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Area forecast discussion 
National Weather Service Grand Junction Colorado
1047 PM MDT Sat Apr 19 2014

Short term...(this evening through Sunday night)
issued at 325 PM MDT Sat Apr 19 2014

Split flow across the forecast area has allowed a series of weak
systems to impact the area today. Early morning wave lifted across
western Colorado...triggering widespread light showers across the
lower valleys...including Grand Junction. Quantitative precipitation forecast amounts were
generally under a tenth of an inch. Second wave lifting northeast
across New Mexico is trying to sneak back up into the southern
valleys this afternoon. However...northern branch wave is expected
to drive the southern wave a bit more eastward this
evening...leading to minimal impact on our forecast area. With
northern energy shearing apart and southern stream sliding to our
east...dynamical support for widespread precipitation has
diminished greatly. Still working on a fairly unstable atmosphere
with enough juice to keep scattered convection rolling into the
evening hours. Focus will remain across the higher terrain...but a
few light showers should drift over the valleys from time to time.
Morning sounding came in with precipitable water values around six
tenths of an inch...roughly 2 Standard deviations above normal for
this time of season. So potential for locally heavy rain or snow
may be realized near stronger cells...although this would be
isolated and not anticipating any problems with flooding or
increased snowmelt due to rain on snow. After a cool side of
normal day today...temperatures expected to rebound back to above
seasonal norms on Sunday.

Long term...(monday through saturday)
issued at 325 PM MDT Sat Apr 19 2014

The work week begins as a fast moving ridge passes over the area
on Monday. Other than possibly a few light mountain showers in the
afternoon...a benign Spring day will be in store with temperatures
well above normal

Tuesday-Wednesday promises to be more interesting as the next significant
storm system moves into the Pacific northwest on Tuesday...then across
the northern rockies on Wednesday. While the bulk of the upper
level system will remain to our associated cold front
will reach northeast Utah late Tuesday night...then will sweep across
the remainder of the forecast area on Wednesday. But the action will
mostly take place on Tuesday as the southwest flow strengthens ahead
of the upper trough and surface cold front. 700 mb winds are
expected to reach 40-45 kts in the afternoon...with the strongest
flow over eastern Utah. This strong and warm flow will mix into the
valleys during the afternoon. Therefore there will be the
potential for fire weather concerns...and blowing dust and/or
another dust on snow event.

Cooler temperatures will develop behind the cold front on
Wednesday...with a chance of showers...mainly mountains and north.
The cool northwest flow will persist into Thursday...with
rebounding temperatures on Friday as a ridge passes. The next
Pacific trough then reloads on Saturday with increasing southwest
winds and warming temperatures.


Aviation...(for the 06z tafs through 06z Sunday night)
issued at 1047 PM MDT Sat Apr 19 2014

This storm system is refocusing over southeast Colorado late this
evening with kgjx radar showing a much quieter scene than prior to
Sunset. Mountain obscuration will be possible mainly south of
Interstate 70 along The Spine of The Divide and eastward. VFR
conditions will be forecast to prevail overnight and through the
day on Sunday. Afternoon showers and isolated thunderstorms will
pop again with the focus mainly on the terrain. A stray shower
into the valleys is unlikely to limit flight conditions for long
but may temporarily bring MVFR conditions and gusty winds.


Fire weather...
issued at 325 PM MDT Sat Apr 19 2014

A strong low pressure system will move into the Pacific northwest
on Tuesday then pass north of the forecast area Tuesday night
through Wednesday. While the main upper level disturbance will
remain to our associated cold front will approach
Tuesday afternoon and evening...and then move into northeast Utah
late Tuesday night and across the remainder of the forecast area
on Wednesday.

The main impact for western Colorado and eastern Utah will be
strong southwest winds on Tuesday as the gradient tightens ahead
of the upper disturbance...and the surface front. In addition to
the strong winds...very warm temperatures are expected. Since most
moisture will stay north of our area...the rising temperatures will
push relative humidity below 15 percent in places across the lower
elevations of southwest Colorado and southeast Utah. The strong
winds and low relative humidity will combine for possible critical
fire weather conditions on Tuesday afternoon in portions of
southwest Colorado where fuels are dry.

Cooler temperatures and a little better moisture are expected on
Wednesday behind the front. However along the far southern
border...gusty winds winds and dry conditions will persist. Calmer
weather will again follow later in the work week as another ridge
develops. With more uncertainty...another approaching low pressure
trough may result in increased southwest flow on Saturday.


Gjt watches/warnings/advisories...


Short term...jdc