Weather Service Report


563 
FXUS65 KBOI 311622
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1022 AM MDT TUE MAR 31 2015

.DISCUSSION...WINDY DAY ON TAP FOR MUCH OF THE AREA. A SURFACE
PRESSURE TROUGH HAS ALREADY MOVED THROUGH THE CWA THIS
MORNING...BUT THE REAL COLD FRONT WILL MOVE THROUGH FROM LATE
MORNING IN ERN OREGON THROUGH EARLY EVENING IN THE WESTERN MAGIC
VALLEY. THIS FRONT WILL HAVE ACCOMPANYING SHOWERS WHICH WILL AID
IN MIXING DOWN STRONGER WINDS. THEREFORE WE WILL LET THE WIND
ADVISORY STAND AS IS. WE SUSPECT IT MAY NEED TO BE EXTENDED A
LITTLE LONGER INTO THE EVENING IN THE FAR SE PORTION OF THE
CWA...BUT WILL MAKE THAT DECISION BASED ON TIMING AS THE AFTERNOON
UNFOLDS. FOR NOW...WILL EXTEND THE AREA OF SLIGHT CHANCE THUNDER
TO COVER THE REMAINDER OF THE NRN PORTION OF THE CWA FOR THIS
AFTERNOON AND EVENING. WILL ALSO RAISE MAX TEMPS FOR MUCH OF
THE AREA. UPDATE OUT SHORTLY.

&&

.AVIATION...VFR WITH INCREASING CLOUDS...LOWERING INTO LATE
MORNING. CHANCE SHOWERS BEGIN BY 19Z IN SE OREGON WITH AN EAST
MOVING FRONT ALONG A NE-SW LINE. EXPECT BRIEF MVFR ACROSS
E-CENTRAL OREGON AND W-CENTRAL ID MTNS WITH SHOWERS...AND POSSIBLE
THUNDER. COULD SEE VCSH IN THE MAGIC VALLEY...BUT THIS WILL BE
MORE OF A WIND EVENT. NW 15-25KT SURFACE WINDS WITH GUSTS UP TO
40KT IN THE UPPER TREASURE TO MAGIC VALLEYS AND SOUTH AFTER
31/21Z...DECREASING TO 5-10KT OVERNIGHT. WINDS ALOFT NEAR 10K FT
MSL...SW 20-30KT....BECOMING WNW 20-30KT 01/00Z...AND WNW 10-20KT
BY 01/18Z.

&&

.PREV DISCUSSION...
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.

&&

.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

DISCUSSION...SP
AVIATION.....AB
PREV SHORT TERM...LC
PREV LONG TERM....JA

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