FXUS65 KBOI 251038
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
338 AM MST FRI DEC 25 2009

.SHORT TERM...TODAY THROUGH SATURDAY...GFS/NAM/UKMET AND EC ALL
AGREE ON A CUT OFF UPPER LEVEL HIGH OVER SW CANADA. THEY ALSO AGREE
THAT THIS WILL ALLOW A LOBE OF LOW PRESSURE AND HEIGHT FALLS
ACROSS SW IDAHO AND SE OREGON WHICH SWINGS INTO THE AREA FROM THE
EAST AND REACHES THE NW WA COAST LATE SATURDAY. AT THE SURFACE A
LOBE OF HIGH PRESSURE WILL WORK INTO THE AREA FROM THE EAST/HIGH
PLAINS STATES FOR CONTINUED VERY COLD WEATHER IN THE CAMAS
PRAIRIE...WEST CENTRAL MOUNTAINS AND UPPER WEISER RIVER BASIN
WHERE HIGHS STRUGGLED INTO THE TEENS THURSDAY. ALSO WITH THE WEAK
UPPER LOBE CROSSING THE REGION...MOISTURE LOOKS TO BE LIMITED TO
HIGH CLOUDS SO EXPECT DRY CONDTIONS. LOW CLOUDS IN THE NW MAGIC
VALLEY LOOK TO EXPAND WESTWARD AS EAST WINDS PICK UP. FINALLY
AREAS OF FOG AND HAZE LOOK TO PERSIST ESPECIALLY OVER OREGON
THROUGH SATURDAY AS ONLY SLIGHT WEAKENING OF THE STEEP INVERION
LOOKS TO OCCUR SATURDAY.

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...A SPLIT FLOW JUST 
OFFSHORE LEAVES OUR AREA DRY SUNDAY AND MONDAY. STARTING TUESDAY 
UNCERTAINTY INCREASES. ALTHOUGH THE MODELS ALL SHOW PROGRESSIVE 
PATTERNS...THE GFS AND ITS ENSEMBLE MEAN TRANSITION INTO ZONAL 
FLOW...WHILE THE ECMWF WANTS TO BUILD A FAIRLY HIGH AMPLITUDE RIDGE 
OFFSHORE AND MOVE IT INLAND THURSDAY AND FRIDAY. THE CANADIAN 
OPERATIONAL MODEL IS SIMILAR TO THE ECMWF BUT BUILDS THE RIDGE ABOUT 
A DAY LATER. DUE TO THIS UNCERTAINTY WE TRENDED POPS UP TO 
CLIMATOLOGY TUESDAY AND CONTINUED THIS THROUGH THE END OF THE 
PERIOD. TEMPERATURES FROM BOTH THE ANALOG METHOD AND BIAS CORRECTED 
MOS ALL APPEARED TOO COLD FOR THE PATTERN. WARMEST SOLUTIONS WERE 
THE GFSBC AND ECMWFBC MAXS WHICH WE USED SUNDAY AND MONDAY TO RAISE 
HIGHS BY A COUPLE OF DEGREES. OTHERWISE WE LEFT TEMPERATURES 
ALONE...AS THEY WERE ALREADY A LITTLE WARMER THAN MOST MODEL OUTPUT. 
 
 &&

.AVIATION...THE STRATUS COVERING THE UPPER SNAKE RIVER VALLEY 
EXTENDS OVER THE KJER AREA THIS MORNING WITH MVFR CEILINGS. EXPECT 
THIS TO SCATTER OUT BY 18Z. OTHERWISE VFR CONDITIONS PREVAIL AS THE 
AIRMASS REMAINS QUITE DRY. VFR CONDITIONS WILL CONTINUE THROUGH 
TONIGHT UNDER MOSTLY CLEAR SKIES...EXCEPT FOR AREAS OF HAZE AND 
PATCHY NIGHT AND MORNING FOG.IN BAKER AND HARNEY COUNTIES. NO 
SIGNIFICANT CHANGES ARE EXPECTED THROUGH THE WEEKEND. SURFACE WINDS 
WILL BE LIGHT. WINDS ALOFT WILL BE MODERATE NORTHERLY. 

&&

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

$$

WEATHER.GOV/BOISE

SHORT TERM...VM
LONG TERM....JT
AVIATION.....JT