Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Albuquerque nm
1122 am MDT Monday Aug 31 2015
18z taf cycle
VFR terminals forecast to persist through the taf period outside
of MVFR impacts associated with isolated/scattered showers and
thunderstorms later today and this evening. Terminals with highest
probabilities of thunderstorm impacts are kgup...kfmn...ksaf and
kaeg...in that order.
Previous discussion...328 am MDT Monday Aug 31 2015...
daily rounds of scattered to isolated showers and thunderstorms
will continue to favor central and western areas this week...
though some drier air is forecast to enter northern areas from the
west around middle week. An upper level trough will cross the
northwest United States at the end of the week. This should draw
enhanced subtropical moisture over New Mexico this weekend with
increased coverage of precipitation and cooler temperatures.
models are trending moister for middle week than in previous runs.
The westerly wind shift that could bring drier air into northern
areas is not very pronounced in the latest set of graphical
guidance...so confidence is decreasing in a significant downtick
in thunderstorm coverage across northern areas during the Wednesday and
A tropical system is expected to develop off mexicos West Coast
this week. It may develop into a named storm...Kevin. The GFS and
European model (ecmwf) draw the system northward as the week progresses and depict
its remnants moving north northeastward across New Mexico late
Friday through Saturday. Quantitative precipitation forecast amounts dont look so high at this
point...but they are fairly widespread suggesting broad coverage
of light to perhaps moderate rain amounts varying around a quarter
the main monsoonal moisture plume currently found
over Arizona will gradually shift eastward during the week. The
moisture will be diffuse at times or thin some as it progresses
eastward but it will be over most of the forecast area. The steering
flow for the storms will gradually shift more out of the
west/southwest as the upper high slides south of the area. The
steering flow for the storms should also increase due to the
approach of a longwave Pacific trough. Thunderstorm chances will be
most minimal...at least initially...across southeast/ec areas due to
residual impacts from the stable/drier airmass aloft. The airmass
will gradually moisten through the week across those portions of the
forecast area. Weather models also show an increase in breeziness
across the eastern plains due to a strengthening leeside trough.
Surface dewpoints are expected to lower considerably across the
northern tier Wednesday/Thursday although decided to temper that lowering based
on the overall upper air pattern and projected surface wind flow.
Confidence is pretty high for this scenario through at least
Some slight uncertainty exists for Friday/weekend based on
moisture/precipitation differences between the European model (ecmwf)/GFS/Canadian
models. All eyes will be on tropical disturbance south of the Baja California.
It is expected to strengthen and move northward and eventually get
caught up within the longwave trough. It is still hard to know
whether the main center of circulation flows northward into New
Mexico but at the very least...the upper half of its moisture
profile should get sheared out over the state. All of the models
show precipitation water values increasing during this period...just
differences in amount and timing. The Canadian model is the quickest
while the European model (ecmwf) is the driest. Still like the GFS models which shows
longer duration/heavier rainfall starting Friday and continuing into
the weekend. Cloud cover/humidity values would certainly increase.
The GFS model also remains bullish for a moderately strong back door
cold frontal intrusion and added moisture/lift Sunday night into
Monday. The European model (ecmwf) hints at this but remains a little more skeptical.
Once again...like the GFS a bit more. Decided to increase surface
dewpoints thus relative humidity values above model guidance for this period. High
temperatures would also trend cooler than normal. Widespread wetting rain
would be a likely scenario during this period although expect day to
day fluctuations due to cloud cover and stability considerations.
Ventilation is expected to be pretty good through Thursday due to
moderately strong transport winds and moderately high mixing
heights. The GFS model indicates a lower transition Friday/Saturday
due to the influx of moisture and less mixing potential.