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000
FXUS65 KBYZ 131512
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
912 AM MDT THU MAR 13 2014

.UPDATE...
SW WINDS HAVE INCREASED AT KLVM EARLY THIS MORNING WITH A GUST TO
50 KTS NOTED AT 8 AM. THIS A RESULT OF FAIRLY TIGHT PRESSURE
GRADIENTS AND STRONG STABILITY AS INDICATED BY THE BELOW ZERO
MORNING TEMPS IN YELLOWSTONE PARK. FRONTAL PASSAGE WILL END THESE
ENHANCED WINDS QUICKLY BY 17Z OR SO...THUS NO NEED FOR AN
ADVISORY.

SHORTWAVE IN NW FLOW CURRENTLY DROPPING INTO NORTHERN MT. LOOKS
AS IF FORCING ASSOCIATED WITH THIS FEATURE ALONG WITH MODEST
DIURNAL INSTABILITY WILL BE ENOUGH FOR AT LEAST A CU FIELD AND
PERHAPS SOME SPRINKLES ACROSS OUR EAST BY LATER THIS AFTERNOON.
HAVE ADDED A SMALL POP FOR SPRINKLES IN THE 21-03Z TIME FRAME TO
COVER THIS. OTHERWISE A MAINLY DRY FRONTAL PASSAGE WITH GUSTY NW
WINDS IN ITS WAKE FOR TODAY. HAVE ADJUSTED WINDS/GUSTS UP A BIT
FOR THIS AFTERNOON ACROSS OUR EAST. TEMPS WILL BE ABOVE NORMAL
WITH HIGHS INTO THE UPPER 40S TO MID 50S...PER INCREASED MIXING
FROM THE COLD ADVECTION.

JKL

&&

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

NEW MODEL CYCLES IN GOOD AGREEMENT IN THE SHORT TERM AND DO NOT
INDICATE ANY SURPRISES OR NEED FOR SIGNIFICANT CHANGES TO
INHERITED FORECAST.

WEAK SHORT WAVE IN NW FLOW TODAY AND ASSOCIATED WEAK COLD FRONT
WILL MOVE INTO OUR FORECAST AREA...PASSING THROUGH BILLINGS AROUND
MIDDAY. ANY COOLING SEEMS TO BE OFFSET BY DECENT MIXING AND
GUIDANCE CONTINUES TO SHOW TEMPS SIMILAR TO OR A LITTLE WARMER
THAN YESTERDAY FOR MOST LOCATIONS. THE SYSTEM LACKS LOW LEVEL
MOISTURE SO BREEZY CONDITIONS WILL BE THE MAIN AFFECT.

A MORE VIGOROUS SHORT WAVE WILL TAKE AIM AT OUR FORECAST AREA
FOR THE END OF THE WORK WEEK. THIS SYSTEM WILL PRODUCE A FEW
MOUNTAIN SHOWERS BY FRIDAY AFTERNOON...WITH A GOOD CHANCE OF RAIN
AND SNOW SPREADING ACROSS THE LOWER ELEVATIONS FRIDAY NIGHT INTO
SATURDAY. I DO NOT ANTICIPATE MUCH SNOW ACCUMULATION AT THE LOWER
ELEVATIONS FRIDAY NIGHT...BUT A FEW INCHES IN THE HIGH COUNTRY
SEEMS REASONABLE. SO DESPITE HIGH POPS AND GOOD FORCING...THIS
SYSTEM MAY BE RELATIVELY LOW IMPACT FOR US OVERALL. RANCHERS WILL
WANT TO PROTECT NEWBORN LIVESTOCK DUE TO WET/COOL/BREEZY
CONDITIONS. BT

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

VERY MINOR CHANGES TO THE EXTENDED PERIOD...AS MODELS CONTINUE TO
FAVOR SOMEWHAT PROGRESSIVE PATTERN THROUGH THE EXTENDED PERIOD.

THE FORECAST PERIOD BEGINS SATURDAY WITH SLIGHTLY COOLER AND
WETTER WEATHER ON SATURDAY...AS A SHORTWAVE MOVES ACROSS THE
REGION. MODELS DID COME IN A BIT WARMER...BUT ONLY WARMED UP
SLIGHTLY...PRIMARILY WEST...AS CLOUD COVER AND PRECIP SHOULD BE
LIMITING FACTORS IN WARM UP. ALSO RAISED POPS SLIGHTLY IN THE
EAST. CANNOT RULE OUT SHOWERS IN THE WEST...BUT POTENTIAL IN LEE
OF MOUNTAINS CONTINUES TO LOOKS SOMEWHAT LIMITED BY DOWNSLOPE
FLOW.

UPPER RIDGING BUILDS IN QUICKLY BEHIND THE DEPARTING SHORTWAVE
SATURDAY NIGHT AND SUNDAY. DOWNSLOPE FLOW WILL REMAIN IN PLACE AS
RIDGE BUILDS INTO THE REGION...SO EXPECT TEMPERATURES WELL ABOVE
NORMAL. WARM TEMPS WILL COMBINE WITH STEEP LAPSE RATES...TO
SUPPORT GOOD MIXING...AND THEREFORE GUSTY WIND POTENTIAL FOR MUCH
OF THE REGION THROUGH SUNDAY AFTERNOON. ADDITIONALLY THE
INCREASING PRESSURE GRADIENT WILL SUPPORT STRONG AND GUSTY WINDS
IN THE GAP AREAS...FROM LIVINGSTON TO BIG TIMBER...AND POSSIBLY
HARLOWTON FOR SUNDAY AND MONDAY.

SOME VARIABILITY ARISES AFTER SUNDAY...WITH THE SPECIFICS OF HOW
MODELS HANDLE THE NEXT PACIFIC TROF...BUT MODELS DO SHARE PRETTY
GOOD AGREEMENT ON PRESENCE OF WAVE...AND TIMING. OVERALL MODELS
FAVOR AN UNSETTLED PERIOD FROM MONDAY EVENING ON THROUGH TUESDAY
NIGHT. CONFIDENCE WITH THIS SYSTEM REMAINS A BIT LOW...BUT
IMPROVING WITH TIMING CONSISTENCY. ONLY MADE SLIGHT ADJUSTMENTS
FOR COORDINATION THROUGH THIS PERIOD.

MODELS GET A BIT MORE VARIABLE AFTER THIS POINT...FAVORING
GRADUALLY WARMING TEMPERATURES...AS RIDGING BUILDS BACK INTO THE
REGION. THERE ARE ALSO INDICATIONS THAT ISOLATED TO SCATTERED
SHOWERS WILL BE POSSIBLE WITH RIDGING NOT AMPLIFYING QUITE AS
MUCH...AND SEVERAL WAVES RADIATING THROUGH THE FLOW. CONTINUE WITH
SLIGHT POPS THROUGH THE END OF THE PERIOD.AAG
&&

.AVIATION...

SW GUSTS OF 40-50 KTS AT KLVM WILL DECREASE RAPIDLY WITH A FRONTAL
PASSAGE AROUND 17Z. THIS FRONT WILL BRING INCREASED NW WINDS
ELSEWHERE WITH GUSTS OF 20-30 KTS EAST OF KBIL DURING THE
AFTERNOON. OTHERWISE...VFR WILL PREVAIL TODAY...THOUGH SCATTERED
TO BROKEN CLOUD DECKS OF 4-5KFT AGL MAY PRODUCE A FEW SPRINKLES
NEAR KMLS AND KBHK FROM 21-03Z. EXPECT VFR CONDITIONS WITH
DECREASED WINDS TONIGHT. JKL

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY FRI     SAT     SUN     MON     TUE     WED
-------------------------------------------------------
BIL 054 032/054 035/050 032/065 039/056 033/046 030/049
    0/N 00/B    52/O    10/N    02/W    33/W    22/W
LVM 049 027/051 031/046 029/060 035/052 030/046 027/050
    0/N 01/N    52/O    10/N    13/W    33/W    22/W
HDN 054 029/055 034/049 033/067 038/057 034/048 032/051
    0/N 01/B    54/O    10/N    03/W    43/W    22/W
MLS 054 029/054 033/043 032/060 039/055 033/045 029/050
    1/N 11/B    77/O    20/N    13/W    33/W    22/W
4BQ 055 029/055 033/043 032/062 038/058 033/046 030/047
    1/N 11/B    66/O    30/N    12/W    33/W    22/W
BHK 054 027/050 028/036 027/057 035/055 030/042 028/048
    1/N 10/B    66/O    20/N    24/W    33/W    22/W
SHR 053 026/053 031/048 026/063 033/057 029/046 025/048
    0/N 00/B    55/O    20/U    02/W    44/W    33/W

&&

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

&&

$$
WEATHER.GOV/BILLINGS