FXUS65 KTFX 011333
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
633 AM MST TUE DEC 1 2009
.UPDATE...
UPDATED CURRENT FORECAST TO REMOVE POPS FROM GREAT FALLS
NORTHWARD...AND TO INCREASE POPS SOUTH OF GREAT FALLS. EXPECT
SNOWFALL TO CONTINUE OVER MUCH OF SOUTHWEST MONTANA THROUGH 10 AM
THIS MORNING...THEN BEGIN TO TAPPER OFF LATE THIS MORNING THROUGH
THE AFTERNOON HOURS. A FEW SNOW REPORTS HAVE COME IN SO FAR...BUT
OVERALL...1 TO 2 INCHES AT LOWER ELEVATIONS AND 2 TO 4 INCHES IN
THE MOUNTAINS. BRUSDA
&&
.AVIATION...
UPDATED 1200Z.
LIGHT SNOW CONTINUES TO AFFECT PORTIONS OF SOUTHWEST AND CENTRAL
MONTANA THIS MORNING. AT 12Z...THE BACK EDGE OF THE SNOWFALL
EXTENDED FROM GREAT FALLS TO JUST NORTH OF LEWISTOWN. THIS AREA OF
SNOWFALL CONTINUES TO PUSH SOUTHWARD...AND WILL AFFECT HELENA AND
BOZEMAN THROUGH THE MORNING. EXPECT IFR/LIFR CONDITIONS THROUGH THE
MORNING OVER SOUTHWEST MONTANA...ALONG WITH MOUNTAINS OBSCURED.
DRIER AIR IS SLOWLY MOVING SOUTHWARD INTO NORTH CENTRAL
MONTANA...AND GENERALLY VFR CONDITIONS CAN BE EXPECTED IN THE HAVRE
AND CUT BANK AREAS. DRIER AND MORE STABLE AIR SHOULD MOVE INTO THE
ENTIRE REGION AFTER 02Z WEDNESDAY...WITH VFR CONDITIONS PREVAILING
THROUGH THE OVERNIGHT HOURS. BRUSDA
&&
.PREV DISCUSSION...
/ISSUED 500 AM MST TUE DEC 1 2009/
TODAY THROUGH THURSDAY...AN UPPER LEVEL LOW PRESSURE TROF WILL MOVE
THROUGH THE REGION TODAY WHILE TO THE WEST...A SHARP RIDGE IS
BUILDING OVER THE EASTERN PACIFIC. THIS WILL KEEP
STRONG...COOL...NORTH FLOW OVER THE ZONES THROUGH THE PERIOD.
AIRMASS WILL TO DRY QUICKLY TODAY...MOST PRECIP SHOULD BE FINISHED
ACROSS THE NORTH AND CENTRAL ZONES IN THE MORNING EXCEPT FOR SOME OF
THE HIGHER ELEVATIONS. GOOD LOW LEVEL MOISTURE WILL REMAIN ACROSS
THE SW ZONES ALONG WITH SOME DECENT LIFT. THE AIRMASS WILL REMAIN
COLD AND WILL CONTINUE TO COOL THROUGH WEDNESDAY. TEMPERATURES ALOFT
WILL BEGIN TO WARM ON WEDNESDAY AND BY THURSDAY...THE UPPER LEVEL
HIGH PRESSURE RIDGE WILL HAVE BUILT OVER THE PACIFIC NORTHWEST. THIS
POSITION WILL STILL KEEP NORTH FLOW OVER THE ZONES...AND ALTHOUGH
THE AIRMASS WILL HAVE BEGUN TO WARM...MOST WARMING WILL BE AT MID TO
UPPER LEVELS AND NOT THE SURFACE. SOME SLIGHT IMPROVEMENT WILL
BEGIN ON THURSDAY BUT TEMPS WILL REMAIN WELL BELOW NORMALS THROUGH
THE PERIOD. ZELZER
THURSDAY NIGHT THROUGH SUNDAY NIGHT...A TRANSITION TO A RE-ENFORCING
SHOT OF WINTER WEATHER WILL OCCUR DURING THIS TIME. EXPECT A COOL
START FRIDAY MORNING...AS SURFACE WINDS BACK AROUND TO THE WEST.
HOWEVER...THE WEST WINDS WILL NOT BE STRONG ENOUGH TO RAISE TEMPS TO
PREVIOUSLY FORECASTED HIGHS...THUS FRIDAY AFTERNOON TEMPERATURES
HAVE BEEN LOWERED A BIT. THEN A SECOND SHOT...AND A MUCH STRONGER
COLD FRONT WILL MOVE THROUGH THE REGION LATE FRIDAY NIGHT AND INTO
SATURDAY. EXPECT ANOTHER ROUND OF LIGHT SNOW TO ACCOMPANY THE
FRONTAL PASSAGE...EXCEPT IN THE HAVRE AREA...WHERE LITTLE/NO
SNOWFALL IS EXPECTED. SNOW ACCUMULATIONS FROM FRIDAY NIGHT THROUGH
SATURDAY LOOK TO BE ON THE LIGHT SIDE...WITH LOWER ELEVATIONS
RECEIVING 1 TO 2 INCHES OF SNOWFALL...AND 2 TO 4 INCHES IN THE
MOUNTAINS. TEMPERATURES WILL START A GOOD FALLING TREND ON
SATURDAY...WITH AFTERNOON HIGHS MOSTLY IN THE UPPER TEENS/LOWER 20S.
EXPECT EVEN COLDER AIR TO MOVE INTO THE REGION FOR SATURDAY NIGHT
THROUGH SUNDAY...WITH AFTERNOON HIGHS ON SUNDAY RANGING FROM 20 TO
25 DEGREES BELOW NORMAL. INTERESTING...BUT SINCE LITTLE/NO SNOWFALL
IS EXPECTED IN THE HAVRE AREA...TEMPERATURES IN THIS REGION WILL
ACTUALLY BE A FEW DEGREES WARMER WHEN COMPARED TO CUT BANK OR GREAT
FALLS. THERE WILL BE A SMALL CHANCE OF SNOW SHOWERS SATURDAY
NIGHT THROUGH SUNDAY NIGHT...BUT ANY PRECIP WILL VERY LIGHT AND
ISOLATED. BRUSDA
MONDAY AND TUESDAY...MODELS SHOW A COLD UPPER LEVEL LOW OVER CENTRAL
CANADA...BRINGING COLD ARCTIC AIR INTO THE REGION UNDER A NORTHERLY
FLOW ALOFT. TEMPERATURES WILL CONTINUE TO BE WELL BELOW AVERAGE WITH
ISOLATED SNOW SHOWERS. HOWEVER...THERE WILL BE SOME MODERATION BY
TUESDAY. WILLIAMSON DC
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 28 8 26 4 / 10 10 0 0
CTB 28 4 26 3 / 10 10 0 0
HLN 34 18 27 8 / 100 10 10 0
BZN 26 0 26 1 / 100 10 0 0
WEY 22 -3 18 -6 / 60 10 10 10
DLN 26 8 24 2 / 50 10 0 0
HVR 28 5 27 3 / 10 10 10 10
LWT 24 3 23 2 / 60 10 10 10
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
WEATHER.GOV/GREATFALLS
