FXUS65 KTFX 110407
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
907 PM MST THU DEC 10 2009
.UPDATE...
CURRENT FORECAST IS ON TRACK...WITH JUST A FEW MINOR ADJUSTMENTS.
LOWERED TEMPERATURES A TAD IN THE HAVRE AREA...AS THEY HAVE COOLED
OFF NICELY THIS EVENING. A FEW ISOLATED MOUNTAIN SNOW SHOWERS OR
FLURRIES ARE POSSIBLE TONIGHT...BUT NO ACCUMULATIONS ARE EXPECTED
AND THE LOWER ELEVATIONS SHOULD REMAIN DRY. ALSO ADJUSTED WIND
SPEEDS MOST AREAS...ESPECIALLY IN THE CUT BANK AREA WHERE IT IS A
BIT BREEZY THIS EVENING.
LOOKING AHEAD...FAIRLY QUIET WEATHER EXPECTED FRIDAY AND SATURDAY
MORNING...AS THE AREA WILL GENERALLY BE IN-BETWEEN STORM SYSTEMS.
THEN ALL SIGNS POINT TO A SHORT BLAST OF ARCTIC AIR TO MOVE INTO
NORTH CENTRAL MONTANA LATE SATURDAY AFTERNOON AND EVENING...BUT EXIT
THE REGION ON TUESDAY OR WEDNESDAY. EXPECT TEMPERATURES TO PLUMMET
TO AROUND 10 BELOW BEHIND THE COLD FRONT SATURDAY NIGHT...ALONG WITH
INCREASING CHANCES FOR ACCUMULATING SNOWFALL. MIDNIGHT SHIFT WILL
EVALUATE HOW COLD WE WILL GET...BUT MOST LIKELY THEY WILL CONTINUE
TO LOWER CURRENT FORECASTED TEMPERATURES FOR SUNDAY AND MONDAY. THE
COLD AIR SHOULD BEGIN TO EXIT THE REGION TUESDAY AFTERNOON OR
NIGHT...WITH A VERY NICE WARM UP EXPECTED FOR THE SECOND HALF OF
NEXT WEEK. BRUSDA
&&
.AVIATION...
UPDATED 2350Z.
MOIST NORTHWEST FLOW ALOFT CONTINUES ACROSS MONTANA TONIGHT AND
FRIDAY. ISOLATED MOUNTAIN SNOW SHOWERS ARE EXPECTED AT TIMES ALONG
WITH LOCAL MOUNTAIN OBSCURATIONS...BUT LOWER ELEVATIONS AND
TERMINALS ARE EXPECTED TO REMAIN DRY WITH VFR CONDITIONS.
SOUTHWEST TO WEST SURFACE WINDS WILL REMAIN BREEZY ACROSS THE
ENTIRE FORECAST AREA. MPJ
&&
.PREV DISCUSSION...
/ISSUED 450 PM MST THU DEC 10 2009/
TONIGHT THROUGH SATURDAY...THE ZONES ARE UNDERNEATH NORTHWEST FLOW
ALOFT WHICH IS ASSOCIATED WITH A LOW PRESSURE SYSTEM IN CANADA.
WESTERLY FLOW TO THE SOUTH OF THE ZONES IS ASSOCIATED WITH A
SHORTWAVE OVER THE PACIFIC. HIGH PRESSURE ALOFT WILL CONTINUE TO
BUILD OVER THE REGION AND SEVERAL DISTURBANCES WILL MOVE THROUGH THE
NORTHWEST FLOW ALOFT. THE UPPER LEVEL FLOW GRADUALLY SHIFTS TO THE
WEST THROUGH THE PERIOD AND MID LEVEL WINDS REMAIN STRONG. LIGHT
SNOW ASSOCIATED WITH THE CURRENT UPPER LEVEL DISTURBANCE WILL AFFECT
MOSTLY THE SOUTHWEST ZONES DURING THE EVENING. THE CHANCE FOR PRECIP
WILL REMAIN SLIGHT FRIDAY BUT THE CHANCE BEGINS TO INCREASE LATE
FRIDAY AS A BOUNDARY SETS UP ACROSS THE HI-LINE. A SECOND SOURCE OF
PRECIP WILL MOVE UP TOWARDS THE SOUTHWEST THAT IS ASSOCIATED WITH
THE PACIFIC SHORTWAVE. HIGHEST CHANCE OF PRECIP WILL BE OVER THE
EXTREME SOUTHERN MOUNTAINS WHERE SNOW SHOULD BE ACCUMULATING BY
SATURDAY. TEMPS WILL REMAIN AT OR BELOW SEASONAL NORMALS BUT BEGIN
TO APPROACH NORMALS BY SATURDAY. ZELZER
SATURDAY NIGHT THROUGH THURSDAY...MEDIUM RANGE MODELS CONTINUE TO
EXHIBIT GENERAL SIMILARITIES DURING THE PERIOD. A CLOSED UPPER LOW
OVER CENTRAL CANADA WILL PUSH A LARGE AREA OF MOISTURE SOUTH ACROSS
THE CANADIAN BORDER ON SUNDAY MERGING WITH MOISTURE WORKING ITS WAY
NORTH FROM THE SOUTHWEST US. THE RESULT WILL BE ACCUMULATING
SNOWFALL OVER THE ROCKY MOUNTAIN FRONT AND SCATTERED SNOW OVER MOST
OF THE REST OF COUNTY WARNING AREA. A SURFACE COLD FRONT WILL MOVE
ACROSS THE AREA SUNDAY BRINGING MUCH COLDER AIR AS FAR SOUTH AS
GREAT FALLS WHILE ONLY COOLING SOUTHWEST MONTANA A BIT. SCATTERED
SNOW AND COLD TEMPS WILL CONTINUE MONDAY AS THE AREA REMAINS UNDER
NORTHWEST FLOW ALOFT. THE REMAINDER OF THE PERIOD WILL SEE A DRYING
AND WARMING TREND AS A WEAK UPPER RIDGE MOVES ACROSS THE CONTINENTAL
DIVIDE BY THURSDAY. ISOLATED SNOW SHOWERS WILL REMAIN A POSSIBILITY
FOR THE WESTERN MOUNTAINS AS WELL AS THE MOUNTAINS OF SOUTHWEST
MONTANA. TEMPS WILL REMAIN BELOW SEASONAL AVERAGES UNTIL THE MIDDLE
OF NEXT WEEK WHEN IT APPEARS A STRONGER WARMING TREND MAY BEGIN.
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 9 29 16 31 / 0 10 10 20
CTB 6 24 8 24 / 0 10 30 30
HLN 4 24 8 28 / 0 10 10 20
BZN -3 22 2 30 / 0 10 20 30
WEY -10 17 3 24 / 20 10 60 60
DLN -1 23 7 30 / 0 10 20 30
HVR -7 22 4 22 / 0 10 30 20
LWT 1 27 6 29 / 10 10 10 20
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
WEATHER.GOV/GREATFALLS
