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Area forecast discussion 
National Weather Service Salt Lake City Utah
521 PM MDT Wednesday Jul 27 2016

Synopsis...high pressure will maintain hot and dry conditions
through much of the remainder of the work week. This high will
move east late in the week allowing moisture to slowly increase
from the south Friday through the upcoming weekend.

&&

Short term (through 06z sunday)...500 mb analysis continues to
indicate the center of a strengthening (and closed) high over
southern Nevada this afternoon. Very dry air within northwesterly
flow aloft has expanded southeast across most all of the area over
the last 24 hours, but have noted isolated buildups of the most
prone terrain of the extreme south today on the extreme northern
periphery of the moisture gradient pinned over northern Arizona.
Similar convective conditions can be expected once again tomorrow,
but the main take away in the short term will continue to be the
heat.

Kslc just recently exceeded 100f for the third day in a row, this
after a few degree cooldown in the vertical environment as the
drier air advected in last night. Guidance continues to depict a
net strengthening of the high tomorrow through Friday aiding a net
warming of the airmass once again however. With this said, it
looks like a lock that Salt Lake will exceed 100f for the next few
days as well. Regarding utahs Dixie the heat will become
excessive, with expectations of exceeding 110f Thu/Fri (have a
forecast of 113f for tomorrow) making the heat impactful. Opted to
issue an excessive heat warning for Washington County Thu/Fri as
such temps will increase the potential for heat related illnesses
and more dangerous.

The aforementioned moisture gradient currently pinned south along
the Utah/Arizona border will slowly shift north and west Friday promoting
isolated storms across the southwest. Instability looks marginal
but differential heating will likely overwhelm any suppression
during the peak heating hours. This gradient will continue to
shift north Saturday as the high center re-orients over northern
Arizona increasing the threat of convection nearly areawide. Precipitable water
values look to range in the .80-1.00 inch range at that time, with
sufficient instability for deeper convection namely across the
south and west, but bulk of this will remain at or above 500 mb so
storms will largely remain high based and dry. Continued to
gradually increase pops across the area.

Long term (after 06z sunday)...moisture which is forecast to
spread across the forecast area early in the weekend will remain
in place through Monday maintaining a threat of showers and
thunderstorms each day. The mid level ridge axis is forecast to
remain south of the area during this time keeping deeper
monsoonal moisture suppressed south over AZ, with precipitable water values across
southern and central Utah remaining below 1 inch. However as the
airmass slowly moistens from top down across the forecast area
storms are expected to transition from dry to wet with some
potential for locally heavy rainfall across southern Utah. The GFS
and ec differ with respect to how much if any drying occurs by
midweek, and as such have maintained low pops through day 7. With
the increase in cloud cover and slightly cooler 700mb temperatures
should trend slightly downward.

&&

Aviation...VFR conditions will prevail at kslc through the taf
period with northwest winds switching back to the south between
03-04z.

&&

Fire weather...the extended hot and dry period will continue
through the end of the week before mid and upper level moisture
begins to increase from south to north late Friday into Saturday.
Isolated buildups similar to those over the high terrain of the
extreme south today are expected over the southwestern mountains
again tomorrow...with a greater chance of isolated dry storms over
the mountains of southwest Utah Friday. This threat will increase
substantially for Saturday as the mid and upper moisture expands
north across the district. With extremely dry fuels in
place...especially across central and northern Utah... the
potential for new starts Saturday is heightened and it will be
likely that we will be highlighting this further in future shifts.

The thunderstorm potential will continue Sunday into early next
week but storms will likely be trending more wet along with rising
humidity.

&&

Slc watches/warnings/advisories...
Utah...excessive heat warning from noon Thursday to 9 PM MDT Friday for
utz019.

Wyoming...none.
&&

$$

Merrill/Seaman

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visit...
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