Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Denver/Boulder Colorado
309 PM MDT Wednesday Mar 12 2014
Short term...a fairly weak west to northwesterly flow aloft will
be over Colorado through Thursday. The weak upper low will be well
to the south and west of Colorado as it drops into southern Nevada/Southern
California...with just a slight increase middle and high level over western
Colorado late in the day. Temperatures will moderate another 10 to 15
degrees over this afternoons highs.
Long term...models have trended much weaker with the northern
portion of a disjointed trough coming over Colorado early Friday.
However there will still be a cold front...and the clouds
associated with the southern part of the trough. Just a slight
chance of some snow in the mountains...mainly south of Interstate
70. With some sun and warming coming in already it will probably
not be that much colder.
Saturday trough is looking stronger though there is lots of
variety in the ensembles. NAM has a quick moving trough and shower
band Saturday morning...operational GFS is a bit slower/stronger
and would have a little upslope snow event later in the day. Many
GFS ensembles and the European model (ecmwf) put more energy into the west part of
the trough and have less lift over the Front Range. Current
forecast has appropriate probability of precipitation/temperatures for now...could be
colder if the earlier NAM timing is correct. Possibility it could
be a similar setup to yesterday but it really does not look as
strong. I did raise the mountain probability of precipitation as that is looking pretty
Drying and warming Sunday into Monday...I raised temperatures a bit over
the model consensus as there is really pretty good agreement on
this being a sunny...warm...dry day under the ridge.
Ensembles go into disarray after the ridge passes...with the next
trough coming sometime between Tuesday and Thursday. For now will
hedge cooler with some low probability of precipitation mainly in the mountains starting
Tuesday. European model (ecmwf) clustering has a better trough after
Wednesday...but I did hedge sky/pops/temps on Wednesday a bit in
case the truth winds up in between.
Aviation...VFR ceilings/visibilities over the next 24 hours. Typical diurnal
wind pattern will prevail through 18z Thursday. Good mixing layer
in the afternoon...so westerly winds may likely prevail Thursday afternoon.