Area Forecast Discussion
Issued by NWS Pueblo, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS65 KPUB 210543

Area Forecast Discussion
National Weather Service Pueblo CO
1143 PM MDT Wed Sep 20 2017

.SHORT TERM...(This evening through Thursday)
Issued at 251 PM MDT Wed Sep 20 2017


Skies clear across the region at 2 pm. Temps across the region were
generally in the 70s with 60s up in parts of El Paso county.
Winds were typically s-se across the plains with mainly sw flow at
higher elevations.


Clear skies with another relatively cool night in store given the
clear skies and light winds. expect temps mainly around 50 with
local mid 40s readings possible.


Red flag conditions will once again be possible as deeps sw flow
will be over the region along with a fairly good mixed layer. This
will allow the very dry air to mix down and expect min RH values to
fall into the 10-15% range. The dry air combined with max temps in
the 90s and southwest winds of 20 to 30 mph will promote conditions
favorable for rapid fire spread. High cloud fcst procedure indicates
it will likely be rather dry aloft tomorrow so it should be mostly
clear across the area during the afternoon time period.

.LONG TERM...(Thursday night through Wednesday)
Issued at 251 PM MDT Wed Sep 20 2017

Not much change to the forecast thinking with the potential for
severe weather Friday and Saturday, and more fall-like conditions
into early next week.

Thursday upper level trough is forecast to dig over the
western conus Thursday night. This will begin to increase
southwesterly flow across the region overnight. A few light
showers are expected to move into the San Juan and La Garita
mountain ranges after midnight. Otherwise dry conditions will
prevail across the region.

Friday and Saturday...Friday looks like an interesting day. Models
have been in good agreement with with an upper disturbance
rotating around the main system to the west. This will set the
stage for near critical fire weather conditions, mountain showers
and thunderstorms, and the possibility of severe weather near the
Kansas border. For the mountains, expect shower and thunderstorm
coverage to increase throughout the day. Locally heavy rainfall
may be possible along the Continental Divide, along with lightning
and small hail. Mixing and reduced humidity values will produce an
area of near critical fire weather conditions along the I-25
corridor Friday afternoon. Any outdoor burning is discouraged for
Friday afternoon. Further east across the Plains, models have been
consistent in developing a dryline, generally east of Haswell to
Kim line. Thunderstorms are forecast to develop by mid to late
afternoon along and east of this line. Modest CAPE and decent
shear should allow for at least a few severe thunderstorms with
large hail greater than one inch in diameter and wind gusting in
excess of 60 mph being the main threats. This activity should
spread east into Kansas during the evening hours. Expect more
scattered showers, and possibly an isolated thunderstorm across
the region overnight into Saturday morning. Temperatures on Friday
will remain warm with upper 80s to lower 90s.

The main upper system will be nearly stationary through Saturday
with another upper disturbance lifting north across Colorado by
the afternoon. Showers and thunderstorms will be ongoing across
the mountains throughout the day with locally heavy rainfall and
lightning, along with small hail possible along the Continental
Divide. There is the possibility of another round of strong to
severe thunderstorms across the far Eastern Plains Saturday
afternoon. Models develop a surface low near Pueblo with a dryline
developing to the east. Again, modest CAPE and decent shear could
lead to stronger storms, especially near the Kansas border. This
will need to be monitored. Temperatures will be slightly cooler
across the region with 70s for highs. This should help with
humidity recoveries and reduce fire weather conditions for
Saturday afternoon.

Sunday and Monday...the upper level system will start to shift
eastward with widespread shower activity across the region. This
will help bring snow levels down over the mountain areas into
early next week. Accumulating snow will be possible, especially
above 9000 feet with temperatures much cooler over the mountains.
Over the lower elevations, periods of showers are forecast to
persist into early next week as upper level disturbances eject
across southern Colorado. Temperatures will only reach the 60s for
highs over the lower elevations.

Tuesday to Wednesday...models are different in the upper pattern
evolution. The GFS splits off an upper low over Arizona with
continued energy moving north across Colorado and continued
showers and thunderstorms. The ECMWF is much slower ejecting out
the main system, and brings it across Colorado early to mid next
week. This would also bring showers to the area, but likely limit
thunderstorm potential. The ECMWF would continue to bring cooler
weather to the area, while the GFS would be slightly warmer.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1115 PM MDT Wed Sep 20 2017

VFR conditions expected over the next 24 hours. Southwest winds
will increase between 17z-18z for KALS and KCOS, and around 20z
for KPUB. Gusts to around 25-30 kts will be possible through
01-02z before winds decrease again into the evening. -KT


Red Flag Warning from noon to 7 PM MDT Thursday for COZ226>237.



AVIATION...KT is the U.S. government's official web portal to all federal, state and local government web resources and services.