000 
FXUS65 KBOI 071025
AFDBOI

SOUTHWEST IDAHO/SOUTHEAST OREGON AREA FORECAST DISCUSSION 
NATIONAL WEATHER SERVICE BOISE IDAHO
325 AM MST SUN JAN 7 2001

FIRST SHORTWAVE THAT ESTABLISHES WESTERN U.S. TROUGH WILL PUSH INTO 
AREA FROM THE WEST ON SUNDAY NIGHT. HOWEVER IT STRETCHES AND SPLITS 
APART AS EASTERN U.S. TROUGH IS SLOW TO PULL OUT AND OUR PERSISTENT 
RIDGE CANT GET OUT OF THE WAY FAST ENOUGH. PREFER AVN SOLUTION THAT 
IS SLOWEST AND MOST SPLIT WITH THE INCOMING SYSTEM BY MONDAY 
AFTERNOON. SLOW SPEED OF SYSTEM MEANS THAT MOISTURE WILL REMAIN OVER 
CWFA FOR LONG PERIOD OF TIME...BUT WITH VERY WEAK DYNAMICS. WILL GO 
WITH LIKELY POPS IN PARTS OF SOUTHEAST OREGON WHERE LOW-LEVEL 
UPSPLOPE INTO BLUE MOUNTAINS WILL FAVOR PRECIP...BUT ONLY GO CHANCE 
ELSEWHERE...AND EVEN SLIGHT CHANCE FURTHER EAST...SINCE DYNAMICS 
WEAKEN WHILE MOISTURE AND LOW-LEVEL FLOW DIMINISH AS THE SYSTEM 
SLOWLY TRANSLATES EASTWARD. GIVEN WEAKENING DYNAMICS OF 
SYSTEM...BELIEVE NO HIGHLIGHTS ARE NEEDED AT THIS TIME. INCREASING 
SURFACE PRESSURE GRADIENTS ALREADY PICKING UP WIND ACROSS SOME 
VALLEYS THIS MORNING AND BELIEVE THIS WILL HELP MIX AIRMASS AND 
RAISE TEMPERATURES EXCEPT IN LOWEST VALLEY LOCATIONS TODAY. THEN 
STEADY ON MONDAY AS CLOUDS AND PRECIP MOVE ACROSS THE AREA.

IN EXTENDED PERIOD...STILL LOTS OF TIMING DIFFERENCES AMONG MODELS 
SO BELIEVE A RELATIVELY BROAD BRUSH APPROACH IS BEST. HOWEVER... 
WILL BREAK OUT TUESDAY PERIOD FOR THE OREGON ZONES TO INTRODUCE 
BREEZY WINDS AND LATE DAY TIMING TO PRECIP THERE SINCE I AM PRETTY 
CONFIDENT THEY WILL BE BETWEEN SYSTEMS ON MONDAY NIGHT AND EARLY 
TUESDAY. AM ALSO PRETTY CONFIDENT THAT BY END OF PERIOD WE WILL 
BE COOLER...WITH ECMWF/UKMET IN RELATIVE AGREEMENT WITH MRF THAT 
MAIN PART OF LONGWAVE TROUGH WILL HAVE PASSED BY AND SYSTEMS WILL BE 
COMING MORE OUT OF THE NORTHWEST BY THAT TIME. HOWEVER...WILL LET 
DAY SHIFT LOOK AT THIS FURTHER BEFORE MODIFYING WORDING THAT FARm OUT 
IN THE EXTENDED FORECAST. BARKER.

.BOI...NONE.