046
FXUS65 KSLC 222112
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
312 PM MDT Sat Jun 22 2024

.SYNOPSIS...Lingering moisture will continue to bring the threat
of thunderstorms to portions of eastern Utah through the early
evening. Moisture will increase over southern Utah Sunday as
northern Utah stays dry with dangerous heat expected for valley
locations. Moisture will persist over southern Utah to start the
work week as temperatures become slightly less hot over northern
Utah.

&&

.SHORT TERM (Through 12Z Monday)...Utah and southwest Wyoming are
under a roughly zonal flow aloft this afternoon, allowing drier
air from western Utah to advect into eastern Utah. As a result,
seeing a steady decline in PWs, though satellite derived PWs are
still around 0.7 over the majority of eastern Utah. Also seeing a
bit of lingering jet support and shortwave energy from yesterday`s
trough that is providing modest instability and shear. Thus, have
seen isolated convection develop over eastern Utah, with some
storms producing heavy rainfall, primarily over Capitol Reef
National Park. The threat of storms will diminish during the early
evening with the loss of daytime heating and as instability
continues to move east of the area.

By Sunday, high pressure will amplify over the area, giving a more
southerly component to the flow aloft. This will advect deeper
moisture back into southern Utah, bringing a threat of isolated to
widely scattered convection capable of producing gusty winds and
heavy rainfall. Meanwhile, the amplifying ridge will bring a very
hot airmass over northern Utah with temperatures in the upper 90s
to around 100F anticipated Sunday afternoon for the valleys of
northern Utah, values up to 15F above normal for this time of
year. HeatRisk data indicates these temperatures will be
dangerously hot for many northern and central Utah valleys.
Current suite of Excessive Heat Warnings and Heat Advisories seems
to cover this threat well.

.LONG TERM (After 12Z Monday), Issued 404 AM MDT...On Monday, a
trough passing through north of the region will help flatten the
ridge and help nudge temperatures down very slightly, but the
overall pattern persists into midweek. Broad ridging will extend
from the southern Plains into the Desert Southwest, resulting in
H7 temps locally around 15C to 19C. At the surface, this will
yield continued anomalous heat, with daily afternoon high
temperatures around 5F to 15F above climatological normal for late
June, and overnight lows around 10F to 15F above normal. In
comparison to yesterday`s guidance, temperatures have trended
downward very slightly, such that HeatRisk no longer is as bullish
on the necessity of subsequent heat headlines. That said, if
guidance heads back the other way with things ultimately trending
nearer the 75th percentile or so, headlines may yet need to be
considered. In any case, the point remains that it will be quite
hot for the vast majority of locations in the forecast area, with
limited overnight cooling/recovery. Heat related safety should
still be kept in mind, especially for those working or recreating
outdoors. Stay hydrated and take frequent breaks if at all
possible, and ideally wear light and loose fitting clothing.

Aside from the heat, enough moisture continues to push into the
region around the ridge to result in daily diurnal convection
through midweek. Coverage of this convection will tend to be
maximized from southern to central Utah, primarily firing off
terrain and drifting into adjacent valleys. While convection will
be fairly isolated to scattered in nature, those recreating in
rain sensitive places such as slot canyon, typically dry washes,
or slickrock areas should remain weather aware. Coverage looks to
spread a little further northward on Wednesday, up into the Uintas
or so.

Thursday into Friday guidance continues to maintain some moderate
consensus that a deepening Pacific trough will shift inland,
flattening the trough, and depending on the amplitude, potentially
shoving a cold frontal boundary southward at least into portions
of the forecast region. As a result, precipitation chances
increase Thursday afternoon (particularly along/east of the I-15
corridor), and temperatures are forecast to fall nearer to
climatological normal.

&&

.AVIATION...KSLC...VFR conditions will prevail through the
valid TAF period.  Through 23Z, there is a very low chance (less
than 10%) of convection forming over the Oquirrh Mountains, then
drifting into the valley, and potentially producing gusty outflow
winds. A northwest lake breeze should switch to a typical southeast
drainage wind, perhaps enhanced a bit by southerly aloft, around 04Z.

.REST OF UTAH AND SOUTHWEST WYOMING...Isolated convective
activity will continue through the evening hours to the south and
east of a KEVW to KBCE line.  Any convection will be capable of
producing gusty outflows winds and a brief period of reduced
ceilings and visibilities.  Otherwise, expect VFR conditions with
typical diurnal wind patterns.

&&

.FIRE WEATHER...Isolated showers and thunderstorms have developed
over eastern Utah this afternoon, which will tend to dissipate
this evening. Northern Utah will stay dry tomorrow, becoming
dangerously hot. Over southern Utah, moisture will linger,
allowing for additional convective development. Northern Utah will
become a but less hot Monday but stay dry as moisture lingers over
southern Utah. Southern Utah will dry for the middle to latter
part of the week as winds increase, bringing the threat of
critical fire weather conditions.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Excessive Heat Warning from 9 AM to 9 PM MDT Sunday for
     UTZ101>105.

     Heat Advisory from 9 AM to 9 PM MDT Sunday for UTZ106-116-118-
     119.

WY...None.
&&

$$

SHORT TERM/FIRE WEATHER...Traphagan
LONG TERM...Warthen
AVIATION...Barjenbruch

For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity