Flooding in Idaho, March 10 to 20, 2012

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE POCATELLO ID
248 AM MST SAT MAR 10 2012

.SHORT TERM...TODAY THROUGH TUESDAY. UPPER LEVEL FLOW WILL SLOWLY
BECOME SOUTHWESTERLY TONIGHT AS UPPER RIDGING WEAKENS OVER THE AREA.
THE FLOW WILL GRADUALLY BECOME STRONGER SUNDAY MORNING AND ADVECT
MOISTURE OVER THE CENTRAL MOUNTAINS...THEN SPREAD EASTWARD INTO
EASTERN IDAHO BY SUNDAY EVENING. VALLEY LOCATIONS SHOULD RECEIVE
RAIN AS HIGHER ELEVATIONS RECEIVE SNOWFALL. MODELS CONTINUE THE
TRANSITION TO A WETTER PATTERN THROUGH WEDNESDAY. A SHORTWAVE WILL
MOVE THROUGH THE REGION ON SUNDAY. AFTER IT PASSES...PRECIPITATION
WILL CONTINUE WHERE UPSLOPE REMAINS THE GREATEST--MAINLY THE CENTRAL
RANGES AND EASTERN HIGHLANDS. THE THREAT OF FLOODING DUE TO SNOWMELT
REMAINS HIGH OVER THE WEEKEND...AND ADDITIONAL FLOODING MAY BE
TRIGGERED THROUGH MONDAY AS RAIN FALLS UPON SNOW OVER THE LOWER
ELEVATIONS. THUS...WILL BE CONTINUING THE FLOOD WATCH FOR THE AREA.
SNOWFALL TOTALS ARE EXPECTED TO BE 10 TO 15 INCHES OVER THE CENTRAL
MOUNTAINS THROUGH TUESDAY NIGHT ABOVE 6500 FT.  HINSBERGER

LONG TERM...TUESDAY THROUGH FRIDAY. AN UNSETTLED AND WET PATTERN IS
EXPECTED NEXT WEEK WITH THE PRESENCE OF A LOW PRESSURE TROUGH OVER
THE EASTERN PACIFIC AND EMBEDDED DISTURBANCES IN THE FLOW KICKING
OUT AND ACROSS IDAHO. CURRENT MODEL RUNS FOCUS ONE EMBEDDED WAVE
DAYTIME TUESDAY AND ANOTHER ABOUT THURSDAY MORNING. SNOW LEVELS WILL
BE ELEVATED AROUND 6000 TO 7000 FEET MOST OF THE WEEK WITH
OCCASIONAL DIPS LOWER WITH COLD AIR FOLLOWING EACH EMBEDDED
DISTURBANCE. MODEL PRECIPITATION IS IN EXCESS OF 2 INCHES LIQUID
EQUIVALENT ACCUMULATIVE FROM TUESDAY THROUGH NEXT SATURDAY OVER THE
HIGHER PEAKS IN THE SAWTOOTH RECREATION AREA. FURTHER REFINING THE
FORECAST WILL BE A CHALLENGE. THERE MAY BE TIMES WHEN HEAVY SNOW
ACCUMULATION IS POSSIBLE AT ELEVATION WHILE RUN OFF WILL BE A
CONCERN FOR SMALL STREAMS AT LOWER ELEVATION. THE BEST CHANCE FOR
PRECIPITATION IN THE SNAKE PLAIN WILL BE WITH PASSING DISTURBANCES.
MODELS DIFFERENCES SHOW UP FROM WEDNESDAY ON. BOTH THE GFS AND ECM
DEEPEN THE TROUGH OVER THE EASTERN PACIFIC WITH TIME. THE GFS IS
FASTER WITH EMBEDDED IMPULSES...FASTER TO AMPLIFY THE TROUGH OFF
SHORE BY WEDNESDAY AND FORCE MORE RIDGING AND DRY AIR OVER EASTERN
IDAHO. CURRENT FORECAST IS A MODEL BLEND OF THE TWO. RS
&&

.AVIATION...INCREASING MIDDLE AND HIGH LEVEL CLOUDS EXPECTED
SATURDAY NIGHT...OTHERWISE WIDESPREAD VFR CONDITIONS. MVFR CEILINGS
DEVELOP AT KSUN LATE SUNDAY AFTERNOON. RS
&&

.PIH WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH MONDAY EVENING IDZ018>020-022-023-025-031.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE POCATELLO ID
417 AM MST SAT MAR 10 2012

IDZ017>025-031-032-111130-
EASTERN MAGIC VALLEY-SAWTOOTH MOUNTAINS-UPPER SNAKE HIGHLANDS-
UPPER SNAKE RIVER PLAIN-LOWER SNAKE RIVER PLAIN-
SOUTH CENTRAL HIGHLANDS-CARIBOU HIGHLANDS-
CACHE VALLEY/IDAHO PORTION-WASATCH MOUNTAINS/IDAHO PORTION-
BIG AND LITTLE WOOD RIVER REGION-LOST RIVER/PAHSIMEROI-
417 AM MST SAT MAR 10 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN IDAHO.

.DAY ONE...TODAY AND TONIGHT

RAPID SNOWMELT WILL INCREASE THE AREAL FLOODING THREAT OVER PARTS
OF EASTERN IDAHO.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH FRIDAY

THE FLOODING THREAT CONTINUES THROUGH MONDAY. MODERATE TO LOCALLY
HEAVY AMOUNTS OF SNOWFALL ARE EXPECTED TO BLANKET PARTS OF THE
CENTRAL MOUNTAINS PERIODICALLY THROUGHOUT THE WEEK. SOME AREAS CAN
SEE 1 TO 2 FEET OF NEW SNOW NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

WE ASK TRAINED SPOTTERS AND CITIZENS TO REPORT SIGNIFICANT
WEATHER CONDITIONS WHEN IT IS SAFE TO DO SO. THESE CONDITIONS MAY
INCLUDE HAIL...TORNADOES...STRONG WIND...DUST STORMS...SNOWFALL...
EXTREME COLD TEMPERATURES...FREEZING RAIN OR HEAVY RAIN...DENSE
FOG...AND FLOODING OR ICE JAMS. INFORMATION ABOUT THESE HAZARDOUS
CONDITIONS SHOULD BE CALLED INTO YOUR NATIONAL WEATHER SERVICE
OFFICE IN POCATELLO USING THE 1-800 SEVERE WEATHER HOTLINE...OR
208-233-0834.