Area forecast discussion
National Weather Service Salt Lake City Utah
906 PM MDT Sat may 25 2013
Synopsis...a warm and dry southwest flow will prevail through
Sunday. A cooler and wetter pattern will develop across the region
beginning early in the week.
&&
Discussion...a cool upper low extends from southwestern Canada off the
pacnw coast this evening with a dry and warm southwest flow over our
County Warning Area. A weak short wave ejecting out of the West Coast low lifted
north through Idaho this afternoon but was close enough to nudge the surface
thermal trough south of slc and switched the winds to northerly from
the Salt Lake and Tooele valleys north to the Idaho border.
Models shift this surface trough back north and west of the County Warning Area
later tonight or early sun ahead of the next...and somewhat
deeper...upper short wave trough rounding the base of the West Coast
low and lifting into the northern rockies late tomorrow into tomorrow
evening. This should kick up the south winds again tomorrow...keeping
temperatures above normal and also sends another weak surface boundary
south into northern Utah late aftn/eve.
This boundary may be able to support a little high based
convection over the far northern County Warning Area late Sun afternoon and
overnight...and remains stalled across the north through Monday with a
slightly better chance of convection along and north of it Monday.
Meanwhile...the south should see one more breezy warm dry day.
Latest models continue to send a large portion of the West Coast
trough inland Monday night and into the County Warning Area Tuesday afternoon accompanied by
an organized cold front and sufficient moisture for fairly
widespread showers that could last through much of Tuesday night.
Additional upper troughs are then forecast into the western states
through the rest of the week keeping it cooler and unsettled over our
area...although models disagree on how far south the threat of precipitation
gets.
No updates planned at this time.
&&
Aviation...northerly winds at the slc terminal are expected to
Switch Back to southeasterly between 04-05z with a 20 percent chance
that winds will not switch until around 06z. South winds will become
gusty again after about 16z Sunday morning. VFR conditions will
prevail through the valid taf period with any ceilings well above 7000 feet.
&&
Fire weather...upper level trough near the West Coast will keep the
district under deep southwest flow aloft through early next week.
Gusty south winds and relative humidity values below 15 percent that
occurred in many valley locations across the state in the afternoon
are expected again on Sunday ahead of an approaching front.
Overnight relative humidity recovery will remain poor all areas
tonight and across southern Utah Sunday night. Although weather
conditions will reach critical thresholds again Sunday in many
areas...fuels remain non-critical at this time per latest reports.
There is also the threat for isolated dry thunderstorms across
northern Utah on Sunday.
A weak cold front front will move into the state Sunday night which
will bring cooler temperatures...diminished winds...and increased
relative humidity values to the state on Monday. A series of weak
systems will then bring an increased threat of precipitation as well
as cooler temperatures and higher relative humidity values during the middle of the
coming week.
&&
Slc watches/warnings/advisories...
Utah...none.
Wyoming...none.
&&
$$
Wilensky
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