414
FXUS65 KTFX 080428
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
928 PM MST FRI MAR 7 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- TEMPERATURES WARM WELL ABOVE NORMAL THROUGH THE WEEKEND, WITH
THE WARMEST READINGS OCCURRING OVER THE PLAINS OF CENTRAL AND
NORTH CENTRAL MONTANA, WHERE DOWNSLOPING WINDS WILL BE THE
STRONGEST.
- HIGH WINDS CHANCES ARE INCREASING FROM SUNDAY THROUGH EARLY
MONDAY, MOST NOTABLY ALONG THE ROCKY MOUNTAIN AND ADJACENT
PLAINS.
- A MORE ACTIVE WEATHER PATTERN DEVELOPS NEXT WEEK.
UPDATE
/ISSUED 838 PM MST FRI MAR 7 2025/
THE ONLY UPDATE TO THE OVERNIGHT PERIOD OF THE FORECAST WAS TO
LOWER LOW TEMPERATURES 3 TO 5 DEGREES OVER THE PLAINS OF NORTH
CENTRAL AND CENTRAL MONTANA, WHERE WINDS HAVE BECOME LESS GUSTY.
THESE LOW TEMPERATURES COULD OCCUR WITHIN A FEW HOURS AFTER
MIDNIGHT, AS WINDS SHOULD BECOME GUSTY AGAIN AFTER THEN.
THE REMAINDER OF THE FORECAST REMAINS DRY WITH WARMING DUE TO
INCREASING WINDS AT LEAST THROUGH THE WEEKEND.
-COULSTON
DISCUSSION
/ISSUED 838 PM MST FRI MAR 7 2025/
- METEOROLOGICAL OVERVIEW:
BROAD, UPPER LEVEL RIDGING WILL BUILD IN OVER THE WESTERN CONUS
THROUGH THE FIRST HALF OF THE UPCOMING WEEKEND, WITH THE RIDGE
BEGINNING TO FLATTEN DURING THE DAY ON SUNDAY AS SEVERAL SHORTWAVES
WITHIN A SPLITTING FLOW SLIDE EAST FROM THE EASTERN PACIFIC, WITH
ONE SHORTWAVE MOVING OVER THE INTERNATIONAL BORDER WHILE THE SECOND
SLOWLY MEANDERS ACROSS CALIFORNIA AND THE DESERT SOUTHWEST. THIS
PATTERN WILL HELP TO SUPPORT WARMING TEMPERATURES THROUGH THE WEEEKEND
AND OVERALL DRY CONDITIONS DUE TO INCREASING DOWNSLOPING WINDS. HIGH
TEMPERATURES THIS WEEKEND WILL WARM WELL ABOVE NORMAL OVER THE
PLAINS, WITH THE VALLEYS OF CENTRAL AND SOUTHWEST MONTANA WARMING
ABOVE TO WELL ABOVE NORMAL. THE AFOREMENTIONED DOWNSLOPING SOUTHWEST
TO WEST WINDS WILL BE ESPECIALLY STRONG ALONG THE CONTINENTAL DIVIDE
AND ISLAND RANGES OF CENTRAL MONTANA AS LEE-SIDE SURFACE TROUGHING
SHARPENS AND LEADS TO A STRENGTHENING PRESSURE GRADIENT ACROSS THE
AREAS. THE STRONG AND GUSTY SOUTHWEST TO WEST WINDS WILL THEN SPREAD
FURTHER EAST AND SOUTH THROUGH SUNDAY NIGHT AND INTO THE DAY ON
MONDAY AS CROSS BARRIER FLOW PEAKS AHEAD OF THE POTENT SHORTWAVE
MOVING ALONG THE INTERNATIONAL BORDER, WITH A COLD FRONT THEN DIVING
SOUTH FROM ALBERTA THROUGH PORTIONS OF SOUTHWEST MONTANA DURING THE
MORNING HOURS ON MONDAY. IN ADDITION TO THE STRONG AND GUSTY WINDS
THE AFOREMENTIONED SHORTWAVE AND COLD FRONT WILL ALSO BRING A RETURN
CHANCE FOR MAINLY MOUNTAIN PRECIPITATION, WHICH WILL BE
PREDOMINATELY IN THE FORM OF SNOW. - MOLDAN
A ZONAL (W TO E) FLOW PATTERN FOLLOWS THE UPPER LEVEL WAVE THROUGH
THE FIRST HALF OF NEXT WEEK WITH SOME COOLING AND A CHANCE FOR BRIEF
PRECIPITATION ON MONDAY/MONDAY NIGHT WITH THE PASSAGE OF A COLD
FRONT. BY LATE NEXT NEXT WEEK, LONGER RAGE MODELS/ENSEMBLES ARE IN
REASONABLY GOOD AGREEMENT ON THE LARGER SCALE PATTERN, DEPICTING A
FAIRLY POTENT UPPER LEVEL TROUGH PROGRESSING ACROSS WESTERN US FOR
INCREASING PRECIPITATION CHANCES AND ADDITIONAL COOLING. - HOENISCH
- FORECAST CONFIDENCE & SCENARIOS:
HIGH WINDS THROUGH MONDAY : CLIMATE ANOMALY INDICATORS LIKE THE
NAEFS AND ECMWF EFI CONTINUE TO SUPPORT THE POTENTIAL FOR AN
ANOMALOUS, IF NOT CLIMATOLOGICALLY EXTREME, WIND EVENT OVER PORTIONS
OF THE WEEKEND THROUGH MONDAY MORNING/EARLY AFTERNOON. ANALYSIS OF
H700 WIND SPEEDS PER NAEFS GUIDANCE SUPPORTS SPEEDS RANGING FROM 2-3
STANDARD DEVIATIONS ABOVE NORMAL BY AS EARLY AS SATURDAY NIGHT OVER
THE ROCKY MOUNTAIN FRONT, WITH THESE ANOMALOUS VALUES EXPANDING
FURTHER EAST OVER THE ADJACENT PLAINS WEST OF THE I-15 CORRIDOR ON
SUNDAY BEFORE OVERSPREADING ALL OF NORTH CENTRAL MONTANA THROUGH
EARLY MONDAY MORNING AND INTO PORTIONS OF SOUTHWEST MONTANA BY THE
LATE MORNING HOURS. THESE ANOMALOUS WIND SPEEDS OF 45-60KTS ARE WELL
IN EXCESS OF THE 90TH PERCENTILE OF CLIMATOLOGY PER NAEFS GUIDANCE,
WITH PORTIONS OF THE CENTRAL AND NORTH CENTRAL MONTANA PLAINS
EXCEEDING THE 99TH PERCENTILE. ECMWF EFIS SIMILARLY SUPPORT THE
POTENTIAL FOR A CLIMATOLOGICALLY EXTREME EVENT BY AS EARLY AS
SATURDAY AFTERNOON/EVENING, WITH VALUES OF 0.5 TO 0.7 ALONG THE
ROCKY MOUNTAIN FRONT, WITH THESE VALUES INCREASING SLIGHTLY AND
EXPANDING FURTHER EAST TO THE I-15 CORRIDOR AND SOUTH ALONG THE MT
HWY 200/US HWY 87 CORRIDORS ON SUNDAY. BY MONDAY THE ECMWF EFIS PEAK
ACROSS MOST OF SOUTHWEST AND ALL OF CENTRAL AND NORTH CENTRAL
MONTANA, WITH PEAK VALUES OF 0.7 TO NEARLY 0.9 ALONG THE ROCKY
MOUNTAIN FRONT AND ACROSS THE HI-LINE OF NORTH CENTRAL MONTANA.
BUFKIT ANALYSIS FOR THE ROCKY MOUNTAIN FRONT AND CUT BANK AREA
SUPPORTS FAVORABLE WINDS (I.E. GREATER THAN 50KTS) WITHIN/BENEATH AN
IDEAL THERMAL PROFILE (I.E. INVERSION AT OR NEAR RIDGETOPS) DURING
TWO SEPARATE PERIODS FROM LATE THIS EVENING THROUGH EARLY SATURDAY
MORNING AND THEN AGAIN FROM LATE SATURDAY EVENING THROUGH EARLY
SUNDAY MORNING, WITH CONDITIONS BECOMING LESS SUPPORTIVE THROUGH THE
LATE MORNING HOURS ON SUNDAY AS RIDGETOP STABILITY WEAKENS AND LOW
TO MID-LEVEL LAPSE RATES STEEPEN LEADING TO BETTER MIXING. WHILE
THIS WEAKENING OF THE RIDGETOP STABILITY ON SUNDAY MORNING WILL LEAD
TO WEAKENING MOUNTAIN WAVE ACTIVITY THE DEEPER MIXING THAT ENSUES
WHILE THE ATMOSPHERIC COLUMN BECOMES MORE UNIDIRECTIONAL WILL
SUPPORT HIGHER MOMENTUM TRANSFER AND A SUBSEQUENT THREAT FOR HIGH
WINDS GUSTS, WITH A PROLONGED PERIOD OF HIGH SUSTAINED WINDS
BECOMING A BIGGER CONCERN FOR THESE AREAS FROM SUNDAY AFTERNOON
THROUGH MONDAY MORNING.
NBM PROBABILITIES FOR HIGH SUSTAINED WIND SPEEDS (50+ MPH) AT
BROWNING FOR SATURDAY, SUNDAY, AND MONDAY ARE CURRENTLY 20%, 55%,
AND 35% RESPECTIVELY; WHILE THE PROBABILITY FOR HIGH WIND GUSTS (75+
MPH) ARE 25%, 55%, AND 40% RESPECTIVELY. NBM PROBABILITIES FOR HIGH
SUSTAINED WIND SPEEDS (40+ MPH) AT CUT BANK FOR SATURDAY, SUNDAY,
AND MONDAY ARE 35%, 65%, AND 80% RESPECTIVELY; WHILE THE PROBABILITY
FOR HIGH WIND GUSTS (58+ MPH) ARE 30%, 65%, AND 75% RESPECTIVELY.
WITH ALL THIS INFORMATION IN MIND CONFIDENCE HAS INCREASED TO ISSUE
A HIGH WIND WATCH FOR THE EAST GLACIER PARK REGION, SOUTHERN ROCKY
MOUNTAIN FRONT, NORTHERN AND SOUTHERN HIGH PLAINS, AND EASTERN
GLACIER/WESTERN TOOLE/CENTRAL PONDERA COUNTIES FROM LATE SUNDAY
MORNING THROUGH NOON MONDAY. WHILE THERE MAY BE SHORT (LESS THAN 6
HOURS), BUT INTENSE, PERIODS OF MOUNTAIN WAVE ACTIVITY ALONG THE
ROCKY MOUNTAIN FRONT TO AS FAR EAST AS CUT BANK THAT LEAD TO HIGH
WIND GUSTS/SUSTAINED SPEEDS FROM LATE THIS EVENING THROUGH EARLY
SATURDAY MORNING AND THEN AGAIN FROM LATE SATURDAY EVENING THROUGH
EARLY SUNDAY MORNING I FELT IT WAS BEST TO HIGHLIGHT THE MOST
SIGNIFICANT AND WIDESPREAD PERIOD OF WINDS THAT THE HIGH WIND WATCH
NOW COVERS. FURTHER EXPANSION OF THE HIGH WIND WATCH EAST AND SOUTH
MAY BE NEEDED WITH SUCCEEDING SHIFTS; HOWEVER, GIVEN THE LATER ONSET
OF WINDS HERE AND THE FACT THAT THIS ONSET IS OCCURRING DURING THE
OVERNIGHT HOURS ON SUNDAY I HAVE HELD OFF FOR NOW. - MOLDAN
MONDAY COLD FRONT: TIMING OF THE PACIFIC COLD FRONT THROUGH SW MT
MONDAY AFTERNOON AND COOLING ALOFT MAY SUPPORT ENOUGH INSTABILITY
FOR CONVECTIVE SHOWERS (RAIN/SNOW/GRAUPEL) ALONG WITH BRIEF STRONGER
WIND GUSTS.
LATE WEEK TROUGH: OVERALL AGREEMENT FOR AN AMPLIFIED/NEGATIVELY
TILTED TROUGH MOVING THROUGH THE WESTERN US LATE NEXT WEEK SUPPORTS
A SPRING-TYPE STORM SYSTEM WITH MORE IMPACTFUL PRECIPITATION/SNOW
POSSIBLE DEPENDING ON DETAILS STILL TO BE RESOLVED. HOENISCH
AVIATION
08/06Z TAF PERIOD.
VFR CONDITIONS PREVAIL THROUGH THE TAF PERIOD. EXPECT MAINLY A
BROKEN LAYER OF HIGH CLOUDS THROUGH THE PERIOD, ALONG WITH BREEZY
WINDS AT TIMES OVER THE PLAINS OF NORTH CENTRAL MT. BRUSDA
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION
WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 28 57 46 62 / 0 0 0 0
CTB 33 52 41 62 / 0 0 0 0
HLN 24 49 30 55 / 0 0 0 0
BZN 13 43 21 48 / 0 0 0 0
WYS 2 36 10 38 / 0 0 0 0
DLN 15 47 23 50 / 0 0 0 0
HVR 26 59 42 62 / 0 0 0 0
LWT 22 51 36 55 / 0 0 0 0
TFX WATCHES/WARNINGS/ADVISORIES
HIGH WIND WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON FOR
EAST GLACIER PARK REGION-EASTERN GLACIER, WESTERN TOOLE, AND
CENTRAL PONDERA-NORTHERN HIGH PLAINS-SOUTHERN HIGH PLAINS-
SOUTHERN ROCKY MOUNTAIN FRONT.
HTTP://WWW.WEATHER.GOV/GREATFALLS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page