Area Forecast Discussion
Issued by NWS Boise, ID

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000
FXUS65 KBOI 131650
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
950 AM MST SAT FEB 13 2016

.DISCUSSION...FOG HAS FORMED IN PARTS OF THE UPPER AND LOWER
TREASURE VALLEY THIS MORNING...BUT SHOWS SIGNS OF BURNING OFF NOW
AND IS NOT EXPECTED TO MAKE IT TO NOON MST. SKIES WILL BE MOSTLY
CLEAR THIS AFTERNOON...BUT WILL INCREASE RAPIDLY FROM THE
NORTHWEST LATE THIS AFTERNOON INTO THIS EVENING AS A WARM FRONT
ALONG WITH A SIGNIFICANT PUSH OF MOISTURE MOVES IN. LATEST MODEL
TRENDS INCREASE QPF WITH THIS SYSTEM...AND WE WILL LIKELY RAISE
POPS AND QPF IN THE AFTERNOON PACKAGE AFTER THE FULL SUITE OF
MORNING DATA ARRIVES. NO CHANGES AT THIS TIME.

&&

.AVIATION...LOCAL MVFR/IFR CONDITIONS IN PATCHY VALLEY FOG BEFORE
18Z. OTHERWISE VFR CONDITIONS TODAY. PRECIPITATION WILL SPREAD
INTO BAKER COUNTY AND THE WEST CENTRAL MOUNTAINS AS EARLY AS
SUN/03Z UNDER A NW FLOW ALOFT...WILL BECOME WIDESPREAD THROUGH THE
REGION BEFORE SUN/12Z. SNOW LEVELS AROUND 4-5K FEET MSL. SURFACE
WINDS...WEST TO NORTHWEST 5-15 KTS. WINDS ALOFT THROUGH 10K FT
MSL...WEST 20-30 KT...BECOMING NW 35-50 KTS BEFORE SUN/18Z.

OUTLOOK FOR SUNDAY...WIDESPREAD PRECIPITATION WILL DECREASE AFTER
18Z TO ISO-SCT SHOWERS ACROSS THE HIGHER ELEVATIONS. SNOW LEVELS
WILL RISE TO 5-7K FEET MSL IN THE AFTERNOON.

&&

.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH SUNDAY...UPPER TROUGH WILL MOVE
THROUGH THE AREA TODAY. THE BULK OF THE MOISTURE WILL BE TO OUR
NORTH. THE SOUTHERN EDGE OF THE TROUGH WILL BRING SHOWERS TO THE
BOISE MOUNTAINS AND WEST CENTRAL MOUNTAINS THIS MORNING...AND THEN
WILL DECREASE DURING THE AFTERNOON AS THE TROUGH EXITS TO OUR
EAST. THE WEAK INVERSION THIS MORNING WILL BE REMOVED THIS
AFTERNOON AS NORTHWEST WINDS AND COLDER AIR ALOFT FOLLOWS A COLD
FRONT. TEMPERATURES WILL BE COOLER IN THE MOUNTAINS AND SLIGHTLY
WARMER IN THE VALLEYS.

A SURGE OF PACIFIC MOISTURE ALONG A WARM FRONT WILL BRING
WIDESPREAD PRECIPITATION TO MUCH OF THE AREA BY LATE TONIGHT. THE
PRECIP WILL START IN THE NORTH THIS EVENING AND SPREAD SOUTH
OVERNIGHT. THE PRECIP WILL CONTINUE SUNDAY MORNING...AND THEN
DECREASE DURING THE AFTERNOON AS THE WARM FRONT LIFTS NORTHWARD.
SNOW LEVELS WILL RANGE FROM 4000 FEET IN THE NORTH TO 6000 FEET
NEAR THE NEVADA BORDER...RISING TO 5000 FEET IN THE NORTH AND 7500
FEET IN SE OREGON BEHIND THE WARM FRONT. TOTAL RAINFALL AMOUNTS
WILL AVERAGE A TENTH /0.10/ OF AN INCH IN THE VALLEYS. TOTAL
SNOWFALL AMOUNTS WILL GENERALLY RANGE FROM 1 TO 3 INCHES IN THE
HIGHER ELEVATIONS...WITH SEVERAL INCHES EXPECTED IN THE FAR
NORTHERN MOUNTAINS...INCLUDING BAKER COUNTY AND THE WEST CENTRAL
MOUNTAINS. IT WILL BECOME BREEZY DURING THE AFTERNOON ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA...INCLUDING MOST OF SE OREGON
AND THE UPPER TREASURE/WESTERN MAGIC VALLEYS. TEMPERATURES WILL BE
WARMER...WITH HIGHS 5-10 DEGREES ABOVE NORMAL.

LONG TERM...SUNDAY NIGHT THROUGH SATURDAY...AN UPPER LEVEL HIGH
PRESSURE RIDGE WILL BE THE DOMINANT FEATURE. FORECAST SOUNDINGS
SHOW THAT WESTERLY FLOW THROUGH THE RIDGE WILL BE STRONG ENOUGH TO
ENHANCE MIXING...INHIBITING FORMATION OF A TEMPERATURE INVERSIONS
IN THE VALLEYS. SO TEMPERATURES WILL BE MILD...WITH LOWS 10-15
DEGREES ABOVE NORMAL AND HIGHS 5-10 DEGREES ABOVE NORMAL.
PREDOMINANTLY DRY WEATHER WILL BE INTERRUPTED BY A PACIFIC WEATHER
SYSTEM WEDNESDAY NIGHT AND THURSDAY...WHICH MODELS HAVE BEEN
CONSISTENTLY FORECASTING WITH GOOD AGREEMENT ON TIMING. MOST OF
THE PRECIPITATION IS EXPECTED TO FALL OVER THE WEST CENTRAL IDAHO
AND BOISE MOUNTAINS...WITH SNOW LEVELS 5000 TO 6000 FEET. MODELS
SHOW A WEAK DISTURBANCE CROSSING THE AREA NEXT WEEKEND...BUT THERE
IS STILL SIGNIFICANT DISAGREEMENT ON TIMING AND EXTENT OF
PRECIPITATION.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...SP
AVIATION.....AB
PREV SHORT TERM...BW
PREV LONG TERM....JT


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