Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 200924
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
224 AM MST TUE JAN 20 2015

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT. THERE ARE TWO THINGS
WE ARE KEEPING ON OUR EYE ON TODAY. THE FIRST IS SOME HIGH AND MID
LEVEL MOISTURE STILL WORKING ACROSS THE STATE. THE MODELS ARE
STILL TRYING TO PRODUCE A FEW SNOW SHOWERS ALONG THE WYOMING
BORDER FROM ISLAND PARK TO NEAR PALISADES. WHILE RADAR IS
INDICATING THERE MIGHT BE SOMETHING OUT THERE...WE HAVEN`T SEEN
MUCH. IF ANYTHING FALLS...IT WILL BE LIGHT THAT IS FOR SURE. THE
OTHER IS STRATUS AND SOME FREEZING FOG ACROSS THE SNAKE PLAIN AND
EASTERN HIGHLANDS...INCLUDING ISLAND PARK...THE TETON VALLEY AND
DOWN TO NEAR SODA SPRINGS. THE FOG HAS BEEN DENSE AT TIMES SO BE
AWARE OF QUICK CHANGES IN VISIBILITY AND MAYBE SOME SLICK SPOTS.
THIS SHOULD THIN OUT THIS AFTERNOON ALTHOUGH WE WOULDN`T BE
SURPRISED TO SEE SOME POCKETS HANGING TOUGH AS THE WIND FLOW
WEAKENS DURING THE DAY.

THINGS SHOULD BE QUIET UNTIL THURSDAY IN TERMS OF ANY CHANCE OF
RAIN OR SNOW. HIGH PRESSURE STRENGTHENS SOMEWHAT ACROSS THE
WEST...INCLUDING HERE IN EASTERN IDAHO. THAT MEANS VALLEY
INVERSIONS ARE BACK WITH SOME LOW CLOUDS AND FREEZING FOG FOR MANY
LOCATIONS. STRATUS AND FOG WILL BE MOST PREVALENT FROM THE LATE
EVENING HOURS THROUGH EARLY AFTERNOON BOTH TOMORROW AND THURSDAY.
WE WENT WITH PATCHY AND DENSE FREEZING FOG IN THE FORECAST...WITH
THE IDEA WE WILL LIKELY NEED TO ADJUST THINGS AS EVERYTHING
EVOLVES DAILY. WHERE THE INVERSIONS HOLD AND SKIES MORE
CLOUDY...HIGHS WILL ONLY BE IN THE 20S AND LOW 30S FOR THE MOST
PART. WHERE THEY WEAKEN AND UP IN THE MOUNTAINS...WE WILL SEE A
MIX OF SUN AND HIGH CLOUDS WITH HIGHS TRYING TO PUSH TOWARD 40 BY
THURSDAY. THE QUESTION IN THE SHORT TERM IS WHAT HAPPENS THURSDAY
NIGHT AS WEAKENING WAVE CROSSES EASTERN IDAHO. THE MODELS DO BRING
MORE CLOUDS IN AND SOME LIGHT MOUNTAIN SNOW ACROSS THE
NORTH ALONG THE BORDER WITH MONTANA AND LEMHI COUNTY. WE DID
INCLUDE A VERY SMALL CHANCE IN THOSE AREAS. THE BIGGER QUESTION IS
WILL THIS WAVE BE ENOUGH TO ELIMINATE STRATUS AND FOG. WE KEPT
WITH PERSISTENCE AND INCLUDED IT MAINLY FOR THE SNAKE PLAIN AND
INTO THE ISLAND PARK AREA...BANKING ON THE SYSTEM TO NOT BE
STRONG ENOUGH TO GET RID OF IT.  KEYES

.LONG TERM...FRIDAY THROUGH NEXT TUESDAY. THE GFS AND ECMWF CONTINUE
TO SHOW A HIGH PRESSURE RIDGE GRADUALLY BUILDING INTO THE COASTAL
STATES WITH WEAK SYSTEMS TOPPING THE RIDGE AND PLUNGING SOUTH INTO
THE UPPER MID-WEST. UNDER THIS FLOW REGIME...HAVE MAINTAINED
THE SLIGHT CHANCE MENTION OF PRECIPITATION ALONG THE MONTANA/WYOMING
BORDER REGIONS AND CONTINUED TO UNDERCUT MEX STATISTICAL TEMPERATURE
GUIDANCE DUE TO THE LIKELIHOOD OF AN INVERTED TEMPERATURE PROFILE.
HUSTON

&&

.AVIATION...A BROAD AREA OF STRATUS (MVFR CIGS) WAS EXPANDING
ACROSS  THE SNAKE RIVER PLAIN EARLY THIS MORNING AND EXTENDING
WESTWARD TOWARD SHOSHONE. MODEL CROSS SECTIONS SUGGEST THAT THE
STRATUS WILL LINGER AT KPIH AND KIDA THROUGH AT LEAST NOON THEN
GRADUALLY ERODE FROM SW TO NE DURING THE AFTN/EVE. KBYI AND KSUN
REMAIN LARGELY VFR WITH SOME PASSING HIGH CLOUDS. DIFFICULT TO SAY
WHAT MAY HAPPEN LATE TONIGHT/WEDNESDAY MORNING AS THE MODELS SHOW
LINGERING LOW LEVEL MOISTURE BUT NOT AT THE LEVELS SEEN THIS
MORNING. THE STATISTICAL GUIDANCE WAS LARGELY SPLIT ON THE ISSUE.
THE TREND IS USUALLY YOUR FRIEND...THUS WE WILL LIKELY GO WITH
PERSISTENCE FOR NOW AND INDICATE SOME SORT OF STRATUS AND/OR FOG AT
KIDA AND KPIH. HUSTON

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$







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