Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 110212
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
812 PM MDT THU APR 10 2014

.UPDATE...

MINOR UPDATE TONIGHT...TO LOWER OVERNIGHT LOWS...MOST
SIGNIFICANTLY AROUND BILLINGS AND SOUTHWEST PORTIONS OF THE CWA.
ALSO LOWERED WINDS AROUND LIVINGSTON FOR THE OVERNIGHT
PERIOD...AS HAVE CURRENT REPORTS HAVE DROPPED WELL BELOW FORECAST
NUMBERS.

WINDS HAVE DECREASED ACROSS THE REGION...AND ARE EXPECTED TO
REMAIN GENERALLY LIGHT OVERNIGHT. SKIES CONTINUE TO CLEAR...AND
ARE EXPECTED TO REMAIN CLEAR TO PARTLY CLOUDY OVERNIGHT. THIS
SHOULD ALLOW FOR GOOD POTENTIAL FOR COOLING OVERNIGHT. ALTHOUGH
INHERITED FORECAST WAS IN LINE WITH MUCH OF GUIDANCE...OPTED TO
LOWER OVERNIGHT LOWS SLIGHTLY WITH A NOD TOWARD NAM GUIDANCE. THIS
BRINGS TEMPS IN BILLINGS AREA TO MID 30S AS OPPOSED TO HIGH 30S.
OTHERWISE...INHERITED FORECAST APPEARS IN GOOD SHAPE OVERALL. AAG

&&

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

SUBSIDENCE AND DEEP MIXING BEHIND A WEAK SHORTWAVE HAS LEFT THE
AREA UNDER CLEAR SKIES AND MILD TEMPERATURES...BUT WITH GUSTY
WINDS. THE WINDS WILL DECREASE AFTER SUNSET THIS EVENING...AS THE
ATMOSPHERE DECOUPLES. RELATIVELY CLEAR SKIES OVERNIGHT...AND WITH
A MILD AIRMASS REMAINING IN PLACE WILL ALLOW TEMPERATURES TO FALL
INTO THE 30S FOR MOST LOCATIONS.

FRIDAY WILL BE A FANTASTIC DAY ACROSS THE FORECAST AREA...WITH THE
MILD AIRMASS REMAINING IN PLACE AHEAD OF THE APPROACHING WEATHER
SYSTEM. DEEP MIXING AND DOWNSLOPE FLOW WILL ALLOW MUCH OF THE
FORECAST AREA TO SEE HIGH TEMPERATURES IN THE UPPER 60S TO LOW
70S. IN FACT...INCREASED TEMPERATURES SLIGHTLY WITH THIS FORECAST
PACKAGE. WINDS WILL PICK UP AGAIN TOMORROW AFTERNOON ACROSS THE
AREA.

WHILE WE ENJOY THE PLEASANT DAY ON FRIDAY...THE STAGE WILL BECOME
SET FOR OUR NEXT WEATHER SYSTEM TO IMPACT THE AREA FOR SATURDAY
INTO SUNDAY. AS RIDGING DEVELOPS INTO THE GULF OF
ALASKA...TROUGHING WILL PUSH SOUTH INTO THE FORECAST AREA DURING
THE DAY SATURDAY. AS THE NORTHERLY FLOW BECOMES ESTABLISHED ON THE
EAST SIDE OF THE RIDGE...THIS WILL ALLOW THE TROUGH TO DIG INTO
THE CONUS DURING THE DAY SATURDAY...AND PLACE THE WAVE JUST WEST
OF THE FORECAST AREA BY LATE SATURDAY. THIS WILL ALLOW A COLD
FRONT TO SURGE ACROSS THE FORECAST AREA EARLY SATURDAY
MORNING...WITH DEEPENING NORTHEASTERLY FLOW THROUGH THE DAY
SATURDAY. TEMPERATURES ON SATURDAY WILL THUS BE MUCH COOLER...WITH
MOST LOCATIONS TOPPING OUT IN THE 40S. BY SATURDAY
AFTERNOON...STRONG QG FORCING FROM THE WAVE...ALONG WITH DEEP
UPSLOPE FLOW TO 700 MB WILL BRING WIDESPREAD PRECIPITATION ACROSS
THE WESTERN TWO THIRDS OF THE FORECAST AREA.

GIVEN THE MID SPRING TIMING OF THIS STORM...TEMPERATURES AND
PRECIPITATION TYPE ARE AN ISSUE. MODEL AGREEMENT CONTINUES TO
SUGGEST THAT PRECIPITATION WILL START AS RAIN FOR MUCH OF THE
FORECAST AREA. THE MAIN EXCEPTION TO THIS WILL BE IN THE HIGHER
ELEVATIONS ALONG THE FOOTHILLS AND IN THE MOUNTAINS. EXPECT TO SEE
LOCATIONS ACROSS THE PLAINS TRANSITION TO ALL SNOW AFTER 9PM ON
SATURDAY NIGHT AS THE COLDER TEMPERATURES CONTINUE TO ADVECT INTO
THE FORECAST AREA...AND WE LOSE THE INFLUENCE OF THE SUN.

THE HIGHEST QPF AMOUNTS WILL BE ALONG AND WEST OF LINE FROM
RYEGATE TO BILLINGS TO ASHLAND...WITH THE HIGHEST AMOUNTS LOCATED
IMMEDIATELY ALONG THE FOOTHILLS FROM LIVINGSTON TO RED LODGE TO
SHERIDAN. THE HIGHEST QPF AMOUNTS ALONG THE FOOTHILLS WILL
COINCIDE WITH THE HIGHER ELEVATION LOCATIONS...THESE AREAS WILL
ALSO SEE SNOW AS THE PREDOMINATE P-TYPE AND THUS WILL SEE THE
HIGHEST SNOW ACCUMULATIONS. SNOW AMOUNTS WILL DECREASE QUICKLY
TOWARD THE NORTH AND EAST OFF THE FOOTHILLS. ANY SNOW THAT DOES
ACCUMULATE IN LOWER ELEVATION LOCATIONS...LIKE BILLINGS...WILL
MAINLY BE ON GRASSY AND ELEVATED SURFACES DUE TO THE MARGINAL
TEMPERATURES AND WARM SURFACE TEMPERATURES.

CHURCH

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

EXTENDED PERIOD BEGINS SUNDAY MORNING WITH AN UPPER LEVEL JET
DIGGING ITS WAY INT0 NORTHERN MONTANA. THIS 120KT JET WILL HELP
TRANSITION THE WEEKEND WEATHER SYSTEM OFF TO THE EAST AND
SUBSEQUENTLY BE REPLACED BY A RIDGE. THIS RIDGE WILL HELP KEEP
TEMPS AROUND NORMAL FOR THE START OF THE WORK WEEK. HOWEVER...AT
THIS POINT...MODEL GUIDANCE BEGINS TO DIVERGE.

MOST OF THE GUIDANCE QUICKLY BREAKS DOWN THE RIDGE BY LATE
TUESDAY NIGHT. HOWEVER...THE MORE MAINSTREAM MODELS EACH DO IT
DIFFERENTLY. THE GFS SOLUTION IS FASTER AND BRINGS IN AN UPPER
LEVEL LOW OFF THE COAST OF OREGON WHILE THE EC SOLUTION IS SLOWER
AND BRINGS IN AN UPPER LOW OFF THE COAST OF BRITISH COLUMBIA.

BASED ON THIS...MINIMAL CHANGES WERE MADE TO THE GOING FORECAST.
WHAT WE DO KNOW IS THAT PATTERNS SIMILAR TO THIS PROVE TO BE
SOMEWHAT UNSETTLED. DAY TIME TEMPS WILL DIP BELOW 50 F BY LATE
NEXT WEEK. AS FAR AS PRECIPITATION IS CONCERNED...WENT WITH A
MODEL BLEND WITH A HINT OF CLIMO FOR THOSE GRIDS.

WILL SAY THAT IF THE GFS SOLUTION PANS OUT...THURSDAY AND FRIDAY
OF NEXT WEEK COULD BE INTERESTING DAYS FOR POTENTIAL PRECIP
CHANCES. SINGER

&&

.AVIATION...

WINDS HAVE DIMINISHED ACROSS THE REGION THIS EVENING...AND ARE
EXPECTED TO CONTINUE TO DECREASE AND REMAIN LIGHT OVERNIGHT. SKIES
WILL REMAIN MAINLY CLEAR FOR ALL ROUTES OVERNIGHT. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    FRI     SAT     SUN     MON     TUE     WED     THU
-----------------------------------------------------------
BIL 035/070 041/048 027/042 031/055 037/057 034/047 034/047
    00/N    37/R    73/O    11/U    02/W    33/W    33/W
LVM 034/068 038/048 025/045 029/057 036/059 034/046 031/046
    00/N    37/R    83/O    11/U    03/W    33/W    33/W
HDN 034/072 039/050 028/044 028/059 034/060 033/048 032/048
    00/B    17/R    63/O    11/U    02/W    22/W    22/W
MLS 034/071 038/051 026/042 028/054 031/052 032/047 028/047
    00/B    24/R    22/R    11/B    12/W    22/W    22/W
4BQ 033/072 040/053 027/044 025/055 031/057 032/045 032/045
    00/B    15/R    43/O    11/U    12/W    22/W    22/W
BHK 032/067 037/049 025/038 024/049 025/046 027/044 026/044
    01/B    23/R    12/O    01/B    12/W    22/W    23/W
SHR 035/070 039/050 026/039 025/053 033/058 033/046 033/046
    00/B    37/R    85/O    21/U    02/W    33/W    33/W

&&

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

&&

$$
WEATHER.GOV/BILLINGS



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