451
FXUS65 KBOI 301618
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1018 AM MDT MON JUN 30 2025
DISCUSSION
AN UPPER LEVEL TROUGH REMAINS OFF THE CA COAST
WITH UNUSUAL ISOLATED THUNDERSTORMS OVER THE MARINE LAYER. THIS
SYSTEM IS BRINGING MID LEVEL MOISTURE AND SMOKE TO THE AREA FROM
THE SOUTH. A 10-20 PERCENT CHANCE OF THUNDERSTORMS IS FORECAST
THIS AFTERNOON ALONG THE NV BORDER AND SOUTH CENTRAL OR. GUSTY
OUTFLOW WINDS UP TO 45 MPH POSSIBLE WITH THE STORMS THIS
AFTERNOON ALONG THE NV BORDER AND WESTERN HARNEY COUNTY.
TEMPERATURES WILL WARM AROUND 5-10 DEGREES TODAY. ISOLATED
SHOWERS AND THUNDERSTORMS CONTINUE INTO TUESDAY MORNING, MAINLY
OVER EASTERN OR. A DRY SLOT WITH THE SYSTEM MOVES INTO SOUTHEAST
OR AND SOUTHWEST ID TUESDAY AFTERNOON, LIMITING THUNDERSTORM
THREAT, AND ALLOWING WARMER AIR. TEMPERATURES WILL BE IN THE LOW
100S IN THE TREASURE VALLEY AND WEISER RIVER BASIN ON TUESDAY
WHERE A HEAT ADVISORY REMAINS IN EFFECT. A SHORTWAVE MOVES INTO
THE PACIFIC NW ON WEDNESDAY, BRINGING A WEAK COLD FRONT, AND A
20 PERCENT CHANCE OF SHOWERS AND STORMS. FORECAST WAS UPDATED TO
ADD MENTION OF THUNDER THIS AFTERNOON ALONG NV BORDER.
AVIATION
MAINLY VFR. ISOLATED SHOWERS AND THUNDERSTORMS THIS
AFTERNOON AND EARLY EVENING NEAR THE NV BORDER WITH GUSTS UP TO 40
KT. HIGH DENSITY ALTITUDE DUE TO HEAT. SURFACE WINDS: VARIABLE 10 KT
OR LESS EXCEPT SE IN THE SNAKE PLAIN, BECOMING NW-NE 5-15 KT THIS
AFTERNOON. WINDS ALOFT AT 10KFT MSL: VARIABLE 10 KT OR LESS,
BECOMING E-SE 10-20 KT AFTER 00Z/TUE.
KBOI...VFR. HIGH DENSITY ALTITUDE THIS AFTERNOON DUE TO HEAT.
SURFACE WINDS: SE 5-10 KT BECOMING NW BY MID-AFTERNOON.
PREV DISCUSSION
SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...HOT THROUGH
WEDNESDAY, WITH TUESDAY THE HOTTEST DAY. HEAT ADVISORY CONTINUES
TUESDAY AS ORIGINALLY ISSUED. AN UPPER RIDGE SUPPORTING THE HOT
WEATHER WAS STILL BUILDING OVER SOUTHERN IDAHO THIS MORNING,
WITH AN UPPER LOW OFF THE CA COAST CIRCULATING MID/HIGH LEVEL
MOISTURE NORTHWARD TOWARD OUR CWA. THIS MOISTURE WILL BE THE
BASIS FOR ISOLATED HIGH-BASED THUNDERSTORMS IN SOUTHERNMOST
PARTS OF OUR CWA THIS AFTERNOON. SO FAR, NO LIGHTNING HAS BEEN
DETECTED IN NORTHERN NV OR SOUTH-CENTRAL OR, AND HARDLY ANY
CLOUDS EITHER, BUT MOISTURE COULD BE SEEN ON WATER VAPOR
SATELLITE IMAGERY. LATEST HI-RES NAMNEST MODEL SHOWS HIGH-
BASED THUNDERSTORMS FORMING ALONG THE NV/ID BORDER AROUND
3 PM MDT AND MOVING NORTHWARD, AND STRONGER STORMS WITH OUTFLOW
WINDS 45-50 MPH IN HARNEY COUNTY THIS EVENING. RAINFALL WITH
ALL THESE STORMS SHOULD BE MINIMAL AS THE LOWER ATMOSPHERIC
LAYERS WILL STILL BE VERY DRY. ON TUESDAY THE UPPER LOW, NOW
ON THE CA COAST, WILL STILL CIRCULATE MOISTURE INTO SOUTHERN
OR, BUT MORE HIGH-LEVEL MONSOON MOISTURE WILL APPROACH IDAHO
FROM EASTERN NV AND UTAH. ON WEDNESDAY THE CA LOW WILL BE
INLAND WITH THE MAIN MOISTURE DIRECTED INTO SOUTHERN AND EASTERN
ID RATHER THAN OR, WHILE A NEW PACIFIC UPPER TROUGH APPROACHES
THE NORTHWEST COAST. A COLD FRONT SHOULD FORM IN EASTERN OR
EARLY WEDNESDAY, WITH AT LEAST A 15% CHANCE OF THUNDERSTORMS
LATER WEDNESDAY IN IDAHO ALONG AND AHEAD OF THE EASTWARD-MOVING
FRONT. GREATEST CHANCES (30-40%) ARE INDICATED IN EASTERN
VALLEY COUNTY/ID. OVERALL, POPS WILL SLOWLY INCREASE THROUGH
WEDNESDAY AS THE LOWER ATMOSPHERIC LAYERS MOISTEN. WEDNESDAY
WILL STILL BE HOT IN IDAHO, BUT COOLER IN OREGON BEHIND THE COLD
FRONT.
LONG TERM...THURSDAY THROUGH MONDAY...THURSDAY A SHORTWAVE
TROUGH AMPLIFIES TO OUR SOUTH, ALLOWING FOR A 20% CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE AREA. THE CHANCE
FOR PRECIPITATION IS LOWER IN SE OREGON AS THERE IS SOME
DETERMINISTIC MODEL DISAGREEMENT IN THE TRACK OF THE CORE OF
THE TROUGH. THAT TROUGH QUICKLY MAKES WAY FOR ANOTHER SHORTWAVE
TROUGH FRIDAY EVENING, KEEPING A 10-20% CHANCE OF PRECIPITATION
ACROSS THE AREA. FOLLOWING THE HEAT IN THE SHORT-TERM, THESE
TROUGHS WILL COOL US DOWN TO ABOUT NORMAL BY FRIDAY. THE
THUNDERSTORM RISK BOTH OF THESE DAYS REMAINS A CONCERN FOR FIRE
WEATHER ESPECIALLY FOLLOWING THE HEAT, THOUGH MODEL DISAGREEMENTS
ARE CAUSE FOR A HIGHER LEVEL OF UNCERTAINTY IN THE FORECAST.
DETERMINISTIC MODELS DIVERGE SIGNIFICANTLY SATURDAY THROUGH MONDAY,
THOUGH ENSEMBLES AND ALL CLUSTERS SUGGEST GENERAL TROUGHING ALONG
THE PACNW COAST. THIS WOULD PUT US UNDER SOUTHWEST FLOW ALOFT,
WARMING AND DRYING THE REGION.
BOI WATCHES/WARNINGS/ADVISORIES
ID...HEAT ADVISORY FROM 11 AM TO 8 PM MDT TUESDAY IDZ012-014-033.
OR...HEAT ADVISORY FROM 11 AM MDT /10 AM PDT/ TO 8 PM MDT /7 PM
PDT/ TUESDAY ORZ064.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
DISCUSSION...KA
AVIATION.....ST
SHORT TERM...LC
LONG TERM....JM
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