FXUS65 KPIH 142137
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
237 PM MST MON DEC 14 2009
.SHORT TERM...TONIGHT THROUGH WEDNESDAY. MAINLY ISOLATED SNOW
SHOWERS CONTINUE THIS AFTERNOON PER SFC OBSERVATIONS AND
INDICATIONS FROM AREA WEB CAMS. HAVE LEFT POPS IN FOR EARLY THIS
EVENING BUT ANTICIPATE END TO PRECIP WITH SUNSET. PROBLEM BEGINS
WITH NEXT SYSTEM PUSHING INTO COAST THIS AFTERNOON. MODELS STILL
TRYING TO PUSH PRECIP INTO FCST AREA AFTER MIDNIGHT. THIS TIMING
APPEARS FAST GIVEN LOCATION OF CURRENT IR ENHANCEMENT STILL ON
COAST SIDE OF CASCADES. BULK OF PRECIP BEGINS AFTER 12Z...AND
FAVORS UPSLOPE AREAS OF CENTRAL MTNS. HAVE INCREASED POPS ACROSS
THE REGION AND WILL UPGRADE THE WINTER STORM WATCH FOR IDZ018 AND
IDZ031 TO A WARNING. GIVEN SOUTHWARD EXTENT OF PRECIP INTO EASTERN
MAGIC VALLEY AND SOUTHERN HIGHLANDS HAVE ALSO ISSUED A WINTER
WEATHER ADVISORY FOR IDZ017 AND IDZ022. MOISTURE SPREADS ACROSS
THE REST OF THE FCST AREA DURING THE DAY TUESDAY...AND FAVORABLE
OROGRAPHICS SHOULD KEEP HIGHER SNOWFALL AMOUNTS IN THE UPPER SNAKE
HIGHLANDS. AS A RESULT WILL ISSUE A WINTER STORM WATCH FOR IDZ019
BEGINNING TUESDAY AFTERNOON. SNOWFALL TOTALS THROUGH WEDNESDAY
AFTERNOON SHOULD RANGE FROM 2 TO 4 INCHES IN THE SNAKE VALLEY TO
ROUGHLY OVER A FOOT ABOVE 7000 FEET. DMH
.LONG TERM...WED NIGHT THROUGH NEXT MON NIGHT. LONG WAVE FORECAST
CONTINUES TREND OF AMPLIFYING LONGWAVE RIDGING WITH AXIS VERY CLOSE
TO OR JUST WEST OF THE FORECAST AREA. HAVE STUCK WITH THE DRIER GFS
GUIDANCE RATHER THAN THE MUCH WETTER ECMWF DURING THE FIRST THREE
DAYS. AFTER THIS...TOOK A MEAN FOR SAT NIGHT. SECOND HALF OF
WEEKEND AND MON ARE VERY MUCH IN DOUBT WITH STRONG DIVERGENCE AMONG
THE SOLUTIONS. GFS HAS LOW OVER THE FORECAST AREA...ECMWF HAS HIGH
PRESSURE STRONG ENOUGH TO KEEP STORM TRACK IN PANHANDLE OR FURTHER
NORTH. HAVE LEFT ALONE FOR NOW...AS THE LONG WAVE FAVORS THE HIGH
THAT IS IN THE ECMWF. MESSICK.
&&
.AVIATION...AREAS OF MORNING LOW STRATUS CONTINUE TO SLOWLY BURN OFF
THIS AFTERNOON WITH ALL LOCATIONS REPORTING AT LEAST MARGINAL VFR
CONDTIONS AT THIS TIME...STRATUS MAY REFORM IN PORTIONS OF THE SNAKE
RIVER PLAIN TONIGHT ESPECIALLY IN THE UPPER REGIONS NEAR IDAHO FALLS
ALTHOUGH MOISTURE PROFILES DO NOT SUPPORT WIDESPREAD STRATUS AT THIS
TIME...IN THE CENTRAL MOUNTAINS IFR CONDITIONS WILL DEVELOP LATER
TONIGHT AND INTO TOMORROW AS THE NEXT WAVE MOVES IN FROM THE WEST
AND BRINGS LOWER CEILINGS AS WELL AS SOME SNOW AFTER AROUND 10Z
TUESDAY. HATTINGS/MESSICK
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
AFTERNOON FOR IDZ019.
WINTER WEATHER ADVISORY FROM 5 AM TUESDAY TO 11 AM MST WEDNESDAY
FOR IDZ017-022.
WINTER STORM WARNING FROM 5 AM TUESDAY TO 11 AM MST WEDNESDAY
FOR IDZ018-031.
&&
$$
