Weather Service Report


137 
FXUS65 KBYZ 280248
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT 
848 PM MDT THU AUG 27 2015

.UPDATE...
ONLY SUBTLE FORCING ACROSS THE FORECAST AREA THIS EVENING...AND
WITH THE CLOUD COVER AND SMOKE...THE INSTABILITY NEVER PEAKED
TODAY. SO MOST OF THE CONVECTION THIS EVENING OVER OUR AREA IS
DYING OFF...THOUGH A FEW SHOWERS AND STRAY LIGHTNING STRIKE MAY
STILL OCCUR IN THE WESTERN FOOTHILLS AND MOUNTAINS. REDUCED POPS
FOR REST OF NIGHT. BT

&&

.SHORT TERM...VALID FOR FRI AND SAT...

LAST PIECE OF UPPER LEVEL ENERGY IS APPROACHING WESTERN MONTANA
AS OF 20Z THIS AFTERNOON. ASSOCIATED WITH THIS FEATURE IS AN AN
AREA OF MONSOONAL MOISTURE ROTATING AROUND THE RIDGE AXIS. THIS
MONSOONAL MOISTURE...COMBINED WITH MEAGER INSTABILITY AND GOOD
LAPSE RATES ALOFT...HAS AIDED IN THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS TO OUR WEST THIS AFTERNOON. THROUGHOUT THE REMAINDER
OF THE AFTERNOON/EVENING ADDITIONAL SHOWERS AND STORMS COULD
FORM....MOSTLY OVER LOCATIONS JUST SOUTH OF BILLINGS. AN ISOLATED
STORM OR TWO MAY BECOME STRONG WITH 40-50MPH WIND GUSTS AND VERY
SMALL HAIL BUT NOTHING SEVERE IS EXPECTED.

RESIDUAL UPPER LEVEL ENERGY MOVES OUT OF THE REGION TONIGHT AND IN ITS
WAKE SHORTWAVE RIDGING...WARMER TEMPERATURES...AND AN ABSENCE OF
RAIN CHANCES TAKES HOLD UNTIL LATE SATURDAY EVENING. THE BIGGEST
IMPACTS IN THE SHORT TERM REVOLVE AROUND A WEAK AND DYING COLD
FRONT THAT LIMPS INTO OUR AREA SATURDAY NIGHT. AHEAD OF THE FRONT
MAX TEMPERATURES WILL BE VERY WARM SATURDAY AFTERNOON AND LOW
RELATIVE IN THE LOW TEENS WILL BE COMMON OUT EAST. FURTHER WEST
RELATIVE HUMIDITIES WILL REMAIN HIGHER...IN THE LOW 20S...BUT
WINDS WILL BE ELEVATED IN THE 15-25MPH RANGE WITH 30-35MPH GUSTS.
WHILE FIRE CONCERNS WILL BE ELEVATED...WILL HOLD OFF ISSUING A
WATCH AS EASTERN LOCATIONS WILL HAVE MINIMAL WINDS AND RECENT
RAINS LENDS BELIEF THAT FUELS ARE NOT VERY STRESSED. FURTHER WEST
DO NOT BELIEVE RELATIVE HUMIDITIES WILL BE LOW ENOUGH FOR FIRE
CRITERIA. WHILE DO NOT BELIEVE WATCH CRITERIA WILL BE MET...FIRE
CONCERNS WILL CERTAINLY BE ELEVATED AND THOSE OUTDOORS THIS
WEEKEND NEED TO TAKE FIRE PRECAUTIONS SERIOUSLY.

AS THE FRONT MOVES IN LATE SATURDAY NIGHT WE SHOULD BE ABLE TO
SQUEEZE OUT A FEW SHOWERS AND ISOLATED THUNDERSTORMS OVERNIGHT.
HOWEVER...WE ARE NOT EXPECTING MUCH RAIN AS COVERAGE WILL BE
SMALL. APPEARS THE COOLEST TEMPERATURES WILL HOLD OFF UNTIL THE
EXTENDED PERIOD FOR NOW. DOBBS/SCHULTZ

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


AT THIS TIME...DETERMINISTIC EURO AND GFS MODELS ARE IN GOOD
AGREEMENT THROUGH TUES IN THE EXTENDED PERIOD...AS SUPPORTED BY
MODEL SPREAD IN GEFS UP TO THIS TIME. MODELS THEN HAVE DIFFERENCES IN
BEHAVIOR OF LARGER SCALE EMBEDDED SHORTWAVES WITHIN THE
APPROACHING PACIFIC TROUGH BY THE END OF THE PERIOD BUT GENERALLY
MAINTAIN SW FLOW.

A FEW WEAK IMPULSES WITHIN THE SW FLOW SHOULD MOVE ACROSS THE
FORECAST AREA BRINGING SLIGHT SHOWER/THUNDERSTORM CHANCES...MAINLY
SUNDAY MORNING AND INTO THE AFTERNOON WITH SOME MOUNTAIN POPS
TUESDAY ASSOCIATED WITH MODERATE TO LOW INSTABILITY. THERE IS A
MARGINAL CHANCE OF STORMS OUT IN THE FAR EAST LATE IN THE
AFTERNOON TUES AS WELL NEAR A SECONDARY INSTABILITY SOURCE.
ANOTHER COLD FRONT APPEARS POSSIBLE AS LATE AS THU MORNING OR AS
EARLY AS WED AFTERNOON IN THE GFS AND EURO...RESPECTIVELY.

TEMPERATURES WILL BE AROUND NORMAL SUNDAY FOLLOWING THE FRONTAL
PASSAGE THAT MORNING AND INTO NEXT WEEK WITH READINGS MAINLY IN
THE LOWER TO MIDDLE 80S. TEMPERATURES MAY BE LOWER ON THURSDAY
DEPENDING ON STRENGTH AND TIMING OF NEXT FRONT. MROWELL

&&

.AVIATION...

SHOWER CHANCES WILL BE DIMINISHING THROUGH THE EVENING. SOME
TERMINALS COULD RECEIVE GUSTY AND ERRATIC WINDS NEARING 25 KNOTS
ASSOCIATED WITH GUST FRONTS FROM DECAYING STORMS. ANY STRONG WINDS
WILL REDUCE TO BELOW 10 KNOTS AFTER 04-05Z TONIGHT. AREAS OF
SMOKE WILL COULD REDUCE VISIBILITIES NEAR 6 MILES THROUGH THE
NIGHT. FOR THE REMAINDER OF THE PERIOD LIGHT WINDS AND VFR
CONDITIONS SHOULD PREVAIL. DOBBS
&&

.PRELIMINARY POINT TEMP/POPS...

    FRI     SAT     SUN     MON     TUE     WED     THU     
-----------------------------------------------------------
BIL 063/090 062/097 063/082 054/083 055/086 059/085 054/080
    10/K    01/B    22/T    21/U    11/U    11/B    11/B
LVM 057/086 057/090 056/079 046/080 047/082 050/082 046/078
    20/K    02/T    22/T    21/B    11/B    11/B    11/B
HDN 059/091 058/099 062/085 054/086 055/089 057/088 053/083
    10/K    01/B    12/T    21/U    11/U    11/B    11/B
MLS 063/093 063/101 065/086 057/086 057/090 060/090 057/085
    10/K    00/G    12/T    21/B    11/U    11/U    11/B
4BQ 062/091 060/099 061/087 057/086 057/089 060/091 056/086
    10/K    00/U    12/T    22/T    11/U    11/B    11/U
BHK 058/090 058/097 061/087 056/086 056/088 058/091 056/086
    10/K    00/U    12/T    22/T    12/T    22/T    11/U
SHR 059/088 054/095 058/085 051/085 050/087 052/088 051/084
    11/K    00/U    12/T    21/B    11/U    11/B    11/U

&&

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

&&

$$
WEATHER.GOV/BILLINGS

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