098  
FXUS65 KBOI 301614  
AFDBOI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOISE ID  
1014 AM MDT THU MAR 30 2017  
   
DISCUSSION
 
IMPRESSIVE COLD FRONT ACCOMPANIED BY STRONG WINDS IS  
MOVING THROUGH SW IDAHO. THE FRONT IS EAST OF MOUNTAIN HOME AND  
WILL MOVE INTO THE WESTERN MAGIC VALLEY BEFORE NOON. GUSTS TO  
AROUND 40 MPH AND ISOLATED THUNDERSTORMS WILL ACCOMPANY THE  
FRONT. WINDS WILL INCREASE DURING THE AFTERNOON ESPECIALLY EAST OF  
BOISE AS WINDS WILL REACH HIGH WIND CRITERIA FROM NEAR MOUNTAIN  
HOME, EAST TO TWIN FALLS, AND SOUTH TO THE NEVADA BORDER. SNOW  
LEVELS HAVE DROPPED TO NEAR VALLEY FLOORS BEHIND THE FRONT WITH  
SNOW OR RAIN/SNOW MIX IN THE TREASURE VALLEY. LITTLE ACCUMULATION  
IS EXPECTED, ALTHOUGH THERE MAY BE A DUSTING ON GRASSY AREAS THIS  
MORNING. FORECAST WILL BE UPDATED FOR LOWER SNOW LEVELS TODAY.  
 

 
   
AVIATION
 
VFR WITH MVFR/IFR WITHIN HEAVY SHOWERS AND HIGHER  
ELEVATIONS. SHOWERS PUSHING THROUGH THE REGION WILL CONTINUE TO PUSH  
EASTWARD THROUGH THE REST OF THURSDAY AND CONTINUE THROUGH FRIDAY  
MORNING DOWN IN SOUTHERN TWIN FALLS COUNTY AND THE SOUTHERN  
HIGHLANDS. SNOW LEVELS BELOW 4000 FEET MSL. WIND ADVISORY OUT  
THROUGH 06Z FRIDAY FOR MUCH OF THE AREA. A WIND WARNING IS OUT FOR  
THE UPPER TREASURE VALLEY, SOUTHWEST HIGHLANDS, WESTERN MAGIC  
VALLEY, AND SOUTHERN TWIN FALLS COUNTY THROUGH 06Z FRIDAY. SURFACE  
WINDS, VARIABLE 20-45 KTS. WINDS ALOFT TO 10K FEET MSL, NORTHERLY 40-  
50 KTS.  
 

 
   
HYDROLOGY
 
RUNOFF FROM RAIN SINCE YESTERDAY WILL CAUSE RISES IN  
AREA RIVERS AND STREAMS. COLDER AIR WILL ARRIVE BEHIND A COLD  
FRONT TODAY WHICH WILL DECREASE SNOWMELT OVER THE MOUNTAINS  
THROUGH FRIDAY. FLOOD WARNINGS ARE IN EFFECT FOR A FEW RIVERS.  
FLOOD WATCHES REMAIN IN EFFECT FOR THE MALHEUR RIVER AT VALE, OR,  
AND THE PAYETTE RIVER AT EMMETT, ID. A FLOOD WATCH ALSO REMAINS IN  
EFFECT FOR THE BIG WOOD RIVER IN GOODING COUNTY, ID, DUE TO  
OUTFLOW FROM MAGIC DAM ON THE MAGIC RESERVOIR.  
 

 
   
PREV DISCUSSION
 
 
SHORT TERM...TODAY THROUGH FRIDAY...UPPER LEVEL TROUGH IS PUSHING  
INTO SOUTHERN OREGON THIS MORNING WITH RAPID SHOWER DEVELOPMENT  
AND ISOLATED THUNDERSTORMS JUST EAST OF THE VORT MAX NEAR  
LAKEVIEW, OR. THE COLD FRONT IS NEAR JOHN DAY, OR AND BAKER CITY  
AT THE TIME OF THIS WRITING, WHICH IS VERY CLOSE TO WHAT THE  
MODELS HAD. THE UPPER LEVEL TROUGH BEGINS TO SPLIT FROM THE PARENT  
JET STREAM AND BECOME A CLOSED LOW BY THIS AFTERNOON MOVING INTO  
NV. AS WITH CLOSED LOWS, MODELS HAVE A HARD TIME PINPOINTING THE  
LOCATION CENTER, AND THE LOCATION OF THE TROUGH IS CRUCIAL TO  
PRECIPITATION AND WIND FORECASTS. LATEST MODELS NOW TAKE THE  
CENTER OF THE CLOSED LOW A LITTLE FARTHER SOUTH THAN THE PREVIOUS  
FORECASTS, ACROSS NORTHERN NEVADA INSTEAD OF DIRECTLY OVERHEAD.  
STILL EXPECT ISOLATED THUNDERSTORMS TO DEVELOP SOUTH OF A LINE  
FROM BURNS, OR TO ONTARIO, OR THIS MORNING AHEAD OF THE COLD FRONT  
AS THIS TROUGH MOVES ACROSS SOUTHERN OR INTO NORTHERN NV.  
WIDESPREAD PRECIPITATION IS EXPECTED WITH THIS SYSTEM. THE COLD  
FRONT WILL PASS THROUGH THE AREA THIS MORNING BRINGING POSSIBLE  
WIND GUSTS TO 50 MPH. AFTER THE FRONTAL PASSAGE, SNOW LEVELS DROP  
TO AROUND 3000-3500 FEET WITH LITTLE TO NO ACCUMULATION IN THE  
VALLEYS, AND SNOW AMOUNTS OF 6 TO 11 INCHES EXPECTED ON THE  
MOUNTAIN PEAKS ABOVE 7000 FEET. WINDS ARE EXPECTED TO INCREASE TO  
ADVISORY LEVEL FOR EASTERN OREGON AND PORTIONS OF SOUTHWEST IDAHO.  
HIGH WINDS WITH GUSTS TO 55 MPH ARE EXPECTED NEAR MOUNTAIN HOME  
TOWARD THE MAGIC VALLEY CORRIDOR AND PARTS OF OWYHEE COUNTY, WHERE  
A HIGH WIND WARNING REMAINS IN EFFECT. A WINTER WEATHER ADVISORY  
REMAINS IN EFFECT IN THE SOUTHWEST IDAHO HIGHLANDS AND SOUTHERN  
TWIN FALLS COUNTY, FOR SNOW AND WIND AS TRAVEL COULD BECOME  
DIFFICULT ON IDAHO STATE HIGHWAY 51 AND HIGHWAY 93 THROUGH FRIDAY  
MORNING. EXPECT BREEZY CONDITIONS TO CONTINUE ON FRIDAY WITH  
CLEARING AND DRYING AS THE TROUGH MOVES INTO THE FOUR CORNERS  
REGION.  
 
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...AN UPPER LEVEL RIDGE  
WILL CONTINUE TO BUILD OVER THE REGION SATURDAY FOR MILD CONDITIONS.  
A WEAK SHORTWAVE WILL MOVE ACROSS THE REGION SATURDAY NIGHT,  
FLATTENING OUT THE RIDGE AND COOLING TEMPERATURES BY A FEW DEGREES.  
LOOKING FOR A SLIGHT CHANCE OF SHOWERS ACROSS THE NORTHERN MOUNTAINS  
WITH THIS SHORTWAVE. BY SUNDAY AFTERNOON, AN UPPER LEVEL TROUGH WILL  
MOVE INLAND FROM OVER THE PACIFIC AND CROSS INTO THE REGION SUNDAY  
EVENING. EXPECTING BREEZY CONDITIONS AND SHOWERS ACROSS THE REGION  
WITH THIS SYSTEM. MONDAY WILL BE THE COOLEST DAY OF THE EXTENDED  
FORECAST. A DRY NORTHWEST FLOW WILL CUT OFF ALL PRECIPITATION BY  
TUESDAY MORNING. DRY CONDITIONS WILL PERSIST INTO WEDNESDAY  
AFTERNOON. NEXT TROUGH WILL MOVE INTO THE REGION WEDNESDAY NIGHT AND  
IS EXPECTED TO BRING WIDESPREAD SHOWERS INTO THE END OF THE WEEK.  
TEMPERATURES WILL BE WITHIN 5 DEGREES OF NORMAL THROUGHOUT THE  
PERIOD.  
 

 
   
BOI WATCHES/WARNINGS/ADVISORIES
 
 
ID...HIGH WIND WARNING UNTIL MIDNIGHT MDT TONIGHT IDZ014>016-030.  
FLOOD WATCH THROUGH FRIDAY AFTERNOON IDZ016.  
WINTER WEATHER ADVISORY UNTIL 6 AM MDT FRIDAY IDZ015-030.  
WIND ADVISORY UNTIL MIDNIGHT MDT TONIGHT IDZ012-029.  
OR...WIND ADVISORY UNTIL MIDNIGHT MDT /11 PM PDT/ TONIGHT ORZ061>064.  
 

 
 

 
 
WWW.WEATHER.GOV/BOISE  
WWW.FACEBOOK.COM/NWSBOISE  
WWW.TWITTER.COM/NWSBOISE  
 
DISCUSSION...BW  
AVIATION.....JC  
HYDROLOGY...KA/BW  
PREV SHORT TERM...KA  
PREV LONG TERM....AB  
 
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