Area forecast discussion
National Weather Service Grand Junction Colorado
917 PM MDT Sat may 25 2013
Update...
issued at 917 PM MDT Sat may 25 2013
Gusty southwest winds across southwest Colorado have diminished
this evening with humidity values slowly climbing back above 15
percent. As a result...the red flag warning for today has been
allowed to expire. Few high clouds also drifting through the
forecast area with little impact on the seasonable weather.
&&
Short term...(this evening through Sunday night)
issued at 321 PM MDT Sat may 25 2013
Dry and warm southwest flow will continue across the region
tonight through Sunday night sustaining above normal temperatures.
Breezy southwest winds will diminish with cooling this evening
then increase again Sunday afternoon and evening as mixing
deepens. Expect increased high clouds early Sunday...thinning as
the day progresses.
Long term...(monday through saturday)
issued at 321 PM MDT Sat may 25 2013
Models are coming into good agreement with the GFS generally
leading the way. There are still some uncertainty with the
details especially how fast the moisture will work into the
region.
Monday the mean trough along the West Coast begins to move inland.
One associated wave lifts through the northern rockies early
Monday morning with a second approaching The Four Corners in the
afternoon. Both of these are dry and lack a surface reflection.
Temperatures remain above normal.
Tuesday the negative tilt trough works through the Great Basin and
over the forecast area by Wednesday morning. The associated cold
front looks to pass in the late afternoon-evening. Prior to
frontal passage...scattered thunderstorms may be high-based
producing more lightning and gusty winds than rain.
Post frontal...winds veer to west and the storms will produce more
rainfall as the 90kt jet nose pushes into The Four Corners area.
Snow levels may lower to 8500-9000kft early Wednesday but quickly
rebound back to 11kft through the day. Temperatures fall below
normal. Showers continue through Thursday centered on the central
Colorado zones.
Another wave digs into the back of the trough on Friday. This is
stronger in the GFS. This keeps cooler unsettled conditions
continuing over the northern County Warning Area through Friday. The trough ejects
east by Saturday for a drying trend.
&&
Aviation...(for the 06z tafs through 06z Sunday night)
issued at 917 PM MDT Sat may 25 2013
VFR conditions will continue across the region for the next 24
hours. Breezy southwest winds ranging from 15 to 25 miles per hour on average
will redevelop around 18z Sunday afternoon resulting in areas
moderate mechanical turbulence through 03z Monday.
&&
Fire weather...
issued at 917 PM MDT Sat may 25 2013
Red flag conditions have diminished this evening across southwest
Colorado and allowed the warning to expire. Next round of red flag
conditions arrives Sunday afternoon and will continue through middle
evening for these same zones...207 and 291. Low humidity...gusty
winds...and a Haines index of 6 can again be expected.
Latest guidance indicated a decrease in high clouds during the
afternoon which...in conjunction with weak shortwave
trough...will allow for what appears to be sufficiently deep
mixing to generate widespread wind gusts over 25 miles per hour. Airmass will
remain warm and dry so relative humidity below 15 percent almost certain.
As the larger-scale western trough begins to move inland next
week....an increase in the winds and high/middle level moisture may
lead to more fire weather issues including dry thunderstorm activity
on Tuesday. Cooler and wetter conditions are expected beginning
Tuesday night.
&&
Gjt watches/warnings/advisories...
Colorado...red flag warning from noon to 9 PM MDT Sunday for coz207-291.
Utah...none.
&&
$$
Update...jdc
short term...no layers
long term...Joe
aviation...jdc
fire weather...tgjt
