Area forecast discussion
National Weather Service Salt Lake City Utah
311 PM MDT Tuesday Jun 18 2013
Synopsis...a warm and dry southwest flow aloft will continue
across the Great Basin through tomorrow morning. A dry cold front
will push across northern and central Utah on Wednesday while the
south remains hot and dry.
&&
Discussion...ridge continues to shift slowly eastward as the
broad closed low pushes into the Pacific northwest. Satellite
water vapor image places the low center near 120w 140n at this
time with a thin ribbon of lower clouds and rain showers just east
of the coastal range. These clouds and showers will never reach
Utah as the low will eventually track up over the ridge. A very
dry airmass over Utah will remain through tomorrow morning over
the north before the dry cold front pushes in and turns the gusty
southwest winds to the west or northwest. The front should push
through the Wasatch front around noon and settle over central Utah
by early evening. Any convection will be restricted to far
northern mountains and will be mainly dry due to the dry airmass
in place.
Temperatures over the northern half of the state will drop to more
seasonal levels. The clear skies will aid in cooling while the
southwest winds will counter. Still lowered the overnight lows 4-5
degrees over the north to be more in line with the latest
guidance. Isolated lightning and local gusty and erratic winds
will be the biggest threats from this activity.
The Wind Advisory remains in place for this afternoon and evening
for west central Utah. Could see advisory levels again tomorrow
over the southeast...but have elected to leave that decision to
the middle shift with access to a later model run.
Dry and windy conditions will keep the fire community on the
alert. See fire weather discussion below. Red flag warnings into
Thursday will continue.
As the system eventually pulls off to the east this weekend...the
ridge will slowly rebuild across the area. Temperatures will remain
near seasonal norms through Friday and then continue to rise
through the weekend. Hot temperatures and southwest winds will
redevelop into next week as another low drops into the waters off
the Pacific northwest coast.
&&
Aviation...gusty south winds are expected to continue this
afternoon before decreasing a bit overnight. South winds may
periodically hit aww criteria through at least 2300 UTC. However...
there is a 20 percent chance that a lake breeze will move across the
terminal late this afternoon. Otherwise...VFR conditions expected
through the period.
Outlook...cold front is expected to bring a switch to northwest
winds at the terminal between 1500-1700 UTC on Wednesday.
&&
Fire weather...combination of increasing southwest flow aloft and
the approach of a dry cold front will promote gusty southwesterly
winds well into this evening. Wind gusts are expected to exceed 40
miles per hour for many areas across the western/southern portions...and
combined with single digit relative humidity will drive critical fire weather
conditions where fuels are cured...most recent to turn critical were
zones 478 and 492 below 6500 feet. The dry cold front will enter far
northwestern Utah tonight then push south/east into central Utah
over the next 24 hours...stalling across central portions for the
remainder of the week. South and east of the front very dry and
breezy conditions will continue into and through Thursday and
possibly Friday. North and west of the front gusty northwest/west
winds will occur on Wednesday afternoon and evening before tapering.
Added rfw for zones 478 and 492 below 6500 feet through tomorrow
evening as a result...with the other critical zones remaining within
going rfw through Thursday evening.
High pressure will settle into the region this weekend creating
more stable conditions with less winds...though the airmass will
remain extremely dry.
&&
Slc watches/warnings/advisories...
Utah...red flag warning until 10 PM MDT Thursday below 7000 feet for
utz488-489-493-494.
Red flag warning until 10 PM MDT Thursday below 9000 feet for
utz496.
Red flag warning until 10 PM MDT Wednesday below 6500 feet for
utz478-492.
Red flag warning until 10 PM MDT Thursday below 6000 feet for
utz495.
Wind Advisory until 9 PM MDT this evening for utz015-016.
Red flag warning until 10 PM MDT Thursday for utz497-498.
Wyoming...none.
&&
$$
Public.........Young
fire weather...Merrill
aviation.......Graham
For more information from National oceanic and atmospheric administration/S National Weather Service visit...
http://weather.Gov/saltlakecity (all lower case)
For frequently asked questions about the area forecast discussion
visit...
http://weather.Gov/saltlakecity/general/afd_faqs.Php (all lower case)
