FXUS65 KBOI 262138
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
238 PM MST SAT DEC 26 2009

.SHORT TERM...TONIGHT THROUGH MONDAY...THE COMBINATION OF EASTERLY 
WINDS AND SUNSHINE PROVIDED ENOUGH MIXING TO ERODE NEARLY ALL OF THE 
LOW STRATUS IN THE WESTERN MAGIC VALLEY AND UPPER TREASURE VALLEY 
THIS AFTERNOON. HOWEVER...THE STRATUS REMAINS LOCKED IN PLACE IN THE 
VALLEYS OF FAR SOUTHWEST IDAHO/SOUTHEAST OREGON BELOW ABOUT THE 5000 
FOOT LEVEL. IN THOSE AREAS...THERE WILL STILL BE SOME SHRINKING 
ALONG THE EDGES ALONG WITH BREAKS IN THE CLOUDS FOR THE REMAINDER OF 
THE AFTERNOON. FOR TONIGHT...EXPECT THE STRATUS TO REMAIN ACROSS SE 
OREGON OVERNIGHT AND WILL LIKELY RE-DEVELOP ALONG WITH THE 
POSSIBILITY OF PATCHY FOG IN THE UPPER TREASURE/WESTERN MAGIC 
VALLEYS ONCE AGAIN...BUT TO WHAT EXTENT REMAINS TO BE SEEN. 

HIGH PRESSURE RIDGE ALOFT WILL CONTINUE TO LOSE ITS GRIP ON THE 
REGION AS A NEGATIVELY-TILTED TROUGH ENTERS CALIFORNIA. THE TROUGH 
WILL SLOWLY ADVANCE NORTHEAST SPREADING CLOUDS AND A CHANCE OF SNOW 
SHOWERS INTO SE OREGON ON SUNDAY. THE TROUGH WILL CONTINUE TO WORK 
NORTHEAST SUNDAY NIGHT-MONDAY BUT WILL WEAKEN AS IT ENCOUNTERS AN 
AREA OF HIGH PRESSURE ALOFT SITUATED NORTH AND EAST OF THE REGION. 
WILL CONTINUE THE LOW-END POPS IN SE OREGON AND PORTIONS OF SW IDAHO 
SUNDAY NIGHT AND MONDAY.

TEMPERATURES WILL REMAIN COLD...WITH GREATER DIURNAL CHANGES OUTSIDE 
OF THE STRATUS WITH LESS OF A DIURNAL CHANGE FOR AREAS TRAPPED IN 
THE STRATUS. WILL MAKE SOME TEMP ADJUSTMENTS THAT WAY FOR TONIGHT 
AND SUNDAY. NOT SURE AT THIS TIME IF THE AFOREMENTIONED TROUGH WILL 
HAVE ANY EFFECT ON THE INVERSION SINCE THIS IS NOT A TYPICAL FRONTAL 
SYSTEM WHICH WOULD BE ACCOMPANIED BY WINDS AND A CHANGE IN AIRMASS 
...AND COULD ACTUALLY MAKE IT WORSE IF THE SYSTEM CONTRIBUTES ANY 
MOISTURE TO THE BOUNDARY LAYER.

REGARDING THE AIR STAGNATION ADVISORY IN PORTIONS OF SE 
OREGON...CONDITIONS ARE IMPROVING THERE WITH WINDS IN THE 10-20 MPH 
RANGE IN BURNS AND BAKER CITY. THESE WINDS...ALONG WITH A CHANCE OF 
SNOW SHOWERS SUNDAY-MONDAY...WILL BE ENOUGH TO ALLOW THE ADVISORY TO 
EXPIRE ON SCHEDULE AT 4 PM PST THIS AFTERNOON.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...STILL LOOKS LIKE IDAHO 
AND SOUTHEAST OREGON WILL BE ON THE NORTHERN EDGE OF A FAIRLY 
SIGNIFICANT STORM THAT WILL SWING THROUGH CALIFORNIA AND POINTS EAST 
MONDAY NIGHT. ONE WEAK SYSTEM MOVES THROUGH TUESDAY WITH ANOTHER 
PACIFIC STORM HEADING INTO THE AREA BY WEDNESDAY MORNING. THE 
WEDNESDAY STORM SEEMS TO CARRY MORE POTENTIAL FOR SNOW INTO IDAHO 
AND SOUTHWEST OREGON. AND YET ANOTHER PACIFIC STORM SEEM TO BE 
POISED TO HEAD INTO THE AREA BY SATURDAY. TEMPERATURES WITH THESE 
STORMS SHOULD REMAIN ON THE COOL SIDE WITH SNOW LIKELY EVEN IN THE 
LOWER VALLEYS. NONE OF THE STORMS SEEM EXCEPTIONALLY STRONG AT THIS 
POINT IN TIME BUT SOME LIGHT ACCUMULATION IN THE VALLEYS WITH A FEW 
INCHES IN THE MOUNTAINS IS LIKELY.
 
&&

.AVIATION...WIDESPREAD MVFR/IFR CONTINUES OVER THE LOWER ELEVATIONS 
FROM BOISE WEST. SOME MIXING HAS THINNED THE CLOUDS TO THE EAST. 
EXPECT LOW CLOUDS TO THICKEN UP FROM BOISE WEST TONIGHT WITH FOG A 
MORE LIKELY POSSIBILITY IN THE SNAKE RIVER PLAIN EAST OF BOISE. 
HIGHER ELEVATIONS REMAIN CLEAR. SOME INCREASE IN HIGH CLOUDS FROM 
THE SOUTHWEST AS THE REMAINS OF A WEAK PACIFIC STORM HEADS INLAND 
TONIGHT. EXPECT WIDESPREAD MVFR/IFR TO PERSIST SUNDAY MORNING IN THE 
LOWER VALLEYS.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...AIR STAGNATION ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR
     ORZ061-ORZ062.
&&

$$

WEATHER.GOV/BOISE

SHORT TERM...BW
LONG TERM....PF/LH
AVIATION.....PF