Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 270535
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1130 PM MDT SUN APR 26 2015

UPDATE TO AVIATION

.UPDATE...

HAVE MADE MAINLY MINOR CHANGES TO THE GOING FORECAST AS THE UPPER
TROUGH AND ASSOCIATED MOISTURE MOVES AWAY FROM THE FORECAST AREA
OVERNIGHT. BIGGEST CHANGE MADE WAS TO DROP MINIMUM TEMPERATURES DOWN
SEVERAL DEGREES IN AREAS WHERE SKIES ARE CLEARING OUT. HAVE ALSO
MADE SOME TWEAKS TO SKY CONDITION AND WINDS AND VERY MINOR CHANGES
TO POPS/WEATHER. MODELS CONTINUE TO SHOW THAT THE NEXT FEW DAYS WILL
BE MOSTLY CLEAR AND WARMER. MPJ

&&

.AVIATION...
UPDATED 0530Z.

VFR CONDITIONS ARE GENERALLY EXPECTED ACROSS THE AREA THROUGH AT
LEAST MONDAY EVENING, UNLESS OTHERWISE MENTIONED. ONLY AREAS OF MID
LEVEL CLOUDS AND A FEW WEAK SHOWERS WILL LINGER OVER THE MOUNTAINS
OF SOUTHWEST/CENTRAL MONTANA THROUGH AROUND 09Z, BUT AM NOT
EXPECTING THEM TO IMPACT THE NEARBY TERMINALS (INCLUDING KBZN AND
KLWT). OTHERWISE, SKIES WILL CONTINUE TO CLEAR ACROSS THE AREA
OVERNIGHT, WITH ONLY SCATTERED TO BROKEN THIN HIGH CLOUDS MOVING
INTO THE AREA WITH HIGH PRESSURE ALOFT. AM NOT EXPECTING THESE
CLOUDS TO BE AN IMPACT, SO HAVE LEFT MOST AREAS SKC. HOWEVER, THE
AREAS THAT RECEIVED PRECIPITATION TODAY (KHLN, KBZN, KLWT) HAVE A
GOOD CHANCE OF SEEING AREAS OF IFR/LIFR FOG DEVELOPMENT BETWEEN 09Z
AND 15Z DUE TO THE CLEARING SKIES AND LIGHT WINDS. LIGHT SOUTHERLY
WINDS ARE GENERALLY EXPECTED THROUGH THE PERIOD.  COULSTON

&&

.PREV DISCUSSION...
/ISSUED 550 PM MDT SUN APR 26 2015/

THIS AFTERNOON THROUGH TUESDAY EVENING. LATEST ANALYSIS SHOWS THE
SHORTWAVE TROF THAT HAS KEPT EXTENSIVE CLOUDINESS AND SCATTERED
AREAS OF LIGHT RAIN AND SNOW OVER THE SOUTHERN HALF OF OUR REGION
TODAY CONTINUING TO SLOWLY EXIT EASTWARD. THE WIDESPREAD OVERCAST
CONDITIONS WILL PERSIST INTO EARLY EVENING FOLLOWED BY GRADUAL
CLEARING FROM WEST TO EAST TONIGHT. LIKEWISE, PRECIPITATION WILL
TAPER OFF OVER THE NEXT FEW HOURS. SINCE WEBCAMS AND WEATHER
OBSERVER REPORTS CONFIRM ONLY LIGHT AMOUNTS OF RAIN- AND SNOWFALL
(DEPENDING ON ELEVATION) AND LITTLE ADDITIONAL PRECIP EXPECTED, WE
HAVE CANCELLED THE EARLIER WINTER WEATHER ADVISORY OVER PARTS OF
THE SOUTHWEST COUNTIES. THREE-DAY PERIOD OF GREAT SPRING
CONDITIONS BEGINS TOMORROW MORNING. A HIGH PRESSURE RIDGE,
CURRENTLY CENTERED ALONG THE PACIFIC COAST, HEADS INLAND AND MOVES
INTO THE NORTHERN ROCKIES AND GREAT BASIN ON TUES, BRINGING MOSTLY
FAIR SKIES AND DRY CONDITIONS. WINDS ALOFT WILL GRADUALLY SHIFT
FROM CURRENT NORTHERLY DIRECTION TO WEST- SOUTHWEST, DRIVING A
SIGNIFICANT JUMP IN TEMPERATURES. MUCH OF THE REGION WILL MAKE IT
INTO THE LOW-TO- MID 60S TOMORROW AND THE UPPER 70S ON TUES.
WARANAUSKAS

TUESDAY NIGHT THROUGH SUNDAY...THE PERIOD BEGINS WITH THE UPPER
RIDGE MOVING TO EASTERN MONTANA BY EARLY WEDNESDAY AS AN UPPER
TROF APPROACHES THE PACIFIC NORTHWEST. SOUTHWEST FLOW ALOFT WILL
BEGIN TO BRING AN INCREASE IN MOISTURE TO THE AREA. SHOWERS
WEDNESDAY AFTERNOON WILL BE CONFINED TO THE ROCKY MOUNTAIN FRONT.
BY LATE WEDNESDAY NIGHT, THE UPPER TROF WILL CROSS THE CONTINENTAL
DIVIDE AND RESULT IN WIDESPREAD SCATTERED SHOWERS THROUGH THE DAY
THURSDAY. THURSDAY NIGHT WILL FIND THE TROF ALREADY OVER EASTERN
MONTANA AND PRECIPITATION WILL BE ENDING OVER THE PLAINS. THE
MODELS BEGIN TO OFFER VARYING SOLUTIONS FOR FRIDAY. THOUGH THEY
ALL HAVE GENERALLY WESTERLY FLOW ALOFT, THE GFS BRINGS A WEAK
UPPER TROF ACROSS THE AREA. SCATTERED SHOWERS WILL BE POSSIBLE
OVER SOUTHWEST MONTANA AND OVER THE WESTERN PLAINS. BOTH THE
CANADIAN AND GFS MODELS HAVE DOWN SLOPE WESTERLY FLOW ALOFT FOR
SATURDAY WHILE THE ECMWF BRINGS A WEAK UPPER TROF THROUGH AND
SUBSEQUENT PRECIPITATION. HAVE GONE WITH A COMPROMISE SOLUTION
SATURDAY BY KEEPING THE PLAINS DRY AND DEVELOPING SOME MOUNTAIN
SHOWERS. SAME SOLUTION FOR SUNDAY AS THE CANADIAN AND GFS MODELS
TRY TO DEVELOP UPPER RIDGING OVER THE AREA WHILE THE ECMWF IS
FASTER WITH AN UPPER TROF MOVING INTO THE PACIFIC NORTHWEST.
SOUTHWEST MOUNTAINS SHOULD SEE SOME SHOWERS WHILE THE PLAINS
CONTINUE TO BE DRY. TEMPERATURES WILL CONTINUE ABOVE SEASONAL
AVERAGES.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  29  64  37  76 /  10   0   0   0
CTB  29  64  33  75 /   0   0   0   0
HLN  31  64  37  76 /  10   0   0   0
BZN  27  59  31  71 /  20   0   0   0
WEY  22  58  26  66 /  20   0   0   0
DLN  29  61  34  73 /  20   0   0   0
HVR  27  66  34  76 /   0   0   0   0
LWT  29  62  36  73 /  20   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

WEATHER.GOV/GREATFALLS


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