Area Forecast Discussion
Issued by NWS Great Falls, MT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KTFX 272147
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
347 PM MDT THU AUG 27 2015

.DISCUSSION...
TONIGHT THROUGH SATURDAY...GUSTY SOUTHWEST WINDS AND LOW HUMIDITY
ARE CAUSING CRITICAL FIRE WEATHER CONDITIONS AT SOME LOCATIONS
THIS AFTERNOON ALONG THE ROCKY MOUNTAIN FRONT AND ADJACENT PLAINS.
THE RED FLAG WARNING WILL CONTINUE FOR FIRE WEATHER ZONE 112
THROUGH THIS EVENING. SMOKE HAS THICKENED THIS AFTERNOON AND IS
LIKELY TO PERSIST WITH DEEP WEST-SOUTHWESTERLY FLOW. SCATTERED
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP THIS EVENING
ACROSS CENTRAL AND SOUTHWEST MONTANA. SOME OF THIS ACTIVITY COULD
PRODUCE ERRATIC GUSTY WINDS AND FIRE STARTS FROM LIGHTNING. HEAVY
RAIN IS POSSIBLE UNDER STRONGER STORMS FOR THE SOUTHWEST...WHILE
OTHERS REMAIN WEAK WITH ONLY LIGHT PRECIPITATION. CONDITIONS
STABILIZE ON FRIDAY WITH SHORTWAVE RIDGING AND DRY AIR ALOFT
PASSING THROUGH THE REGION. DRY AND WARM CONDITIONS WILL CONTINUE
THROUGH THE DAY SATURDAY WITH WINDS INCREASING AHEAD OF A DRY COLD
FRONT THAT WILL MOVE THROUGH THE AREA BRINGING GUSTY WINDS AND LOW
HUMIDITY VALUES AHEAD OF THE FRONT. THE LACK OF MOISTURE WITH THE
FRONTAL PASSAGE WILL LIMIT SHOWER AND THUNDERSTORM
DEVELOPMENT...BUT THERE IS ALMOST NO SIGNIFICANT PRECIPITATION
EXPECTED WITH THIS FRONTAL PASSAGE. ADDITIONAL FIRE WEATHER
HIGHLIGHTS MAY BECOME NECESSARY AS THIS FRONT APPROACHES. NUTTER

SATURDAY NIGHT THROUGH THURSDAY...MEDIUM RANGE MODEL SOLUTIONS
REMAIN IN RELATIVELY GOOD AGREEMENT THROUGH MUCH OF THE FORECAST
PERIOD. HOWEVER, BOTH HAVE TRENDED TOWARD A SOMEWHAT DRIER FORECAST
SO HAVE AGREED WITH SURROUNDING OFFICES TO PULL BACK POPS A BIT. AS
NOTED YESTERDAY, THE MAIN PLAYERS IN THE FORECAST ARE AN UPPER LEVEL
TROUGH OVER THE GULF OF ALASKA/SOUTHEAST ALASKA AND RIDGING OVER THE
HIGH PLAINS. MONTANA REMAINS BENEATH AN SOMEWHAT UNSTABLE SOUTHWEST
FLOW ALOFT THROUGH THE PERIOD AND BOTH MODELS ATTEMPT TO SLOWLY
PROGRESS THE UPPER TROUGH INTO WESTERN CANADA. THE ECMWF IS A BIT
MORE AGGRESSIVE WITH THIS THAN THE GFS BUT IT APPEARS THAT BOTH
MODELS MAY BE OVERDOING HOW FAR EASTWARD THIS FEATURE CAN MOVE GIVEN
THE UPPER RIDGE AND THE VERY WARM LATE SUMMER TEMPERATURES THAT WILL
TEND TO SUPPORT RIDGE STABILITY OVER THE PLAINS. HAVE MADE ONLY
MINOR CHANGES TO THE GOING FORECAST PACKAGE, MAINLY TO EASE BACK ON
POPS AND SURFACE WIND SPEEDS. TEMPERATURES FROM MONDAY ONWARD ARE
EXPECTED TO BE NEAR OR SLIGHTLY ABOVE SEASONAL AVERAGES AS GUIDANCE
FROM BOTH MODELS SUPPORT COOLER TEMPERATURES THAN THOSE OF THIS
WEEK. MPJ

&&

.AVIATION...
UPDATED 1750Z.
WEST TO SOUTHWEST FLOW ALOFT CONTINUES. SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP AFTER 18Z OVER SOUTHWEST
MONTANA AND MOVE SLOWLY NORTH AND EAST. CONVECTIVE ACTIVITY SHOULD
END BY 06Z WITH PARTIAL CLEARING  VFR CONDITIONS PREVAIL THOUGH
AREAS OF MVFR WILL PERSIST DUE TO SMOKE AND REDUCED VISIBILITIES.
MVFR CONDITIONS ARE ALSO POSSIBLE IN THE VICINITY OF THUNDERSTORMS
ALONG WITH GUSTY ERRATIC WINDS. MOUNTAINS OBSCURED AT TIMES.

&&

.FIRE WEATHER...
DRY AND WINDY CONDITIONS ARE EXPECTED ALONG THE ROCKY MOUNTAIN
FRONT AND ADJACENT HIGH PLAINS. A RED FLAG WARNING IS IN EFFECT
FOR FIRE WEATHER ZONE 112. MONSOONAL MOISTURE WILL MOVE INTO THE
REST OF THE AREA AND COULD PRODUCE A MIX OF WET AND DRY
THUNDERSTORMS ARE EXPECTED. CONDITIONS STABILIZE ON FRIDAY.
SATURDAY WILL BE ANOTHER NEAR CRITICAL FIRE WEATHER DAY AS AN
APPROACHING DRY COLD FRONT WILL CREATE THE POTENTIAL FOR GUSTY
WINDS WITH LITTLE TO NO MOISTURE ASSOCIATED WITH THE FRONT
ADDITIONAL HIGHLIGHTS MAY BECOME NECESSARY AHEAD OF THE COLD
FRONT. SUK

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  58  90  62  90 /  10   0  10  10
CTB  54  88  56  85 /   0  10  10  20
HLN  52  90  55  90 /  10  10  10  20
BZN  50  87  53  91 /  20   0  10  10
WEY  37  79  41  81 /  40   0  10  20
DLN  49  86  53  87 /  10  10  10  10
HVR  57  90  58  94 /  10   0   0  10
LWT  56  88  60  93 /  10   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR MTZ112.

&&

$$

WEATHER.GOV/GREATFALLS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.