Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 251954

Area Forecast Discussion
National Weather Service Pocatello ID
154 PM MDT WED MAY 25 2016

.SHORT TERM...One more day where Southeast Idaho is between the
low pressure trough over Montana and the low pressure circulation
moving into the southwestern states. Forcing is not as strong this
afternoon as yesterday and precipitable water values are a little
lower, but temperature lapse rates are still pretty steep.
Quarter inch hail was reported near Grace this afternoon. Thursday
we begin to see a new disturbance sliding southward through
British Columbia, then turning east through the panhandle
Thursday night and Friday. Air mass will still be pretty moist and
unstable Thursday with most afternoon thunderstorms favoring the
mountains. Friday a cold front trails from a passing surface low
in Canada on the edge of a negative tilted trough. Looking for
some vigorous showers and thunderstorms over the central mountains
and Arco Desert area. Winds will be rather breezy in the Snake
Plain, a Lake Wind Advisory is likely for American Falls
Reservoir. Flow becomes more zonal or westerly on Saturday, with
more dry air working in. Afternoon thunderstorms decrease further,
but areas along the Montana and Idaho border will still see active
convection. RS

.LONG TERM...Sat night through next Wed night. 500mb long wave
pattern expected to be nearly stagnant this entire period, with a
trough at the coast and weak zonal or southwesterly air flow over
the Gem State. The GFS is wetter for the most part during this
period, but have tried to compromise between that solution and the
ECMWF guidance. Thus there is slight chance to low chance PoPs
somewhere in the forecast area each day. The apparent best chance
for showers and afternoon/evening thunderstorms is Sun afternoon
through Memorial Day afteroon. There has been a drying trend to
every other day in this extended forecast. With the cloud cover,
temperatures are very near climatic normals, so nothing excessively
hot, nor unusually cold. There are no significant troughs that might
lead to a severe weather day, at least at this point. The only thing
to watch for is a potentially windy day on Sun or Mon with the
previouly-mentioned main weather feature of the period.


.AVIATION...Enough instability and moisture around to generate
-TSRA, but barely to qualify for isolated have
continued the VCTS. Winds are gusty but mainly aimed down do not see much impact to airdrome operations unless
-TSRA develop and move in. KIDA has been slow to lose the marginal
VFR CIGs but believe it should evaporate during the early afternoon.
Convective activity is all solar-generated so -SHRA/-TSRA should
subside during the evening.


.PIH Watches/Warnings/Advisories...None.


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