Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 281429
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
829 AM MDT SUN SEP 28 2014

.UPDATE...
LARGE UPPER LOW CONTINUES TO MOVE SLOWLY OVER NEVADA. FLOW ALOFT
REMAINS DIFFLUENT OVER OUR REGION...WITH UPSLOPE LOW LEVEL
WINDS...BUT OTHERWISE FORCING IS WEAK WITH JET ENERGY WELL TO OUR
SOUTH. LATEST RADAR SHOWS SHOWERS ACROSS OUR WEST BUT LITTLE
ELSEWHERE. MODEL SOUNDINGS SHOW MOISTURE REMAINING SHALLOW
THROUGH THE DAY ACROSS OUR CENTRAL AND EAST PARTS...SO WITH
CONFIDENCE HAVE LOWERED POPS TO SCATTERED EVERYWHERE BILLINGS
EAST...AND ANY PCPN WILL BE LIGHT. WILL KEEP LIKELY POPS IN OUR
WESTERN UPSLOPE AREAS. HAVE ALSO REMOVED MENTION OF TSTMS IN OUR
SOUTHEAST THROUGH 00Z...CONSISTENT WITH LATEST SSEO AND SREF
CONVECTIVE PARAMETERS. ANY POTENTIAL FOR TSTMS IN SOUTHEAST MT
SHOULD HOLD OFF UNTIL TONIGHT WHEN STRONGER ENERGY FINALLY LIFTS
THROUGH WY. JKL

&&

.SHORT TERM...VALID FOR TDY AND MON...

LARGE UPPER LOW CONTINUES TO BE SITUATED OVER NEVADA THIS
MORNING. MODELS KEEP THE LOW IN THIS POSITION THROUGH TONIGHT
PROVIDING A MOIST SOUTHERLY FLOW ALOFT AND AN AREA OF UPPER LEVEL
DIVERGENCE ACROSS OUR FORECAST AREA. SATELLITE CURRENTLY SHOWING
COLDER CLOUD TOPS MOVINGS NORTH-NORTHWEST INTO SOUTHWEST MONTANA
WITH A DRY SLOT MOVING INTO THE SOUTHEAST PORTIONS OF THE STATE.
AS A RESULT...BULK OF THE SHOWER ACTIVITY AND ASSOCIATED LIKELY
POPS WILL BE ACROSS OUR CENTRAL AND WESTERN ZONES THROUGHOUT THE
DAY WITH JUST A CHANCE ACROSS OUR EAST. CAPES ARE VERY MINIMAL AT
BEST SO NOT EXPECTING ANY THUNDERSTORM ACTIVITY EXCEPT MAYBE AN
OUTSIDE CHANCE ACROSS OUR FAR EASTERN AREAS.

THE LOW BEGINS TO SLOWLY SHIFT NORTH AND NORTHEAST DURING THE DAY
MONDAY SHIFTING THE BULK OF THE SHOWER ACTIVITY EASTWARD AS WELL.
AT THE SAME TIME...A SURFACE LOW REALLY GETS ORGANIZED ACROSS
NORTHEAST COLORADO AND MOVES INTO NORTHEAST WYOMING MONDAY NIGHT
AND WESTERN SOUTH DAKOTA ON TUESDAY. PRESSURE GRADIENTS TIGHTEN UP
QUITE A BIT AS WELL RESULTING IN A GUSTY NORTHWEST WIND MONDAY AND
MONDAY NIGHT ACROSS OUR EAST. MODELS ARE PLACING QUITE A BIT OF
QPF ACROSS OUR EASTERN ZONES LATE MONDAY AFTERNOON THROUGH MONDAY
NIGHT WHEN PRECIP AMOUNTS MAY BE IN THE 1-2 INCH RANGE.
ELSEWHERE...SCATTERED SHOWERS WILL BE POSSIBLE WITH CHANCES
LOWERING AS YOU GO FURTHER WEST. HIGHS TODAY WILL BE COOLER THAN
SATURDAY WITH 50S COMMON ACROSS THE ENTIRE FORECAST AREA.
TEMPERATURES MONDAY WILL REBOUND SLIGHTLY WITH READINGS IN THE
60S...WHICH IS CLOSER TO NORMAL FOR THIS TIME OF YEAR. HOOLEY

.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...

MODELS CONTINUE TO REMAIN IN GOOD AGREEMENT THROUGH THE EARLY
PART OF THE EXTENDED FORECAST IN SLOWLY LIFTING A CLOSED UPPER LOW
NORTHWARD INTO THE WESTERN DAKOTAS ON TUESDAY. GFS/ECMWF AND GEM
MODELS ARE ALL IN GOOD AGREEMENT WITH THE LOCATION AND SPEED OF
THE LOW. THE NAM12 HAS THE FASTEST WITH THE UPPER LOW AND IS THE
OUTLIER. GFS/ECMWF AND GEM MODELS ARE PROGGING ARE EASTERN ZONES
TO GET OVER A HALF INCH OF PRECIPITATION AS MOISTURE IS WRAPPED
AROUND THE LOW. MODELS ALSO CONTINUING TO SHOW STRONG Q VECTOR
FORCING AND HAVE GONE WITH CATEGORICAL POPS. LOW MOVES QUICKLY OUT
OF THE AREA TUESDAY NIGHT AND LEAVES A BROAD CYCLONIC FLOW ALOFT
OVER THE AREA WEDNESDAY THROUGH THURSDAY. MODELS DEPICT Q VECTOR
FORCING CONTINUING OVER THE AREA BUT MOISTURE ALOFT STILL LOOKS
LIMITED AND DOWN SLOPE NORTHWEST WINDS WILL ALSO BE OVER THE AREA.
HAVE KEPT ISOLATED TO SCATTERED POPS ACROSS THE AREA. UPPER RIDGE
BUILDING BACK INTO THE AREA BY FRIDAY AND WILL REMAIN OVER THE
REGION THROUGH THE WEEKEND. TEMPERATURES WILL BE BELOW SEASONAL
VALUES TUESDAY THROUGH THURSDAY BUT WILL WARM TO ABOVE NORMAL
FRIDAY THROUGH THE COMING WEEKEND. RICHMOND
&&

.AVIATION...

WIDESPREAD MVFR CONDITIONS WILL BE FOUND ACROSS OUR FORECAST AREA
TODAY WITH POCKETS OF IFR...ESPECIALLY IN THE UPSLOPE AREAS ALONG
NORTH FACING TERRAIN. IFR TO LIFR CONDITIONS ARE EXPECTED AT MANY
LOCATIONS TONIGHT AS AREAS OF RAIN AND FOG SPREAD NORTHWARD FROM
WYOMING INTO SOUTHEAST MONTANA. BT
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY MON     TUE     WED     THU     FRI     SAT
-------------------------------------------------------
BIL 054 043/065 048/068 045/059 041/054 035/062 043/071
    4/W 63/W    22/W    22/W    12/W    10/U    11/U
LVM 053 041/065 045/064 036/058 034/053 031/062 037/069
    7/W 62/W    23/W    32/W    12/W    20/U    01/U
HDN 056 043/065 045/069 043/060 040/057 035/063 040/072
    4/W 64/W    22/W    13/W    12/W    20/U    11/U
MLS 056 044/064 048/064 045/057 040/057 034/060 039/067
    3/W 67/W    67/W    22/W    12/W    10/B    11/U
4BQ 058 044/063 048/062 044/058 039/057 034/058 038/066
    3/W 77/T    67/W    22/W    12/W    20/B    11/U
BHK 056 042/059 048/061 043/057 038/055 033/054 036/062
    3/W 68/T    98/W    42/W    22/W    20/B    11/U
SHR 057 042/066 045/065 041/057 034/053 031/059 037/068
    4/W 74/W    22/W    22/W    12/W    20/U    11/U

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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