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fxus65 kpub 151729 

Area forecast discussion
National Weather Service Pueblo Colorado
1129 am MDT sun Sep 15 2019

Short term...(today and tonight)
issued at 339 am MDT sun Sep 15 2019


The synoptic features associated with the short term forecast period
are an upper level ridge to the east, a low pressure center located
over the Pacific northwest, and a subtropical closed low located to
the south of Colorado. The ridge located to the east is being
amplified by Tropical Storm Humberto, located over the Atlantic,
just off of the coast of Florida. The amplified ridge to the east
and the low pressure center over the Pacific northwest is creating
southwesterly flow over Colorado, which is where the the subtropical
low will propagate. The subtropical low is projected to propagate
over western Colorado, and while it propagates to the north-
northeast, subtropical moisture will travel with it. The response
will be showers and thunderstorms over the eastern San Juans, La
Garita, sawatch, and Sangre de Cristo Mountains. Expect the
thunderstorms to begin over the eastern San Juans and southern
Sangre de Cristo Mountains at around 1400 MDT this afternoon. The
storms are anticipated to linger throughout the short term forecast
period over the eastern San Juans and la garitas, but are expected
to dissipate by around sunset to midnight over the rest of the
region. Flash flooding is possible over the Spring and Hayden Pass
burn scars when thunderstorms develop this afternoon. With the upper
level flow being from the southwest, above average high temperatures
are expected this afternoon. High temperature values are anticipated
to be in the low to mid 90s over the plains, the mid 70s to low 80s
over the mountain valleys and the 50s to 70s over the mountains.
Pressure gradient fields reveal a tight gradient over the eastern
plains this afternoon, so gusty south to southwesterly winds are
expected, with sustained speeds around 15 to 25 mph and gusts around
25 to 35 mph.

Tonight and Monday morning:

Lingering showers and thunderstorms will remain over the eastern
mountains and dissipate elsewhere. The subtropical moisture
associated with the subtropical low pressure center will keep
temperatures warm overnight over the mountains and mountain valleys.
Low temperature values are expected to be in the upper 50s to low
60s over plains, the mid 40s to low 50s over the mountains valleys,
and the 30 to 40s over the mountains.

Long term...(monday through saturday)
issued at 339 am MDT sun Sep 15 2019

Upper low continues to lift northward across Colorado during the
day on Monday, although best upward motion will be slightly out
of phase with daytime heating, as system will be mainly north and
east of the region by mid-afternoon. Still a risk of a
thunderstorms over most of the mountains and interior valleys,
with best chance for storms over the San Juans early in the day.
Lee surface trough and fairly strong S-SW winds from I-25
eastward will limit precip chances over the plains, though a storm
or two might develop near the trough by late afternoon, as some
weak low level moisture convergence develops. May be enough cloud
cover Monday to keep Max temps just a couple degf cooler than
sun, though difference will be minor as mid level temps change
little and deep mixing continues.

Main western U.S. Upper trough then approaches the region Mon
night into Tue, before lifting into the nrn plains by early Wed
morning. Shower and thunderstorm chances ahead of the trough will
continue along the Continental Divide until trough passes early
Wed, while remaining mountains, valleys and the eastern plains see
only some very isolated activity as air mass dries under
increasing wly flow. In fact, with breezy to windy conditions
developing Tue afternoon as Lee surface trough deepens on the
plains, a few locations along and east of the mountains may get
close to critical fire weather conditions for a few hours, as
temps climb and humidity drops toward 15 percent.

Weak front then slides through the region early Wed morning as
trough passes, though with next system already moving onshore
across the Pacific NW, only minor cooling is expected as W-SW flow
redevelops Wed afternoon. Trough then swings eastward through the
Great Basin Thu before lifting through the central rockies on
Fri, and with system tapping into a least a modest amount of mid-
level moisture, most of the region should see scattered
thunderstorms Thu into Fri, before drier wly flow again sweeps
across the state by the weekend. Max temps will remain well above
seasonal averages Wed-Fri, before some very modest cooling
develops next weekend.


Aviation...(for the 12z tafs through 12z Monday morning)
issued at 339 am MDT sun Sep 15 2019


VFR conditions will be the primary weather conditions during the
next 24 hours. However. Some passing showers and thunderstorms
will be possible through the period, especially this afternoon and

Kcos and kpub:

VFR conditions are expected throughout the forecast period for kcos
and kpub. Winds will be light and diurnally driven.


Pub watches/warnings/advisories...

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