231  
FXUS65 KBOI 282024  
AFDBOI  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BOISE ID  
224 PM MDT THU MAR 28 2024  
   
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
 
A TROUGH REMAINS  
OFF THE WA COAST THIS AFTERNOON WITH WEST-SOUTHWEST FLOW OVER  
SOUTHEAST OR AND SOUTHWEST ID. COLD AIR ALOFT ASSOCIATED WITH  
THE UPPER LEVEL TROUGH REMAINS OVER THE AREA THIS AFTERNOON WITH  
500MB TEMPERATURES NEAR -30C. THIS COMBINED SUNNY BREAKS AND  
THE LATE MARCH SUN ANGLE HAS DESTABILIZED THE ATMOSPHERE, AIDING  
IN SHOWER AND THUNDERSTORM DEVELOPMENT. SOME SHOWERS MAY  
PRODUCE BRIEF HEAVY RAIN, SMALL HAIL, GRAUPEL AND GUSTY WINDS UP  
TO 40 MPH THIS AFTERNOON AND EVENING. THE TROUGH OFF THE PACIFIC  
NW COAST WILL MOVE SOUTH ALONG THE OR COAST ON FRIDAY MORNING  
AND REACH THE NORTHERN CA COAST BY FRIDAY AFTERNOON. THIS WILL  
SHIFT THE UPPER LEVEL FLOW ALOFT TO THE SOUTH, BRINGING IN  
SLIGHTLY WARMER AIR ALOFT ON FRIDAY AFTERNOON. STILL ENOUGH COLD  
AIR ALOFT FOR SCATTERED SHOWERS, MAINLY OVER THE MOUNTAINS ON  
FRIDAY AND SATURDAY AFTERNOONS. THE TROUGH MOVES INLAND ON  
SATURDAY INTO THE GREAT BASIN ACROSS NV/UT, BRINGING THE  
HIGHEST CHANCE OF PRECIPITATION SOUTH ALONG THE NV BORDER. STILL  
SOME UNCERTAINTY ON THE PLACEMENT OF THE TROUGH, AND IF IT IS  
50-150 MILES FARTHER NORTH, COULD BE A SIGNIFICANT  
PRECIPITATION EVENT, ESPECIALLY FOR SOUTHWEST ID ON SATURDAY  
NIGHT INTO SUNDAY. THE DIFFERENCES IN SNOW AMOUNT RANGES IN THE  
ENSEMBLES OVER THE SOUTHERN ID MOUNTAINS ARE 5-10" SATURDAY AND  
SUNDAY, MEANING IF THE STORM TRACKS NORTH OF THE CURRENT  
FORECAST, SNOW AMOUNTS WILL BE 5-10 INCHES HIGHER THAN THE  
CURRENT FORECAST, WITH 0.5 TO 1.00 INCH HIGHER PRECIPITATION.  
   
LONG TERM...SUNDAY THROUGH THURSDAY
 
LINGERING MOISTURE WITH THE  
UPPER LEVEL TROUGH WILL KEEP A SLIGHT CHANCE OF PRECIPITATION (10-  
30%) ON SUNDAY, BUT WILL BE ALMOST ENTIRELY EAST OF A LINE FROM KBOI-  
KMYL. THE ID-NV BORDER ALSO SEES THE SAME CHANCE OF PRECIPITATION.  
IF THE TROUGH MOVES EVEN A SMALL AMOUNT FURTHER EAST THAN FORECAST,  
CHANCES FOR PRECIPITATION IN OUR AREA WILL DROP SIGNIFICANTLY. SNOW  
LEVELS 4000-5000 FT MSL, WITH HEAVIER SNOW MOSTLY CONFINED TO HIGHER  
TERRAIN ALONG THE ID-NV BORDER, OTHERWISE SCATTERED RAIN AND SNOW  
SHOWERS ARE EXPECTED. STRONG GUSTS ARE LIKELY SUNDAY AFTERNOON, AS  
THE WESTERN AND CENTRAL PORTIONS OF OUR CWA WILL BE UNDER CLEAR  
SKIES AND A STRONGER SURFACE PRESSURE GRADIENT SETS UP WEST OF A  
SURFACE LOW. GUSTS IN AN AREA THAT ROUGHLY EXTENDS FROM BAKER CITY  
DOWN TO MTN HOME WILL BE IN THE 30-40 MPH RANGE, WITH A FEW ISOLATED  
INSTANCES OF 45 MPH. BY MONDAY MORNING, THERE IS GREAT MODEL  
CONSENSUS IN CARRYING THE TROUGH OUT OF OUR AREA AND A HIGH PRESSURE  
RIDGE SETTING IN. THIS WILL KICK OFF A WARMING TREND AND CLEAR SKIES  
THROUGH AT LEAST WEDNESDAY EVENING. THERE IS A LOW CHANCE (<10%) OF  
AN 80F HIGH TEMPERATURE ON TUESDAY OR WEDNESDAY. THE BEST CHANCES  
FOR THOSE VERY WARM TEMPS EXIST ON WEDNESDAY, BUT ONLY IN MODELS  
THAT DELAY THE ARRIVAL OF OUR NEXT SYSTEM. MODELS ARE TRENDING  
TOWARDS AN EARLIER ARRIVAL OF ANOTHER TROUGH WEDNESDAY  
NIGHT/THURSDAY MORNING. IF THEY CONTINUE TO BRING IT IN EARLIER,  
WINDS ON WEDNESDAY COULD BE GUSTY AND TEMPS MAY NOT WARM UP AS MUCH.  
SNOW LEVELS DROP FROM 7000-8000 FT MSL AHEAD OF THE SYSTEM TO ABOUT  
4000-5000 FT MSL BEHIND THE SYSTEM.  
 

 
   
AVIATION
 
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IMPACTING  
MOST OF THE AREA THIS AFTERNOON/EVENING. GRAUPEL AND PEA-SIZE HAIL  
POSSIBLE IN MOST STORMS. WHILE STORM AND SHOWER ACTIVITY WILL  
DECREASE AFTER SUNSET, THERE MAY BE LINGERING ACTIVITY UNTIL  
MIDNIGHT. SNOW LEVELS 4000-5000 FT MSL. MOUNTAINS OBSCURED. SURFACE  
WINDS: W-S 10-20 KT, GUSTS 20-30 KT. WINDS ALOFT AT 10KFT MSL: WSW  
15-25KT.  
 
WEEKEND OUTLOOK...MVFR/LOCAL IFR IN ISOLATED SHOWERS THROUGH THE  
WEEKEND, MAINLY OVER THE CENTRAL ID MOUNTAINS AND NEAR THE NEVADA  
BORDER/MAGIC VALLEY. SNOW LEVELS WILL BE AROUND 4500-5500 FT MSL.  
SURFACE WINDS WILL BE NE-NW 5-15 KT, WITH BREEZY AFTERNOON WINDS NW  
10-20KT WITH GUSTS TO 30 KT.  
 

 
   
BOI WATCHES/WARNINGS/ADVISORIES
 
 
ID...NONE.  
OR...NONE.  
 

 
 

 
 
WWW.WEATHER.GOV/BOISE  
 
INTERACT WITH US VIA SOCIAL MEDIA:  
WWW.FACEBOOK.COM/NWSBOISE  
WWW.TWITTER.COM/NWSBOISE  
 
SHORT TERM...KA  
LONG TERM....JM  
AVIATION.....JM  
 
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