snow
on the ground. Tried to hint at the possibility with the use of
vcfg and scattered low ceilings after 10z.
Previous discussion...330 am MST Thursday Dec 18 2014...
another upper level trough will pass eastward over the state today
and tonight with additional rain and snow showers favoring the
mountains and locations south of Interstate 40. An inch or two of
snow will be possible in the mountains...mainly south of Highway
60. Elsewhere accumulations will be light and spotty. After
widespread below normal temperatures today and Friday...a
temperature rebound will begin in earnest Saturday with high
temperatures reaching above normal areawide again Monday.
Northwest winds should also become breezy to windy on Monday.
with 700 mb temperatures in the -4 to -6 range...the snow level should
vary around 5000 to 6000 feet today before plummeting to valley
bottoms tonight. Models are tracking the better dynamics with the
passing upper level trough south of our forecast area...but we
will need to keep an eye on the south central mountains to be sure
they dont accumulate advisory level snow amounts. It looks like a
westerly upslope flow event for them...decreasing our confidence
they will get more than a few inches of snow.
After a ridge of high pressure crosses early in the weekend...a
dry upper level trough is forecast to amplify over the state on
Saturday before shifting eastward on Sunday. Northwest flow aloft is
expected to strengthen in the wake of that trough as the nose of a
speed maximum in the polar jet dips southeastward over the area.
Northwest winds should become breezy in many locations Sunday
afternoon as a Lee trough also deepens. Breezy to windy conditions
are then expected Monday.
A broad upper level low pressure system will deepen over the middle
section of the country Monday through middle week. It will send a
back door cold front into the forecast area Monday night and
Tuesday...and this front should remain entrenched on the eastern
plains through at least Wednesday night or Thursday.
another Pacific wave will graze the forecast area today. Wetting
moisture is not likely although cant rule out localized wetting
results across far southern areas. Drier period Friday into the
weekend and should last into early next week. Northwest flow winds
should crank up Sunday and intensify into early next week. Humidity
does not look to be an issue with higher values through the period.
Ventilation rates will certainly vary with lower numbers today.
Perhaps some slight improvements on Friday. The more robust
improvements come on Sunday and should last into early next week.
Still looking at an unsettled pattern for middle to late next week.
Still way to early to say wetting results but expect a cool down.
Satellite imagery shows the next Pacific wave over Southern
California and southwest Arizona. This wave is expected to impact
southern portions of the state more than northern portions. Spot
showers containing measurable precipitation will be possible over
the fire weather area. Perhaps some localized wetting results across
far southern portions of the area. Ventilation appears to be the
main story with much lower rates compared to Wednesday. Humidity
values will remain unseasonably high.
The wave will be east of the area on Friday and allow slight
ridging. Humidity values will lower...especially as a middle level dry
intrusions tries to build over the area. This particular intrusion
looks to be at moderately strong. Tried to adjust dewpoints/relative humidity
accordingly although with residual low level moisture from past
systems...dewpoints should drop too much. Regardless...relative humidity values
should still be unseasonably high most areas. High temperatures will
warm but still remain below normal. Vent rates will improve somewhat
as the flow turns northwesterly and intensifies some. The highest
rates will be found along a line from Grants/Montana Taylor to the
Estancia basin/Chupadera Mesa.
Models seem to have bumped up their timing of the next Pacific wave
for the weekend. The wave should slide over the area
Saturday/Saturday night although with little fanfare. Drier
conditions are expected. Ventilation rates should improve slightly
due to the wave passage on Saturday but improve more on Sunday due
to a strengthening northwest flow behind the wave. Could still be some
residual middle level dry intrusion impacts to the dewpoints and relative humidity
Saturday across the eastern third to half...otherwise rising
humidity on Sunday. Models seem to really increase surface dewpoints
Sunday. Would have thought a decrease was in order due to another
dry intrusion although it appears to remain to the west based on
Monday/Tuesday and perhaps even Wednesday show intensifying northwest flow
aloft thus breezy/windy conditions at the surface. Models have been
showing this trend the past couple of days and GFS/European model (ecmwf) appear to
be in good alignment with their run to run consistency. Confidence
is moderate to good for this period. Expect decent ventilation rates
and drier overall conditions. Cant rule out some light showers
across the far north.
Confidence wanes for late next week. Models show an unsettled period
due to a deep Pacific low sliding down The Rockies/Great Basin. As
of right now...wetting moisture/snow is very possible with this
system although models showed a deep low with snow for this weekend
and that appears to not have panned out. European model (ecmwf) has the low further
west than GFS so a wetter scenario. The European model (ecmwf) showed the Pacific low
further west for this weekend so not sure what to think. Will be
monitoring the trend closely. Either way...looks like cooler air
would infiltrate the area.