Weather Service Report


117 
FXUS65 KPIH 190159
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
759 PM MDT FRI APR 18 2014

.UPDATE...SHORTWAVE AXIS CLEARLY PAST EASTERN IDAHO THIS EVENING
WITH VIS/IR SAT IMAGERY SHOWING LITTLE REMAINING IMPACT ALONG EVEN
EASTERN BORDER. MINOR FEATURE MOVING QUICKLY THROUGH CENTRAL
MOUNTAINS INTO THE SNAKE PLAIN THIS EVENING BUT LITTLE IMPACT
OTHER THAN MID/UPPER CLOUD BAND. DECREASED POPS FOR TONIGHT. WINDS
DECREASING ALREADY THIS EVENING PER MESONET OBSERVATIONS WITH ONLY
TWO SITES OVER ARCO DESERT STILL GUSTING INTO LOW 40S RANGE.
REMAINDER OF SITES IN UPPER SNAKE BELOW 30MPH THRESHOLD FOR
ADVISORY AND TREND SHOULD CONTINUE WITH RAPID DECREASE NEXT FEW
HOURS WITH SUNSET. THUS HAVE ALREADY EXPIRED WIND ADVISORY FOR THE
EVENING. DMH

&&

.PREV DISCUSSION... /ISSUED 114 PM MDT FRI APR 18 2014/ 

SHORT TERM...RADAR CONFIRMS A FEW SHOWERS LEFT IN THE CARIBOU
HIGHLANDS THIS AFTERNOON AND THOSE SHOULD BE ACROSS THE BORDER OR
DISSIPATED BY 6 PM. THERE WAS SOME INCREASE IN WINDS NEAR IDAHO
FALLS THIS AFTERNOON WHICH LOOKS LIKE IT IS DROPPING OFF LAST HOUR.
MODELS FAVOR A CONTINUED DECREASE IN THE SURFACE PRESSURE
GRADIENT...ALTHOUGH THE SURFACE LOW HAS NOT MOVED EAST OUT OF
WYOMING JUST YET. NO SIGNS OF THE GROUND DRYING OUT AND BLOWING
DUST SO WILL LET WINDS GRADUALLY DIE OFF WITHOUT AND ADVISORY. THE
NAM12 MODEL KEEPS HINTING AT SOME INSTABILITY AND POTENTIAL FOR
SHOWERS IN THE SOUTH CENTRAL HIGHLANDS SATURDAY AFTERNOON. THERE
IS SOME HINT OF A SURFACE TROUGH IN THAT AREA PLUS MIDDLE LEVEL
MOISTURE...DECIDED IT WAS WORTH A SLIGHT CHANCE OF SHOWERS IN THE
FORECAST. OTHERWISE...OTHER THAN A LITTLE BREEZY IN THE AFTERNOON
BOTH SATURDAY AND SUNDAY...THE EASTER WEEKEND LOOKS PRETTY DRY
UNDER MILD WESTERLY FLOW. TEMPERATURES EXPECTED TO REBOUND AFTER
TODAY BACK TO THE 65-70F RANGE FOR MOST VALLEY AREAS. RS

LONG TERM...MONDAY NIGHT THROUGH FRIDAY NIGHT. WE ARE STILL LOOKING 
AT DECENT SHOT OF RAIN AND SNOW COMING FOR TUESDAY AND WEDNESDAY. 
THERE ARE STILL SOME MAJOR DIFFERENCES BETWEEN THE MODELS THAT WILL 
DEFINITELY DETERMINE HOW MUCH MOISTURE FALLS AND HOW LOW THE SNOW 
LEVELS WILL FALL. THE ECMWF IS STILL A BIT FASTER MOVING THROUGH A 
MORE OPEN SYSTEM VS A CLOSED LOW SHOWN BY THE GFS. IF THE LATTER 
MODEL PANS OUT...WE WILL DEFINITELY SEE A LOT MORE SNOW IN THE 
MOUNTAINS. SNOW LEVELS COULD GET LOW ENOUGH THAT A MIX IS POSSIBLE 
AT NIGHT AND WITH HEAVIER SHOWERS TUESDAY AND WEDNESDAY. IF ANY SNOW 
FALLS AT VALLEY ELEVATIONS...IT WOULD NOT BE STICKING AROUND VERY 
LONG IT LOOKS LIKE RIGHT NOW. WE WILL HAVE TO DEAL WITH BREEZY 
CONDITIONS DURING THIS PERIOD AS WELL. HOPEFULLY...THERE WILL ENOUGH 
MOISTURE TO WET THE GROUND AND PREVENT ISSUES WITH BLOWING DUST AND 
SAND. OF NOTE...THE ENSEMBLES WE LOOK AT WERE SHOWING THAT THE 
CURRENT SCENARIO OF A CLOSED LOW IN THE GFS THIS FAR SOUTH WAS 
WEAKLY SUPPORTED.  HOWEVER...IT SEEMS THAT THE GFS OVERALL HAS BEEN 
A BIT MORE CONSISTENT OVER THE PAST FEW RUNS. FOR THE END OF NEXT 
WEEK...THE MODELS TRY TO BRING A BRIEF RIDGE OVER THE STATE AND 
SOUTHWEST FLOW AS THE NEXT BIG STORM FORMS OFFSHORE.  DUE TO THE 
DIFFERENCES BETWEEN THE OVERALL PATTERN PROGRESSION IN THE 
MODELS...WE OPTED TO KEEP THE PREVIOUS IDEA OF A JUST A FEW SHOWERS 
IN THE PLAIN AND A LOW CHANCE IN THE MOUNTAINS. KEYES

AVIATION...GUSTY WINDS CONTINUE IN THE WAKE OF THIS MORNING'S COLD 
FRONT AND RAINFALL. MOST AREAS ARE VFR BUT WE MAY SEE AN OCCASIONAL 
DIP TO MVFR THROUGH THIS EVENING. OTHERWISE...VFR WEATHER SHOULD BE 
AROUND ALL WEEKEND. IT WILL BE A BIT BREEZY BOTH AFTERNOONS WITH AN 
OUTSIDE CHANCE OF A MOUNTAIN SHOWER. KEYES

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 8 PM MDT THIS EVENING IDZ020.

&&

$$





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