Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 111806
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1101 AM MST THU FEB 11 2016

...AVIATION SECTION UPDATED...

.DISCUSSION...

TODAY THROUGH SATURDAY...HIGHLY AMPLIFIED PATTERN REMAINS IN PLACE
WITH BROAD RIDGE ACROSS THE WESTERN US AND DEEP TROUGH OVER THE
EASTERN HALF OF N-AMERICA WITH COLD LOW CENTER NOW DROPPING S ACROSS
HUDSON BAY. ARCTIC AIRMASS SLIDING SOUTH FROM CANADA AROUND THE
HUDSON BAY LOW WILL REMAIN WELL EAST OF THE REGION, HOWEVER A WEAK
BOUNDARY BETWEEN THE MILDER AIRMASS THAT HAS BEEN IN PLACE OVER
THE NORTHERN ROCKIES AND COOLER AIRMASS TO THE N AND E REMAINS IN
PLACE THIS MORNING FROM NEAR LETHBRIDGE SE THROUGH HAVRE, WITH
TEMPERATURES NEAR OR JUST BELOW FREEZING TO THE NE OF THIS
BOUNDARY AS WELL AS SOME AREAS OF FOG. SURFACE LOW PRESSURE
TROUGH CURRENTLY LOCATED ACROSS CENTRAL MT WILL SLIDE SE TODAY AS
WEAK SHORTWAVE ENERGY STREAMS OVER THE RIDGE AND THIS SHOULD
ALLOW THE FRONTAL BOUNDARY AND COOLER AIR TO BACK SOUTHWESTWARD
ACROSS NORTH CENTRAL MT THIS EVENING. GENERALLY DRY CONDITIONS
WILL PREVAIL TODAY WITH PERIODS OF BROKEN MID-HIGH CLOUD-COVER
STREAMING ACROSS THE REGION. PLUME OF MOISTURE LURKING OFFSHORE ON
SATELLITE IMAGERY THIS MORNING WILL STREAM NE INTO THE PACIFIC NW
AND NORTHERN ROCKIES TONIGHT, MAKING ITS WAY OVER THE UPPER RIDGE
AXIS AND ACROSS MT FRIDAY. MODELS CONTINUE TO PRODUCE AN
INCREASING AREA OF LIGHT PRECIPITATION AS THIS MOISTURE PLUME
MOVES EAST ACROSS THE FORECAST AREA, PARTICULARLY OVER EASTERN
PORTIONS OF NORTH-CENTRAL MT AS THE MOISTURE OVERRUNS THE SHALLOW
COOL AIRMASS. HAVE INCREASED POPS CONSIDERABLY FOR FRIDAY AND ALSO
MENTIONED THE POSSIBILITY OF FREEZING PRECIP, WHERE POTENTIAL FOR
WARM ADVECTION OVER COOL SURFACE CONDITIONS IS MOST LIKELY,
BETWEEN GREAT FALLS AND HAVRE. THE RIDGE AXIS SHIFTS EAST ACROSS
THE FORECAST AREA FRIDAY NIGHT FOR DRYING CONDITIONS AHEAD OF THE
NEXT SHORTWAVE FORECAST TO MOVE INTO THE NORTHERN ROCKIES
SATURDAY. BULK OF THE ENERGY WITH THIS SHORTWAVE MOVES ACROSS SW
MT SATURDAY AFTERNOON FOR AN INCREASING CHANCE OF SHOWERS THERE AS
WELL AS AREAS FURTHER NORTH ALONG THE CONTINENTAL DIVIDE. SNOW
LEVELS OVER WESTERN AND SW MT LOWER TO AROUND 5000 FT SATURDAY
UNDER COOLING ALOFT AND SOME MINOR SNOW ACCUMULATION IS POSSIBLE
OVER MTN PASSES SATURDAY AFTERNOON FROM PASSING SNOW SHOWER
ACTIVITY. HOENISCH

SATURDAY NIGHT THROUGH THURSDAY...OVERALL THE WEATHER PATTERN WILL
BE A BIT MORE ACTIVE THAN PREVIOUSLY THOUGHT OVER THE PAST FEW DAYS.
EVEN THOUGH NO MAJOR PRECIPITATION STORMS ARE EXPECTED...SOME
PRECIPITATION SHOULD BE PLANNED FOR...ALONG WITH THE POTENTIAL FOR
STRONG WINDS ON BOTH MONDAY AND TUESDAY. SCATTERED RAIN/SNOW SHOWERS
WILL AFFECT MUCH OF THE REGION THROUGH THE EXTENDED PERIOD...WITH
THE SHOWERS DECREASING IN COVERAGE A BIT ON WEDNESDAY...ONLY TO
BECOME A BIT MORE WIDESPREAD ONCE AGAIN NEXT THURSDAY. LIQUID
PRECIPITATION AMOUNTS CONTINUE TO LOOK LOW...GENERALLY LESS THAN
0.10 INCHES EACH DAY. ADDITIONALLY...THE POTENTIAL EXISTS FOR
POSSIBLE PERIODS OF HIGH WINDS BOTH ON MONDAY AND TUESDAY OVER NORTH
CENTRAL MT. HIGH WIND HIGHLIGHTS MAY BE NEEDED FOR PORTIONS OF THE
REGION DURING THIS PERIOD. OVERALL...TEMPERATURES WILL CONTINUE TO
BE ABOVE NORMAL THROUGH THE EXTENDED...WITH AREAS OVER THE NORTHERN
PLAINS HAVING THE WARMEST TEMPERATURES. BRUSDA

&&

.AVIATION...
UPDATED 1801Z.
VFR CONDITIONS ARE EXPECTED AT ALL TAF SITES THROUGH 00Z/FRI...THEN
FORECAST CONFIDENCE BEGINS TO DROP AFTER THIS POINT. DESPITE THE
UPPER LEVEL RIDGE IN PLACE...MOISTURE/LIGHT PRECIP IS EXPECTED TO
MOVE NE THROUGH THE RIDGE AND ACROSS CENTRAL AND SOUTHWEST MONTANA
TONIGHT THROUGH FRIDAY. TEMPERATURES AT THE SURFACE AND JUST ABOVE
THE SURFACE ARE EXPECTED TO BE NEAR OR JUST ABOVE FREEZING WHICH
LENDS TO A LOWER CONFIDENCE FORECAST REGARDING PRECIPITATION TYPE
AND AVIATION IMPACTS. FOR NOW WENT WITH A RAIN/SNOW MIX FOR
KGTF/KCTB/KHVR/KLWT...BUT THE PRECIP TYPE WILL LIKELY NEED SOME
REFINEMENT IN LATER FORECASTS. A BRIEF PERIOD OF FZRA CANNOT BE
RULED OUT AT THE ABOVE-MENTIONED SITES BUT CONFIDENCE IS TOO LOW TO
INCLUDE IN THE TAFS FOR NOW. ACROSS SW MT...SOME POCKETS OF FZRA
CANNOT BE RULED OUT EITHER...ESPECIALLY VICINITY KHLN...BUT
CONFIDENCE REMAINS LOW IN THIS AREA AS WELL. OF NOTE...CONFIDENCE IS
HIGHER THAT MVFR OR LOWER CIGS WILL OCCUR ACROSS EASTERN SECTIONS OF
CENTRAL...ESPECIALLY IN THE VICINITY OF KHVR/KLWT AS AN EASTERLY
FLOW BRINGS LOW LEVEL CLOUDS INTO THE AREA. MARTIN

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  56  32  50  36 /   0  10  60  10
CTB  51  29  42  32 /   0  10  60  10
HLN  46  31  47  33 /  10  30  30  10
BZN  42  26  43  26 /   0  30  30  10
WEY  35  20  37  20 /   0  20  10  10
DLN  44  31  45  30 /   0  20  10  10
HVR  48  26  37  28 /  10  10  60  20
LWT  47  27  40  32 /   0  10  60  10

&&

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

&&

$$

WEATHER.GOV/GREATFALLS


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