Area Forecast Discussion
Issued by NWS Boise, ID

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000
FXUS65 KBOI 192213
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
313 PM MST FRI DEC 19 2014

.SHORT TERM...TONIGHT THROUGH SUNDAY...A VERY STRONG AND WET
WINTER STORM IS ON ITS WAY INTO THE REGION TOMORROW THROUGH
SUNDAY. A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR THE WEST-
CENTRAL AND BOISE MOUNTAINS AND CAMAS PRAIRIE. SEE THE ADVISORY FOR
DETAILS ON TIMING AND SNOW AMOUNTS. SNOW LEVELS WILL INITIALLY BE
AROUND 4000 FEET...BUT WILL RISE RAPIDLY SATURDAY NIGHT INTO EARLY
SUNDAY AS A WARM FRONT PUSHES INTO THE REGION FROM THE SOUTHWEST.
SNOW LEVELS NEAR MCCALL WILL BE VERY CLOSE TO THE GROUND SUNDAY
MORNING INTO SUNDAY AFTERNOON...LEADING TO CONSIDERABLE
UNCERTAINTY ON FINAL SNOW TOTALS. AT THIS POINT...WE ARE GOING
WITH A FORECAST THAT CHANGES IT TO A MIX SUNDAY MORNING...WHICH
SIGNIFICANTLY LIMITS THE SNOW THAT WOULD OCCUR SHOULD IT REMAIN
ALL SNOW THROUGH SUNDAY. THE CURRENT FORECAST OF AROUND 9 INCHES
IN MCCALL BY MIDDAY SUNDAY COULD END UP BEING CLOSER TO 15 INCHES
SHOULD IT REMAIN ALL SNOW. ELSEWHERE...NO SNOW IS EXPECTED IN THE
TREASURE VALLEY. RAINFALL WILL LIKELY INCREASE MID-AFTERNOON
SATURDAY AND THE HEAVIEST RAIN IS EXPECT TO LAST INTO THE EVENING. AS
SNOW LEVELS RISE SATURDAY NIGHT INTO SUNDAY MORNING...EVEN PLACES
LIKE BOGUS BASIN WILL CHANGE OVER TO RAIN AND REMAIN ALL RAIN
SUNDAY AFTERNOON. TEMPS WILL STAY ABOVE NORMAL THROUGH THE SHORT
TERM. WINDS WILL BE LIGHT FOR MOST AREAS. HOWEVER...RIDGES ABOVE
AROUND 6000 FEET IN ERN OREGON AND ABOVE 7000 FEET IN SW IDAHO
WILL SEE GUSTS TO 40 MPH SATURDAY NIGHT AND EARLY SUNDAY. RAINFALL
AMOUNTS WILL BE HIGH EVEN IN LOWER ELEVATIONS. TOTALS IN THE SHORT
TERM WILL RANGE FROM A HALF INCH TO ONE INCH IN THE VALLEYS...WITH
TOTALS...OR LIQUID EQUIVALENT AMOUNTS...OF ONE TO TWO AND A HALF
INCHES IN THE MOUNTAINS. THERE ARE NO CONCERNS WITH RIVER FLOODING
OWING TO THE PRESENT CAPACITY AVAILABLE IN THE RIVER SYSTEMS.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...SUNDAY NIGHT
WIDESPREAD RAIN AND SNOW WILL CONTINUE OVER THE MOUNTAINS BUT
DECREASE TO SCATTERED SHOWERS IN THE VALLEYS...WITH SNOW LEVELS
RANGING FROM 5000 FEET IN THE NORTH TO 8000 FEET IN THE SOUTH. ON
MONDAY SHOWERS WILL DECREASE IN COVERAGE WITH ONLY LIGHT AMOUNTS
UNDER DRIER MORE NORTHERLY UPPER LEVEL FLOW AHEAD OF A BUILDING
RIDGE. MODELS ALL SHOW THE RIDGE SHIFTING INLAND OVER THE
INTERMOUNTAIN REGION ON TUESDAY...THEN WEAKENING ON WEDNESDAY AHEAD
OF THE NEXT PACIFIC WEATHER SYSTEM. PRECIPITATION WILL BE CONFINED
MAINLY OVER OUR NORTHERN MOUNTAINS MONDAY NIGHT THROUGH TUESDAY
NIGHT...THEN SPREAD ACROSS MOST OF OUR CWA ON WEDNESDAY. SNOW LEVELS
ON WEDNESDAY WILL RANGE FROM ABOUT 4500 FEET OVER THE MOUNTAINS OF
BAKER COUNTY OREGON AND CENTRAL IDAHO UP TO 7000 FEET ALONG THE
NEVADA BORDER. TEMPERATURES WILL REMAIN 10 TO 15 DEGREES ABOVE
AVERAGE.

WEDNESDAY NIGHT THROUGH FRIDAY...A COLD MOIST SHORTWAVE WILL AFFECT
OUR REGION BEGINNING WEDNESDAY NIGHT INTO CHRISTMAS MORNING. MOST OF
THE PRECIPITATION WILL TAPER OFF BY CHRISTMAS AFTERNOON EXCEPT FOR
HIGHER ELEVATIONS. THERE IS SOME UNCERTAINTY ABOUT WHAT FORM THE
PRECIPITATION WILL TAKE AS MODEL RUNS HAVE BEEN INCONSISTENT.
CURRENTLY IT LOOKS LIKE SNOW LEVELS MAY NOT FALL BELOW 3000 FT UNTIL
THE BULK OF PRECIPITATION HAS PASSED. TEMPERATURES WILL DECREASE TO
NEAR NORMAL WITH THE PASSING SHORTWAVE. COLD TEMPERATURES AND A
CHANCE OF PRECIPITATION IN THE MOUNTAINS WILL CONTINUE THROUGH
FRIDAY.

&&

.AVIATION...SNOW ABOVE 4500 FT MSL...WITH MOUNTAIN OBSCURATION AND
AREAS OF MVFR AND LOCAL IFR CONDITIONS...WILL CONTINUE THROUGH THIS
EVENING OVER THE CENTRAL IDAHO MOUNTAINS INCLUDING KMYL. LOWER
ELEVATIONS WILL SEE MAINLY VFR CONDITIONS WITH SCATTERED RAIN
SHOWERS. AFTER 06Z AREAS OF MVFR SNOW...AND RAIN BELOW 3500 FT
MSL...WILL SPREAD INTO HARNEY COUNTY...THEN ACROSS MOST OF SOUTHEAST
OREGON AND SOUTHWEST IDAHO AFTER 12Z. AFTER 18Z EXPECT WIDESPREAD
MVFR AND LOCAL IFR CONDITIONS WITH SNOW LEVELS NEAR 4000 FT MSL.
SURFACE WINDS...EAST TO SOUTH 10-20 KTS. WINDS ALOFT...SOUTHWEST 15-
25 KTS UP THROUGH 10K FT MSL.

OUTLOOK FOR SATURDAY NIGHT AND SUNDAY...CONDITIONS WILL IMPROVE TO
MAINLY VFR ACROSS SOUTHEAST OREGON SOUTH OF A KBNO-KONO LINE. EXPECT
LITTLE OR NO IMPROVEMENT FOR SOUTHWEST IDAHO AND BAKER COUNTY
OREGON.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WINTER WEATHER ADVISORY FROM 11 AM SATURDAY TO 11 AM MST SUNDAY
     IDZ011-013.
     WINTER WEATHER ADVISORY FROM 11 AM SATURDAY TO 5 AM MST SUNDAY
     IDZ028.
OR...NONE.

&&

$$

WEATHER.GOV/BOISE

SHORT TERM...SP
LONG TERM....JT/AB
AVIATION.....JT



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