903
FXUS65 KBOI 230955 CCA
AFDBOI
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE BOISE ID
326 AM MDT SAT OCT 23 2021
SHORT TERM...TODAY THROUGH MONDAY NIGHT
PRECIPITATION HAS
GENERALLY ENDED IN OUR CWA FOR THE TIME BEING. THE NEXT PACIFIC
TROUGH WAS NEARING THE COAST THIS MORNING BUT WILL WEAKEN AS IT
COMES INLAND TO OUR CWA WITH ONLY LIGHT RAIN SHOWERS TODAY AND
TONIGHT. THESE SHOWERS SHOULD BE MAINLY IN THE MOUNTAINS WITH
RAIN AMOUNTS LESS THAN A TENTH OF AN INCH. AN INTENSE STORM WILL
DEVELOP IN THE NORTH PACIFIC LATER TODAY AND TONIGHT AND MOVE TO
NEAR 45/130 OFF WASHINGTON SUNDAY. FROM THAT POSITION THE STORM
WILL SEND A MAJOR SURGE OF PRECIPITATION INLAND INTO OUR CWA
SUNDAY THROUGH MIDDAY MONDAY. IN ADDITION, SOUTHEAST WINDS WILL
INCREASE IN EASTERN OREGON AND IN SOUTHERNMOST IDAHO. SUSTAINED
WINDS 25 TO 35 MPH WITH GUSTS TO 55 MPH ARE EXPECTED. GUSTS TO 65
MPH WILL BLOW OVER THE HIGHER MOUNTAINS. A WIND ADVISORY HAS BEEN
ISSUED FOR NEARLY ALL OF EASTERN OREGON, AND IDAHO SOUTH OF OF THE
SNAKE RIVER. HEAVY RAIN WILL BEGIN IN HARNEY COUNTY/OR EARLY
SUNDAY MORNING AND SPREAD RAPIDLY EAST-NORTHEAST ACROSS WESTERN
IDAHO BY NOON AND CONTINUE THROUGH SUNDAY NIGHT. RAIN WILL CONTINUE
INTO MONDAY ON THE IDAHO SIDE, BUT WILL DECREASE IN EASTERN OREGON.
TOTAL RAINFALL BETWEEN 6 AM MDT SUNDAY AND 6 PM MDT MONDAY WILL BE
1 TO 2 INCHES IN THE MOUNTAINS OF EASTERN OREGON AND THROUGHOUT
WESTERN IDAHO NORTH OF THE SNAKE BASIN. AMOUNTS IN THE SNAKE BASIN
DURING THAT TIME PERIOD SHOULD BE .50 TO .75 INCH, AND IN SOUTHERN
HARNEY AND MALHEUR COUNTIES ABOUT A HALF INCH. FOR THE ENTIRE STORM
ANOTHER HALF INCH MAY FALL. HEAVY RAIN FALLING ON STEEP TERRAIN
MAY BRING DOWN MUD AND ROCKS, AND TRAVELERS WOULD BE WISE TO AVOID
THOSE AREAS. PRECIPITATION WILL BE ALMOST ENTIRELY RAIN, WITH
ACCUMULATING SNOW ONLY ABOVE 6500-7000 FEET.
LONG TERM...TUESDAY THROUGH SATURDAY
A SHORTWAVE TROUGH WILL
ARRIVE ON TUESDAY AFTERNOON WITH SHOWERS EXPECTED THROUGH
WEDNESDAY. SNOW LEVELS WILL BE AROUND 5500-6500FT WITH THIS
SYSTEM. ZONAL FLOW WILL GENERALLY CONTINUE WEDNESDAY THROUGH
FRIDAY BUT THE STORM TRACK WILL MOVE NORTHWARD AS A WEAK RIDGE
SETS UP OVER THE GREAT BASIN. THIS WILL BRING GENERALLY DRY
CONDITIONS, WITH A SLIGHT CHANCE OF SHOWERS ACROSS THE MOUNTAINS
NORTH OF A LINE FROM BURNS/OR TO BOISE. TEMPERATURES WILL WARM
TO AROUND 5-10 DEGREES ABOVE NORMAL BY THURSDAY LASTING THROUGH
FRIDAY. A FRONTAL SYSTEM MAY ARRIVE FROM THE NORTHWEST ON
SATURDAY, BUT FORECAST CONFIDENCE REMAINS LOW.
AVIATION
MOSTLY VFR. PATCHY FOG IN MOUNTAIN VALLEYS THROUGH THIS
MORNING, INCLUDING KBKE. ISOLATED TO SCATTERED SHOWERS TODAY ACROSS
THE REGION. LOCAL MVFR/IFR CONDITIONS IN SHOWERS WITH MOUNTAIN
OBSCURATION CONTINUING. SNOW LEVEL 6000 FT MSL. SURFACE WINDS: SW-SE
5-15KT. WINDS ALOFT AT 10K FT MSL: SW-W 15-25KT.
SUNDAY OUTLOOK...WIDESPREAD RAIN WILL ARRIVE WEST TO EAST SUNDAY
MORNING, WITH PERIODS OF MODERATE TO HEAVY RAIN EXPECTED. SNOW
LEVELS 6000-7000FT MSL SUNDAY MORNING RISING TO 8000-9000 FT MSL
BY SUNDAY EVENING. MOUNTAINS OBSCURED. MVFR TO LIFR IN RAIN/SNOW.
SURFACE WINDS SW-SE 20-30KT WITH GUSTS 35-45KT. WINDS ALOFT AT
10KFT MSL INCREASING TO SW 50-70KT IN EASTERN OR BY 15Z/SUN AND
SOUTHWEST ID BY 21Z/SUN.
BOI WATCHES/WARNINGS/ADVISORIES
ID...WIND ADVISORY FROM NOON TO 9 PM MDT SUNDAY IDZ015-029-030.
OR...WIND ADVISORY FROM NOON MDT /11 AM PDT/ TO 9 PM MDT /8 PM PDT/
SUNDAY ORZ061>063.
WWW.WEATHER.GOV/BOISE
WWW.FACEBOOK.COM/NWSBOISE
WWW.TWITTER.COM/NWSBOISE
SHORT TERM...LC
LONG TERM....KA
AVIATION.....KA
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