Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
1002 am MDT Tuesday Oct 21 2014
Synopsis...a Pacific cold front will cross Utah today with weak
high pressure building in on Wednesday. Dry and mild southwest
flow will return for Thursday through Saturday.
Discussion...a fairly sharp upper trough is lifting from northern Nevada
into Idaho this morning. Southerly flow over our County Warning Area is sufficiently moist
to support a band of showers and isolated thunderstorms under the best
upper level lift. The associated cold front is moving into northwestern Utah
and should reach slc by 17z.
The upper support outran the surface cold front preventing the
showers from organizing into a more robust band along the Wasatch
front. Bands of scattered showers did cross the Wasatch front
earlier this morning and expect one last band right with the cold
front but coverage will not be all that large.
Showers are still expected to develop along the stalling front
this afternoon stretching from northestern southwestward across central Utah while
the north and far SW dries. A few showers could linger along the
old front into the night but clearing skies over the north should
allow temperatures to dip to chilly levels tonight.
Weak ridging aloft follows this trough for Wednesday and the old front
lifts north as a warm front. Only expect some cloudiness and no precipitation
with the warm front. The ridge axis shifts east Thursday but heights
continue to rise Thursday and Friday with a warm dry southwesterly flow in place.
Updated earlier to lower probability of precipitation for most areas today and adjust
sky cover. Raised wind speeds across the north through the day
particularly Post frontal across the northwest deserts. May need to
update again to further lower probability of precipitation across the north this afternoon.
Aviation...a cold front will move across the slc terminal between
1620 and 1630z based on the current speed ascertained from the tdwr.
Winds will shift from south to northwest with gusts over 30 miles per hour
likely ahead and up to an hour behind the front. Any temporary ceilings
are expected to remain above 7k feet above ground level.
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http://weather.Gov/saltlakecity/general/afd_faqs.Php (all lower case)