Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
355 PM MDT Monday Jul 28 2014
Synopsis...a very moist monsoon airmass will remain over the area
through Tuesday. Some partial drying of the airmass will occur
later in the week.
Discussion...widespread showers and thunderstorms with embedded
heavy rain is in progress across much of the forecast area. Expect
activity to continue through much of the evening. Report of one
mudslide on Road east of Montana. Nebo...expect more of the same from
other areas that take a direct hit from thunderstorms.
With slight easterly component and active convection over the
Wasatch mountains...convection may drift or redevelop westward
into the urban corridor next few hours.
Models vary quite a bit on extent of organization of precipitation area
over northwest Utah tonight...with 12z NAM being most enthusiastic
and 12z ec being least. Have gone with general idea of widespread
stratiform light rain with a few embedded thunderstorms overnight
and into Tuesday morning. Precipitation and widespread cloud cover will
combine to bring an unseasonably cool day to the north Tuesday.
Some drying Wednesday as upper wave passes to the east of the
forecast area...but overall the pattern returns to typical monsoon
with ridge/high over the Colorado plateau...airmass drys to
typical values for this time of year...but diurnal terrain driven
convection should persist most days through the rest of the week
and into the weekend.
Aviation...VFR conditions are expected through the evening hours at
the slc terminal. West to northwest winds are expected to switch to
the southeast between 01z and 03z...but showers and thunderstorms in
the vicinity of the terminal will cause periods of gusty and/or
erratic winds through the evening. There is a 20 percent chance of a
thunderstorm directly impacting the terminal during this time.
Fire weather...deep moisture has spread across the entire district
allowing surface humidity values to climb over the last 24
hours...especially across the far north. Scattered to numerous
showers and storms have developed across the district this
afternoon...with focused activity across central Utah and moving
north to northwest at this time.
Shower and storm activity will trend to dissipate south to north
tonight but expecting continued showers and isolated storms to
continue across the north as an upper level disturbance Will Park
nearly stationary there. Minimal drying is expected tomorrow but
shower and storm activity should be a little less than today.
Humidity will remain very elevated for the next 36 hours and
elevated wetting rain potential will continue.
A drying trend will spread north Wednesday but sufficient moisture
will remain across the region for afternoon and evening mountain
thunderstorms each day through the end of the week. Wetting rain
potential will be on the decrease however.
Utah...Flash Flood Watch until 9 PM MDT this evening for utz016-019>021-
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