981
FXUS65 KTFX 072019
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
219 PM MDT FRI AUG 7 2026
KEY MESSAGES
- IT WILL BE BREEZY THIS AFTERNOON AND SATURDAY.
- IT WILL BE HOT AND DRY THROUGH TUESDAY.
- A BRIEF COOL DOWN IS EXPECTED WEDNESDAY THROUGH NEXT FRIDAY
WITH ISOLATED SHOWERS RETURNING PRIMARILY TO NORTH-CENTRAL
MONTANA.
DISCUSSION
- METEOROLOGICAL OVERVIEW:
THIS AFTERNOON/EVENING AN UPPER-LEVEL RIDGE WILL FLATTEN. THIS WILL
KEEP WARM TEMPERATURES AND DRY WEATHER ACROSS NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA THIS AFTERNOON. ASSOCIATED WITH
THE UPPER-LEVEL RIDGE FLATTENING THERE IS MODESTLY STRONG LOW-
LEVEL AND UPPER-LEVEL WINDS. THIS WILL BRING BREEZY CONDITIONS TO
THE AREA THIS AFTERNOON AND EVENING. ON SATURDAY THERE WILL BE
UPPER-LEVEL ZONAL FLOW OVER NORTH-CENTRAL MONTANA. THIS WILL
ALLOW THE WARM AND DRY CONDITIONS TO PERSIST. DUE TO MODESTLY
STRONG LOW-LEVEL AND MID-LEVEL WINDS IT WILL ALSO BE BREEZY
ACROSS NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. ON
SUNDAY UPPER-LEVEL ZONAL FLOW PERSISTS OVER NORTH-CENTRAL,
CENTRAL, AND SOUTHWESTERN MONTANA UNTIL SUNDAY AFTERNOON/EVENING
WHEN AN UPPER-LEVEL RIDGE BUILDS BACK IN OVER THE AREA. THIS WILL
BRING SLIGHTLY COOLER TEMPERATURES TO THE AREA WITH DRY WEATHER.
SMOKE FROM REGIONAL WILDFIRES WILL BE AROUND THROUGHOUT THE NEXT
FEW DAYS.
ON MONDAY AND TUESDAY THE UPPER-LEVEL RIDGE REMAINS OVER NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONDAY. THIS WILL KEEP WARM
AND DRY WEATHER FOR THE AREA ON MONDAY AND TUESDAY. WEDNESDAY
THROUGH NEXT FRIDAY THE UPPER-LEVEL RIDGE REMAINS OVER NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. WEDNESDAY THROUGH
FRIDAY MONSOONAL MOISTURE GRADUALLY MAKES IT UP TO MONTANA. THIS
WILL BRING PRECIPITATION CHANCES AND COOLER TEMPERATURES TO THE
AREA WEDNESDAY THROUGH NEXT FRIDAY. WEDNESDAY THROUGH FRIDAY THE
GREATEST FORCING IS ALONG THE HI-LINE AND SO THAT IS WHERE THE
GREATEST CHANCES FOR PRECIPITATION ARE. SEE THE FORECAST
CONFIDENCE & SCENARIOS SECTION FOR DETAILS. -IG
- FORECAST CONFIDENCE & SCENARIOS:
ON SATURDAY THERE IS GREATER THAN A 70% CHANCE FOR WIND GUSTS OF
25 MPH OR GREATER ACROSS MOST OF NORTH-CENTRAL, CENTRAL, AND
SOUTHWESTERN MONTANA. ON SATURDAY THE HREF (HI-RESOLUTION ENSEMBLE
FORECAST) HAS A 50 - 70% CHANCE FOR WIND SPEEDS OF 15 MPH OR
GREATER AND RELATIVE HUMIDITY LESS THAN 20% ACROSS MUCH OF FERGUS
COUNTY AND PORTIONS OF CHOTEAU COUNTY. SINCE THE MAJORITY OF THE
ZONE WILL NOT HAVE 15 MPH WIND SPEEDS AND/OR CONSISTENT WIND
GUSTS IN EXCESS OF 25 MPH COMBINED WITH RELATIVE HUMIDITY LESS
THAN 20% FOR THREE HOURS AND SINCE THIS IS A MARGINAL EVENT AT
THIS TIME A RED FLAG WARNING WAS NOT ISSUED FOR THE FIRE WEATHER
ZONE CONTAINING MOST OF FERGUS AND CHOTEAU COUNTIES.
ON WEDNESDAY THERE IS A 30% CHANCE FOR THUNDERSTORMS ACROSS THE HI-
LINE AND A 15% CHANCE FOR THUNDERSTORMS ACROSS THE REST OF NORTH-
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. ON THURSDAY AND FRIDAY
THERE IS A 15 - 30% CHANCE FOR THUNDERSTORMS ACROSS MOST OF
NORTH-CENTRAL MONTANA. WEDNESDAY THROUGH THURSDAY THERE IS A 60%
CHANCE FOR A QUARTER INCH OF RAIN OR GREATER ALONG THE HI-LINE.
ACROSS THE REST OF NORTH-CENTRAL MONTANA THERE IS A 20 - 40%
CHANCE FOR A QUARTER INCH OF RAIN OR GREATER WEDNESDAY THROUGH
THURSDAY. -IG
AVIATION
07/18Z TAF PERIOD
WILDFIRE SMOKE WILL BE AN ONGOING CONCERN THROUGH THE WEEKEND.
FOR MOST TERMINALS ACROSS CENTRAL AND NORTH-CENTRAL MONTANA THE
PRIMARY IMPACT WILL BE TO SLANTWISE VISIBILITY WITH PERIODS OF
MOUNTAIN OBSCURATION EXPECTED.
GREATER SURFACE VISIBILITY IMPACTS WILL BE OBSERVED ACROSS
SOUTHWEST MONTANA WITH HEAVIER SMOKE COMING FROM THE FIRES IN THE
PIONEER MOUNTAINS EXPECTED TO REACH KBZN AND KEKS AFTER 07/21Z
AND LASTING THROUGH AT LEAST 08/04Z. DURING THIS TIME PERIODS OF
MVFR/IFR VISIBILITY ARE POSSIBLE WITH WIDESPREAD MOUNTAIN
OBSCURATION EXPECTED ACROSS THE REGION.
KWYS AND THE SURROUNDING VALLEY IS UNIQUELY POSITIONED SUCH THAT
SMOKE MODELS ARE NOT CURRENTLY FORECASTING SIGNIFICANT REDUCTIONS
IN SURFACE VISIBILITY ALTHOUGH REDUCTIONS IN SLANTWISE VISIBILITY
ARE STILL EXPECTED.
FOR KGTF: WINDS WILL START OFF LIGHT OUT OF THE WEST/NORTHWEST AND
SHIFT TO THE NORTHEAST/EAST BY LATER IN THE AFTERNOON BUT
CROSSWINDS ARE NOT EXPECTED TO EXCEED 15KTS AT THIS TIME. WINDS
INITIALLY START TO PICK UP OUT OF THE SOUTHWEST AFTER 08/10Z AND
START TO VEER TO THE NORTHWEST BY THE LATE MORNING TOWARDS THE END
OF THE TAF PERIOD. ON THE HIGHER END, CROSSWINDS IN THE 10-12KT
RANGE ARE POSSIBLE BUT RIGHT NOW THERE IS LOW CONFIDENCE IN
EXCEEDING A 15KT CROSSWIND AT THIS TIME.
REGARDING WILDFIRE SMOKE, THE MAIN CONCERN FOR TODAY WILL BE
REDUCTIONS IN SLANTWISE VISIBILITY. A LARGER CONCERN FOR
SURFACE VISIBILITY IMPACTS ARE POSSIBLE TOMORROW AFTERNOON
COINCIDING WITH THE WIND SHIFT TO THE NORTHWEST WHICH IS EXPECTED
TO BRING DOWN SOME OF THE SMOKE GENERATED BY FIRES IN NORTHWEST
MONTANA. -THOR
FIRE WEATHER
A RED FLAG WARNING REMAINS IN EFFECT FOR THE SOUTHERN DISTRICTS
THROUGH SATURDAY. THE COMBINATION OF GUSTY AFTERNOON WINDS, LOW
HUMIDITY AND HOT TEMPERATURES WILL CREATE CRITICAL FIRE WEATHER
CONDITONS. BECAUSE OF ALL THE SMOKE, SOME LOCATIONS MIGHT NOT MIX
THE WINDS ALOFT ON FRI/SAT. NO PRECIPITATION IS EXPECTED THROUGH
AT LEAST SUNDAY. IG/BRUSDA
PRELIMINARY POINT TEMPS/POPS
GTF 56 90 57 86 / 0 0 0 0
CTB 52 82 51 79 / 0 0 0 0
HLN 57 93 57 90 / 0 0 0 0
BZN 55 94 54 90 / 0 0 0 0
WYS 45 88 45 88 / 0 0 10 0
DLN 54 91 53 89 / 0 0 0 0
HVR 52 89 56 86 / 0 0 0 0
LWT 55 87 55 83 / 0 0 10 0
TFX WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING UNTIL 9 PM MDT SATURDAY FOR CENTRAL AND EASTERN
LEWIS AND CLARK NATIONAL FOREST AREAS-HELENA AND TOWNSEND RANGER
DISTRICTS OF THE HELENA NATIONAL FOREST-LINCOLN RANGER DISTRICT
OF THE HELENA NATIONAL FOREST.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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