Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 270254
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
854 PM MDT THU MAR 26 2015

.UPDATE...
SHOWER ACTIVITY REMAINING FAIRLY LIGHT AND FAST MOVING OVER
SOUTHEAST MONTANA THIS EVENING. MOIST NORTHWEST FLOW ALOFT WILL
CONTINUE THROUGH THE NIGHT WITH WESTERN AREAS STAYING DRY.
UPDATED FORECAST TO CHANGE WORDING TO SPRINKLES AS OPPOSED TO
SHOWERS BECAUSE DO NOT EXPECT TO MANY PLACES TO GET MEASURABLE
PRECIP. BORSUM

&&

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

SOMEWHAT BENIGN PATTERN EXPECTED THIS EVENING WITH BUILDING 500MB
HEIGHTS IN THE WEST AND SOME LINGERING INSTABILITY/BAROCLINICITY
OVER OUR FAR EASTERN SECTIONS. WILL CONTINUE TO CARRY SOME LOW
POPS IN THE EAST AND DOWN TOWARD THE BIG HORNS. ANY DYNAMIC
FORCING SHOULD SLIDE EAST BY FRIDAY MORNING. RIDGING WILL KICK IN
FULL FORCE FRIDAY WITH A GOOD SHOT OF RECORD TEMPERATURES AT
LIVINGSTON AND BILLINGS. BREEZY CONDITIONS WILL DEVELOP IN THE
WEST AS WE WARM UP AND MIX DOWN. FRIDAY NIGHT LOOKS QUITE MILD FOR
THIS TIME OF YEAR.

SATURDAY STILL LOOKS LIKE AN ACTIVE DAY. TEMPS AT 850MB SUGGEST
ANOTHER WARM START TO THE DAY AIDED BY DOWNSLOPE FLOW AHEAD OF AN
APPROACHING TROUGH FROM THE WEST. THE GFS AND ECMWF HAVE YET TO
RESOLVE THEIR DIFFERENCES WITH THE 12Z CYCLE...AS THE GFS REMAINS
FASTER WITH FRONT AND ASSOCIATED UPPER DYNAMICS WHILE THE ECMWF IS
THE SLOWEST OF ANY PROGGS. THE NAM SUPPORTS THE FASTER GFS. I HAVE
BASICALLY STUCK WITH A COMPROMISE AT THIS TIME AS WE ARE STILL TWO
DAYS OUT AND NO INDICATIONS WHICH WAY TO LEAN. THIS MEANS A
FRONTAL PASSAGE AROUND MID AFTERNOON AT BILLINGS /3-4 PM/. THE
GFS IS ALSO INDICATING STRONGER WINDS THAN THE OTHER MODELS WITH
POTENTIAL FOR SOME REALLY STRONG POST FRONTAL GUSTS IN THE
BILLINGS AREA /60 MPH/. I AM NOT TOO IMPRESSED WITH THE JET WINDS
ALOFT /LIMITING DOWNWARD MOTION/ THOUGH SO WILL NOT ISSUE ANY
WIND HIGHLIGHTS AT THIS TIME. WINDS IN THE WEST MAY BE STRONGEST
AT BIG TIMBER AND HARLOWTON RATHER THAN LIVINGSTON WHERE THE
DIRECTION IS TOO WESTERLY TO HIT PROLONGED HIGHLIGHT CRITERIA. I
WOULD NOT BE SURPRISED TO SEE HARLOWTON HIT HIGH WIND CRITERIA
BASED ON LOCAL RESEARCH MODELS...SO WE WILL KEEP A CLOSE EYE ON
THIS.

QPF PROGGS ALL SHOW DECENT PRECIPITATION WITH THE TROUGH
PASSAGE...WHICH LOOKS GOOD TO ME AS Q-VECTOR FORCING IS PRETTY
STRONG AND EVEN QUITE SHARP ON THE ECMWF. I DECIDED NOT TO ADD
THUNDER TO ANY ZONES YET DUE TO THE SHORT WINDOW FOR BEST MOISTURE
AND INSTABILITY ALONG WITH FRONTAL TIMING UNCERTAINTY. BUT WE WILL
EVALUATE AGAIN TOMORROW FOR THE POSSIBILITY OF THUNDER IN OUR
EASTERN SECTIONS.

TO SUMMARIZE...SATURDAY WILL BE A WINDY DAY IN THE WEST...TURNING
VERY WINDY IN THE EAST BY EVENING. A GOOD CHANCE OF SHOWERS WITH
THE TROUGH PASSAGE. THE DYNAMICS SHIFT EAST QUICKLY SATURDAY NIGHT
SO WINDS/PRECIPITATION SHOULD DECREASE RAPIDLY FOR MOST AREAS. BT


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

DECENT AGREEMENT ON THE MEDIUM RANGE MODELS. FORECAST LOOKS DRY
WITH WARMING TEMPERATURES SUNDAY THROUGH TUESDAY. THIS DUE TO A
BUILDING UPPER RIDGE AHEAD OF THE NEXT ADVANCING UPSTREAM TROUGH.
THIS TROUGH PUSHES THROUGH THE REGION TUESDAY AND TUESDAY NIGHT.
TIMING WILL BE VERY CRUCIAL FOR HIGH TEMPERATURES ON TUESDAY AS AN
EARLIER PASSAGE WOULD CAUSE COOLER THAN FORECAST HIGHS. THE GFS
WAS SLOWER WITH THE FRONTAL PASSAGE AND THEREFORE WARMER. DID
RAISE TEMPERATURES OVER THE SOUTHEAST TUESDAY AS EVEN THE ECMWF
WAS SLOW TO GET THE FRONT INTO SOUTHEAST MONTANA.

LOOKS MORE LIKE A WIND PRODUCING SYSTEM WITH THE MAIN ENERGY
SLIDING OVER NORTHERN MONTANA. DID RAISE POPS SOME FOR TUESDAY
AFTERNOON AND NIGHT HOWEVER AS THE LAST COUPLE OF MODEL RUNS WERE
TRENDING FARTHER SOUTH WITH THE MAIN ENERGY. SYSTEM MAY TURN OUT
TO BE VERY SIMILAR TO ONE ON SUNDAY...EXCEPT POSSIBLY SLIGHTLY
DRIER. WEDNESDAY LOOKS DRY AND COOLER BEHIND THE TROUGH. THURSDAY
COULD BE INTERESTING AS THE NEXT UPSTREAM TROUGH DIGS TOWARD THE
GREAT BASIN. MODEL DIFFERENCE EXIST WITH THIS SYSTEM THOUGH WITH
THE ECMWF DIGGING ENERGY FARTHER SOUTH AND THUS PROVIDING A BETTER
CHANCE OF TURNING WET. WILL HAVE TO WAIT THIS OUT AND SEE HOW THE
MODELS RESOLVE THEIR DIFFERENCES. FOR NOW WILL GET SOME POPS IN
THERE AS THE PATTERN DOES LOOK UNSETTLED. TWH
&&

.AVIATION...

VFR WILL PREVAIL TONIGHT AND FRI...ALTHOUGH THERE MAY BE SOME
SPRINKLES OVER AREAS E AND S OF KBIL TONIGHT. THE
BEARTOOTHS...ABSAROKAS AND NE BIGHORNS WILL HAVE AREAS OF MOUNTAIN
OBSCURATION TONIGHT. OTHERWISE...GUSTY W SURFACE WINDS WILL
PERSIST W OF KBIL TONIGHT. EXPECT GUSTY W TO NW WINDS ACROSS THE
REGION ON FRI. LOW-LEVEL WIND SHEAR WILL BE PRESENT AT ALL SITES
EXCEPT KLVM TONIGHT. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    FRI     SAT     SUN     MON     TUE     WED     THU
-----------------------------------------------------------
BIL 044/073 047/072 040/065 041/070 045/068 038/058 036/054
    10/B    05/W    20/B    00/U    03/W    32/W    23/W
LVM 042/072 045/065 035/065 040/068 042/063 031/055 029/050
    00/N    04/W    11/B    00/U    04/W    22/W    23/W
HDN 039/075 040/075 037/066 035/072 039/072 036/059 033/056
    10/B    05/W    20/B    00/U    03/W    32/W    22/W
MLS 041/070 042/075 037/063 037/069 038/072 037/057 032/054
    10/E    04/W    20/B    00/U    02/W    32/W    22/W
4BQ 039/070 039/078 036/064 036/070 039/075 035/058 032/054
    10/B    02/W    30/B    00/U    01/N    31/N    12/W
BHK 034/064 037/072 035/061 033/066 037/071 035/054 030/052
    20/E    03/W    30/B    00/B    02/W    31/N    12/W
SHR 039/070 040/075 036/065 035/070 038/073 034/055 032/051
    10/B    02/W    30/B    00/B    02/W    32/W    23/W

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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