Scientific Forecaster Discussion
fxus65 kpub 200524
Area forecast discussion
National Weather Service Pueblo Colorado
1124 PM MDT Thu Sep 19 2019
Short term...(this evening through friday)
issued at 335 PM MDT Thu Sep 19 2019
..high fire danger and possible severe storms across portions of
southeast Colorado on Friday...
Current water vapor imagery and upper air analysis is indicating
moderate southwest flow aloft across the area as a broad upper
trough continues to dig into the Great Basin, with an embedded short
wave translating across southeastern Arizona at this time. At the
surface, induced Lee low near La Junta is keeping breezy south to
southeast winds and dew pts in the 50s across the far southeast
plains, as dew pts further west have mixed out into the upper 20s to
upper 30s across the I-25 corridor. Regional radars are indicating
scattered storms across the far southeast plains, with isolated to
scattered showers and storms lifting northeast across west central
New Mexico at this time.
This afternoon...with low level moisture across the far southeast
plains and a few more hours of heating, should continue to see
storms lifting north and east into western Kansas through the late
afternoon and early evening. Storm Prediction Center meso analysis has mixed layer CAPES
of 1000-2000 j/kg across the far southeast plains at this time,
however, lack of mid level flow and shear remains a limiting factor
for super cell development.
For tonight and Friday...long wave trough digging into the Great
Basin remains progged to start to lift out across eastern Utah
tonight and into western Wyoming through the day tomorrow. This
will allow for increasing southwest flow across the region tonight
which becomes more westerly into tomorrow afternoon. Models
continue to indicate increasing in mid level moisture and lift
ahead of the embedded short wave keeping scattered showers and
isolated thunderstorms across the area tonight into early Friday
morning, with the best coverage along and west of the contdvd.
Snow levels to remain high (aoa 12,000 ft) though can not rule out
some light snow across the higher peaks along The Divide. Breezy
southwest winds expected to mix down across the lower elevations
through the day tomorrow helping to mix out low level moisture and
creating a dryline across the far southeast plains. Convergence
along this boundary, along with stronger mid level flow, could
help develop late afternoon thunderstorms, some of which could be
strong to severe, producing large hail and damaging winds. Storm Prediction Center day
2 outlook continues to indicate much of southeast Colorado east
of the I-25 corridor in a marginal risk. West of the boundary,
fire danger will be increased with spotty red flag conditions
expected along and west of the I-25 corridor. However, red flag
conditions do not look to be widespread enough or of a long enough
duration to issue a red flag warning. However, with well above
seasonal temperatures in the 80s and 90s, combined with low
afternoon humidity levels and gusty winds, any outdoor burning
should not be planned.
Long term...(friday night through thursday)
issued at 335 PM MDT Thu Sep 19 2019
Recent longer range models suggest that precipitation will be on
a decreasing trend Friday evening before ending Friday night over
the County Warning Area.
Then, a relatively moist northerly component surface surge is
expected to move across eastern sections from later Saturday into
Saturday night, increasing the potential for showers and
thunderstorms over primarily eastern locations of the County Warning Area during
the Saturday evening into Saturday night time-frame and have
reflected this potential in grids and zones.
Transitory upper ridging should then provide southern Colorado
with dry conditions from Sunday into Sunday night in advance of
next upper system potentially impacting southern Colorado from
Monday into possibly Tuesday, with recent computer simulations
keeping primary precipitation focus with this system generally
to the south and east of the County Warning Area during this time-frame.
Outside of basically isolated afternoon and evening showers and
thunderstorms, majority of County Warning Area should experience generally dry
conditions on Wednesday and Thursday.
Regarding winds, at this time, the highest potential for gusty
gradient winds during the longer term should be experienced from
Friday evening into Friday night, later Saturday into Saturday
night, Tuesday night and then again by later next Thursday.
Elevated/localized fire weather threats during the longer term
are also anticipated at times from this weekend into Monday.
Regarding temperatures, generally above seasonal later September
temperatures should be realized over the majority of the County Warning Area
during the balance of the longer term, with coolest conditions
projected this weekend, with warmest temperatures expected by the
middle of next week. In addition, the potential exists that below
freezing temperatures may occur over the San Luis valley by
Sunday morning and if latest trends continue, freeze highlights
may become warranted.
Aviation...(for the 06z tafs through 06z Friday night)
issued at 1115 PM MDT Thu Sep 19 2019
Upper low pressure system and associated trough over the western
third of the US will gradually shift across the Great Basin and
into the northern rockies over the next 24 hours. This will
produce brisk south to southwest winds across the region, with
winds expected to become stronger and gusty after 18z with gusts
to 35 mph possible at times.
Otherwise, VFR conditions are expected for much of the forecast
area over the next 24 hrs, including the three main taf sites of
kcos, kpub and kals.