Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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951
FXUS65 KSLC 270900
AFDSLC

Area Forecast Discussion
National Weather Service Salt Lake City UT
300 AM MDT FRI MAY 27 2016

.SYNOPSIS...Several weak disturbances will cross the region
through the first part of next week.

&&

.SHORT TERM (THROUGH 12Z SUNDAY)...
Water Vapor loop shows a wave crossing Western Utah, with a
closed low over British Columbia. AMDAR 400-200MB wind
observations place a 75-90kt Northwesterly jet into the Pacific
Northwest. GOES/HRRR/00Z KSLC RAOB indicate the precipitable water
value ranges from 0.20"- 0.40" mountains to 0.40"-0.60" most
valleys.

Short Range Ensembles indicate plenty of instability today mainly
along and East of the Wasatch spine. This plus Northwesterly flow
off the initiation location continues to support the idea that
the best coverage will be along the Wasatch spine Eastward this
afternoon and evening.

Drying takes place between today and tomorrow, with Westerly flow
enhanced by the elongation Eastward of the British Columbia low.
Ridging occurs over Southern Utah. Instability is mainly noted
along the higher terrain. With this flow regime, any convection
that develops over the Northern Mountains should progress
Eastward. Flow is much weaker across the South so storms should
stay near the initiation point. Left Dixie and Lake Powell dry but
this will have to be reassessed again.

Warming/Drying trend across the South into Sunday. Snow level should
range between 10-11KFT.

.LONG TERM (After 12Z Sunday)...Sunday looks to remain active
convection-wise, as the area remains under deformation between the
trough north of the area and a weak low moving across southern
California. These two features phase as they cross the CWA on
Monday, leading to continued isolated to widely scattered showers,
but also drawing in some dry air from the west in their wake.

There is still some disagreement in the models about how much low-
level cold air advection will occur across northern Utah on Tuesday
as the northern branch trough exits the region. The max temperature
forecast for Tuesday remains a bit of a compromise between the
warmer ECMWF and the cooler GFS.

Models are still in good agreement that a high amplitude ridge will
build over the region Wednesday through Friday of next week. Much
drier air will move over the CWA through this period, providing a
break from the active weather. Appropriately, it will also produce
much warmer temperatures for the first few days of meteorological
summer.

&&

.AVIATION...There is a 20 percent chance of gusty, erratic
winds at the SLC terminal today due to isolated showers and
thunderstorms across northern Utah. Otherwise, winds are expected
to switch to the northwest around 17Z-19Z.

&&

.FIRE WEATHER...Isolated to scattered convection can be expected
today and tomorrow across the region. In addition to the threat of
lightning, convection is likely to contain dry microburst wind
gusts due to the drying sub-cloud layer.

A drying/warming trend is forecast for Southern Utah through the
weekend.

Another weak system will graze Southern Utah during the weekend
keeping similar conditions in place heading into next week. Gusty
Northwest winds are possible Monday into Tuesday as this system
departs.

&&

.SLC Watches/Warnings/Advisories...
UT...None.
WY...None.
&&

$$

SHORT TERM/FIRE WEATHER...Rogowski
LONG TERM/AVIATION...Schoening

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