FXUS65 KBYZ 061609
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
909 AM MST SUN DEC 6 2009
.SHORT TERM...VALID FOR TDY AND MON...
MINOR MORNING UPDATE AGAIN THIS TODAY. ADJUSTED DAYTIME HIGHS
SLIGHTLY AROUND THE AREA...DOWN SLIGHTLY EAST WHERE ARE GETTING
SNOW...AND UP SLIGHTLY WEST WHERE IS WARMING UP A LITTLE MORE
QUICKLY THIS MORNING. THE MAJORITY OF TEMPS REMAINED ABOUT THE
SAME. ALSO RAISED POPS ACROSS MUCH OF THE AREA FOR CONTINUING
WIDESPREAD LIGHT SNOW. LITTLE ACCUMULATION IS EXPECTED DUE TO COLD
TEMPS...BUT SNOW LIKELY THROUGH THE DAY. GILSTAD
...PREVIOUS DISCUSSION...
LIGHT SNOW CONTINUES TO FALL ACROSS THE FORECAST AREA...WITH THE
MAIN CONCENTRATION OF STEADY PRECIPITATION OVER CENTRAL AND
WESTERN ZONES. A DEEP UPPER TROUGH WAS POSITIONED OVER THE GREAT
BASIN WITH THE EASTERN PART OF THE LOW OVER IDAHO. THE LOW WAS
SPINNING MOISTURE OVER TOP OF MONTANA WITH A WEAK SPOKE OF ENERGY
SWINGING UP FROM WYOMING. THE LIGHT SNOW WILL GRADUALLY TAPER OFF
THOUGH THE DAY AS THE WAVE MOVES NORTH AND THE ATMOSPHERE COOLS
ENOUGH TO TAKE THE STRONG DENDRITE GROWTH ZONE OUT OF PLAY. LIGHT
SNOW WILL CONTINUE OVER CENTRAL AND WESTERN ZONES TODAY...BUT NOT
MUCH FURTHER ACCUMULATION EXPECTED. WILL THEREFORE CANCEL
REMAINING HIGHLIGHTS...BUT MENTION AN ADDITIONAL INCH OR LESS OF
SNOW LIKELY TODAY. THE COLD AIR WAS GRADUALLY PRESSING SOUTHWARD
INTO THE AREA AS MOST READINGS HAVE FALLEN INTO THE SINGLE
DIGITS. WILL NOT GET MUCH RECOVERY TODAY WITH COLD AIR ADVECTION
AND 850MB TEMPERATURES HOVERING AROUND -18C. THE CHANCE OF LIGHT
SNOW WILL LINGER TONIGHT WITH A MOIST COLD AIRMASS. TEMPERATURES
WILL FALL WELL BELOW ZERO TONIGHT AS THE UPPER TROUGH DEEPENS.
WILL NOT TAKE MUCH WIND TO GET BITTERLY COLD WIND CHILLS TONIGHT.
THE SURFACE HIGH CONTAINING THE ARCTIC AIR WILL BE BUILDING INTO
THE FORECAST AREA AND THIS WILL KEEP GRADIENTS LIGHT. SO...AM NOT
EXPECTING WINDS TO BE GREATER THAN 10MPH...EXCEPT POSSIBLY AT
LIVINGSTON. WILL LET THE DAY SHIFT TAKE A CLOSER LOOK AT THE
POSSIBILITY OF A WIND CHILL ADVISORY FOR TONIGHT. ANOTHER VERY
COLD DAY IS EXPECTED MONDAY WITH A CONTINUED CHANCE OF LIGHT
SNOW. CLOUDS WILL KEEP HIGHS WELL DOWN AS READINGS STRUGGLE TO
GET ABOVE ZERO. THE UPPER LOW STARTS TO KICK OUT AND PULL SOME Q
VECTOR FORCING OVER THE SOUTHERN AND EASTERN ZONES MONDAY
AFTERNOON AND NIGHT. KEPT POPS IN FOR THIS BUT WILL NEED TO BE
MONITORED FOR POSSIBLY LIKELY LIGHT SNOW AGAIN. MONDAY NIGHT WILL
LIKELY BE THE COLDEST NIGHT IN THE BASE OF THE TROUGH. HUMPHREY
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
LARGE TROUGH TO REMAIN OVER THE FORECAST AREA ON TUESDAY WITH THE
BULK OF THE ENERGY OVER THE FOUR CORNERS REGION. WINDS TURN
NORTHERLY ON TUESDAY WITH A WEAK UP SLOPE FLOW DEVELOPING AND
THUS HAVE KEPT SCATTERED POPS GOING. DO NOT THINK WE WILL SEE A LOT
OF ACCUMULATION BUT IS MORE OF A HIGH POP...LOW QPF AND SNOW
AMOUNT TYPE OF DAY. TROUGH SWINGS OUT BY WEDNESDAY LEAVING AN
UNSTABLE NORTHWEST FLOW THROUGH THE END OF THE WEEK. DID ADD SOME
LOW POPS TO THE PLAINS FOR THESE PERIODS GIVEN THERE IS SOME
ENERGY MOVING THROUGH THE FLOW. AGAIN...NOT EXPECTING MUCH
ACCUMULATIONS. SOME DIFFERENCES EMERGE IN THE MODELS BY SATURDAY
WHERE THE ECMWF BRINGS IN A RIDGE WHERE THE GFS HOLDS ON TO THE
NORTHWEST FLOW FOR AN EXTRA DAY. SO DID NOT MAKE ANY CHANGES TO
THESE PERIODS.
TEMPERATURES WILL BE VERY COLD ON TUESDAY MORNING WITH TEMPS WELL
BELOW ZERO AND HIGHS IN THE SINGLE DIGITS FOR HIGHS THAT DAY.
TEMPERATURES WILL SLOWLY WARM UP THROUGH THE END OF THE WEEK AND
COULD REACH THE 20S BY THE END OF THE WEEK IN MOST PLACES. SOLUM
&&
.AVIATION...
LIGHT SNOW AND LOW CLOUDS WILL CONTINUE ACROSS MUCH OF THE AREA
TODAY INTO MONDAY DUE IN PART TO UPSLOPE ENHANCEMENT FROM KSHR AND
KBIL WESTWARD AND OVERRUNNING ACROSS SOUTHEASTERN MT...INCLUDING
KMLS. EXPECT MVFR...IFR AND LIFR CONDITIONS ALONG WITH MOUNTAIN
OBSCURATIONS THROUGH THE PERIOD. CAMPBELL/FRIEDERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 005 909/901 912/001 908/012 005/019 010/020 016/028
9/S 63/S 34/S 02/S 22/S 22/S 20/B
LVM 009 915/901 918/003 910/016 006/022 011/026 017/031
9/S 64/S 23/S 22/S 22/S 22/S 22/S
HDN 007 908/004 907/006 908/018 003/023 005/024 008/029
7/S 52/S 34/S 02/S 22/S 22/S 20/B
MLS 006 909/005 912/005 907/013 000/016 002/016 001/023
6/S 22/S 24/S 02/S 22/S 22/S 20/B
4BQ 006 906/008 906/008 907/014 002/022 004/022 008/030
5/S 42/S 34/S 02/S 22/S 22/S 20/B
BHK 006 908/005 907/005 908/011 000/019 001/015 006/022
6/S 21/E 24/S 02/S 22/S 22/S 20/B
SHR 008 910/005 908/009 911/015 901/024 004/027 009/033
7/S 63/S 34/S 02/S 22/S 22/S 20/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
