FXUS65 KBOI 291556
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
855 AM MST SUN NOV 29 2009

.DISCUSSION...CLEAR SKIES EXCEPT FOR THE STRIP OF FOG AND STRATUS 
WHICH HAS PERSISTED ACROSS THE NRN PART OF THE MAGIC VALLEY AND SERN 
ELMORE COUNTY SINCE YESTERDAY.  TEMPS BECAME SEASONABLY COLD 
OVERNIGHT IN ALL AREAS...FAIRFIELD THE COLDEST WITH -2F AT 7 AM 
MST.  1Z BOI RAOB SHOWED SIGNIFICANT WARMING ABOVE 700 MB SINCE 
YESTERDAY...LOWER LEVELS EXCEPT NEAR THE SURFACE WILL WARM FURTHER
TODAY DUE TO HIGH PRESSURE ALOFT.  WEAK SHORT WAVE TROUGH WILL 
FLATTEN THE UPPER RIDGE MONDAY BUT WITH LITTLE EFFECT ON WX IN OUR 
CWA.  LITTLE OR NO FOG TONIGHT EXCEPT FOR NRN MAGIC VALLEY...AS AIR 
MASS DRIED OUT SIGNIFICANTLY YESTERDAY.

LATEST GFS EVOLVES A TRUE ARCTIC SURGE INTO OUR AREA LATE NEXT 
WEEK...NOT YET SUPPORTED BY ECM.  NCEP HAS TAKEN NOTE OF THE GFS AND 
WE WILL PASS ALONG THEIR THOUGHTS AS WE CONTINUE TO RECEIVE THEM.
FOR NOW NO UPDATES.

&&

.AVIATION...LOCAL IFR IN LOW STRATUS AND FOG THIS MORNING OVER THE 
WESTERN MAGIC VALLEY AND UP AGAINST THE FOOTHILLS IN THE UPPER 
TREASURE VALLEY EAST OF KBOI.  EXPECT THIS STRATUS AND FOG TO ERODE 
OVER MOST LOCATIONS BY THIS AFTERNOON BUT COULD SEE AN AREA OF 
STRATUS REMAIN AGAINST THE FOOTHILLS NORTH OF KJER.  ELSEWHERE VFR 
CONDITIONS UNDER CLEAR SKIES WITH LIGHT WINDS SURFACE AND ALOFT.

FOR TONIGHT EXPECT THE STRATUS TO EXPAND WESTWARD AGAIN AND COULD 
POSSIBLY REACH KBOI BY MONDAY MORNING.  CAN ALSO EXPECT ISOLATED IFR 
IN FOG IN MOUNTAIN VALLEYS.

&&

.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH MONDAY...LARGE DOME OF SURFACE HIGH 
PRESSURE WITH 1032 CENTER OVER EASTERN OREGON AT 2 AM WILL EXPAND 
OVER IDAHO TODAY. PATCH OF STRATUS AND FREEZING FOG IN SOUTH CENTRAL 
IDAHO LOOKS TO LAST THROUGH 18Z. WEST UPSLOPE WINDS IN THE MAGIC 
VALLEY ARE EXPECTED TO DEVELOP LATE THIS AFTERNOON TO ERODE AND 
DISSIPATE IT. CURRENT RH NOT AS MOIST DUE TO VERY DRY AIR MUCH OF 
THE AREA SATURDAY AND GUSTY WINDS FRIDAY/SAT DRYING OUT AREA FROM 
RECENT PRECIP. SO HAVE CUT BACK FOG COVERAGE. MET TEMPERATURES ON 
TRACK WITH MAV/MEX PROBABLY TOO COOL EXCEPT CAMAS PRAIRIE AND FAR 
NORTHWEST MAGIC VALLEY. MONDAY THE HIGH CENTER SHIFTS EAST FOR LIGHT 
DIURNAL WINDS. MET TEMPS STILL LOOK TO BE A BETTER FIT DUE TO RECENT 
MAV/MEX POOR HANDLING OF WARMTH IN SE WINDS WITH DRY INVERSION.

LONG TERM...MONDAY NIGHT THROUGH SATURDAY...LONGWAVE RIDGE WILL KEEP 
AREA DRY WITH NEAR NORMAL TEMPS UNTIL NEXT WEEKEND. A WEAK FEATURE 
PROGGED TO MOVE DOWN THE CONTINENTAL DIVIDE ON TUESDAY WILL DO 
LITTLE MORE THAN INCREASE CLOUDS AND COOL TEMPS ACROSS THE SW ID 
MTNS. WHILE DETAILS ARE STILL HARD TO PIN DOWN...MODELS ARE HINTING 
AT RETROGRESSION OF THE LONGWAVE RIDGE AXIS TO OFF THE NW COAST FOR 
NEXT WEEKEND WHICH COULD BRING A COLDER AIRMASS TO THE REGION. STILL 
ENOUGH UNCERTAINTY IN MODEL SOLUTIONS TO YET BUY INTO THIS POTENTIAL 
...SO HAVE TRENDED TEMPS/POPS TOWARDS CLIMO FOR FRI/SAT NEXT WEEK. 

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...LC
AVIATION.....JA
PREV SHORT TERM...VM
PREV LONG TERM....DG