Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
944 am MDT Wednesday may 27 2015
Synopsis...an upper low moving out of the Pacific northwest will
impact much of Utah through Thursday. High pressure will
strengthen across the region late in the week through the upcoming
weekend resulting in a warming and drying trend.
Discussion...an upper low pressure system is spinning over Idaho
this morning...with Utah and southwest Wyoming continuing to be
impacted by waves on the south end of this low. One such
disturbance is moving through northern Utah as of 1530z...and has
maintained a line of showers with isolated thunderstorms across
Tooele and Box Elder counties for the past few hours. This band
will impact the Wasatch front and Cache Valley between 1530z and
17z...with rainfall and brief gusty winds most likely.
While there may be a brief period of stability following this line
of showers late this morning...still expecting another active day
of convection this afternoon. Somewhat drier and more stable air
has begun moving into southern Utah...so that area may not be as
active as in past days...but still cannot rule out some isolated
activity...especially coming off the higher terrain.
The moist and unstable conditions continue through tonight and
Thursday...as the low continues to slide southward slowly. The
forecast area finally looks to get a period of drier weather
beginning Friday or Saturday...as the storm exits to the east and
high pressure builds over the Great Basin.
Updated the forecast earlier to increase probability of precipitation for those in the
track of the band of showers. Otherwise...the forecast looks
good...and no further updates are anticipated this morning.
Aviation...showers and isolated thunderstorms will move through
kslc terminal area in the 15z-19z window. Periodic ceilings at or below 6000ft
above ground level can be expected...and a 10 percent chance exists that lightning
will impact the terminal. A brief break in showers/storms is
possible behind this wave midday...but additional storms should
redevelop in the vicinity of the terminal middle afternoon and linger
through the evening. Southerly winds have transitioned to northwest
for the day.
Fire weather...today and tomorrow will be warm and fairly dry
across the south...while the north remains cool and moist. The best
chance for a wetting rain is also across the north. Rain will
overspread through the morning...with numerous showers and scattered
thunderstorms this afternoon. It should remain active across the
north tonight and tomorrow as well. The strongest activity will
bring a chance for cloud to ground lightning...gusty/erratic
winds...and small hail.
The pattern shifts Friday through the weekend as a ridge builds in.
Expect very warm conditions and a drying trend across all of Utah.
The chance for afternoon showers and thunderstorms will thin each
day and be relegated to the mountains for the most part. Southerly
winds will become gusty Sunday...increasing through
Tuesday...increasing the likelihood of seeing critical meteorological
fire weather conditions into early next week.
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http://weather.Gov/saltlakecity/general/afd_faqs.Php (all lower case)