783
FXUS65 KPIH 300520
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
1120 PM MDT SAT MAR 29 2025
KEY MESSAGES
- RAIN AND SNOW SHOWERS WILL SLOWLY DIMINISH TONIGHT, CONTINUING
THROUGH EARLY SUNDAY MORNING IN THE MOUNTAINS EAST OF I-15 TO
THE WYOMING BORDER. OVERALL IMPACTS WILL BE VERY LIMITED.
- A BRIEF RIDGE OF HIGH PRESSURE ON SUNDAY WILL BRING A RETURN
TO MOSTLY DRY CONDITIONS ACROSS THE SNAKE RIVER PLAIN AS
LOCALIZED SNOW SHOWERS CONTINUE IN SOME MOUNTAIN AREAS.
- DAILY PRECIPITATION CHANCES WILL INCREASE FOR EARLY NEXT WEEK
AS A SERIES OF PACIFIC SYSTEMS SUPPORT A MIX OF RAIN/SNOW
SHOWERS AND NEAR NORMAL TO BELOW NORMAL TEMPERATURES.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 117 PM MDT SAT MAR 29 2025
SATELLITE IMAGERY SHOWS WEAKLY CLOSED LOW SPINNING THROUGH IDAHO
EARLY THIS AFTERNOON. MIX OF CLOUDS AND SUN HAVE ALLOWED FOR A
FEW SHOWERS TO DEVELOP AHEAD OF THE LOW, AND A FEW THUNDERSTORMS
WILL STILL BE POSSIBLE THIS AFTERNOON IN AREA OF BEST
INSTABILITY NORTH OF THE LOW. SNOW LEVELS HAVE RISEN SLIGHTLY
WITH THE WARMER TEMPERATURES OF THE DAY, RISING TO 6000-6500 FT
AHEAD OF THE TROUGH AXIS ASSOCIATED WITH THE LOW, AND 5500-6000
FT BEHIND IT THIS AFTERNOON. LOWER ELEVATIONS SHOULD SEE RAIN,
AND THOUGH MOST OF THE SNAKE PLAIN SHOULD BE THE DRIEST OF EAST
IDAHO, CAN'T REALLY RULE OUT A SHOWER ANYWHERE TODAY. SNOW
LEVELS FALL BACK TO VALLEY FLOORS OVERNIGHT TONIGHT WITH LOW
TEMPERATURES BACK TO OR JUST BELOW FREEZING. WRAP AROUND
MOISTURE LINGERS ACROSS THE CENTRAL MOUNTAINS AND ALONG THE
DIVIDE OVERNIGHT, WHILE THE TROUGH STILL LINGERS ALONG THE
EASTERN HIGHLANDS. THERE IS STILL A VERY LOW CONFIDENCE CHANCE
OF LIGHT SNOWS FROM THE WRAP AROUND MOISTURE MAKING IT INTO THE
NORTHERN PORTIONS OF THE SNAKE PLAIN, WITH THE NAM NEST BRINGING
A VERY HINT OF LIGHT PRECIP AS FAR SOUTH AS THE MUD LAKE AREA.
THE LATEST RUNS OF THE OTHER HIGH-RES MODELS HAVE REMAINED DRY
THAT FAR SOUTH, SO HAVE LEFT OUT FOR NOW, BUT THIS MAY BE AN
IMPACT TO WATCH FOR GOING FORWARD INTO TONIGHT. SNOW TOTALS
REMAIN LIGHT, MAXING OUT ROUGHLY 3-5" HIGHER ELEVATIONS ALONG
THE MONTANA BORDER.
SUNDAY STARTS OUT DRY FOR MOST AREAS, BUT WEAK SHORTWAVE EJECTS
NORTHEAST ACROSS IDAHO VERY LATE IN THE DAY. THERE SHOULD BE
ENOUGH SUNSHINE AVAILABLE DURING THE AFTERNOON, THAT AFTERNOON
BUILD-UPS OVER THE SNOWPACK COULD DROP A WEAK SHOWER ACROSS
HIGHER TERRAIN. NOT A SURPRISE THAT THE NBM DEVELOPED BARELY-
THERE 15% POPS ACROSS HIGHER TERRAIN THIS TIME OF YEAR AHEAD OF
THIS SHORTWAVE FEATURE FOR SUNDAY AFTERNOON. BETTER POP AND MORE
ORGANIZED QPF DEVELOP DURING THE EVENING AND OVERNIGHT ACROSS
EAST IDAHO LEADING INTO EARLY NEXT WEEK. TEMPERATURES WARM UP
FOR OVERNIGHT LOWS, SO RAIN WOULD BE EXPECTED AT MOST LOWER
ELEVATIONS.
LONG TERM /MONDAY THROUGH SATURDAY/
ISSUED AT 117 PM MDT SAT MAR 29 2025
THE EXTENDED FORECAST REMAIN AN ACTIVE ONE AS WE WRAP UP MARCH AND
HEAD INTO APRIL. MONDAY WILL STILL BE A "WARMER" DAY WITH HIGHS IN
THE LOW 50S IN THE EASTERN MAGIC VALLEY AND SNAKE RIVER PLAIN WITH
PRECIPITATION CHANCES MAKING THEIR RETURN EARLY MONDAY MORNING AS
THE FIRST WAVE OF ENERGY IS EJECTED FROM A LOW SITTING OFF THE COAST
OF THE PNW MOVES THROUGH OUR AREA. WITH TEMPERATURES WELL ABOVE
FREEZING ON MONDAY AND FALLING TO VERY NEAR FREEZING BY TUESDAY
MORNING, VERY LITTLE TO NO SNOW ACCUMULATION IS EXPECTED DOWN IN THE
EASTERN MAGIC VALLEY AND SNAKE RIVER PLAIN AND ANY SNOW THAT DOES
FALL IN THE UPPER SNAKE RIVER PLAIN WOULD MOSTLY LIKELY STAY BELOW
AN INCH. AS YOU WOULD VENTURE TO GUESS, SNOW TOTALS WILL BE
INCREASING AS YOU GO UP IN ELEVATION WITH THE NBM SHOWING ABOUT A 20
TO 30 PERCENT CHANCE OF AT LEAST 6 INCHES OF SNOW AT GALENA SUMMIT,
A 50 TO 60 PERCENT CHANCE OF AT LEAST 6 INCHES OF SNOW IN THE ISLAND
PARK AREA, AND A 50 TO 60 PERCENT CHANCE OF AT LEAST 8 INCHES OF
SNOW AT EMIGRATION SUMMIT IN THE 48 HOURS FROM MONDAY TO WEDNESDAY
MORNING. THE COLD FRONT THAT COMES THROUGH ON MONDAY WILL BRING
AFTERNOON HIGHS BACK DOWN INTO THE 40S FOR TUESDAY, WEDNESDAY, AND
THURSDAY. LOOK FOR WIND GUSTS TO INCREASE ON TUESDAY, TOO, INTO THE
35 TO 40 MPH RANGE IN THE EASTERN MAGIC VALLEY AND LOWER SNAKE RIVER
PLAIN. WE WILL SEE A BRIEF LULL IN THE ACTIVITY ON WEDNESDAY, BUT
THEN THE NEXT SYSTEM MOVES RIGHT INTO FOR THE SECOND HALF OF THE
WEEK, SO THE OVERALL ACTIVE PATTERN CONTINUES. MODELS ARE SHOWING A
PRETTY SOLID BLOCKING PATTERN SETTING UP OVER THE WEST NEXT WEEKEND
TO GIVE US A BREAK FROM THE PRECIPITATION, BUT WE WILL HAVE TO SEE
HOW THE FORECAST HOLDS BETWEEN NOW AND THEN.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1120 PM MDT SAT MAR 29 2025
TWEAKED INITIAL CONDITIONS IN THE 06Z TAFS TO NUDGE TOWARD
CURRENT OBSERVATIONAL TRENDS, BUT NO MAJOR CHANGES WERE NEEDED
EXCEPT AT KDIJ WHERE THE ONGOING TEMPO WAS LOWERED TO 2SM AND
EXTENDED TO 09Z FOR BRIEF PERIODS OF -SN BASED ON VERIFICATION
SO FAR AND RADAR TRENDS. STILL VERY LOW CONFIDENCE ON HOW ANY
FOG OR (MORE LIKELY) LOW STRATUS MAY EVOLVE IN THE SNAKE
PLAIN/SHOSHONE CORRIDOR OVERNIGHT BASED ON THE LATEST GUIDANCE
LATE THIS EVENING. DELAYED CURRENT FEW015 MENTION BY AN EXTRA
HOUR AT KPIH AND KBYI, BUT OTHERWISE NO CHANGES MADE. IF SOME
DEVELOPMENT OCCURS, STILL SEEING SUPPORT FOR THOSE LOW CLOUDS TO
ERODE FROM SW TO NE BETWEEN 13Z/7AM AND 16Z/10AM AS THE NEXT
HIGHER-LEVEL CLOUD SHIELD ADVANCES IN. MOST OF THE PREVIOUS
DISCUSSION IS INCLUDED BELOW.
ISSUED AT 554 PM MDT SAT MAR 29 2025
TRENDS FOR THE EVENING INTO THE FIRST PART OF THE OVERNIGHT
WILL GENERALLY BE DIMINISHING SHOWERS, VERY SLOWLY DECREASING
WINDS, AND CLOUD COVER TRENDING TOWARD SCT. WE LARGELY FOCUSED
ON REFINING TIMING ON END OF VCSH AND STEPPING THE WINDS DOWN IN
THE 00Z TAFS JUST ISSUED. COULD STILL SEE A BRIEF PERIOD OF -SN
AT KDIJ SOMETIME BETWEEN 04Z/10PM AND 09Z/3AM PER A COUPLE OF
THE CAMS, SO KEPT THE TEMPO GOING THERE. THE HREF DOES SUPPORT A
FAIRLY MOIST LOW-LEVEL AIRMASS TONIGHT WITH GOOD COVERAGE OF RH
VALUES OVER 90%, AND BOTH THE HRRR AND NBM ARE RESPONDING WITH
SOME COMBINATION OF LOW STRATUS AND/OR BR/FOG, BUT IT'S A REALLY
MESSY SETUP. A BREAK IN HIGH-LEVEL CLOUDS FOR THE FIRST HALF OF
THE NIGHT MAY ALLOW FOR A PERIOD OF BETTER RADIATIONAL COOLING,
BUT ANOTHER SHIELD OF SCT TO BKN HIGH-LEVEL CLOUDS IS FORECAST
TO ARRIVE FROM THE PACIFIC BY EARLY MORNING, WHICH WOULD TEND TO
FAVOR STRATUS OVER FOG AND MAY EVEN KEEP ANY STRATUS
DEVELOPMENT A BIT HIGHER OFF THE SFC. MEANWHILE, BOTH THE HRRR
AND NBM FOCUS BEST FOG/STRATUS POTENTIAL OUT OVER THE SNAKE
PLAIN AND SHOSHONE LAVA BEDS NE TO THE ARCO DESERT, KEEPING
KBYI, KPIH, AND KIDA RIGHT ON THE EDGE. AND, A TREND TOWARD
BREAKING ANY DEVELOPMENT UP IS NOTED EARLY TO MID-MORNING
SUNDAY...PERHAPS IN RESPONSE TO THE ADVANCING HIGH-LEVEL CLOUD
SHIELD. ALSO MEANWHILE, MOS GUIDANCE SHOWS NO HITS TO CIGS/VSBYS
ANYWHERE, AND SFC WINDS STAY A BIT ELEVATED FOR A GOOD PORTION
OF THE NIGHT AT KPIH AND KIDA WHICH ISN'T FAVORABLE FOR FOG. ALL
THINGS CONSIDERED...WE HAVE NO CONFIDENCE ON HOW THIS WILL PLAY
OUT. WENT AHEAD AND HINTED AT A PERIOD OF LOWER CLOUDS (FEW015)
AT KBYI/KPIH/KIDA ROUGHLY TIMED OUT WITH NBM/HRRR GUIDANCE FOR
START TIMES, AND JUST LET IT RIDE UNTIL AFTERNOON WIND/VCSH FM
GROUPS KICK IN SUNDAY. SUNDAY IN SOME RESPECTS SHOULD BROADLY
SERVE AS A BREAK BETWEEN SYSTEMS, BUT THERE IS JUST ENOUGH
MOISTURE/INSTABILITY THAT WE ARE CARRYING SOME GENEROUS VCSH
SUNDAY AFTERNOON. OVERALL FORECAST CONFIDENCE IS HIGH IN LOW-
IMPACT, VFR CONDITIONS AT THE TAF TERMINALS AFTER ABOUT 16-
17Z/10-11AM SUNDAY, AND WINDS REGIONWIDE LOOK LIGHTER SUNDAY
AFTERNOON WITH JUST THE NORMAL DIURNAL PATTERN AT KSUN (NO
CROSSWINDS). LOOKING AHEAD, MONDAY WILL FEATURE A RETURN OF MORE
WIDESPREAD RAIN/SNOW, AND LOWER CIGS, AS A MORE SUBSTANTIAL LOW
PRESSURE SYSTEM MOVES INTO THE REGION.
PIH WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...DMH
LONG TERM...AMM
AVIATION...KSMITH
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