408
FXUS65 KMSO 021850
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1250 PM MDT WED JUL 2 2025
DISCUSSION
KEY MESSAGES:
- STRONG TO ISOLATED SEVERE THUNDERSTORMS TODAY MAINLY ACROSS
WEST CENTRAL MONTANA, SOUTHWEST MONTANA, AND LEMHI COUNTY, IDAHO
- A TROUGH FRIDAY AND SATURDAY WILL BRING THUNDERSTORMS AND
POTENTIALLY HEAVY RAIN NEAR AND ALONG THE DIVIDE FRIDAY INTO
SATURDAY MORNING.
- LONG RANGE ENSEMBLES ARE SHOWING POTENTIAL FOR AN EXTENDED HOT,
DRY PERIOD THROUGH MID JULY.
OUR PRIMARY FOCUS THROUGH THIS EVENING IS MONITORING THE
DEVELOPMENT OF STRONG TO ISOLATED SEVERE THUNDERSTORMS. MOSTLY
SUNNY SKIES ARE SEEN IN GOES SATELLITE IMAGERY EARLY THIS
AFTERNOON, WITH MESOSCALE ANALYSIS HIGHLIGHTING UPWARDS OF 500
J/KG OF MLCAPE ACROSS WEST-CENTRAL MT AND NORTH-CENTRAL ID. THE
ATMOSPHERE WILL CONTINUE TO DESTABILIZE THROUGH THIS AFTERNOON,
WITH CONVECTION DEVELOPING BETWEEN 1-3PM MDT ACROSS NORTH-CENTRAL
IDAHO AND SOUTHWEST MONTANA. THUNDERSTORMS WILL TRACK NORTHWARD
ACROSS WEST-CENTRAL MONTANA BETWEEN 4-7PM MDT. HIGH RESOLUTION
MODELS ALONG WITH INSTABILITY AND SHEAR PROFILES ALL POINT TOWARDS
DISCRETE STORMS INITIALLY, EVOLVING INTO LINEAR SEGMENTS AS
STORMS MATURE AND GROW THROUGH THIS EVENING. THE LAST TWO RUNS OF
THE HREF HAS POINTED TOWARDS HIGH PROBABILITIES (70-90%) FOR
STRONG OUTFLOW WINDS ACROSS THE BITTERROOT VALLEY AND POINTS EAST
ALONG THE I-90 CORRIDOR TOWARDS THE DIVIDE. THIS MATCHES UP WELL
STATISTICAL MODELS AND FORECAST SOUNDINGS, THEREFORE OUR
CONFIDENCE IS HIGHER THAN NORMAL FOR THESE STORMS TO OCCUR AND
PRODUCE GUSTY OUTFLOW WINDS, WITH ISOLATED GUSTS EXCEEDING 60 MPH
WITH THE STRONGEST UPDRAFTS. CONVECTION WILL CONTINUE OVERNIGHT
INTO THURSDAY MORNING, WITH ADDITIONAL ROUNDS OF STORMS ACROSS
CENTRAL IDAHO INTO WEST-CENTRAL MONTANA. VERTICAL PROFILES SUGGEST
INSTABILITY AND MOISTURE WILL REMAIN ELEVATED, INCREASING THE
RISK FOR DRY THUNDERSTORMS.
A TROUGH WITHIN SOUTHWESTERLY FLOW WILL BRING WIDESPREAD SHOWERS
AND THUNDERSTORMS FRIDAY AFTERNOON INTO SATURDAY MORNING. THIS
SYSTEM WILL TAP INTO SUB-TROPICAL MOISTURE, WITH MOISTURE CLIMBING
125-150% OF NORMAL, LEADING TO AN ELEVATED RISK FOR HEAVY RAIN
AND LOCALIZED RUNOFF ISSUES FOR FLOOD PRONE AREAS, SUCH AS BURN
SCARS. ENSEMBLES SUGGEST THE HEAVIEST RAIN WILL FOCUS ACROSS
SOUTHWEST MONTANA AND ALONG THE DIVIDE, WHERE NBM HAS A 40-50%
CHANCE OF 0.50 INCHES OR MORE OF PRECIPITATION ACROSS THE HIGHER
TERRAIN, WITH PROBABILITIES DROPPING NEAR 20% FOR VALLEY AREAS.
FURTHERMORE, PRECIPITATION AMOUNTS HAVE BEEN TRENDING HIGHER
ACROSS FLATHEAD COUNTY, MT, ESPECIALLY IN GLACIER PARK, WHERE
DETERMINISTIC MODEL RUNS SUGGEST A MID-LEVEL LOW WILL DEEPEN JUST
EAST OF THE DIVIDE. THIS SOLUTION IS WORTH MONITORING CLOSELY, AS
CURRENTLY JUST A MINORITY OF ENSEMBLE MEMBERS ARE HIGHLIGHTING 1-2
INCHES OF PRECIPITATION.
IN THE LONGER TERM, GLOBAL ENSEMBLES DEVELOP A BROAD RIDGE OF HIGH
PRESSURE ACROSS THE WESTERN US, LEADING TO A PROLONGED PERIOD OF
HOT AND DRY WEATHER JULY 9TH THROUGH THE 14TH. HOWEVER, IT'S WORTH
NOTING, WHILE STATISTICAL GUIDANCE SHOW A SIMILAR PATTERN, THEY
AREN'T AS INTENSE WITH THE RIDGE OR THE HEAT. ANY WAY YOU LOOK AT
IT, THE PREPONDERANCE OF MODELS POINT TO AN EXTENDED DRY PERIOD OF
A WEEK OR MORE COMING UP.
AVIATION
CONFIDENCE IS HIGH FOR SHOWERS AND THUNDERSTORMS TO
DEVELOP ACROSS THE CLEARWATER AND BITTERROOT MOUNTAINS AND ALONG
THE DIVIDE IN SOUTHWEST MONTANA BETWEEN 02/1900-2100Z. STORMS WILL
GROW INTO CONVECTIVE SYSTEMS AIDED BY MODEST INSTABILITY AND WIND
SHEAR FROM AN APPROACHING TROUGH, LEADING TO AN ELEVATED RISK FOR
STRONG OUTFLOW WINDS GIVEN HOT AND DRY AIR IN THE LOW LEVELS.
THUNDERSTORMS WILL BE IN THE VICINITY OF KSMN, KHRF, AND KBTM BY
02/2200Z, WITH HIGH CONFIDENCE (>70% PROBABILITY) FOR OUTFLOW
WINDS OF AT LEAST 30KTS FROM ANY STORMS THAT DEVELOP AND MOVE NEAR
AREA TERMINALS. A FEW THUNDERSTORMS MAY APPROACH SEVERE CRITERIA,
WITH GUSTS EXCEEDING 50KTS. ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS WILL DEVELOP ALONG A FRONTAL BOUNDARY TONIGHT, WITH
ACTIVITY CONTINUING INTO EARLY THURSDAY MORNING ACROSS NORTH-
CENTRAL ID AND WEST-CENTRAL MT.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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