FXUS65 KPIH 152018 AFDPIH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE POCATELLO ID 118 PM MST FRI NOV 15 2013 .SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT. THE FORECAST REMAINS RELATIVELY UNCHANGED. A POTENT LOW PRESSURE SYSTEM IS ARRIVING FROM THE NORTH. EXPECT SNOW TO ARRIVE IN THE CENTRAL MOUNTAINS BY MIDNIGHT AND SPREAD ACROSS THE ENTIRE REGION BY DAYBREAK ON SATURDAY. SNOW WILL PERSIST ACROSS MUCH OF THE AREA THROUGH SATURDAY MORNING...GRADUALLY COMING TO AN END BY SATURDAY AFTERNOON AND SATURDAY NIGHT. FORECAST SNOW AMOUNTS CHANGE LITTLE FROM PREVIOUS FORECAST. CONTINUE TO EXPECT 1 TO 2 INCHES IN THE SNAKE PLAIN WITH 3 TO 8 INCHES LIKELY IN THE MOUNTAINS AND HIGHLANDS. STRONG WINDS WILL ESCORT THIS SYSTEM. 3O MPH WIND GUSTS ARE LIKELY IN THE MOUNTAINS AND HIGHLANDS WHICH WILL PRODUCE BLOWING AND DRIFTING CONDITIONS. WIND GUSTS TO 50 MPH ARE POSSIBLE IN THE SNAKE PLAIN WITH ISOLATED AREAS OF BLOWING AND DRIFTING SNOW POSSIBLE. THE STRONG WINDS COULD HELP KEEP TEMPS AROUND OR SLIGHTLY ABOVE FREEZING IN THE SNAKE PLAIN. FOR THESE REASONS...WINTER WEATHER ADVISORIES REMAIN IN EFFECT FOR THE MOUNTAIN AND HIGHLANDS WHEREAS A WIND ADVISORY IS IN EFFECT FOR THE SNAKE PLAIN. EXPECT IMPROVING CONDITIONS FOR SUNDAY AS THE STORM SYSTEM PULLS AWAY FROM THE AREA. BRISK AND COLD CONDITIONS STILL LIKELY FOR SUNDAY...BUT NOT AS WINDY. SOME SNOW SHOWERS ARE POSSIBLE IN THE MOUNTAINS AND HIGHLANDS...BUT NOT AS WIDESPREAD. VALLE .LONG TERM...MONDAY THROUGH FRIDAY NIGHT. LOOKING FIRST AT MOISTURE TRANSPORT...NAM BRINGS STRONG MOISTURE ACROSS CENTRAL MOUNTAINS MONDAY MORNING WHILE GFS/ECMWF HOLD OFF ON MOISTURE UNTIL TUESDAY MORNING. OVERALL...MODELS ARE TRENDING TOWARDS A ZONAL FLOW WITH EMBEDDED TROUGH/RIDGE COUPLETS. HOWEVER THERE IS STRONGER MOISTURE TRANSPORT WITHIN THE WESTERLIES THAT WILL RESULT IN HIGHER POPS THROUGH THURSDAY. OPERATIONAL GFS LAGS THE GFS ENSEMBLE MEAN THURSDAY AFTERNOON WITH TROUGHING DEVELOPING OVER THE WEST. ECMWF ENSEMBLE MEAN DEVELOPS UPPER TROUGHING IN A SPLIT PATTERN WITH THE BULK OF THE MOISTURE ALONG AND SOUTH OF INTERSTATE 80 IN UT/NV ASSOCIATED WITH THE SOUTHERN BRANCH WHILE THE NORTHERN BRANCH OVER IDAHO STAYS DRY. GFS MAINTAINS TROUGHING OVER THE WEST...BUT DRIES OUT LATER ON FRIDAY. IF ANYTHING...SOUTHEAST HIGHLANDS SHOULD BE THE MOST IMPACTED LATE NEXT WEEK THOUGH PRECIP AMOUNTS SHOULD BE LIGHT. HINSBERGER && .AVIATION...MVFR CONDITIONS ACROSS THE SNAKE PLAIN SEEN WELL ON VIS AND GOES GEOCAT IMAGERY. FZFG HAS DRIFTED UP THE VALLEY INTO HAILEY AS WINDS SHIFTED SOUTHEASTERLY EARLIER THIS MORNING. UPDATED GFS MOS GUIDANCE CONTINUES LOW CIGS FOR KSUN THROUGH THE AFTERNOON/EVENING...BUT SHOULD SEE IMPROVEMENTS AT OTHER TERMINALS. EARLY TOMORROW MORNING...A COLD FRONT WILL MAKE ITS WAY OUT OF BRITISH COLUMBIA AND INTO SOUTHEAST IDAHO BRINGING SNOW LEVELS INTO THE VALLEYS. WINDS WILL BE STRONG AS THE FRONT PASSES. IT IS POSSIBLE CONDITIONS WILL BE BETTER AT PIH AND BYI IF DOWNSLOPE COMPONENT IS STRONG ENOUGH AS THAT WILL SUPPRESS SNOW UNTIL WINDS SHIFT MORE SOUTHWESTERLY. HINSBERGER && .PIH WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 10 AM TO 8 PM MST SATURDAY IDZ017-020-021. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM MST SATURDAY IDZ018-019-022-023-025-031-032. && $$  FXUS65 KPIH 230843 AFDPIH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE POCATELLO ID 143 AM MST MON DEC 23 2013 .SHORT TERM...TODAY THROUGH THURSDAY. UPPER TROUGH OVER THE PAC NW SHOWING UP ON WV LOOP THIS MORNING WITH EVIDENCE OF A JET STREAK JUST ALONG VANCOUVER ISLAND. GOES IFR PROBABILITY PRODUCE SEEMS IN GOOD AGREEMENT WITH SURFACE OBSERVATIONS WITH RESPECT TO STRATUS DECK IN THE SNAKE PLAIN. WEBCAMS IN THE SOUTHEAST HIGHLANDS SHOWING SIGNS OF SOME LIGHT SNOWFALL ASSOCIATED WITH SOME OF THE THICKER CLOUD COVERAGE. MODELS DROP UPPER TROUGH OVER SOUTHEAST IDAHO LATE TONIGHT AND EARLY TOMORROW AND SHOULD SEE SNOW AND VALLEY RAIN TO SPREAD ACROSS THE REGION THROUGH THE DAY TODAY. WINDS MAY ALSO BE GUSTY...ESPECIALLY OVER THE HIGHER TERRAIN. MOS GUIDANCE NOT SHOWING WINDS STRONG ENOUGH TO SUPPORT A WIND ADVISORY ANYWHERE. UPPER JET OF 90+ KTS WILL BE DROPPING INTO THE AREA TOMORROW NIGHT AROUND THE BASE OF THE TROUGH...BUT WINDS IN THE VALLEY FLOOR SHOULD REMAIN AROUND 10 TO 15 KTS THROUGH THE NIGHT. HIGHER ELEVATIONS ABOVE THE LOW-LEVEL INVERSION WILL BE MORE EXPOSED TO THE WINDS AND MAY SEE GUSTS ABOVE 30 KTS. AFTER THE UPPER SYSTEM PASSES TUESDAY MORNING...WE SHOULD SEE A TAPERING OFF OF THE PRECIP THROUGH THURSDAY AS DRIER WEATHER WILL BE BROUGHT IN BY UPPER RIDGING. HINSBERGER .LONG TERM...THURSDAY THROUGH MONDAY. GFS/ECMWF LOOKING MUCH DRIER AS ERN PAC RIDGE EDGES INTO THE COASTAL STATES AND REMAINS THE DOMINANT FEATURE THROUGHOUT THE FORECAST PERIOD. MODELS DO PICK UP ON ONE WAVE TOPPING THE RIDGE AND DIGGING SE THROUGH THE REGION FRIDAY NIGHT THROUGH SATURDAY NIGHT. GFS HAS CONTINUED THE DRIER/WEAKER RUN OVER RUN PROGRESSION WITH THE WAVE PASSING FURTHER NORTH AND EAST OF THE AREA AND IT LOOKS AS IF THE ECMWF IS SHIFTING IN THAT DIRECTION AS WELL. STILL...HAVE MAINTAINED A SLIGHT CHANCE MENTION OVER THE NRN/ERN MOUNTAINS SATURDAY THROUGH MONDAY OWING TO AT LEAST SOME DEGREE OF UNCERTAINTY. HUSTON && .AVIATION...A FAIRLY BROAD AREA OF FOG AND STRATUS WAS NOTED ACROSS THE REGION EARLY THIS MORNING WITH CIGS/VIS RANGING FROM VFR AT KSUN UNDER A DRIER NW SURFACE FLOW TO LIFR CONDITIONS AT KIDA. SATELLITE IMAGERY WAS SHOWING A FAIRLY STRONG PAC SHORT-WAVE SHIFTING INTO WRN BRITISH COLUMBIA WHICH IS EXPECTED TO CONTINUE DIGGING SE INTO MONTANA TONIGHT WITH INCREASING WIND AND PRECIPITATION CHANCES ANTICIPATED ALONG AND AHEAD OF THE TROUGH BEGINNING LATE THIS AFTERNOON. INCOMING WAVE WILL LIKELY HELP TO MIX OUT A GOOD PORTION OF THE LOW CLOUDS THIS AFTERNOON/EVE (ESPECIALLY AT KBYI AND KPIH)...FOLLOWED BY DRIER CONDITIONS TUESDAY. MODEL CROSS SECTIONS ARE SHOWING THE POTENTIAL FOR A PERIOD OF MVFR/IFR CIGS WITH MIXED PHASE PRECIPITATION AHEAD OF THE FRONT 03-09Z (8PM-2AM MST) TONIGHT. HUSTON && .PIH WATCHES/WARNINGS/ADVISORIES...NONE. && $$