895
FXUS65 KPIH 222039
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
139 PM MST WED JAN 22 2020
SHORT TERM
TONIGHT THROUGH SATURDAY. EARLY AFTERNOON SATELLITE
IMAGERY WAS SHOWING A LOW PRESSURE TROUGH WORKING INTO NW CANADA AND
THE MEAN HIGH PRESSURE RIDGE AXIS POSITIONED OVER THE NW COAST.
NUMERICAL MODELS SUGGEST THAT TRAILING MOISTURE AND ENERGY WILL TOP
THE RIDGE AND SPILL INTO THE REGION TONIGHT IN THE NW FLOW ALOFT.
THUS, LIGHT UPSLOPE SNOWFALL IS EXPECTED ON THE NW FACING ASPECTS OF
THE CNTRL AND ERN MOUNTAINS TONIGHT AND THEN GRADUALLY TAPERING OFF
THURSDAY AS THE RIDGE AXIS SHIFTS EAST INTO IDAHO AHEAD OF THE NEXT
INCOMING PACIFIC STORM SYSTEM. PEAK SNOWFALL ACCUMULATIONS ARE
EXPECTED RUN FROM 1 TO 3 INCHES OVER THE NEXT 24-HOURS, FALLING WELL
BELOW ADVISORY LEVELS. THE NEXT INCOMING STORM ADVANCES THROUGH THE
NW COAST FRIDAY MORNING AS ATTENDING PRECIPITATION SPREADS ACROSS SE
IDAHO THROUGHOUT THE DAY EXITING EAST OF THE WYOMING BORDER BY
FRIDAY EVENING. HERE AGAIN, WITH A FAIRLY FAST MOVING SYSTEM
SWEEPING EAST THROUGH THE MEAN RIDGE AXIS, SNOW ACCUMULATIONS ARE
EXPECTED TO RANGE FROM 1 TO 5 INCHES IN THE CNTRL AND ERN MOUNTAINS
FALLING BELOW ADVISORY CRITERIA. IMPROVING CONDITIONS ARE
ANTICIPATED FRIDAY NIGHT AND SATURDAY AS THE RIDGE REBOUNDS ACROSS
THE REGION AHEAD OF YET ANOTHER PACIFIC STORM ADVANCING TOWARD THE
NW COAST (MORE ON THAT BELOW). WITH ALL THE ACTIVITY, TEMPERATURES
SHOULD REMAIN ABOVE CLIMATOLOGICAL NORMS THROUGH THE FORECAST
PERIOD WITH GOOD ATMOSPHERIC MIXING. HUSTON
LONG TERM
SATURDAY NIGHT THROUGH NEXT WEDNESDAY. UPPER RIDGING
WILL BEGIN TO SHIFT EASTWARD SATURDAY NIGHT. AN UPSTREAM SHORTWAVE
TROUGH WILL BEGIN TO MAKE ITS WAY TOWARDS IDAHO, WITH MODELS
CONTINUING TO PUSH SOME SIGNIFICANT MOISTURE INTO THE AREA. WITH A
SOUTHWESTERLY FLOW DEVELOPING BEHIND THE RIDGE, THE WESTERN SLOPES
OF THE CENTRAL MOUNTAINS WILL BE A PRIME AREA FOR SOME MODERATE TO
HEAVY SNOWFALL. AS FORCING AHEAD OF THE TROUGH NEARS--SOMETIME
AROUND SUNDAY AFTERNOON--PRECIPITATION WILL LIKELY BE MORE
WIDESPREAD. SNOW LEVELS AROUND 5000 TO 6000 WILL BE PRESENT OVER
MOST OF THE SNAKE PLAIN AT THAT TIME, SO THE INTERSTATE CORRIDORS
SHOULD SEE ONLY RAIN. THIS WILL LIKELY CHANGE OVER TO SNOW LATE
SUNDAY NIGHT/MONDAY MORNING, THEN A MIX MONDAY AFTERNOON. MODELS ARE
SHOWING FAIR AGREEMENT WITH THE TIMING OF THE TROUGH, THOUGH THE GFS
IS SLIGHTLY FASTER. THE SYSTEM SHOULD DEPART BY TUESDAY MORNING, BUT
WILL LIKELY BE FOLLOWED UP BY SOME MORE MOISTURE AS MODELS SHOW
EVIDENCE OF ANOTHER WARM FRONT PUSHING INTO THE AREA, AND TAPPING
INTO SOME OF THAT ATMOSPHERIC RIVER MOISTURE IN THE PACIFIC.
HINSBERGER
AVIATION
A WARM FRONT WILL PUSH NORTHEASTWARD ACROSS THE REGION
TONIGHT, THOUGH PRECIP WILL LIKELY FAVOR THE MOUNTAINS. MODELS ARE
KEEPING PRECIP AWAY FROM THE TERMINALS TONIGHT, THOUGH HAVE INCLUDED
VCSH MENTION AT ALL BUT KSUN, WHICH MAY REMAIN 'PRECIP-SHADOWED'
TONIGHT. THERE IS INDICATION IN MOS GUIDANCE AND FORECAST SOUNDINGS
THAT CEILINGS WILL LOWER AS THE FRONT NEARS. KIDA MAY GET TO IFR
CONDITIONS TONIGHT AND POSSIBLY LIFR BY TOMORROW MORNING. HINSBERGER
PIH WATCHES/WARNINGS/ADVISORIES
NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page