Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Salt Lake City Utah
355 PM MDT Monday may 25 2015
Synopsis...a moist and unstable airmass will remain in place
across the region. The next storm system will impact mainly
northern and central Utah through most of the remainder of the
Short term (til 06z friday)...a light west to northwest flow
remains over the County Warning Area this afternoon. Weak short wave ridging is moving
into western Utah and a closed low is dropping S through the pacnw with a
weak short wave rounding the base of this low crossing northern California.
Convection has become generally more isolated this afternoon as the
upstream ridge advances into the County Warning Area. The exception is across the
north where the ridge is flatter and over the northwest deserts that may
be behind the axis already. Expect isolated activity to persist
over most of the County Warning Area into early evening then diminish. The convection
over the northwest is forecast to persist overnight and increase
towards morning as the northern California short wave crosses Nevada and begins to
move into Utah.
This weak wave crosses northern Utah during the day enhancing convection
across mainly the northern half of the County Warning Area.
The weak pacnw low continues to bring a threat of convection to
much of the County Warning Area through the rest of the week. This would mainly
result from additional weak waves rotating through the base of this
low as it tracks slowly southeastward to S central Idaho by 12z Thursday and northestern
Utah by 00z Friday. Timing of these will be difficult so have kept
generally scattered coverage in for each day through Thursday.
Long term (after 06z friday)...the shortwave trough is expected to
be directly over northern Utah and southwest Wyoming by 06z
Friday...shifting eastward over Colorado through Thursday night and
the daytime Friday. This should help confine lingering showers to
the far northern and eastern portions of the County Warning Area Friday...with drier
air slowly beginning to work into southern and western Utah.
After this trough exits the region late Friday...the weekend is
expected to bring a rarely seen occurrence for may 2015...dry and
warm high pressure directly overhead. While some isolated diurnal
showers may still be possible over the higher mountains of northern
and central Utah...most of the County Warning Area should see the warmest and
sunniest conditions in quite some time. In fact...with increasing
southwesterly flow Sunday/Monday and 700mb temperatures increasing to 12-
15c over much of the County Warning Area...the hottest day of the year so far may be
Kept or slightly increased the already warm forecast for the
beginning of next week. This includes maxes in the middle-80s
fahrenheit in many northern valleys...and hitting 90 degrees is not
out of the question. There is also a chance St. George hits 100
degrees for the first time this year. After a rainy month of
may...it looks like mother nature may be trying to flip the switch
just in time for the start of meteorological Summer.
Fire weather...a Pacific low pressure system will maintain a moist
weather pattern tonight through Thursday...with a chance of wetting
rain every day. Coverage of showers and thunderstorms may be highest
in the northern half of Utah...but southern Utah will still see a
few storms through this period. The storm will exit the region
through the day Friday...with significantly drier and warmer
conditions finally expected for next weekend.
Aviation...north to northwest winds will continue at the slc
terminal through 03-05z. Showers are possible in the vicinity of the
terminal between 02 and 05z...and any showers in the area could
cause gusty and erratic winds and occasional ceilings at about 4000-
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