Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 182203

Area Forecast Discussion
National Weather Service Salt Lake City UT
403 PM MDT Wed Jul 18 2018

.SYNOPSIS...High pressure will remain as the main feature over the
region through the week, continuing a dry pattern for northern
Utah. Moisture will remain in place across the south and slowly
creep north late week into the weekend.


.SHORT TERM (Through 00z Sunday)...The ridge of high pressure
continues to wobble over the Four Corners area today and should
essentially remain in place through the remainder of the week.
Northwest steering flow for storms can be seen on satellite
imagery, as storms drift to the southeast early this afternoon.
The focus area continues to be the southern third of Utah where
the best moisture and instability are present. Not expecting as
wide coverage of storms this afternoon/evening as the previous two
days, but still showers and storms should blossom into late

As the ridge stretches and shifts east by Friday, the mid to upper
levels begin to turn southerly, drawing up more moisture from the
Desert Southwest into southern and eastern Utah heading into the
weekend. This shift in flow may also impact the direction of storm
tracks which may play a part in the flooding potential of these
storms. Nonetheless, stability and moisture on the rise with some
diffluence aloft and increasing lapse rates should all point to
increasing coverage for showers and thunderstorms especially
across the south and eastern areas of Utah as the weekend begins.

With this increased moisture, cloud cover will be on the rise.
This may not result in hotter or cooler daytime temperatures but
more insulation during the overnight hours keeping temperatures
warm overnight. As the moisture increases, humidity will be on the
rise as well which may lead to more uncomfortable feeling

Bottom line for the next several days is an unsettled Monsoon
pattern is in place.

.LONG TERM (After 00z Sunday)...Ridge axis begins to shift slowly
westward and continues to draw moisture northward into the forecast
area through the weekend. PWATs over an inch combined with
significant CAPE and LI values will promote convective activity each
afternoon, with the potential to produce heavy rain.

The ridge begins to flatten as a trough moves through the northern
Rockies, creating a more westerly flow aloft and northerly at mid-
levels for the CWA. This flow gradually shunts the southerly
moisture train as the workweek progresses. Have further reduced PoPs
to reflect this model trend and agreement. Temperatures should
remain slightly above seasonal normals through the extended


.AVIATION...VFR conditions will prevail at KSLC through the TAF
period with northwest winds switching to the south around 03Z.


.FIRE WEATHER...High pressure centered over the Four Corners area
will remain in place through the remainder of the week and shift
slightly to the east going into the weekend. Moisture will be
greatest across southern Utah during this time, with a relatively
quiet period today and Thursday before increasing again Friday and
through the weekend. Northwest flow aloft across northern Utah
will continue to stream in drier air and warmer daytime
temperatures. Relative humidity values will remain quite low
today and Thursday in the northern half of Utah before increasing
starting Friday, with values across the south continuing to be
above 20 to 25 percent each day.

Thunderstorm and showers are expected each day across the south,
while the north should remain dry going into the weekend.




LONG TERM...Verzella

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