006
FXUS65 KMSO 020847
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
247 AM MDT FRI JUN 2 2023
DISCUSSION
GOES WATER VAPOR IMAGERY THIS MORNING REVEALS A LOW PRESSURE
SYSTEM ACROSS NORTH-CENTRAL WYOMING. REGIONAL RADAR OBSERVATIONS
SHOW WIDESPREAD PRECIPITATION NORTH AND WEST OF THE LOW ACROSS
CENTRAL MONTANA. THE LOW PRESSURE SYSTEM WILL TRACK OVER
YELLOWSTONE NATIONAL PARK LATE THIS MORNING INTO THE AFTERNOON,
BRINGING AN INCREASE IN SHOWER ACTIVITY ALONG THE DIVIDE AND IN
SOUTHWEST MONTANA. THUNDERSTORMS WILL DEVELOP AFTER 100PM MDT,
WITH THE BEST FOCUS ACROSS IDAHO COUNTY AND LEMHI COUNTY, WHERE
THERE IS A 30-40% PROBABILITY FOR LIGHTNING. PRECIPITATION WILL
FOCUS EAST OF HIGHWAY 93 AND ALONG THE I-90 CORRIDOR EAST OF
MISSOULA, WHERE NBM PROJECTS A 40-50% CHANCE FOR 0.25” ACROSS
VALLEY AREAS. PROBABILITIES FOR 0.25” INCREASE TO 70% ACROSS
MOUNTAIN AREAS. DRIER AIR WILL LIMIT THE POTENTIAL FOR SHOWER
ACTIVITY ACROSS NORTHWEST MONTANA, ESPECIALLY ALONG THE ID/MT
BORDER.
ENSEMBLE MODEL GUIDANCE REMAINS LOCKED INTO A BLOCKING RIDGE OF
HIGH PRESSURE EXTENDING FROM THE CENTRAL US NORTHWARD INTO
SASKATCHEWAN AND MANITOBA CANADA THIS WEEKEND INTO MID NEXT WEEK.
A PERSISTENT SOUTHERLY FLOW PATTERN WILL MAINTAIN ABOVE NORMAL
ATMOSPHERIC MOISTURE ACROSS THE NORTHERN ROCKIES. PUSHES OF
MOISTURE WILL BE TRANSPORTED BY UPPER LEVEL WAVES TRACKING FROM
THE CENTRAL PLAINS OVER THE ROCKIES. DAILY SHOWERS AND
THUNDERSTORMS REMAIN IN THE FORECAST, WITH ACTIVITY FOCUSING
ACROSS LEMHI COUNTY, SOUTHWEST MONTANA, AND AREAS ALONG THE
CONTINENTAL DIVIDE.
BY WEDNESDAY AND THURSDAY NEXT WEEK, CONFIDENCE IS HIGHER THAN
NORMAL FOR A HIGHER ATMOSPHERIC MOISTURE, AS PRECIPITABLE WATER
VALUES REACH 200% OF NORMAL (AS SEEN IN EPS/GEFS/GEPS). MOISTURE
TRANSPORT WILL EXTEND INTO NORTHWEST MONTANA, WHERE NBM HAS A
20-30% PROBABILITY FOR 0.50” OR MORE PRECIPITATION DURING A
48-HOUR PERIOD ENDING THURSDAY EVENING. /LUKINBEAL
AVIATION
A LOW PRESSURE SYSTEM WILL TRACK OVER YELLOWSTONE NATIONAL PARK
LATE THIS MORNING INTO THE AFTERNOON, BRINGING AN INCREASE IN
SHOWER ACTIVITY ALONG THE DIVIDE AND IN SOUTHWEST MONTANA. THE
ATMOSPHERE WILL DESTABILIZE ACROSS IDAHO COUNTY AND LEMHI COUNTY,
WHERE THERE IS A 30-40% PROBABILITY FOR THUNDERSTORMS AFTER
02/1900Z, OR 1PM MDT. AREAS OF LOW CEILINGS AND PRECIPITATION
WILL FOCUS EAST OF US-93 AND ALONG THE I-90 CORRIDOR EAST OF
MISSOULA, WHERE NBM PROJECTS A 40-50% CHANCE FOR 0.25” ACROSS
VALLEY AREAS. DRIER AIR WILL LIMIT THE POTENTIAL FOR SHOWER
ACTIVITY ACROSS NORTHWEST MONTANA, ESPECIALLY ALONG THE ID/MT
BORDER. /LUKINBEAL
CLIMATE
THE THEME OF WARM OVERNIGHT TEMPERATURES OBSERVED DURING MAY,
WILL CONTINUE THROUGH THE FIRST WEEK OF JUNE. MISSOULA SET THE
WARMEST MAY LOW TEMPERATURE AVERAGE IN MAY, WITH KALISPELL AND
BUTTE RECORDING THE 3RD AND 6TH WARMEST RESPECTIVELY. CONFIDENCE
IS HIGH FOR A BROAD RIDGE OF HIGH PRESSURE TO MAINTAIN ABOVE
NORMAL TEMPERATURES AND ATMOSPHERIC MOISTURE DURING THE NEXT 7
DAYS. LOWS WILL RUN ABOUT 10 DEGREES ABOVE NORMAL, AS OVERNIGHT
TEMPERATURES DROP INTO THE 50S ACROSS VALLEY AREAS THROUGH JUNE
8TH.
THE NWS MISSOULA HAS RELEASED THE 2023 SUMMER OUTLOOK FOR THE
NORTHERN ROCKIES, WHICH CAN BE FOUND ON OUR YOUTUBE CHANNEL AT
HTTPS://WWW.YOUTUBE.COM/WATCH?V=SC2FCEZJYO0
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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