Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 011114
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
514 AM MDT TUE SEP 1 2015

.DISCUSSION...
TUESDAY THROUGH THURSDAY...WINDY CONDITIONS WILL DEVELOP AGAIN
TODAY ESPECIALLY ALONG THE ROCKY MOUNTAIN FRONT. A RED FLAG
WARNING HAS BEEN ISSUED FOR FIRE WEATHER ZONE 112. CONDITIONS WILL
ALSO BE CLOSE ON FIRE WEATHER ZONE 114...HOWEVER CONFIDENCE THAT
HUMIDITY VALUES WILL BE DANGEROUSLY LOW IS NOT AS STRONG SO WILL
HOLD OFF ON ISSUING ANY PRODUCT FOR THE TIME BEING. NEAR CRITICAL
FIRE WEATHER CONDITIONS WILL EXIST ON TUESDAY AND WEDNESDAY FOR
MUCH OF THE AREA. MODELS CONTINUE TO SLOW DOWN THE PROGRESSION OF
THE NEXT APPROACHING SYSTEM. HAVE DECREASED POPS AND QPF ON
WEDNESDAY AND INCREASED THEM ON THURSDAY DUE TO THIS CONTINUED
TREND. TEMPERATURES ARE STILL EXPECTED TO REMAIN NEAR SEASONAL
AVERAGES FOR THE NEXT TWO DAYS WITH COOLER CONDITIONS EXPECTED
WEDNESDAY EVENING AND THURSDAY. SOME LOCATIONS AT HIGHER
ELEVATIONS ESPECIALLY ALONG THE ROCKY MOUNTAIN FRONT COULD SEE A
SOME LIGHT SNOWFALL OVERNIGHT WEDNESDAY WITH THIS NEXT SYSTEM. SUK

THURSDAY NIGHT THROUGH TUESDAY...AN UPPER LEVEL LOW PRESSURE TROF
WILL BE OVER THE PACIFIC NORTHWEST THURSDAY NIGHT WITH THE LOW
BEGINNING TO CLOSE AND SLOWING DOWN. THE ASSOCIATED COLD FRONT WILL
BE CROSSING THE ZONES DURING THE NIGHT AND SHOULD BE WELL INTO
SOUTHWEST MONTANA BY MORNING...AND COOLER TEMPS WILL FOLLOW ON
FRIDAY. THE AIR MASS WILL MOISTEN WELL AHEAD OF THE TROF AND
THURSDAY NIGHT AND FRIDAY PRECIPITATION SHOULD BE RATHER
WIDESPREAD...AND MODELS HAVE INCREASED PRECIP VALUES AHEAD OF THE
TROF DURING THE PAST 24 HOURS. THE ECMWF AND GFS ARE QUITE SIMILAR
THROUGH 12Z SAT. BEYOND THIS POINT, THE ECMWF REMAINS A CLOSED LOW
WHILE THE GFS MOVES EAST AS AN OPEN WAVE. WITH THE SLOWER MOVEMENT
OF THE ECMWF, PRECIP WOULD START LATER AND TEMPERATURES WOULD BE
SLOWER TO COOL. WITH THE FASTER MOVEMENT, THE GFS BRINGS THE TROF
OVER THE IDAHO PANHANDLE SATURDAY NIGHT AND THE TROF IS BROADENED AS
A SHORTWAVE MOVES INTO THE TROF FROM THE WEST. THE MODELS DIFFER
HERE AS WELL. THE GFS SHORTWAVE IS MUCH WEAKER AND THE AIR MASS
BEGINS TO DRY SUNDAY NIGHT. THE DEEPER LOW OF THE ECMWF WOULD DELAY
MOVEMENT OF THE TROF EAST AND DELAY ANY DRYING OF THE AIR MASS UNTIL
MONDAY. THIS WOULD KEEP PRECIPITATION IN THE FORECAST LONGER AS WELL
AND KEEP TEMPERATURES COOLER INTO MONDAY. WITH THE MODEL
UNCERTAINTY, WILL REMAIN CAUTIOUS AND BLEND THROUGH THIS PERIOD. THE
AIR MASS WILL BE QUITE DRY AGAIN MONDAY NIGHT AND TUESDAY, HIGH
PRESSURE ALOFT WILL BE BUILDING, AND TEMPERATURES RISING BACK ABOVE
SEASONAL NORMALS. ZELZER


&&

.AVIATION...UPDATED 1113Z.

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE TAF PERIOD. GUSTY
WINDS WILL RETURN TO THE PLAINS OF CENTRAL AND NORTH CENTRAL MONTANA
THIS MORNING THROUGH SUNSET. SOME OBSCURATIONS DUE TO SMOKE WILL
REMAIN POSSIBLE THROUGH THIS TIME. SUK

&&

.FIRE WEATHER...NEW RED FLAG WARNING NOW IN EFFECT FOR FIRE ZONE 112
FOR NOON TO 9 PM TUESDAY. GUSTY WINDS RETURN TO THE ROCKY MTN FRONT
AND ADJACENT PLAINS IN GLACIER/TOOLE/LIBERTY COUNTIES TOMORROW WHICH
WILL COMBINE WITH AFTERNOON HUMIDITY VALUES AGAIN DROPPING INTO THE
15-20 PERCENT RANGE. LOW HUMIDITY WILL ALSO DEVELOP OVER MUCH OF
CENTRAL MT BUT WIND SPEEDS SHOULD REMAIN BELOW CRITICAL FIRE WEATHER
CRITERIA. WARANAUSKAS

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  84  54  81  50 /   0   0  10  30
CTB  77  51  72  44 /   0   0  10  50
HLN  84  50  82  48 /   0   0  10  20
BZN  85  49  86  47 /   0   0  10  10
WEY  77  39  76  37 /   0   0   0   0
DLN  83  49  82  46 /   0   0  10  10
HVR  83  50  82  50 /   0   0   0  30
LWT  83  56  85  47 /   0   0  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 9 PM MDT THIS EVENING FOR
MTZ112.

&&

$$

WEATHER.GOV/GREATFALLS



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