Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Albuquerque nm
548 am MDT Friday Aug 28 2015
12z taf cycle
back door cold front has moved through klvs and ktcc and is closing
in on kcqc. It will continue to slowly slide south and west
today...banking up against the Central Mountain chain through middle/late
afternoon before convection aids in pushing it through the gaps.
Convection will favor the Central Mountain chain during the afternoon...and
perhaps along the front near krow...before spreading eastward onto
the plains. Across western areas...the SW mountains will be favored as
dry air nudges into the northwest. Brief MVFR ceilings/visibilities will be possible
in locally heavy rain. Gusty canyon winds will be possible at
kabq/ksaf late Friday afternoon/evening as the front pushes through.
Previous discussion...333 am MDT Friday Aug 28 2015...
a back door cold front will focus showers and thunderstorms over
the central mountains and portions of the eastern plains today
into tonight. Some storms will contain locally heavy rain. The
higher storm coverage will shift westward during the weekend and
favor the central mountains westward to the Arizona state line.
Locally heavy rain potential will remain...especially along the
Continental Divide. A Pacific trough will gradually draw closer to
the area during early next week and shift the main moisture and
rain focus a little further east across the state.
back door cold front has brought higher dewpoints and moisture
levels to portions of the eastern plains overnight. The abundant
low level moisture will get shunted westward during the day period
based on the GFS/NAM boundary layer wind flow forecasts. A
moist/unstable upslope flow should develop along the central mountains
and provide the focus for storms there. Aided by convection...low
level moisture should drive westward during the overnight period.
Just made small modifications to the pop field to reflect the
latest steering flow forecasts and upslope flow enhancement. Also
added fog for the Moreno Valley this morning based on current
observations. It should be pointed out that the NAM is much less
bullish than the GFS in terms of quantitative precipitation forecast amounts. Decided to favor the
GFS a bit more...especially along the upslope areas.
The center of the middle level high should return to the state on
Saturday. Steering flows will be slow and a slightly drier/more
stable regime should enter eastern areas and limit convection
there. The main pop focus will be found along and west of the
central mountains precipitation water values should be too significant and
expect the normal diurnal convection over the mountains
The approaching Pacific trough should sharpen the moisture
gradient between Arizona/nm Sunday/Sunday night. Suspect this will aid
and focus convection across the western third to half. The
steering flow should also gradually trend more west to east as the
day progresses. Didnt make too many changes in the pop field
although did increase values over the mountains
The Pacific trough is expected to weaken some and reform further west
of the state Mon/Tue. It appears that some sort of partial or
pseudomonsoonal flow would remain over portions of the state
during this period and help fuel showers/thunderstorms. The models
arent excited about widespread heavy quantitative precipitation forecast results at this time but
suspect that could change depending on how the Pacific trough reforms
to the west. Eventually the approach of the trough will shift the
main moisture focus eastward and return better chances for storms
to the east.
It appears that the models are trending towards a fall like
monsoonal transition with Pacific troughs to the west and monsoonal
moisture flowing over New Mexico. At some point the stars should
align and allow for a more significant monsoon burst event over
the forecast area. Stay tuned.
back door front is moving down the plains early this morning. This
will continue to slide south and west through the plains early
today...backing up to the Central Mountain chain by early afternoon.
Upslope flow will aid in thunderstorm development along the Central
Mountain chain. Storms will generally move south or southwest...
though storms across the west Central Highlands will move very
little as the upper high establishes itself across Southeast Arizona. Locally
heavy rains are possible.
Convection along/east of the Central Mountain chain will help force the
front through the gaps of the Central Mountain chain...perhaps producing
some gusty winds below canyons in the Rio Grande Valley this
evening. The front is expected to make it to at least the
Continental Divide...if not the Arizona border. This will replenish moisture at the
low levels across western nm after it was mixed out during the
afternoon today due to middle level dry air nudging into western nm.
The added moisture will set the stage for increased thunderstorm
activity across western nm on Saturday afternoon. Localized wetting rains
will be possible with little storm movement. Increased stability
across the east will limit thunderstorm potential.
Western nm looks to remain favored for showers and thunderstorms
Sunday and Monday as monsoonal moisture is drawn up is southwesterly
flow aloft. Models are indicating that the plume will get tilted
eastward on Tuesday as some drier air works in to northwest nm.
Thereafter...models continue to diverge on solutions. GFS now
showing the monsoon plume reestablishing itself quickly over western
nm on Wednesday...while the European model (ecmwf) shows a much drier scenario. This
is 180 degrees different than 12 hours ago...so continue to expect
some forecast changes middle week and beyond.
Very weak transport winds will lead to areas of poor ventilation
today and Saturday across central and north central nm. Ventilation
looks to improve Sunday through early next week.