Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 161217
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
617 AM MDT THU APR 16 2015

.UPDATE...
QUICK UPDATE TO EXPIRE WINTER WEATHER ADVISORY OVER THE NORTHERN
BIG HORNS. BT

&&

.SHORT TERM...VALID FOR TDY AND FRI...

STRONG DEFORMATION ZONE CONTINUED FROM NORTHERN ROSEBUD COUNTY
INTO THE BIG HORNS OVERNIGHT RESULTING IN A PERSISTENT AREA OF
SNOW AND MODERATE RAIN. WE EXTENDED THE WINTER WEATHER ADVISORY
FOR THE NORTHERN BIG HORNS EARLIER IN THE NIGHT TO 6 AM THIS
MORNING. PROGGS DO FINALLY WEAKEN THE DYNAMICS GOING ON HERE BY
12Z AND I BELIEVE THINGS WILL BREAK UP INTO STRAY POCKETS OF
LINGERING PRECIPITATION BY THEN. SO INHERITED TREND OF DECREASING
POPS FOR THIS MORNING LOOKS GOOD. SOME JET AND VORTICITY DYNAMICS
ALSO PRODUCING SOME SHOWER ACTIVITY MOVING INTO THE SE CORNER OF
CARTER COUNTY. THIS MAY PERSIST INTO THE MID MORNING HOURS SO WILL
KEEP SCATTERED POPS IN THIS LOCATION.

WILL BANK ON TEMPS BEING AFFECTED BY WET SNOW AND MOISTURE IN
BOUNDARY LAYER FROM THE LAST DAY OR SO OF PRECIPITATION...MAINLY
ALONG THE NORTH FACING SLOPES AND NEARBY PLAINS. THUS LOWERED
INHERITED AFTERNOON HIGHS A BIT FOR TODAY. DAY SHIFT WILL NEED TO
MONITOR FOR DEVELOPMENT OF ANY LOW CLOUDS/FOG THIS MORNING THAT
COULD FURTHER LIMIT HEATING TODAY.

DRIER AIR MOVES ACROSS THE FORECAST AREA TONIGHT...AND WITH
RELATIVELY WEAK WINDS AND A CLEAR SKY WE MAY SEE DEVELOPMENT OF
FOG IN AREAS WHERE PRECIPITATION FOCUSED...SUCH AS THE FOOTHILLS
AND CENTRAL ZONES.

FRIDAY LOOKS RELATIVELY UNEVENTFUL...BUT WE MAY SEE A SURGE OF
CLOUD COVER IN THE SOUTHEAST FROM THE UPPER LOW MAKING ITS WAY OUT
OF THE CENTRAL ROCKIES. THIS MAY EVENTUALLY BRING IN SOME SHOWERS
AS WELL FRIDAY NIGHT. BT

.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...

NOT MANY CHANGES NEEDED TO THE EXTENDED. MODELS CONTINUED TO
ADVERTISE A SHORTWAVE AND COLD FRONT PUSHING SE INTO THE AREA ON
SAT...THEN THE SHORTWAVE EXITING THE AREA SAT NIGHT. THE FRONT
WILL MEET UP WITH MOISTURE ROTATING AROUND AN UPPER LOW MOVING OUT
OF CO TO BRING SCATTERED SHOWERS TO AREAS FROM KBIL W AND S...AS
WELL AS TO SE MT. THE AREA WILL DRY OUT LATE SAT NIGHT. CLOUD
COVER OVER THE AREA ON SAT WILL PREVENT TEMPERATURES FROM GETTING
QUITE AS WARM AS PREVIOUSLY ADVERTISED...SO HAVE GONE WITH HIGHS
IN THE 60S. NORTHERLY CYCLONIC FLOW WILL OVERTAKE THE REGION ON
SUN WITH SOME ENERGY IN THE FLOW BRINGING A SLIGHT CHANCE OF
PRECIPITATION TO THE WESTERN AND SOUTHERN ZONES. THE AREA WILL
THEN DRY OUT AGAIN SUN NIGHT THROUGH TUE NIGHT DUE TO LACK OF
ENERGY AND MOISTURE IN THE FLOW. TEMPERATURES WILL BE NEAR
SEASONAL VALUES THROUGH TUE. GFS SHOWED A POSSIBLE BACKDOOR FRONT
MOVING INTO THE AREA ON WED...SO CONTINUED THE POPS OVER AND NEAR
THE MOUNTAINS. ECMWF TRIED TO PUSH A BACKDOOR FRONT INTO THE
REGION WED NIGHT AND THU..WHILE BOTH MODELS INCREASED MOISTURE
FROM THE SW AHEAD OF AN UPPER LEVEL LOW ALONG THE CA COAST. HAD
POPS ACROSS THE ENTIRE AREA DURING THIS TIME FRAME. KEPT
TEMPERATURES JUST ABOVE SEASONAL VALUES WED AND THU...ALTHOUGH THE
ECMWF WAS RUNNING COLDER THAN THE GFS DUE TO THE FRONT ON THU.
ARTHUR
&&

.AVIATION...

ISOLATED TO SCATTERED SHOWERS WILL OCCUR E AND S OF KBIL THROUGH
18Z. MVFR CONDITIONS WILL OCCUR WITH THE SHOWERS WHICH WILL AFFECT
KSHR. EXPECT AREAS OF MOUNTAIN OBSCURATION OVER THE
BEARTOOTHS...ABSAROKAS AND NE BIGHORNS. IN ADDITION...PATCHY FOG
IS POSSIBLE THIS MORNING W AND S OF KBIL. VFR WILL PREVAIL THIS
AFTERNOON AND TONIGHT. PATCHY FOG IS POSSIBLE LATE TONIGHT FROM
KBIL W AND S. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY FRI     SAT     SUN     MON     TUE     WED
-------------------------------------------------------
BIL 054 033/063 040/063 036/058 035/061 038/063 039/061
    1/B 00/U    02/W    31/N    11/U    11/B    11/B
LVM 053 030/065 035/063 033/057 032/061 036/063 036/062
    0/B 00/U    02/W    32/W    11/B    11/B    12/W
HDN 057 032/067 037/066 035/060 034/061 035/064 035/063
    4/W 00/U    02/W    12/W    11/U    11/B    11/B
MLS 058 035/067 039/069 035/058 033/058 034/061 035/058
    1/B 00/U    02/W    21/N    11/N    11/B    11/B
4BQ 057 032/066 038/064 033/057 032/057 032/060 033/058
    2/W 00/U    14/W    31/N    11/B    11/B    11/B
BHK 060 032/068 037/065 033/055 030/055 030/056 031/053
    2/W 00/U    03/W    31/N    11/N    11/B    11/B
SHR 050 030/061 035/061 033/055 032/057 033/060 034/060
    2/W 00/B    13/W    32/W    11/B    11/B    22/W

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS


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