FXUS65 KPIH 111016
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
316 AM MST FRI DEC 11 2009

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT. THE WELL ADVERTISED
CHANGE FROM ARCTIC COLD TO A PATTERN ORIGINATING FROM THE PACIFIC
WILL CONTINUE TODAY. CLOUDS WILL BE INCREASING AHEAD OF A SYSTEM
OUT IN THE PACIFIC. BY TONIGHT...THE FIRST ROUND OF SNOW WILL MOVE
ACROSS THE AREA. SINCE THE COLD AIR WILL BE IN PLACE ESPECIALLY IN
THE VALLEYS WITH THE INVERSION HOLDING...THE SNOW TONIGHT WILL BE
STILL SOMEWHAT FLUFFY WITH UP TO 2 INCHES POSSIBLE FOR THE
MOUNTAINS AND GENERALLY AN INCH OR LESS FOR THE VALLEYS. THE WIND
WILL NOT BE TOO MUCH OF A PROBLEM EXCEPT FOR DRAINAGE WINDS OUT OF
THE SOUTHERN HIGHLANDS INTO THE MAGIC VALLEY. IN THIS AREA...SOME
LOCALIZED BLOWING SNOW IS POSSIBLE. 

FOR SATURDAY AND MOST OF SUNDAY...ITS ONLY GETS MORE MESSY ACROSS ALL OF
EASTERN IDAHO. TEMPERATURES WILL CONTINUE TO WARM. AFTERNOON HIGHS
WILL JUMP UP TO THE LOW AND MID 30S FOR THE LOWER VALLEYS...WITH
LOWS IN THE TEENS AND 20S. THIS WILL MEAN THE SNOW WILL HAVE MORE
MOISTURE CONTENT. THAT ALSO MEANS WE SHOULD SEE SNOW FALLING AND
MELTING DURING THE DAYTIME PLUS MELTING OF EXISTING
SNOWPACK...THEN WATCHING IT REFREEZE AT NIGHT. FURTHER COMPLICATING
THE MATTER IS THE MODELS ARE STRUGGLING ON WHERE TO PLACE THE BULK
OF THE SNOW AS THE MAIN SYSTEM WEAKENS AND APPEARS TO BE MOVING
ACROSS THE REGION A LITTLE FARTHER SOUTH. THIS WOULD PUT THE
HEAVIER OVERALL SNOW ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA...WITH UPSLOPE KEEPING SOME HIGHER AMOUNTS ACROSS THE UPPER
SNAKE HIGHLANDS. THE OVERALL IDEA IS THERE IN BOTH THE GFS AND
NAM...HOWEVER THEY ARE NOT CONSISTENT ON EXACT PLACEMENT OF THE
HEAVIEST AREA OF SNOW. BLOWING SNOW...AND POSSIBLE DRIFTING WILL
LIKELY BE MORE LOCALIZED THROUGH SATURDAY NIGHT WHERE STRONGER
WINDS DEVELOP AT RIDGETOP AND DRAINING INTO THE SNAKE PLAIN. THE
WIND PATTERN OVERALL WILL PICK UP SUNDAY. WITH THE WARMER
TEMPERATURES...THIS MAY ONLY BE AN ISSUE IN THE HIGHER ELEVATIONS.
FOR NOW WILL LET THE DAY SHIFT DECIDE ON ANY WINTER WEATHER
HIGHLIGHTS WITH STILL THIS MUCH UNCERTAINTY INVOLVED. WILL HIGHLIGHT
IN VARIOUS PRODUCTS THAT MANY MOUNTAIN RANGES WILL LIKELY SEE QUITE A
BIT OF SNOW OVER THE WEEKEND...WITH THE SNAKE PLAIN SEEING LOWER
AMOUNTS OF SNOW OVER A 36 HOUR PERIOD. 

FOR SUNDAY NIGHT...THE WEAKENING STORM WILL CONTINUE TO MOVE ON TO
THE EAST AND LEAVE EASTERN IDAHO IN A DRYING WEST TO NORTHWEST
FLOW. SOME ADDITIONAL SNOWFALL IS LIKELY ESPECIALLY ACROSS THE
EASTERN/SOUTHEASTERN MOUNTAINS. IT WILL REMAIN BREEZY WHICH WOULD
SPELL MORE POSSIBLE TO BLOWING/DRIFTING SNOW IN SOME AREAS.  KEYES

.LONG TERM...MONDAY THROUGH NEXT FRIDAY. A MOIST NW FLOW WILL REMAIN 
OVER THE REGION MONDAY AS A RIDGE OF HIGH PRESSURE BUILDS OVER THE 
PAC WEST STATES. THERE ARE SOME RUN TO RUN INCONSISTENCIES...HOWEVER 
THE OVERALL IDEA BETWEEN THE GFS/ECMWF IS TO MAINTAIN A MODEST/DIRTY 
(MOIST) RIDGE OVER THE WEST THROUGH THE PERIOD WITH OCCASIONAL 
TOPPING WAVES PROVIDING ENHANCED OPPORTUNITIES FOR PRECIPITATION 
ACROSS PRIMARILY THE NRN MOUNTAINS. THUS HAVE MAINTAINED SOME 
MENTION OF PRECIPITATION THROUGHOUT THE FORECAST PERIOD. 
TEMPERATURES...HAVING WARMED OVER THE WEEKEND...WILL REMAIN AT OR 
SLIGHTLY BELOW CLIMATOLOGICAL NORMS THROUGH THE PERIOD. HUSTON

&&

.AVIATION...CLEAR SKIES (VFR CONDITIONS) ABOUND EARLY THIS MORNING. 
A WEAK THREAT OF FOG/LOW STRATUS REMAINS A POTENTIAL FOR KIDA/KPIH 
THROUGH MID-MORNING. INCREASING MOISTURE (MVFR TO IFR CIGS AND LIGHT 
SNOW) WILL SPREAD INTO THE REGION AFTER 06Z TONIGHT AS A PACIFIC 
DISTURBANCE MOVES INTO CALIFORNIA. HUSTON

&&

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

$$