Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 240305

Area Forecast Discussion
National Weather Service Pocatello ID
905 PM MDT SUN OCT 23 2016

.UPDATE...Have made a few minor adjustments to precip related
forecast grids for the remainder of the overnight. Satellite
imagery shows deepest moisture stream stretched from near Las
Vegas to just southwest of Salt Lake City this evening. RAP/HRRR
continue timing of northward surge of moisture into Idaho after
09Z around surface high centered just over Wyoming border. Nudged
precip chances upwards slightly in extreme southeast corner but
tweaked QPF down slightly per latest trends. DMH


.PREV DISCUSSION... /issued 202 PM MDT SUN OCT 23 2016/

SHORT TERM...Sunday night through Wednesday. Last couple of days
the models have shifted towards two streams of moisture moving into
this area for Monday. Well, current water vapor satellite imagery
shows one contribution across Southern California and the other
moving north from about Sierra Vista, Arizona. Lightning detection
shows strikes on both of those streams this afternoon. The two
streams merge across the South Central Highlands and Caribou
Highlands early Monday morning, and advance towards Island Park by
afternoon. The main difference is the presence of increased moisture
and instability over the Snake Plain. Made some adjustments to the
forecast to include a chance of showers and slight chance of a
thunderstorm slipping into the Plain for that reason. Also tonight
and early Monday, south winds become breezy in the South Central
Highlands from Oakley to Fort Hall. That will boost low temperatures
into the forties where the wind down slopes. Some gusts to around 30
mph likely overnight, including Interstate 84. Snow levels Monday
are around 10000 feet elevation, so little worry there. We still
have the presence of the developing low pressure disturbance near
the Pacific Northwest Coast. That feature begins to have more
influence on our weather late Monday night and Tuesday, especially
for the Central Mountains. Snow levels begin to drop Tuesday
afternoon to around 8000 feet elevation with 1 to 3 inches
accumulation in the higher elevations. RS

LONG TERM...Wednesday night through Sunday. Ridging expected to
continue to dominate weather pattern into Thursday, but models
struggling to find a consensus beyond that. Both GFS and ECMWF bring
a couple strong shortwaves through the area. GFS tracks one just to
our north on Thursday night while the ECMWF places the forcing much
further into Alberta. The second wave indicated by the ECMWF will
lift through California and draw moisture into Idaho on Friday and
is about 12 hours faster than the GFS with the onset of precip. Thus
have little confidence to make anything but small changes to current
forecast.  Hinsberger

AVIATION...BKN to OVC high clouds should continue today with
generally light winds. Overnight hours will see an increase in
boundary-layer winds in advance of an upper trough lifting out of
southern California. Thus could see low-level wind shear at KPIH,
KIDA, and KBYI in the early morning hours. Showers could make their
way to KPIH, KIDA, and KDIJ tomorrow morning. Hinsberger


.PIH Watches/Warnings/Advisories...

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