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000
FXUS65 KBOI 261021
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
321 AM MST MON JAN 26 2015

.SHORT TERM...TODAY THROUGH TUESDAY...LITTLE CHANGE IN THE WEATHER
PATTERN FROM YESTERDAY. UPPER RIDGE REMAINS LOCKED OVER THE
WESTERN U.S...WHILE AN UPPER LOW OFF THE BAJA IS STARTING TO LIFT
NORTHWARD. FOR TODAY...ANOTHER AFTERNOON OF WELL ABOVE NORMAL
TEMPERATURES ACROSS MUCH OF SE OREGON AND SW IDAHO. AREAS OF DENSE
FOG IN THE TREASURE VALLEY /BOISE WESTWARD/ AND WEISER RIVER
VALLEY WILL LIFT THIS AFTERNOON...THOUGH SE OREGON AND THE LOWER
TREASURE VALLEY WON/T LOSE THE LOW OVERCAST. A RIBBON OF FOG AND
STRATUS SOUTH OF THE SNAKE RIVER IN THE WESTERN MAGIC VALLEY WILL
SCATTER OUT THIS AFTERNOON AS WELL. THAT SAID...SHORTLY AFTER
SUNSET THE FOG/STRATUS THAT/S STILL IN PLACE WILL AGAIN EXPAND
OUT ACROSS THE SNAKE PLAIN THROUGH TUESDAY MORNING. CLOUDS WILL
INCREASE ON TUESDAY AS THE UPPER LOW NEAR BAJA IS DRAWN INTO
NORTHEAST NV BY AFTERNOON. SHOWERS ACCOMPANYING THE LOW WILL
SPREAD NORTH OF THE NV BORDER EARLY TUESDAY AFTERNOON...REACHING
THE WESTERN MAGIC VALLEY BY LATE AFTERNOON. TEMPERATURES REMAIN
ABOVE NORMAL ON TUESDAY THOUGH MTNS WILL SEE 5-10 DEGREES OF
COOLING FROM TODAY.

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY. RAIN AND SNOW...FROM
UPPER LOW WITH ORIGINS IN THE BAJA OF MEXICO...IS EXPECTED TO SPREAD
THROUGH SOUTHWEST AND SOUTH-CENTRAL IDAHO TUESDAY EVENING THROUGH
WEDNESDAY MORNING. MODELS HAVE BECOME VERY CONSISTENT WITH THIS LOW
GETTING ABSORBED INTO THE WESTERLY FLOW AT THIS POINT AND TURNING
TOWARDS THE EAST...SO POPS IN EASTERN OREGON REMAIN RELATIVELY LOW.
ONCE THE LOW MOVES EAST...A RIDGE WILL BEGIN TO BUILD ONCE AGAIN OFF
OF THE PACIFIC COAST. MEANWHILE...ANOTHER UPPER LEVEL LOW IS
EXPECTED TO GET CUT OFF IN THE DESERT SOUTHWEST AND KEEP OUR AREA IN
A DRY NORTHWEST/SPLIT FLOW THROUGH SUNDAY. MODELS ARE SHOWING THE
RIDGE FLATTENING AT SOME POINT AND TRANSITIONING THE AREA INTO A
MORE ZONAL FLOW...WHICH IS WHERE MODELS BEGIN TO REALLY DIVERGE. THE
AMPLITUDE OF THE RIDGE WILL DETERMINE THE POTENTIAL FOR SHORTWAVES
IN THE FLOW TO BRING PRECIP. OTHERWISE...TEMPERATURES SHOULD BE NEAR
OR ABOVE NORMAL THROUGH THE PERIOD.

&&

.AVIATION...AREAS OF MVFR/IFR FOG/STRATUS ARE EXPECTED TO CONTINUE
IN MAGIC/TREASURE/MOUNTAIN VALLEYS THROUGH THE PERIOD. EVERYWHERE
ELSE...VFR. SURFACE WINDS GENERALLY LESS THAN 12 KTS...EXCEPT IN
MAGIC VALLEY WITH UP TO 20 KTS. WINDS ALOFT NEAR 10K FT MSL...SOUTH
25-35 KTS...THEN AFTER 27/03Z...SOUTHWEST 10-15 KTS.

TUESDAY/WEDNESDAY...UPPER LOW MOVES OVER THE AREA WITH MTN
OBSCURATION IN CENTRAL IDAHO MTNS. RAIN/SNOW MAINLY SOUTHEAST OF
LINE FROM KREO TO KMYL.

&&

.AIR STAGNATION...WILL SEE LITTLE CHANGE TO THE INVERSION TODAY
WITH MIXING HEIGHTS OF 1000 TO 1500 FEET IN THE SNAKE RIVER
VALLEY. THE TOP OF THE INVERSION WILL WEAKEN ON TUESDAY ALLOWING
FOR BETTER MIXING AT VALLEY SITES ABOVE 3500-4000 FEET. LOWER
SITES WILL REMAIN CAPPED WITH MIXING HEIGHTS STILL NO MORE THAN
1500 FEET AGL AND WINDS WILL REMAIN LIGHT.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...DENSE FOG ADVISORY UNTIL 11 AM MST THIS MORNING IDZ012-014-033.
OR...DENSE FOG ADVISORY UNTIL 11 AM MST THIS MORNING ORZ064.

&&

$$

WEATHER.GOV/BOISE

SHORT TERM...DG
LONG TERM....EP
AVIATION.....EP
AIR STAGNATION...DG