Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 310857
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
257 AM MDT TUE MAR 31 2015

.SHORT TERM...PACIFIC COLD FRONT WILL MOVE ACROSS EASTERN OREGON
THIS MORNING AND SOUTHWESTERN IDAHO MIDDAY AND EARLY AFTERNOON
FOLLOWED BY GUSTY WEST OR NORTHWEST WINDS.  FRONT LOOKS STRONGER
THAN IT DID IN YESTERDAY/S MODELS AND THE SLIGHTLY LATER TIMING WILL
INCREASE THE THERMAL GRADIENT ACROSS THE FRONT.  STRONG WESTERLY
WINDS ALOFT WILL CONTRIBUTE TO THE STRENGTH OF THE FRONT. STRONGEST
SURFACE WINDS WILL HIT LATE TODAY IN THE SNAKE BASIN EAST OF
MOUNTAIN HOME AS MODELS SHOW TIGHTEST SURFACE PRESSURE GRADIENT IN
THAT AREA AT THAT TIME.  MAX TEMPS TODAY WILL BE ABOUT 20 DEGREES
LOWER THAN YESTERDAY IN OREGON ZONES...BUT IN IDAHO THE FRONT WILL
COME LATE ENOUGH TO ALLOW DAYTIME TEMPS TO RISE INTO THE 60S BEFORE
COOLING IN THE AFTERNOON. THE FULL COOLING WILL ARRIVE WEDNESDAY
WHEN MAX TEMPS WILL ONLY BE IN THE 40S IN THE MOUNTAINS AND LOWER TO
MID 50S IN THE VALLEYS THROUGHOUT OUR CWA.  THE FRONT WILL NOT BE
ESPECIALLY MOIST BUT NUMEROUS LIGHT RAIN AND SNOW SHOWERS WILL FALL
IN NRN ZONES...LITTLE IF ANY PCPN IS EXPECTED SOUTH OF THE SNAKE
BASIN.  AIR MASS WILL BE MARGINALLY UNSTABLE IN THE CENTRAL IDAHO
MOUNTAINS WHERE ISOLATED THUNDERSTORMS ARE BEING FORECAST.  UPPER
TROUGH WILL RE-DEVELOP LIGHT RAIN AND SNOW SHOWERS IN OUR NRN ZONES
WEDNESDAY AFTERNOON.

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...ACTIVE WEATHER PATTERN
STILL ON TRACK THROUGH THE EXTENDED FORECAST.  FIRST TROUGH WILL
MOVE OVER THE FORECAST AREA WEDNESDAY NIGHT AND THURSDAY FOR A
CHANCE OF PRECIPITATION OVER BAKER COUNTY AND THE CENTRAL MOUNTAINS
OF IDAHO WITH SLIGHT CHANCE EVERYWHERE ELSE.  TEMPERATURES ON
THURSDAY WILL BE 5-7 DEGREES BELOW NORMAL.  A LOW-AMPLITUDE RIDGE
WILL MOVE OVER THE REGION THURSDAY NIGHT AND FRIDAY WITH MOSTLY DRY
CONDITIONS.  MODELS HAVE BEEN FAIRLY CONSISTENT WITH THIS RIDGE BUT
DIFFER FROM RUN TO RUN AS TO HOW MUCH IF ANY MOISTURE WILL BE MOVING
THROUGH THE FLOW.  FORECASTER THINKING AT THIS TIME IS THAT ANY
MOISTURE RIDING OVER THE TOP OF THE RIDGE WILL REMAIN TO THE NORTH
OF THE FORECAST AREA SO WILL KEEP THE DRY FORECAST THROUGH FRIDAY.
TEMPERATURES WILL BEGIN TO WARM UNDER THIS WEAK RIDGE WITH HIGH
TEMPERATURES ON FRIDAY WARMING BACK TO NEAR NORMAL.  FROM FRIDAY
NIGHT THROUGH MONDAY FORECASTER CONFIDENCE IN THE MODELS IS LOW.
MODELS SEEM TO BE HAVING A HARD TIME WITH NEXT WEATHER SYSTEM THAT
IS DROPPING SOUTH OUT OF THE GULF OF ALASKA.  THERE IS NO RUN-TO-RUN
CONSISTENCY SO THIS WILL ALSO AFFECT THE TIMING AND PLACEMENT OF ANY
PRECIPITATION.  FOR NOW DO NOT WANT TO YO-YO THE FORECAST WITH THE
CHANGING MODELS SO WILL NOT MAKE ANY CHANGES TO POPS FOR THE WEEKEND
AND INTO EARLY NEXT WEEK.  EVEN WITH THE UNCERTAINTY IN THE MODELS
...IT DOES LOOK LIKE THE REGION WILL BE IN FOR A COOL-DOWN WITH
TEMPERATURES BY SUNDAY FALLING TO AROUND 5 DEGREES BELOW NORMAL AND
SNOW LEVELS BETWEEN 4000 AND 6000 FEET.

&&

.AVIATION...VFR THIS MORNING WITH LOWERING CEILINGS.   THIS
AFTERNOON INCREASING SHOWERS AS A COLD FRONT MOVES FROM WEST TO EAST
THIS AFTERNOON AND THIS EVENING.  LOCAL MVFR CONDITIONS AND MOUNTAIN
OBSCURATION WITH SHOWERS.  SNOW LEVELS LOWERING TO 4K-6K FEET MSL BY
THIS EVENING.  SURFACE WINDS GENERALLY 12 KNOTS OR LESS THIS
MORNING...AFTER 18Z BECOMING WEST-NORTHWEST 15-25 KNOTS WITH GUSTS
NEAR 30 KNOTS...EXCEPT IN THE SNAKE RIVER VALLEY EAST OF KMUO AND
SOUTH TO THE NEVADA BORDER WITH WEST-NORTHWEST WINDS 25-35 KNOTS
WITH GUSTS OF 35-45 KNOTS.  WINDS ALOFT SOUTHWEST 20-30 KNOTS UP
THROUGH 10K FEET MSL THIS MORNING...BECOMING NORTHWESTERLY BY THIS
EVENING.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 9 PM MDT THIS EVENING
     IDZ014>016-030.
OR...NONE.

&&

$$

WEATHER.GOV/BOISE

SHORT TERM...LC
LONG TERM....JA
AVIATION.....JA


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