Area Forecast Discussion
Issued by NWS Pocatello, ID
FXUS65 KPIH 182022
Area Forecast Discussion
National Weather Service Pocatello ID
222 PM MDT WED MAY 18 2016
.SHORT TERM...A minor wave is approaching the Arco Desert this
afternoon. Included mention of an isolated thunderstorm there and
near Bear Lake. Forcing is weak and the thunder might not happen.
The disturbance for thursday appears on track. Marginal
instability for severe thunderstorms in the Upper/Lower Snake
Plain with hail and strong gusty winds. Precipitable water values
from model soundings support the possibility of a few storm cells
producing heavy rain. cold front should cross the Snake Plain
early Thursday afternoon with winds stronger enough to issue a
Lake Wind Advisory for American Falls Reservoir. With the low
moving over the forecast area this weekend, have lowered snow
levels closer to 7500 feet elevation Saturday and closer to 7000
feet Sunday morning. That could be low enough for a little snow on
the higher mountain passes. RS
.LONG TERM...Saturday night through next Wednesday. Both the GFS and
ECMWF models show the closed upper level low over Oregon filling and
moving Northeast through the region Saturday night into Sunday while
secondary energy digging into the Western extent of the trough helps
to maintain a broad upper trough over the region Sunday and Monday.
Expect widespread showers and isolated thunderstorms each day
particularly each afternoon. By Tuesday another system moves into
the area continuing the convection over the area. Expect
temperatures 5 to 10 degrees below normal for daytime highs. Wyatt &&
.AVIATION..A weak high pressure ridge over our area is slowly
breaking down ahead of a deep low pressure system. Residual moisture
coupled with daytime heading across the central mountains could
bring isolated thunderstorms to KSUN this afternoon. Expect vicinity
showers for KIDA and to an lesser extent KPIH late this afternoon
into early evening. Expect winds to pick up slightly this afternoon.
By late tomorrow morning a strong cold front will hit KSUN and move
slowly Southeast through the afternoon impacting all taf sites.
Expect MVFR/IFR cigs and vis with stronger showers on station.
Also...expect thunderstorms on station with the potential for gusty
winds near 30 to 40 mph. Severe thunderstorms with small to medium
hail and winds gusts of 55 to 65 mph is possible at this point.
Lake Wind Advisory from noon to 7 PM MDT Thursday for IDZ021.