Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Denver/Boulder Colorado
434 am MDT Wednesday Sep 2 2015

Short term...(today through tonight )
issued at 434 am MDT Wednesday Sep 2 2015

Another typical late Summer day is in store across northeast
Colorado as some sub-tropical moisture continues to stream across
the state from the southwest. Daytime heating over the mountains
will be enough to generate a round of showers and a few embedded
thunderstorms by mid-afternoon. Some of these showers will drift
out over the I-25 corridor and adjacent plains...producing gusty
winds and some light rainfall. Ahead of the showers...a warm
airmass remains in place over the northeast plains...with morning
temperatures still in the middle 60s at several locations at the
present time. High temperatures should make another foray into the
lower and middle 90s across the plains. The warm temperatures aloft
will be enough to keep the airmass on the eastern plains capped
all afternoon. The only plains locations with the mention of any
probability of precipitation will be along the I-25 corridor. Later tonight...it should be
another mild one as the moist southwest flow aloft continues
across the state. Evening showers should be completely dissipated
by about 9 PM.

Long term...(thursday through tuesday)
issued at 434 am MDT Wednesday Sep 2 2015

An upper level trough will intensify over the western US Thursday into Friday
with south-southwest flow aloft across the area. In addition there will
continue to be some influx of subtropical moisture in the flow with
the potential for a few disturbances to move across as well. The
first disturbance will move north-northeast across the area Thursday afternoon into early
Thursday evening with precipitable water values ranging around .70" in
the mountains with around an inch over the plains. Should see a good chance
of showers and thunderstorms over the higher terrain with a chance along the
Front Range. Over the far plains activity may be more widely scattered.
As for highs will keep readings in the upper 80s to lower 90s
across northestern Colorado.

On Friday appears another disturbance may move north-northeast across the area with
a slight increase in precipitable water values. Thus may see
another good chance of showers/thunderstorms over the higher terrain with a chance
over the plains. As for highs readings may drop a few degrees
depending on amount of cloud cover so will keep readings in the 85
to 90 degree range across the plains.

By Sat the upper level trough is forecast to move into the Great Basin
with southwesterly flow aloft over the area. The GFS continues to show a
good influx of subtropical moisture especially east of the mountains with
precipitable water values as high as 1.25 inches over the plains.
Meanwhile the European model (ecmwf) shows the feed of subtropical moisture
decreasing considerably. For now will keep in a slight chance of
storms however if the GFS ends up being correct then thunderstorm coverage
over the plains could be higher. As for highs will keep readings
in the 80s across northestern Colorado.

For sun the upper level trough will move east-northeast into the northern rockies
with the flow aloft becoming more west-southwest. This allows for a drier
airmass to spread across the area which would keep any thunderstorm
development very isolated if at all. Meanwhile a weak cool fnt may move
across northestern Colorado in the afternoon however highs will stay in the 80s.

By Monday the flow aloft will remain west-southwest with any subtropical moisture
remaining mostly to the south of the area. Thus any thunderstorm activity
will be rather isolated and mainly in the mountains south of I-70. As for
highs readings will be near seasonal levels. On Tuesday the flow aloft
will be more westerly with any subtropical moisture remaining south of
the area so thunderstorms chances will remain very low. Highs will be in
the lower to middle 80s across the plains.

&&

Aviation...(for the tafs through 12z Thursday morning)
issued at 434 am MDT Wednesday Sep 2 2015

No aviation impacts through this morning and into the middle-
afternoon with ceilings well above 10000 feet and visibilities
essentially unlimited. Another round of showers and isolated
thunderstorms is expected to develop over the mountains during
the afternoon and some of these may move out across the Denver
area from late afternoon to early evening. Once again...gusty
winds and light rain will be the main products from the showers.
Ceilings and visibilities should see little impact from the
passing showers. Pressure gradients across eastern Colorado will
be weak and poorly organized through the day resulting in weak
wind fields until gusty winds develop with the late afternoon
showers.

&&

Bou watches/warnings/advisories...
none.
&&

$$

Short term...dankers
long term...rpk
aviation...dankers

National Weather Service Glossary of Abbreviations