540 
FXUS65 KTFX 250458
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1055 PM MDT WED OCT 24 2012

AVIATION SECTION UPDATED

.UPDATE...
AN UPPER RIDGE IS OVER THE FORECAST AREA THIS EVENING AND AM NOT
SEEING MUCH IN THE WAY OF ACTIVITY ON RADAR SO HAVE LOWERED THE
CHANCES OF SNOW. PRECIPITATION OVER IDAHO AT MID-EVENING SHOULD
REACH THE WESTERN MOUNTAINS LATE TONIGHT SO LEFT THE CHANCES OF
SNOW THERE ALONE BUT DID LOWER THE CHANCES OF SNOW OVER PORTIONS
OF SOUTHWEST MONTANA AND PORTIONS OF THE PLAINS FOR THE AFTER
MIDNIGHT PERIOD. REMAINDER OF THE FORECAST LOOKS ON TRACK 
HOWEVER DID ADD A MENTION OF RECORD LOW TEMPERATURES FOR SELECTED
AREAS BOTH TONIGHT AND THURSDAY NIGHT. BLANK

&&


.AVIATION...
UPDATED 0455Z.
ANOTHER UPPER LEVEL DISTURBANCE WILL APPROACH THE ROCKY MOUNTAIN 
FRONT AFTER 09Z TONIGHT. EXPECT SCATTERED LIGHT SNOW TO OVERSPREAD 
THE FRONT RANGE OF THE ROCKIES AND MUCH OF SOUTHWEST MONTANA BETWEEN 
10Z AND 14Z THURSDAY. THE SNOW WILL SPREAD INTO CENTRAL MONTANA 
BETWEEN 14Z AND 18Z THURSDAY. THE HEAVIEST SNOWFALL CAN BE EXPECTED 
OVER THE FRONT RANGE...WHERE MOUNTAINS WILL BE OBSCURED. IFR OR 
LOWER CONDITIONS ARE STILL LIKELY IN MANY AREAS TONIGHT AND THROUGH 
THURSDAY THOUGH DUE TO LOW CEILINGS. EXPECT SLOWLY IMPROVING 
CONDITIONS AFTER 21Z THURSDAY. BRUSDA 

&&

.PREV DISCUSSION...
/ISSUED 555 PM MDT WED OCT 24 2012/
TODAY THROUGH FRIDAY...CANADIAN HIGH PRESSURE WILL CONTINUE TO
NOSE INTO NORTH-CENTRAL MONTANA TONIGHT WITH VERY COLD AIR
RESIDING OVER THE AREA. OVERNIGHT LOWS ARE EXPECTED TO FALL INTO
THE SINGLE DIGITS ABOVE ZERO ALONG THE HI-LINE AND INTO THE TEENS
ELSEWHERE. PATCHY FREEZING FOG IS ALSO POSSIBLE...ESPECIALLY ALONG
RIVER VALLEYS. ON THURSDAY...A WEAK DISTURBANCE ALOFT IS EXPECTED
TO BRING ANOTHER ROUND OF PRECIPITATION TO AREAS ALONG THE
CONTINENTAL DIVIDE BY THURSDAY AND PROGRESS TO AREAS EAST OF THE
DIVIDE BY THURSDAY AFTERNOON. MOST SNOW ACCUMULATIONS WILL BE
LIGHT OVER THE PLAINS WITH ONE TO TWO INCHES POSSIBLE...HOWEVER
OVER THE MOUNTAINS ALONG THE CONTINENTAL DIVIDE AND
SOUTHWEST/CENTRAL MONTANA UP TO FIVE INCHES OF SNOW ARE POSSIBLE.
THIS SNOWFALL MAY CREATE DIFFICULT TRAVEL CONDITIONS WITH SNOW-
COVERED AND SLIPPERY ROADWAYS ALONG WITH BRIEFLY REDUCED
VISIBILITIES IN FALLING SNOW OVER MOUNTAIN PASSES BUT THE IMPACTS
SHOULD NOT BE WIDESPREAD SO NO WINTER WEATHER HIGHLIGHTS ARE
EXPECTED AT THIS TIME. THIS DISTURBANCE WILL QUICKLY DEPART BY
THURSDAY NIGHT WITH CONTINUED COLD CONDITIONS EXPECTED THURSDAY
NIGHT. UNSETTLED NORTHWEST FLOW MAY KEEP A FEW FLURRIES OR LIGHT
SNOW SHOWERS OVER THE AREA ON FRIDAY THOUGH ANY SIGNIFICANT
IMPACTS ARE NOT EXPECTED. MLV

FRIDAY NIGHT THROUGH WEDNESDAY...AREA WILL BE UNDER A WEST TO NW 
FLOW ALOFT THIS WEEKEND AS AN UPPER LEVEL RIDGE ATTEMPTS TO AMPLIFY 
ALONG WEST COAST. WEAK SHORTWAVE ENERGY AND UPPER LEVEL JET IMPULSES 
WILL WILL STREAM OVER THE ROCKIES IN THIS PATTERN...POTENTIALLY 
PRODUCING SOME LIGHT OVERRUNNING PRECIPITATION AT TIMES AS THE UPPER 
LEVELS WARM AND MOIST FLOW OVERRUNS COOLER AIR AT THE SURFACE. 
TEMPERATURES WILL RETURN TO NEAR AVERAGE LEVELS OVER SW MT SATURDAY 
AND NORTH CENTRAL MT BY SUNDAY. THE UPPER LEVEL RIDGE WILL PROGRESS 
INLAND MONDAY AND TUESDAY WITH TEMPERATURES RISING ABOVE SEASONAL 
AVERAGES ACROSS MOST OF THE FORECAST AREA...HOWEVER WEAK 
DISTURBANCES MOVING THROUGH THE RELATIVELY MOIST FLOW FROM THE 
PACIFIC WILL KEEP SUBSTANTIAL CLOUD-OVER OVER THE AREA WITH 
SCATTERED PRECIPITATION MAINLY OVER THE MOUNTAINS. MEDIUM RANGE 
MODELS INDICATE THAT THE RIDGE WILL BEGIN TO BREAKDOWN AROUND THE 
MIDDLE OF NEXT WEEK WITH THE NEXT PACIFIC SYSTEM COMING ONSHORE AND 
APPROACHING THE NORTHERN ROCKIES ON WEDNESDAY...WHICH WILL BRING 
COOLER TEMPERATURES AND INCREASING MOISTURE TO THE REGION. HOENISCH

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  15  28  14  38 /  20  40  20  20 
CTB   9  25   8  32 /  20  30  20  20 
HLN  19  33  17  40 /  20  40  20  20 
BZN  17  36  13  41 /  20  40  20  20 
WEY   9  31   4  32 /  30  60  30  30 
DLN  16  36  14  38 /  20  50  20  20 
HVR  14  31   9  34 /  10  20  20  20 
LWT  13  27  12  35 /  20  40  20  30 

&&

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

$$

WEATHER.GOV/GREATFALLS