319
FXUS65 KMSO 050852
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
252 AM MDT TUE MAY 5 2026
DISCUSSION
KEY MESSAGES:
- A BACKDOOR COLD FRONT CONTINUES TO BRING COOLER TEMPERATURES
AND NORTHEAST WINDS OF 20 TO 30 MPH ACROSS WESTERN MONTANA
TODAY.
- BOATERS ON FLATHEAD LAKE SHOULD ANTICIPATE CHOPPY CONDITIONS
RETURNING TODAY DUE TO GUSTY NORTHEAST WINDS.
- A WARMING TREND BEGINS WEDNESDAY, THOUGH A DISTURBANCE WILL
BRING SHOWERS TO NORTHWEST MONTANA LATE WEDNESDAY, FOLLOWED BY
SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE CONTINENTAL DIVIDE
ON THURSDAY.
A POSITIVELY TILTED RIDGE OF HIGH PRESSURE BUILDING ALONG THE
WEST COAST IS KEEPING THE NORTHERN ROCKIES UNDER NORTHERLY FLOW
ALOFT. A NORTH TO SOUTH ORIENTED JET STREAK WILL BECOME SITUATED
OVER WESTERN MONTANA TODAY. CLOSER TO THE SURFACE, COOLER, DENSE
AIR TO THE EAST AND WARM AIR TO THE WEST WILL RESULT IN A STRONG
EASTERLY PRESSURE GRADIENT OVER WESTERN MONTANA. THE BOTTOM LINE
IS THAT STRONG NORTHEASTERLY WINDS WILL CONTINUE THIS MORNING,
TURNING MORE NORTHERLY LATER IN THE DAY. WINDS SPEEDS WILL REMAIN
BELOW ADVISORY CRITERIA, BUT DO EXPECT CHOPPY CONDITIONS ON
FLATHEAD LAKE THROUGHOUT THE DAY. TEMPERATURES TODAY WILL STAY
AROUND NORMAL FOR THIS TIME OF YEAR.
THE TIGHT PRESSURE GRADIENT WILL RELAX ON WEDNESDAY AS THE RIDGE
OF HIGH PRESSURE MOVES OVER THE NORTHERN ROCKIES. THE RIDGE WILL
SHUT OFF THE GUSTY NORTHERLY WINDS AND INITIATE A WARMING TREND,
WITH WESTERN MONTANA VALLEYS RETURNING TO THE 70S AND THE LOWER
VALLEYS OF NORTH-CENTRAL IDAHO PUSHING INTO THE 80S. HOWEVER, THIS
WILL NOT BE A COMPLETELY DRY RIDGE. MOST GUIDANCE INDICATES A
DISTURBANCE WILL RIDE OVER THE TOP OF THE RIDGE LATE WEDNESDAY
INTO THURSDAY. THIS ATMOSPHERIC FORCING WILL INITIALLY TRIGGER
SHOWERS ACROSS NORTHWEST MONTANA LATE WEDNESDAY, PARTICULARLY
IMPACTING THE GLACIER PARK REGION. AS THE SYSTEM PROGRESSES ON
THURSDAY, INSTABILITY WILL INCREASE SLIGHTLY, SHIFTING THE THREAT
SOUTHEASTWARD AND BRINGING SHOWERS AND ISOLATED THUNDERSTORMS
PRIMARILY ALONG THE CONTINENTAL DIVIDE. SOME ENSEMBLE SOLUTIONS
(ABOUT 40%) SHOW ANOTHER WEAK DISTURBANCE ON SATURDAY BRINGING
WIDESPREAD RAIN.
AVIATION
VFR CONDITIONS WILL PREVAIL ACROSS THE NORTHERN
ROCKIES AIRSPACE. THE PERSISTENT EASTERLY OR NORTHEASTERLY WINDS
OF ABOUT 20-30 KNOTS CONTINUE AT KMSO AND KGPI, WHILE KHRF AND
KSMN WILL SEE A SHIFT TO NORTHERLY WINDS BY ABOUT 05/2200Z. WINDS
REMAIN ELEVATED INTO TONIGHT BEFORE RELAXING ON WEDNESDAY AS A
RIDGE OF HIGH PRESSURE MOVES OVER THE NORTHERN ROCKIES.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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