Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 030208
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
808 PM MDT SAT MAY 2 2015

.UPDATE...
REMOVED CHANCES OF PRECIPITATION OVERNIGHT. AIRMASS IS STILL QUITE
DRY AND TRAJECTORY ON WATER VAPOR INDICATES REGION IS IN A DRY
SLOT EXTENDING BACK TOWARDS NORTHERN CALIFORNIA. EVENING SOUNDINGS
ARE GENERALLY .40 PRECIPITABLE WATER OR LESS AND THIS IS EVEN
BEHIND THE FRONT WHICH HAS PUSHED THROUGH MOST OF THE AREA. THE
STRONGEST RADAR RETURNS NOTED ON BOWMAN RADAR ONLY YIELDED 10000
FOOT CEILINGS AT BAKER. WILL BE VIRGA OUT AND ABOUT BUT WILL NOT
SEE ANY MEASURABLE PRECIPITATION. BORSUM

&&

.SHORT TERM...VALID FOR SUN AND MON...

THE PATTERN WILL BEGIN TO CHANGE OVER THE FORECAST AREA SUN AND
MON. THE FIRST CHANGE WILL OCCUR THIS EVENING AS A COLD FRONT OVER
N MT THIS AFTERNOON...MOVES S THROUGH THE AREA. THE FRONT WILL
USHER IN A SHIFT TO NE WINDS WITH COOLER CONDITIONS ON SUN.

WEAK CAPE WILL BE OVER THE FAR SOUTHERN PORTIONS OF THE AREA THIS
EVENING AND JET DIVERGENCE FROM THE RIGHT-REAR QUADRANT OF A JET
TO THE N WILL PROVIDE LIFT OVER THE AREA. FRONTOGENESIS WILL BE
WEAK WITH THE COLD FRONT...SO KEPT POPS OVER AND NEAR THE
SOUTHERN MOUNTAINS THIS EVENING...THEN SHIFTED THEM E INTO SE MT
OVERNIGHT. AN ISOLATED EVENING THUNDERSTORM IS POSSIBLE. MORE LIFT
FROM A JET WILL AFFECT THE AREA SUN AFTERNOON AND EVENING. CAPES
WILL AGAIN BE LIMITED. CONTINUED WITH POPS OVER AND NEAR THE
MOUNTAINS WITH ISOLATED THUNDER POSSIBLE IN THE AFTERNOON. SPREAD
POPS FURTHER E ACROSS THE S PART OF THE AREA SUN EVENING. MODELS
SHOWED WEAK OVERRUNNING OVER THE REGION AND DISAGREED AS TO HOW
FAR N TO EXTEND THE PRECIPITATION. A LOW-LEVEL JET WILL SET UP
OVER THE E PORTION OF THE AREA SUN NIGHT...USHERING IN GRADUALLY
INCREASING MOISTURE WHICH WILL CONTRIBUTE TO THE CHANGE IN THE
PATTERN. THIS JET WILL PERSIST THROUGH MON NIGHT. CHANCES FOR
PRECIPITATION WILL CONTINUE OVER SHERIDAN COUNTY AND SE MT LATE
SUN NIGHT. HIGHS SUN WILL REACH THE 60S.

ON MON...MOISTURE WILL CONTINUE TO INCREASE OVER THE AREA DUE TO
THE STRONG SE TO S FLOW. SREF SHOWED POSSIBLE CAPES OVER 500 J/KG
OVER WESTERN PARTS OF THE AREA BUT NO SHEAR. LOWERED POPS MON
MORNING AS THE INITIAL SURGE OF MOISTURE MOVES OUT OF THE
REGION...THEN KEPT POPS OVER AND NEAR THE MOUNTAINS DURING THE
AFTERNOON IN AN AREA OF SURFACE CONVERGENCE. SOME STORMS MAY BE
STRONG. CHANCES FOR THUNDERSTORMS WILL CONTINUE MON EVENING...AND
WILL BE FURTHER ONTO THE PLAINS. THE PRECIPITATION CHANCES WILL
THEN WANE MON NIGHT. TEMPERATURES WILL REBOUND INTO THE 70S MON.
ARTHUR

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

THE GENERAL THEME FOR LATER THIS WEEK INTO NEXT WEEKEND IS COOLER
AND WETTER. PATTERN CERTAINLY LOOKING MORE TYPICAL FOR THIS TIME
OF YEAR WITH AN INCREASING CHANCE FOR WIDEPSREAD PRECIPITATION.

MEDIUM RANGE GUIDANCE COMING INTO BETTER AGREEMENT FOR THE OVERALL
PATTERN. UPPER TROUGH BEGINS TO DIG ALONG THE WEST COAST ON
TUESDAY WITH A SIGNIFICANT CHUCK OF ENERGY DIGGING DEEP INTO THE
GREAT BASIN BY LATE IN THE WEEK. THIS WILL RESULT IN A MOIST
SOUTHWEST FLOW INTO OUR REGION SUPPORTED BY GOOD UPPER LEVEL
DIFFLUENCE. EXPECTING PIECES OF ENERGY TO LIFT NORTH ACROSS THE
REGION THROUGH THE UPCOMING EXTENDED PERIOD WHICH WILL HELP
ENHANCE SHOWERS AT TIME. THIS UPPER LOW IS THEN FORECAST TO LIFT
NORTHEAST TOWARD THE AREA BY THE WEEKEND. THIS WILL FURTHER
INCREASE THE DYNAMICS AND DEEPEN AN UPSLOPE FLOW FOR EVEN BETTER
CHANCES FOR RAINFALL AND MOUNTAIN SNOWS FOR THE FRIDAY THROUGH SUNDAY
TIMEFRAME. SOME LOCALLY HEAVY RAINFALL WILL BE POSSIBLE DEPENDING
ON HOW THINGS SET UP. WHILE CERTAINLY THE TIMING/DETAILS TOO
DIFFICULT THIS FAR OUT...HAVE CONTINUED TO INCREASE PRECIPITATION
CHANCES 6-8 DAYS OUT. FRIEDERS

&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL WITH MID LEVEL CEILINGS. BORSUM

&&

.PRELIMINARY POINT TEMP/POPS...

    SUN     MON     TUE     WED     THU     FRI     SAT
-----------------------------------------------------------
BIL 045/065 043/076 048/076 047/063 043/053 038/059 042/059
    11/B    11/B    22/T    43/T    44/W    44/W    55/W
LVM 037/066 037/074 043/075 041/060 038/050 033/053 036/059
    11/B    12/T    23/T    44/T    45/W    54/W    55/W
HDN 044/067 043/078 045/079 047/065 041/053 035/061 041/064
    11/B    21/B    22/T    43/T    44/W    34/W    55/W
MLS 045/066 043/073 048/077 050/066 042/054 037/060 042/062
    10/B    11/B    12/T    43/T    33/W    33/W    34/W
4BQ 046/066 043/070 046/075 049/064 043/054 035/057 041/059
    11/B    32/W    12/T    44/T    43/W    33/W    45/W
BHK 042/063 038/068 043/070 049/061 041/055 033/056 038/059
    11/B    12/W    11/N    44/T    43/W    22/W    44/W
SHR 042/065 041/070 042/073 045/061 040/053 033/056 038/054
    12/T    32/T    23/T    44/T    44/W    45/W    67/W

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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