FXUS65 KPIH 060925
AFDPIH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE POCATELLO/IDAHO FALLS ID
230 AM MST TUE JAN 6 2004

.DISCUSSION...SHORT TERM...TODAY THROUGH THURSDAY...LEADING EDGE OF 
THE WARM AIR ADVECTION PRECIPITATION AS FAR EAST AS PENDLETON OREGON 
ATTM AND CONTINUING TO MOVE/SPREAD EAST.  ETA AND THE MORE SUPERIOR 
GFS AS OF LATE BOTH HAVE THE LIGHT PRECIP BEGINNING IN THE CENTRAL 
MTS BY 18Z AND THEN MOVING INTO THE SNAKE PLAIN AND EASTERN 
HIGHLANDS BY 00Z. QPF SIMILAR IN BOTH THE GFS AND ETA IN LIQUID 
CONTENT.  ETA GENERATES 0.15 AND GFS 0.16 FOR POKY BETWEEN 00Z WEDS 
AND 06Z THU.  FOR IDA...ETA SHOW 0.22 WHILE THE GFS HAS 0.27.  THE 
MOUNTAINS/HIGHLANDS AVERAGE BETWEEN 0.20 AND 0.40 DURING THE SAME 
TIME FRAME.  WITH WAA BEING WEAK...AGREE WITH EARLIER SHIFTS THAT 
COLD AIR/STRATUS DECK WILL NOT BE SCOURED OUT...ESPECIALLY WITH 
LIGHT WINDS.  EVEN THOUGH THE WAA/OVERRUNNING PRECIP WILL REMAIN 
FAIRLY WEAK...THE EVENT WILL LAST ABOUT 24HRS AND WILL ADD UP TO 
AROUND 1 TO 3 INCHES FOR THE SNAKE PLAIN BY 00Z THU (5PM WEDS) AND 2 
TO 5 INCHES FOR THE MOUNTAINS FOR THE SAME TIME...ESPECIALLY WITH A 
SNOW TO RAIN RATIO OF 15 TO 1.  OVERALL DYNAMICS ARE DISORGANIZED 
WITH THIS EVENT...HOWEVER THE BEST OMEGA/WAA COMES IN BETWEEN 12Z 
WEDS AND 18Z WEDS.  GFS ALSO SHOWS SOME INFLUENCE OF THE RR QUAD OF 
A H3 JET OVERHEAD 18Z WEDS WHICH WILL HELP WITH THE LOWER LEVEL WAA 
LIFT.  WILL WORD THE GRIDS/ZONES AS LIGHT SNOW LIKELY FOR WEDS. 
PRECIP WILL BEGIN TO SHUT DOWN WEDNESDAY NIGHT WITH THURSDAY BEING A 
TRANSITION DAY IN BECOMING DRY AS THE H5 RIDGE BEGINS TO 
RE-ESTABLISH ITSELF OVER IDAHO.  STILL THERE WILL BE SOME LEFTOVER 
LIGHT SNOWS EARLY BUT ENDING AS THE DAY PROGRESSES WITH LITTLE 
ACCUMULATION EXPECTED. 

SIMOSKO

.LONG-TERM... FRIDAY THROUGH TUESDAY...
MEAN LONG WAVE CHARTS INDICATE BROAD UPPER RIDGE OVER PIH CWA.  A 
SERIES OF DISTURBANCES MOVE THROUGH THE NORTHERN BRANCH BUT UNLIKE 
THE PAST WEEK...THERE IS NO SUBTROPICAL MOISTURE CONNECTION.  LATEST 
GFSX/MM5 ENSEMBLE AND GFS SUPPORT THIS TREND.  GRIDS IN GOOD SHAPE 
WITH TRENDS FOR SLIGHT CHC POPS FAVORING THE MOUNTAINS WITH DRIER 
AIR MASS OVER THE VALLEYS IN THE 4 TO 7 DAY PERIOD.  EXPECT A 
MODERATION IN TEMPS WITH A RETURN TO MORE NEAR NORMAL LEVELS.

04

&&

.PIH WATCHES/WARNING/ADVISORIES...NONE. 

&&

$$