522
FXUS65 KTFX 101020
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
420 AM MDT MON AUG 10 2026
AVIATION SECTION UPDATED.
KEY MESSAGES
- HAZY, VERY WARM, AND DRY CONDITIONS GENERALLY CONTINUE FOR
THE NEXT COUPLE OF DAYS.
- A PACIFIC WEATHER SYSTEM AND INCREASED MOISTURE WILL INTRODUCE SHOWER
AND THUNDERSTORM ACTIVITY AND COOL TEMPERATURES DOWN LATE
WEDNESDAY THROUGH FRIDAY.
- WHILE SOME AREAS MAY SEE BENEFICIAL RAINS, THIS ACTIVITY MAY
ALSO INITIATE A FEW STRONGER STORMS WITH LOCALIZED STRONG WIND
GUSTS, HAIL, AND FLOODING OF NORMALLY PRONE AREAS.
- SCATTERED SHOWER AND THUNDERSTORM ACTIVITY CAPABLE OF STRONG
WIND GUSTS AND LIGHTNING WILL CONTINUE INTO THE WEEKEND WHILE
TEMPERATURES TREND ABOVE AVERAGE AGAIN.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
RIDGING ALOFT WILL MAINTAIN THE HAZY, VERY WARM, AND DRY
CONDITIONS FOR AT LEAST THE NEXT COUPLE OF DAYS. SHORTWAVE ENERGY
AND INSTABILITY CAPABLE OF INITIATING SHOWER AND THUNDERSTORM
ACTIVITY LOOKS TO REMAIN NORTH OF THE CANADIAN BORDER DURING THIS
PERIOD, THOUGH SOME ISOLATED STORMS MAY BEGIN TO CREEP TOWARDS THE
HI-LINE TUESDAY EVENING AND NIGHT. SEASONABLY BREEZY CONDITIONS
WILL CONTINUE WITH WIND GUSTS EXCEEDING 20 MPH AT TIMES,
ESPECIALLY THIS AFTERNOON AND EVENING.
A PACIFIC TROUGH BEGINS TO MOVE SOUTHEASTWARD THROUGH BC/AB AND
INTO THE NORTHERN ROCKIES SOMETIME WEDNESDAY THROUGH FRIDAY.
ENSEMBLES ARE COMING INTO BETTER AGREEMENT WITH TEMPERATURES
FALLING BELOW AVERAGE THURSDAY AND FRIDAY, BUT STILL DIFFER ON HOW
WIDESPREAD THE RAINFALL WILL BE. SHOWER AND THUNDERSTORM ACTIVITY
LOOKS TO INCREASE FROM NORTH TO SOUTH WITH AREAS ALONG THE HI-
LINE SEEING SCATTERED SHOWERS AND STORMS AS EARLY AS TUESDAY
EVENING. THE WEDNESDAY NIGHT THROUGH THURSDAY TIME PERIOD IS
GENERALLY FAVORED TO SEE THE MOST WIDESPREAD RAINFALL. WHILE SOME
AREAS MAY SEE BENEFICIAL RAINS AND COOLING TEMPERATURES, THE
CONVECTIVE NATURE OF THIS ACTIVITY MAY ALSO BRING SOME STRONG TO
SEVERE STORMS WITH LOCALIZED STRONG GUSTY WINDS, HAIL, AND HEAVY
DOWNPOURS CAPABLE OF FLOODING OF NORMALLY FLOOD PRONE AREAS. ML
CAPE VALUES LOOK TO GENERALLY RUN IN THE 300 TO 800 J/KG RANGE
WITH THE HIGHEST VALUES GRADUALLY MOVING SOUTH INTO CENTRAL AND
SOUTHWEST MONTANA BY LATE THURSDAY INTO FRIDAY.
THE RIDGING ALOFT BEGINS TO BUILD BACK IN HEADING INTO NEXT
WEEKEND, BUT ANOTHER TROUGH APPROACHING THE PACIFIC NW COAST WILL
BRING SOUTHWESTERLY FLOW ALOFT WITHIN STRIKING DISTANCE OF THE
NORTHERN ROCKIES. THIS WILL RESULT IN TEMPERATURES WARMING BACK
UP, ALONG WITH DAILY SCATTERED SHOWER AND THUNDERSTORM ACTIVITY.
- RCG
- FORECAST CONFIDENCE & SCENARIOS:
BREEZY CONDITIONS, SHIFTING WINDS, AND LOCALIZED ELEVATED FIRE
CONCERNS...
THE COMBINATION OF VERY WARM, DRY, AND BREEZY CONDITIONS WILL
RESULT IN LOCALIZED FIRE WEATHER CONDITIONS FOR THE NEXT COUPLE OF
DAYS. SURFACE BOUNDARIES AND OR DIURNAL MIXING WILL BRING WIND
SHIFTS AND GUSTS IN EXCESS OF 20 MPH AT TIMES. AFTERNOON HUMIDITY
WILL FALL TO OR NEAR CRITICALLY LOW LEVELS WITH ONLY MODERATE TO
POOR OVERNIGHT RECOVERIES, DRIEST OVER SOUTHWEST MONTANA. THOSE
WORKING TO CONTAIN ONGOING FIRES SHOULD CONTINUE BE MINDFUL OF THE
DRY CONDITIONS AND BREEZY, SHIFTING WINDS.
COOLER TEMPERATURES, SOME STRONGER STORMS, AND BENEFICIAL RAINS
WEDNESDAY THROUGH FRIDAY...
ENSEMBLE GUIDANCE IS NOW COMING INTO AGREEMENT WITH COOLER AND
WETTER CONDITIONS MOVING IN LATE WEDNESDAY THROUGH FRIDAY. CLIMATE
ANOMALY INDICES, INCLUDING THE ECMWF EXTREME FORECAST INDEX ARE
SHOWING SIGNALS FOR PRECIPITATION AMOUNTS ABOVE CLIMATOLOGY FOR
THIS TIME OF YEAR. WHILE THIS RAINFALL IS DEFINITELY WELCOME, ITS
CONVECTIVE NATURE CAN RESULT IN UNEVEN DISTRIBUTION AND INCREASED
INSTANCES OF STRONGER STORMS CAPABLE OF LOCALIZED STRONG WIND
GUSTS, HAIL, AND EVEN FLOODING OF NORMALLY PRONE AREAS. AT THIS
TIME, THE MOST WIDESPREAD PRECIPITATION LOOKS TO OCCUR ON
THURSDAY.
SCATTERED GUSTY THUNDERSTORMS THIS WEEKEND...
SOUTHWESTERLY FLOW ALOFT APPROACHING THE NORTHERN ROCKIES WILL
MAINTAIN MID-LEVEL MOISTURE AND SHORTWAVE ENERGY THIS WEEKEND
WHILE THE SURFACE BOUNDARY LAYER WARMS UP AND DRIES OUT. IF THIS
PATTERN COMES TO FRUITION, THERE WILL BE SCATTERED SHOWERS AND
THUNDERSTORMS FOR BOTH DAYS, MOSTLY IN THE AFTERNOON AND EVENING.
THE PRIMARY HAZARDS WILL BE LOCALIZED STRONG, GUSTY WINDS, AND
LIGHTNING. - RCG
AVIATION
10/12Z TAF PERIOD
OVERALL, A WESTERLY FLOW ALOFT WILL RESIDE OVER MT THROUGH THE
PERIOD. AT THIS TIME, ANY THUNDERSTORMS SHOULD REMAIN NORTH OF THE
US/CANADIAN BORDER THROUGH THE PERIOD. OTHERWISE, SMOKE WILL BE
THE MAIN IMPACT, WITH SOUTHWEST MT HAVING IFR VISIBILITY AT TIMES
BECAUSE OF SMOKE. MOUNTAINS/PASSES WILL BE OBSCURED ACROSS THE CWA
THROUGH THE PERIOD BECAUSE OF SMOKE.
FOR KGTF: SURFACE WINDS SHOULD GENERALLY BE WESTERLY TODAY.
OVERALL WIND SPEEDS WILL WILL GENERALLY BE LESS THAN 15 KNOTS
THROUGH THE PERIOD, WITH JUST A FEW ISOLATED GUSTS NEAR 20 KNOTS
THIS AFTERNOON. OVERALL THE PROBABILITY OF CROSS WINDS OVER 15
KNOTS IS LESS THAN 20 PERCENT. BRUSDA
PRELIMINARY POINT TEMPS/POPS
GTF 89 55 85 54 / 0 0 0 0
CTB 82 50 77 49 / 0 0 0 20
HLN 88 54 89 55 / 0 0 0 0
BZN 90 52 90 52 / 0 0 0 0
WYS 84 42 85 44 / 0 0 0 0
DLN 88 50 88 51 / 0 0 0 0
HVR 88 54 85 52 / 0 0 0 30
LWT 85 53 82 51 / 0 0 0 0
TFX WATCHES/WARNINGS/ADVISORIES
NONE.
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