Area Forecast Discussion
Issued by NWS Pocatello, ID

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
FXUS65 KPIH 160854

Area Forecast Discussion
National Weather Service Pocatello ID
254 AM MDT SUN OCT 16 2016

.DISCUSSION...Strong shortwave lifting across Idaho this
morning and is causing widespread rain across the area.
Snow levels are around 6500 to 7000 ft as the wave
passes. Expect the heaviest precip to subside around
sunrise as the upper system passes, though instability
in the cool air behind the wave is resulting in some
early morning lightning activity near Boise. Snow amounts
look to be highest in the northern Wasatch range in
southeast Idaho, which may receive about 3 to 5 inches
today. We should also see gusty winds develop over the
area with 30 to 35 mph wind speeds this afternoon across
the Snake Plain.

A second round of moderate to heavy rain is expected tonight as
another shortwave and surface cold front make their way into
Idaho. The heaviest precip will be starting this afternoon over
the South Central and Southeastern Highlands and spreading to
the Central Mountains from about 03Z to 12Z in the overnight
hours. Snow levels in the Central mountains during this second
round will be from about 6000 to 6500 ft, but model snow amounts
have fallen slightly to 3-5 inches for that area. Snow amounts
for the Caribou Highlands and the Northern Wasatch have increased
however, and those areas should see 5 to 8 inches tomorrow night
with snow levels 8000 ft dropping to 7000 ft. The post-frontal
winds Monday afternoon look to be stronger than today`s...possibly
40 to 50 mph. Along with the cold front, instability will be
present to possibly result in thunder Monday afternoon.

The third and final round of precip will begin on Tuesday as an
upper trough begins to exit the coastal waters. Snow levels are
low enough to possibly see a light dusting on the benches, but
overall amounts above 6000 ft should be in the 1 to 3 inch range.
Expect drier weather through the remainder of the period.

.AVIATION...Showers currently over the Snake Plain advance east of
KIDA, KPIH and likely KDIJ by about 15Z. So ceilings expected to
improve and remain VFR most of the day at those sites. KSUN will
take a little longer until 16-17Z. winds in the Snake Plain this
afternoon Southwest 25 to 35 kts between 17 and 23Z. This evening
precipitation band advances back north with an elevated warm frontal
band and ceilings drop back to MVFR at KPIH and KBYI around 16/03-
04Z. Another wave off the Pacific comes in late tonight and early
Monday morning. Another round of strong Southwest winds expected in
the Snake Plain on Monday with frontal band passing in the
afternoon. snow levels this morning near 7000 feet elevation at KSUN
sloping to near 7900 feet elevation at KPIH. By 16/00Z snow level at
KSUN will be near 6600 feet and KPIH near 6500 feet. 16/12Z KSUN
snow levels possibly 200 to 400 feet above the field, possibly a
-RA/SN situation. RS


.FIRE WEATHER...Very moisture rich westerlies off the Pacific
continue across Southeast Idaho today. The second in a series of
embedded waves is crossing the Snake Plain, Southern Sawtooth Forest
and Caribou-Targhee Forest today. There is one twist, that band of
precipitation moves back north early this evening, possibly as far
north as Kimama and Aberdeen through about midnight before being
shunted off to the east, just as the third wave in the series off
the Pacific approaches from the west. Overnight snow levels dip to
near 6500 feet in the central mountains where 1 to 5 inches
accumulation is possible in the upper elevations. Looks like some of
the very moist air is being diverted along the southern border
Sunday Evening, taking some away from the Galena Summit area. This
afternoon will be windy in the Snake Plain with the passage of a
cold front, an advisory has been issued. A second and stronger front
is expected Monday afternoon. Southwest winds in the Upper snake
Plain Monday will be 30 to 4o mph with gusts closer to 50 mph. The
fourth and what should be the last wave in the series is still on
track to come through on Tuesday. After that, a ridge of high
pressure builds in and will bring warmer temperatures and drier
conditions the last half of the week. RS


.PIH Watches/Warnings/Advisories...
Wind Advisory from 11 AM this morning to 6 PM MDT this evening
for IDZ020-021.


$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.