334
FXUS65 KPIH 281956
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
156 PM MDT FRI MAR 28 2025
KEY MESSAGES
- SHOWERS THROUGH THE EVENING MAINLY HIGHER ELEVATIONS
- SHOWERS INCREASE INTO SATURDAY, WITH SNOW LEVELS LOWERING
CLOSE TO VALLEY FLOORS AROUND SUNRISE. SOME VALLEY LOCATIONS
COULD SEE A MIX OR A BRIEF CHANGE-OVER TO SNOW AT THAT TIME WITH
VERY LIGHT ACCUMULATIONS.
- A BRIEF RIDGE OF HIGH PRESSURE ON SUNDAY WILL KEEP CONDITIONS
MOSTLY DRY AHEAD OF A MORE ACTIVE PATTERN BUILDING IN FOR MUCH
OF NEXT WEEK WITH DAILY PRECIPITATION CHANCES RETURNING.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED AT 109 PM MDT FRI MAR 28 2025
AIR QUALITY HAS IMPROVED FOLLOWING DUST INTRUSION FROM NEVADA
BEHIND COLD FRONT LAST NIGHT. WATER VAPOR SATELLITE IMAGERY
SHOWS TWO FEATURES OF NOTE. FIRST IS SHORTWAVE COMPLEX LIFTING
NORTHEAST OUT OF DESERT SOUTHWEST THROUGH NEVADA/UTAH, SPREADING
MID AND HIGH MOISTURE NORTH ACROSS THE SOUTHERN HALF OF THE
FORECAST AREA. A FEW LIGHT RADAR RETURNS ARE ASSOCIATED WITH
THIS FEATURE, EXPECTED TO WEAKLY FILL IN ACROSS THE SOUTHEAST
CORNER THIS AFTERNOON AND EVENING. THE SECOND FEATURE IS
SHORTWAVE LIFTING NORTHEAST THROUGH OREGON TOWARD THE IDAHO
PANHANDLE. THIS FEATURE ALREADY PRODUCING ISOLATED TO SCATTERED
SHOWERS ACROSS THE CENTRAL MOUNTAINS. THE SHOWER ACTIVITY WILL
CONTINUE TO DEVELOP THROUGH THE EVENING, AND IS EXPECTED TO
SPREAD INTO THE REMAINDER OF THE REGION ALONG THE DIVIDE. A
BRIEF BREAK WILL BE POSSIBLE OVERNIGHT BEHIND THIS SYSTEM.
BY EARLY SATURDAY MORNING, NEXT FEATURE EJECTS OUT OF PACIFIC
LOW TOWARD EAST IDAHO AS A WEAKLY CLOSED LOW. SHOWERS REDEVELOP
LATE FRIDAY NIGHT AND BEGIN SPREADING ACROSS EAST IDAHO. EXPECT
SNOW LEVELS TO LOWER TOWARD VALLEY FLOORS FRIDAY NIGHT. SOME
REGIONS COULD SEE SNOW LEVELS LOWER ENOUGH FOR RAIN TO MIX WITH
OR COMPLETELY CHANGE OVER TO SNOW AROUND SUNRISE AS SNOW. THE
BEST CHANCE FOR LIGHT ACCUMULATIONS AT VALLEY FLOORS COINCIDENT
WITH THE INCREASING CHANCES OF PRECIPITATION WILL OCCUR IN THE
EASTERN MAGIC VALLEY AND RAFT RIVER REGIONS. PROBABILISTIC 6HR
SNOWFALL ACCUMULATIONS SUPPORT UP TO 1" OF SNOWFALL AT THE 90TH
PERCENTILES. GIVEN THE RECENT WARM TEMPERATURES, THE GROUND MAY
BE TOO WARM TO SUPPORT MUCH ACCUMULATION WITH FORECAST LOWS
STILL JUST ABOVE FREEZING. TEMPERATURES ON SATURDAY COOL A FEW
MORE DEGREES FROM TODAY'S HIGHS, WITH SHOWERS BECOMING MORE
WIDESPREAD ACROSS EAST IDAHO THROUGHOUT THE DAY. SNOW LEVELS
RISE TO AN AVERAGE OF ABOUT 6000 FT ELEVATION ACROSS THE
FORECAST AREA, SO VALLEY RAIN/MOUNTAIN SNOW SHOULD BE THE RULE
FOR MOST AREAS. SHORTWAVE FEATURE SHIFTS EAST OVERNIGHT SATURDAY
NIGHT, PUSHING PRECIPITATION EAST THROUGH THE PERIOD.
LONG TERM /SUNDAY THROUGH THURSDAY/
ISSUED AT 109 PM MDT FRI MAR 28 2025
BEHIND ONE SHORTWAVE TROUGH, WE GET A VERY SHORT-LIVED BREAK IN OUR
ACTIVE PRECIPITATION PATTERN ON SUNDAY AS A WEAK, TRANSIENT RIDGE
PASSES THROUGH EASTERN IDAHO. HIGHS ON SUNDAY AND MONDAY WILL BE
NEARLY IDENTICAL, IN THE UPPER 40S AND LOW 50S ACROSS THE EASTERN
MAGIC VALLEY AND SNAKE RIVER PLAIN WITH MILD TEMPERATURES IN THE LOW
TO MID 40S IN OUR MID ELEVATION TOWNS. WHILE SUNDAY IS A DRIER DAY,
PRECIPITATION RETURNS ON MONDAY WITH VALLEY RAIN AND MOUNTAIN SNOW.
LOOKING TO MONDAY AND TUESDAY, IVT INCREASES AS WE TAP INTO SOME
MORE OF THE PACIFIC MOISTURE AVAILABLE, WITH THE NBM SHOWING ABOUT A
70 PERCENT CHANCE OF ALMOST ALL OF EASTERN IDAHO SEEING AT LEAST A
TENTH OF AN INCH OF QPF IN THE 48 HOURS FROM MONDAY MORNING TO
WEDNESDAY MORNING. IT ALSO SHOWS ABOUT A 20 TO 40 PERCENT CHANCE OF
A QUARTER INCH OF QPF IN THE EASTERN MAGIC VALLEY AND SNAKE RIVER
PLAIN FOR THE SAME TIME FRAME. TEMPERATURES WILL BE VERY NEAR
FREEZING ON TUESDAY MORNING, SO THERE IS ALSO THE POTENTIAL FOR SOME
LIGHT SNOWFALL IN THE VALLEYS, TOO, THOUGH WE'RE TALKING SNOW TOTALS
GENERALLY LESS THAN AN INCH. IN THAT 48-HOUR TIME RANGE, WE MAY BE
LOOKING AT SOME LOW-END WINTER WEATHER ADVISORY LEVEL SNOWFALL FOR A
FEW OF OUR MOUNTAIN PASSES (ABOUT 6" OF SNOW), PARTICULARLY IN THE
EASTERN HIGHLANDS, THOUGH IT'S STILL A LITTLE TOO EARLY TO COMMIT TO
THOSE SNOW TOTALS. HIGHS REMAIN IN THE 40S FOR WEDNESDAY AND
THURSDAY AS OUR ACTIVE PATTERN CONTINUES. BREEZY WINDS ARE EXPECTED
EACH AFTERNOON, TOO, WITH GUSTS OF 25 TO 35 MPH. IT LOOKS LIKE GUSTS
WILL BE A BIT STRONGER ON TUESDAY AFTERNOON, PUSHING CLOSER TO 40 OR
EVEN 45 MPH IN THE EASTERN MAGIC VALLEY AND LOWER SNAKE RIVER PLAIN.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1124 AM MDT FRI MAR 28 2025
BY NOW, MOST OF THE DUST HAS BEEN ABLE TO MIX OUT AND IS NO LONGER
IMPACTING VIS AT OUR TAF SITES. WINDS ARE PICKING UP A BIT NOW, TOO,
WITH GUSTS EXPECTED TO REMAIN AROUND 20-25 KTS AT BYI, PIH, AND IDA
WITH LIGHTER WINDS EXPECTED AT SUN AND DIJ. OVERALL, EXPECT VFR
CONDITIONS TO PERSIST. TODAY WILL BE MOSTLY DRY, BUT SOME
ELEVATION BASED SHOWERS WILL MEAN THE NEED FOR VCSH TO REMAIN IN
THE FORECAST FOR SUN, DIJ, AND BYI. THE NEXT MORE ORGANIZED
ROUND OF MOISTURE ARRIVES ON SATURDAY AROUND 13-14Z. THE HRRR
WANTS TO BRING THIS MOISTURE INTO MORE OF THE SNAKE RIVER PLAIN
THAN THE NAM NEST WHICH KEEPS MORE OF THE MOISTURE IN THE SOUTH
HILLS AND SOUTHEASTERN HIGHLANDS. SINCE THIS IS ARRIVING TOWARDS
THE END OF THIS TAF FORECAST PERIOD, WILL GO WITH ADDITIONAL
VCSH AT SUN AND PIH FOR NOW AND HIGHLIGHT THE POTENTIAL FOR -RA
AT BYI, THOUGH IT SHOULD BE NOTED THERE IS ABOUT A 10 TO 20
PERCENT CHANCE OF -SN MIXING WITH -RA AT BYI.
HYDROLOGY
ISSUED AT 109 PM MDT FRI MAR 28 2025
TEMPERATURES HAVE COOLED ENOUGH ACROSS EAST IDAHO BEHIND THE
PASSAGE OF THE COLD FRONT LAST NIGHT TO SIGNIFICANTLY SLOW THE
LOW AND MID-ELEVATION SNOW MELT AND RUNOFF. ALTHOUGH SHOWERS ARE
EXPECTED THROUGH THE WEEKEND INTO NEXT WEEK, TEMPERATURES ARE
ALSO EXPECTED TO CONTINUE A SLOW DECLINE, WITH OVERNIGHT LOWS
FORECAST TO DROP TO AROUND OR JUST ABOVE FREEZING, INCLUDING AT
LOWER ELEVATIONS. THIS SHOULD FURTHER MITIGATE THE ACCELERATED
RUNOFF OF THE PREVIOUS WARM SPELL. LOCALIZED IMPACTS WILL STILL
BE POSSIBLE, BUT WIDESPREAD IMPACTS ARE NOT ANTICIPATED.
THEREFORE, THE HYDROLOGIC OUTLOOK WILL NOT BE UPDATED TODAY.
PIH WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...DMH
LONG TERM...AMM
AVIATION...AMM
HYDROLOGY...DMH
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