331
FXUS65 KBYZ 161821
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1221 PM MDT WED OCT 16 2013
.UPDATE...
HAVE UPDATED AGAIN TO RAISE POPS THIS AFTN ESPECIALLY IN NW PARTS
AS FRONT AND SHOWER ACTIVITY IS NEARING JUDITH GAP. SHOWER CHANCES
WILL BEGIN AT BILLINGS AROUND 21Z. HAVE ALSO RAISED TEMPS A FEW
MORE DEGREES IN OUR S/SE...AS SHERIDAN IS ALREADY 54 DEGREES AT
NOON. JKL
SHORTWAVE APPROACHING FROM THE NORTH...AND INCREASING CLOUDS IN
PARK TO WHEATLAND COUNTIES ARE INDICATIVE OF THE UPPER LEVEL
ASCENT ON THE WAY. SFC COLD FRONT IS CURRENTLY IN NORTH CENTRAL
MT NEAR CUT BANK AND POST FRONTAL OBS SHOW SOME PCPN IN SOUTHERN
ALBERTA...INCLUDING A MIX WITH SNOW ALONG THE CANADIAN FRONT
RANGE. EXPECT THIS FRONT TO REACH JUDITH GAP EARLY THIS AFTERNOON
AND BILLINGS BY 22-23Z. WE SHOULD MIX SOME NW MID LEVEL WINDS
PRIOR TO THE FROPA...SO EXPECT TEMPS WITH ENHANCED PREFRONTAL
MIXING TO CLIMB INTO THE 50S AND MIGHT EVEN SEE 60F IN SPOTS. PCPN
CHANCES WILL INCREASE BEHIND THE FRONT AND WILL KEEP SLIGHT POPS
IN BILLINGS BEFORE 00Z...THOUGH MUCH BETTER CHANCES WILL BE
BEGINNING AROUND SUNSET PER LATEST RAP/NAM. NORTHERN ASPECTS OF
OUR SOUTHERN FOOTHILLS WILL BE MOST FAVORED FOR RAIN TO SNOW
SHOWERS TONIGHT AND CURRENT FORECAST HAS THIS COVERED WELL.
WINDS AT LIVINGSTON ARE GUSTING TO 40 MPH SO HAVE RAISED SPEEDS
IN OUR WEST THIS MORNING. HAVE ALSO ADJUSTED SKY COVER
SLIGHTLY...AND RAISED TEMPS A BIT ESPECIALLY IN OUR SOUTH AS
FRONT WILL NOT ARRIVE THERE UNTIL CLOSE TO 00Z. THERMAL GRADIENT
WILL INTENSIFY THROUGH THE DAY AND WE SHOULD SEE A SHARP
TEMPERATURE DROP ONCE THE FRONT PASSES THIS AFTERNOON.
JKL
&&
.SHORT TERM...VALID FOR TDY AND THU...
STRONG SHORT WAVE PUSHING SOUTHWARD OUT OF BRITISH COLUMBIA AND
ALBERTA TODAY. FORECAST MODELS ALL IN GOOD AGREEMENT WITH ONLY
SOME MINOR TIMING ISSUES WITH THE WAVE. COLD FRONT ASSOCIATED WITH
THE UPPER TROUGH IS EXPECTED TO MOVE THROUGH A
LIVINGSTON...BILLINGS TO BAKER LINE AROUND 21Z TODAY. PREFRONTAL
MIXING WILL ALLOW TEMPERATURES TO RISE INTO THE MID TO UPPER 50S
THIS AFTERNOON AND HIGHS TODAY WILL BE NEAR SEASONAL. STRONG
FORCING ALOFT WILL MOVE IN BEHIND THE FRONT WITH RAIN SHOWERS
DEVELOPING OVER OUR NORTHERN ZONES THIS AFTERNOON...SPREADING
SOUTH THROUGH THE EVENING. STRONG UPPER LEVEL FORCING WILL BE THE
RESULT OF LEFT EXIT REGION OF THE JET MOVING OVER THE AREA ALONG
WITH MODERATE QG FORCING. HAVE CONTINUED LIKELY POPS ALONG THE
FOOTHILLS TONIGHT AS 850 MB WINDS WILL BE OUT OF THE NORTH
BRINGING UPSLOPE FLOW TO FOOTHILLS. RAIN WILL CHANCE OVER TO ALL
SNOW BY MIDNIGHT IN THE FOOTHILLS BUT BY THEN...THE MAIN FORCING
WILL BE MOVING OUT OF THE AREA. HAVE IN AROUND 2 INCHES FOR RED
LODGE THROUGH NYE AREA OVERNIGHT. THE HIGHER TERRAIN FROM COLE
CREEK THROUGH PLACER BASIN WILL NOT SEE MUCH PRECIPITATION TONIGHT
AS 700 MB WINDS WILL BE NORTHWEST. THESE NORTHWEST WINDS WILL
HOWEVER BRING GOOD UPSLOPE FLOW INTO THE NORTHEAST BIG HORN
MOUNTAINS. LATEST MODEL RUNS INDICATING DENDRITIC LAYER AROUND 500
MB WITH MAIN FORCING BELOW THIS LEVEL. THUS EXPECT SNOWFALL TO BE
IN THE 2 TO 4 INCH RANGE TONIGHT. FROM BILLINGS EAST
TONIGHT...PRECIPITATION WILL BE LIMITED WITH DOWN SLOPE WINDS OVER
THE AREA AND HAVE KEPT JUST SCATTERED POPS GOING OVERNIGHT.
PRECIPITATION WILL BE EXITING THE SOUTHERN AREAS BY MID MORNING
AND CLOUDS WILL BRIEFLY BE ON THE DECREASE. AN UNSTABLE NORTHWEST
FLOW WILL BE OVER THE AREA WITH STEEP MID LEVEL LAPSE RATES.
SEVERAL SHORT WAVES WILL BE DROPPING SOUTH OUT OF CANADA DURING
THE AFTERNOON AND EVENING HOURS AND WILL BRING SCATTERED RAIN
SHOWERS TO THE AREA. RAIN SHOWERS WILL CHANGE OVER TO SNOW SHOWERS
THURSDAY NIGHT. THESE WAVES WILL BE QUICK HITTERS AND DO NOT SEE
ANY ACCUMULATIONS WITH SNOWFALL. NORTH FLOW ACROSS THE AREA
THURSDAY ALONG WITH LOWERING HEIGHTS WILL KEEP AFTERNOON HIGH
TEMPERATURES IN THE MID TO UPPER 40S WHICH IS ABOUT 10 TO 15
DEGREES BELOW NORMAL FOR THIS TIME OF THE YEAR. RICHMOND
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
UNSETTLED NORTHWEST FLOW WILL PERSISTE OVER THE CWA THROUGHOUT
THE EXTENDED PERIOD...AS AN UPPER RIDGE ALONG THE WEST COAST AND
GENERAL TROUGH OVER THE GREAT LAKES REMAIN STALLED. MODELS
AGREEMENT ON THE OVERALL PATTERN IS GOOD THROUGH THE PERIOD...BUT
DIFFER ON THE TIMING AND AMPLIFICATION OF THE WESTERN RIDGE INTO
THE NORTHERN ROCKIES. GFS IS TAKING THE SLOWER TACK...FAVORING
MINIMAL WARMUP FOR EARLY NEXT WEEK. ALTHOUGH PREVIOUS MODELS RUNS
HAVE TRENDED TOWARD WARMUP...MULTIPLE SHORTWAVES THROUGH THE
NORTHWEST FLOW ARE BECOMING MORE AND MORE EVIDENT THROUGHOUT THE
PERIOD. ALTHOUGH NONE OF THE WAVES APPEAR SIGNIFICANTLY STRONG AT
THIS TIME THEY HAVE PROMPTED INCLUSION OF AT LEAST SLIGHT POPS
THROUGH THE BULK OF THE EXTENDED PERIOD...AS WELL AS INCREASED
CLOUD COVER. IF ANY OF THESE WAVES ENDS UP BEING STRONGER THAN
CURRENTLY ADVERTISED...IT COULD EASILY CURTAIL ANY WARMUP. HAVE
BACKED OFF SIGNIFICANTLY ON TEMPS FOR EARLY WEEK...FAVORING MIDDLE
OF THE ROAD NUMBERS AT THIS TIME...IN PART BASED ON PERSISTENCE.
THEREFORE...SEASONAL TEMPS WITH UNSETTLED WEATHER CAN BE
EXPECTED...ALTHOUGH WITH LITTLE SIGNIFICANT PRECIP INDICATED AT
THIS TIME. AAG
&&
.AVIATION...
EXPECT INCREASING MID AND HIGH CLOUD FROM THE NW TODAY...WITH
AREAS OF SHOWERS AND LOCAL MVFR DEVELOPING NW OF KBIL THIS
AFTERNOON. A COLD FRONT WILL CROSS THE REGION THIS AFTERNOON AND
EARLY EVENING. THIS FRONTAL PASSAGE WILL BE FOLLOWED BY RAIN AND
SNOW SHOWERS ALONG WITH GUSTY NORTH WINDS. LOCALIZED MVFR TO IFR
FLIGHT CONDITIONS CAN BE EXPECTED WITH THE PCPN TONIGHT. JKL
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 057 032/047 034/056 033/058 033/058 036/059 035/055
2/W 62/W 21/B 00/B 02/W 22/W 22/W
LVM 052 026/046 029/055 028/059 030/058 033/059 032/052
2/W 42/W 21/B 00/B 03/W 22/W 32/W
HDN 058 031/048 033/055 032/057 031/059 034/059 033/057
2/W 62/W 22/W 00/B 02/W 22/W 22/W
MLS 058 033/048 034/054 030/058 029/057 032/059 031/057
1/B 62/W 22/W 11/B 12/W 22/W 22/W
4BQ 057 032/045 033/051 031/056 029/057 032/057 031/056
0/B 52/W 22/W 00/B 02/W 22/W 22/W
BHK 057 031/046 032/049 028/055 028/053 031/054 030/053
1/B 52/W 22/W 11/B 12/W 22/W 22/W
SHR 057 031/043 031/051 029/055 029/058 032/057 031/055
0/B 53/W 32/W 00/U 03/W 32/W 33/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS