250
FXUS65 KPIH 191218
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
518 AM MST MON JAN 19 2026
KEY MESSAGES
- FOG AND LOW CLOUDS WILL CONTINUE TO AFFECT SOME AREAS THROUGH
TUESDAY, ESPECIALLY DURING THE OVERNIGHT AND MORNING PERIODS,
AMID A CONTINUED QUIET WEATHER PATTERN FOR THE REGION.
- A PATTERN SHIFT IS EXPECTED BY FRIDAY WITH A TROUGH MOVING
THROUGH, WHICH SHOULD CLEAR OUT THE DAILY FOG AND STRATUS.
HOWEVER, MODELS HAVE PUSHED OFF ANY PRECIPITATION UNTIL NEXT
WEEKEND.
SHORT TERM /THROUGH TUESDAY/
ISSUED AT 231 AM MST MON JAN 19 2026
HIGH PRESSURE WILL REMAIN IN PLACE TODAY AND TUESDAY (AND
THROUGH MOST OF THE WEEK). EXPECT CONTINUED FOG AND STRATUS EACH
MORNING, ESPECIALLY FOR THE EASTERN MAGIC VALLEY, SHOSHONE AREA,
SNAKE PLAIN, AND ADJACENT VALLEYS. THE MORE WIDESPREAD LOWER
FOG WILL CONTINUE TO BE IN THE EASTERN MAGIC VALLEY, BUT EXPECT
FOG TO CONTINUE TO SPREAD NORTHWARD INTO THE SNAKE RIVER PLAIN
AS WELL. A DENSE FOG ADVISORY REMAINS IN EFFECT THIS MORNING FOR
THE EASTERN MAGIC VALLEY, SHOSHONE AREA, AND THE LOWER SNAKE
RIVER PLAIN. A DENSE FOG ADVISORY WILL LIKELY BE NEEDED FOR
THESE ZONES ON TUESDAY MORNING AS WELL.
TEMPERATURES WILL REMAIN IN THE 20S AND 30S WHERE INVERSION AND
LINGERING FOG/STRATUS HOLD TEMPERATURES DOWN, OTHERWISE WE WILL
SEE SOME LOWER 40S AROUND.
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/
ISSUED AT 1244 PM MST SUN JAN 18 2026
WE ARE STILL LOOKING AT A PATTERN CHANGE, BUT IT APPEARS TO MORE
OF ANOTHER SHIFT IN WHERE THE LOW/HIGH PATTERN SETS UP. THE
RIDGE BREAKS DOWN, BUT NOW VERY BRIEFLY AND ENDS UP
REESTABLISHING ITSELF FARTHER OUT IN THE PACIFIC. THERE IS A
CLOSED LOW STILL EXPECTED TO DROP INTO THE SOUTHWEST U.S. AS
THIS HAPPENS, WE STILL ACTIVE WEATHER WITH THE OVERALL LOW
PRESSURE PATTERN OVER THE NORTHERN U.S. SHIFTING WEST. THERE IS
SOME MOISTURE EMBEDDED WITHIN THE PATTERN, SO PRECIPITATION
EVENTUALLY RETURNS, LIKELY LATER THURSDAY OR FRIDAY NOW. IT
STILL LOOKS LIKE THE MOUNTAINS WILL SEE MOST OF WHAT FALLS, BUT
WITH THE FLOW NOW REMAINING MORE NORTHERLY...THAT MEANS MOISTURE
WILL BE MUCH LESS THAN WHEN IT LOOKED LIKE WE MIGHT GET MORE A
DIRECT SHOT FROM THE PACIFIC. ANY MOISTURE WE SEE IS LIKELY NOT
GOING TO PUT ANY DENT INTO OUR LACK OF PRECIPITATION ISSUES OF
LATE, ESPECIALLY AT LOWER ELEVATIONS. TEMPERATURES DO WARM UP
JUST A BIT LATER IN THE WEEK, BUT THAT IS LIKELY DUE JUST LOSING
THE RIDGE AND SOME MIXING TAKES PLACE.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 512 AM MST MON JAN 19 2026
FOG AND STRATUS CONTINUE TO BRING IFR/LIFR CONDITIONS FOR BYI,
PIH AND IDA THIS MORNING UNDER STRONG HIGH PRESSURE. VISIBILITY
HAS IMPROVED FASTER THAN EXPECTED FOR PIH AND IDA THIS MORNING.
EXPECT GRADUAL IMPROVEMENT TO CONTINUE THIS MORNING. PIH AND IDA
ARE LIKELY TO BECOME VFR BY MID TO LATE MORNING. BYI COULD HANG
ON TO STRATUS UNTIL LATE MORNING TO EARLY AFTERNOON. LIGHT
WINDS WILL CONTINUE FOR ALL TAF SITES. FOG AND STRATUS WILL
LIKELY RETURN FOR BYI, PIH AND IDA FOR TOMORROW MORNING AS WELL.
STRONG HIGH PRESSURE WILL NOT LIKELY LIFT UNTIL LATE THIS WEEK.
AIR QUALITY
ISSUED AT 1244 PM MST SUN JAN 18 2026
WE HAVE EXTENDED THE AIR STAGNATION ADVISORY OUT THROUGH TUESDAY
FOR NOW. WE REALLY HAVEN'T SEEN ANY MOVEMENT OF POOR AIR ACROSS
THE POCATELLO AREA AS WELL AS ACROSS THE CACHE VALLEY, EVEN WITH
THE FLOW MORE NORTHERLY AND NO LONGER DIRECTLY UNDER THE
RIDGE. THIS PATTERN SHOULD HOLD THROUGH TUESDAY. WE DO SEE THE
PATTERN CHANGE, OR MORE OF A SHIFT FARTHER WEST AGAIN, BY
MIDWEEK. THE ISSUE THAT WE WILL SEE INCREASE IN WIND AND
PRECIPITATION, BUT MOISTURE POTENTIAL IS LOWER THAN BEFORE AND
THE PATTERN SHIFT MAY NOT BE STRONG OR DIFFERENT ENOUGH TO
COMPLETELY SCOUR THINGS OUT ESPECIALLY DOWN NEAR THE UTAH
BORDER. STAY TUNED.
PIH WATCHES/WARNINGS/ADVISORIES
DENSE FOG ADVISORY UNTIL 10 AM MST THIS MORNING FOR IDZ051-054-
055.
AIR STAGNATION ADVISORY UNTIL NOON MST TUESDAY FOR IDZ054-059.
SHORT TERM...TW
LONG TERM...KEYES
AVIATION...TW
AIR QUALITY...KEYES
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