Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albuquerque nm
608 am MDT sun Sep 21 2014
12z taf cycle
numerous patches of MVFR ceilings...locally IFR...east from central
Montana chain through middle morning then slowly improving thereafter. Row
and tcc taf site mainly impacted. Some spotty rain showers and more
isolated thunderstorms and rain this morning...mainly well south of Interstate 40.
Activity developing northward in scattered if not locally numerous
fashion after about 20z into tonight. Local MVFR ceilings possible
with thunderstorms and rain mainly north and central nm with local IFR ceilings possible
with thunderstorms and rain farther south. May see an expansion in MVFR and perhaps
IFR ceilings or fog after about 05z...but some spotty rain showers and thunderstorms and rain
likely to continue as well overnight.
Previous discussion...417 am MDT sun Sep 21 2014...
an active shower and thunderstorm pattern is expected today through
Monday. An upper level storm system over central California will
slowly track eastward today and pass through the central and
southern rockies Monday. Ahead of this system...an extended period
of moist low level east winds along with a tap of deep monsoon
moisture from Mexico is expected. The combination of these features
will lead to increased shower and thunderstorm activity and the
likelihood of locally heavy rainfall. Locations which have
received heavy rainfall recently will be most susceptible to flash
flooding along with burn scars. A drier weather pattern will
develop by Tuesday and extend through much of the work week with
only isolated shower and thunderstorm activity favoring the higher
terrain and east.
active weather pattern today through Monday. Included a mention of
locally heavy rain for the southeast quarter and portions of wc/SW
nm today...with the potential for locally heavy rainfall/flash
flooding expanding tonight/Monday am especially near/east of the
Central Mountain chain. No changes planned to previous Flash
Flood Watch. While the potential for locally heavy rain will
expand to include more of the area tonight- Monday...much drier
antecedent conditions exist outside the current watch and
combined with somewhat faster storm motions as we transition
through tonight and Monday should preclude significant expansion
of the watch. We/ll continue to closely monitor particularly for
the burn scars.
Weather/pop grids on track for today with only minor changes. Trended
probability of precipitation upward tonight-Monday...especially in the favored SW to NE
corridor as well as areas east of the Central Mountain chain. Despite
the increased moisture/cloud cover...afternoon temperatures will remain
a little above seasonal averages central/west. Thus... outflow
boundary interactions late today into the evening could be rather
effective/dynamic especially between The Divide and Rio Grande/Central
Valley corridor. That coupled with a subtle increase in upper
level dynamics downstream of a closed low forecast to reach northern
Nevada late today should promote a better overall convective
Still expect a significant push of dry air into The Four Corners late
tonight or Monday morning...slowly smearing eastward as the
closed low opens up and passes well north of the state Monday. But
looking at water vapor imagery the European model (ecmwf) may be more correct
keeping the impact of the drier air delayed and less impactful
than the GFS given the robust nature of the monsoon plume that is
poised to advect northward this morning. Plus the closed low over
California is lifting more north currently. Planning for a sharp
west- east middle level moisture gradient somewhere over northwestern nm by
tonight or early Monday...which could focus some decent storms.
For Tuesday and beyond...ridge aloft to the west of nm Tuesday with
drier middle-level air working in from northwest to Southeast. Ridge takes on a
positive tilt going into middle/late week with high over low or Rex
block scenario over the central/Southern Plains states. The European model (ecmwf)
is farther west with trapped low...and is therefore wetter for
late week. Stagnant pattern will not last long...however... as
another very deep trough indicated into the West Coast this
weekend. Much uncertainty on how progressive the trough will end
up but potential impacts for our area most likely sun/Monday of next
week though confidence lower than usual on timing/details. Kj
working our way into a wetter period over the next 48 hours...
perhaps a bit less west central and northwest...a little longer S and east.
Deep rich moisture continues across approximately the southeast third to
half of the forecast area...some of which has been ushered back to the
west and north some since late Saturday. Still looking at potential
for some 15 to 25 miles per hour sustained winds into midday below canyons and
lower passes into some sections of the Rio Grande Valley. Gusts may
still reach 25 to 35 miles per hour at times through the morning in some
normally windier spots below canyons. This afternoon and tonight
will see the more significant uptick in rain coverage and intensity.
From this period through Monday fairly widespread wetting rains are
expected and those areas that received rainfall from Odile will be
more prone to see flooding problems...mostly the southern portions
of fire weather zones 106 through 109. Temperatures will trend downward
today...due to increase moisture...rainfall and cloud cover. All but
roughly the northwest third will be near or below normal. Ventilation will
also trend downward slightly for most areas.
As an upper low opens up some and heads east across The Rockies to
the north...the base of the system will brush northern nm...
resulting in a more westerly flow aloft. This will usher in drier
air into the northwest quarter to third of the state Monday and reduce
shower and storms chances there. But rest of the area will remain
quite active with another pretty healthy crop of showers and storms.
Temperatures will remain near or below normal with the east the most
below the norm. Ventilation today will be near to a little less than
was the case Saturday for majority of the forecast area.
A drying trend is still likely Tuesday through Thursday as an upper
ridge builds over Arizona. Residual moisture along and east of the
central Montana chain still may be enough to ignite a few showers and
storms storms during the afternoon and evening. Several forecast models bring
back some modest chances of spotty rainfall west of Central Mountain
chain as early as Thursday afternoon...but confidence fairly low on that
as am not seeing quite enough moisture transport back into those
areas by then...not to mention that we are into late sept...when
daytime heating is weaker than earlier in the Summer. Looking at
just poor to fair ventilation across most zones Monday...but the northwest
and far north may still manage good values. Those good values will
be mainly across the east Tuesday...while a broader area of poor to
fair ventilation is expected Wednesday.
A deep trough moving across the western Continental U.S. Is still forecast by
extended models around the Friday through next weekend timeframe.
Timing and strength of the system is still in some doubt...another
round of showers and thunderstorms could be in the picture. 43
Flash Flood Watch through Monday evening for the following zones...