FXUS65 KPIH 300302
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
802 PM MST SUN NOV 29 2009

.UPDATE...WILL MAKE NO UPDATES TO CURRENT FORECAST TONIGHT. GRIDS
STILL PAINT PATCHY FOG ACROSS VALLEY REGIONS OF FCST AREA. THIS IS
A QUESTION GIVEN THIN CIRRUS SHIELD MOVING ACROSS FCST AREA AHEAD
OF WEAK SHORTWAVE TOPPING RIDGE AND SKIRTING DIVIDE. TIMING OF
WAVE COULD PUT CLEARING OVER FCST AREA TOWARD EARLY
MORNING...WHICH MAY ALLOW SOME LIGHT FOG TO FORM. WILL LEAVE GRIDS
AS THEY ARE FOR NOW. DMH

&&

.PREV DISCUSSION... /ISSUED 150 PM MST SUN NOV 29 2009/ 

SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT.
CLEARING SKIES AND HIGH PRESSURE TO DOMINATE NEXT 48 HOURS. A
REPEAT OF LAST NIGHT IS EXPECTED WITH COLD MOUNTAIN TEMPERATURES AND
AREAS OF LOW CLOUDS AND PATCHY DENSE FOG IN THE SNAKE RIVER
PLAIN...CACHE VALLEY AND BEAR LAKE AREA. TUESDAY AFTERNOON THE
PRESSURE GRADIENT WILL TIGHTEN SLIGHTLY IN NORTHWEST FLOW ALOFT AS
A SHORTWAVE TROUGH WILL SKIRT BY LAST TUESDAY. A SLIGHT CHANCE OF
SNOW SHOWERS IS EXPECTED IN THE ISLAND PARK AND TETON VALLEY
AREAS. OTHERWISE JUST HIGH CLOUDS FOR THE REST OF THE REGION. 
PRESTON

LONG TERM...WEDNESDAY THROUGH SUNDAY. 
MODELS CONTINUE TO STRUGGLE WITH ANY CONSISTENCY IN THE LONG
RANGE. RIDGE IN PLACE OVER EASTERN IDAHO BEGINS TO BREAK DOWN ON
WEDNESDAY WITH EACH MODEL SHOWING DIFFERENT TIMING AND MEANS OF
THIS BREAKDOWN. THE GFS DEPICTS THE RIDGE FLATTENING ON THURSDAY
WITH SEVERAL WEAK WAVE CLIPPING THE NORTHERN REACHES OF THE
FORECAST AREA. EVENTUALLY THE PARENT TROUGH VERY SLOWLY SINKS
SOUTHWARD ACROSS IDAHO BEGINNING FRIDAY NIGHT AND PERSISTING INTO
NEXT WEEKEND. THE ECMWF MEANWHILE HOLDS ONTO A SHARPER RIDGE
THROUGH FRIDAY NIGHT THEN DROPS A MUCH MORE PROGRESSIVE TROUGH
INTO IDAHO ON SATURDAY. IN ITS WAKE...ZONAL FLOW BUILDS INTO
EASTERN IDAHO. THESE SOLUTIONS VERY CONSIDERABLY FROM PREVIOUS
MODEL RUNS. WILL KEEP THE CURRENT WEATHER PACKAGE AS IS...WITH LOW
CHANCES IN THE MOUNTAINS THURSDAY NIGHT AND BEYOND. 

AVIATION...LOW STRATUS AND FOG ACROSS THE SNAKE PLAIN HAS FINALLY 
DISSIPATED THIS AFTERNOON WITH ALL TAF SITES REPORTING VFR 
CONDITIONS.  EXPECT LOW STRATUS TO RETURN AFTER SUNSET IN THE SNAKE 
PLAIN...BUT TO A LESSER EXTENT THANKS TO SOME BUILDING HIGH CLOUDS. 
BEST CHANCE FOR LIFR WILL BE IN THE UPPER SNAKE VALLEY INCLUDING 
KIDA...HOWEVER THE POTENTIAL EXISTS IN KPIH AND KBYI AS WELL.  
AGAIN...FOG AND STRATUS EXPECTED TO LIFT BY 18Z MONDAY.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$