Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 282044
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
244 PM MDT THU MAY 28 2015

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

WIDESPREAD BUT RATHER UNORGANIZED CONVECTION EXISTS ACROSS OUR
WEST AND SOUTH THIS AFTERNOON. THIS A RESULT OF A VERY MOIST AND
UNSTABLE AIRMASS AND SYNOPTIC SCALE ASCENT ASSOCIATED WITH UPPER
LOW MOVING SLOWLY OVER WESTERN WY. CONVECTION WILL REMAIN NON-
SEVERE WITH LOCALLY HEAVY RAIN AND SMALL HAIL...THE LATTER OF
WHICH WE HAVE ALREADY RECEIVED A FEW REPORTS OF AROUND THE AREA.
SHOULD SEE SOME SHOWERS/TSTMS DEVELOP OVER OUR NORTHEAST PARTS TOO
BEFORE THE END OF THE AFTERNOON AS MID 70S ARE VERY CLOSE TO
CONVECTIVE TEMPS.

LOOKING TO OUR NORTH...THERE IS A CLIPPER IN SASKATCHEWAN AND A
COLD FRONT DROPPING INTO NORTHERN MT...AND A VERY DISTINCT LINE OF
CONVECTION EXISTS ALONG THE SFC FRONT. EXPECT NORTHERLY WINDS TO
BECOME GUSTY AND PCPN TO BECOME ENHANCED ALONG THIS FRONTAL PUSH
INTO OUR AREA THIS EVENING. UPSLOPE AREAS OF OUR SOUTH WILL SEE
PCPN PERSIST THROUGH THE NIGHT AND INTO EARLY FRIDAY MORNING. HAVE
RAISED POPS ACROSS THE REGION LATE THIS AFTERNOON THROUGH TONIGHT.
FRONT WILL BE FOLLOWED BRIEFLY BY A RATHER FALL-LIKE AIRMASS LATE
TONIGHT AND TOMORROW MORNING WITH COOL TEMPS AND AN AREA OF
UPSLOPE STRATUS AS WINDS TURN EASTERLY. MUCH DRIER AIR ASSOCIATED
WITH SFC RIDGE WILL SLIDE INTO THE NORTHERN PLAINS INCLUDING OUR
EAST TOMORROW. THIS DRIER AND MUCH MORE STABLE SFC RIDGE WILL NOT
SUPPORT CONVECTION ACROSS MOST OF OUR CWA TOMORROW AFTERNOON AND
EVENING...THOUGH WE COULD SEE SOME VERY WEAK DIURNAL ACTIVITY OVER
OUR WESTERN MTNS AND FOOTHILLS PER WEAK PACIFIC ENERGY EMBEDDED
WITHIN THE BUILDING FLAT UPPER RIDGE. TEMPS TOMORROW WILL REMAIN
BELOW NORMAL WITH HIGHS IN THE 60S.

NEXT WEAK SHORTWAVE MOVES INTO THE AREA SATURDAY AFTERNOON
BRINGING OUR NEXT CHANCE OF SHOWERS AND THUNDERSTORMS...BUT WITH
WEAK FORCING AND MODEST INSTABILITY THE COVERAGE WILL REMAIN ONLY
ISOLATED TO SCATTERED. FLAT RIDGING SUPPORTS WARMING IN THE LEE OF
THE ROCKIES AND THIS WILL ALLOW FOR TEMPS TO GET WELL INTO THE 70S
EVERYWHERE EXCEPT OUR FAR EAST...WHICH WILL LINGER IN THE UPPER
60S WITH INCREASED SE WINDS ALONG WESTERN FLANK OF DEPARTING SFC
HIGH. SHORTWAVE WILL EXIT TO THE EAST LATE SATURDAY NIGHT AS UPPER
RIDGE REBOUNDS.

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

MODELS IN GOOD AGREEMENT FOR THE START OF THE EXTENDED PERIOD
WITH A FLAT RIDGE ACROSS THE REGION. ANY SHORT WAVES MOVING OUT OF
THE MOUNTAINS /AS TYPICAL THIS TIME OF YEAR/ WILL HAVE TO FIGHT
DOWNSLOPE FLOW. THEREFORE...WE EXPECT MOST OF THE CONVECTION TO
REMAIN OVER AND NEAR THE MOUNTAINS...WITH A LIMITED AMOUNT
SPILLING OVER INTO THE PLAINS. MONDAY THROUGH WEDNESDAY BECOMES A
LITTLE MORE INTERESTING AS A TROUGH PLOWS INTO THE INTERMOUNTAIN
WEST PRODUCING A SOUTHWEST FLOW ALOFT OVER OUR REGION. DEPENDING
ON WHERE THE ASSOCIATED SURFACE LOW SETS UP WE COULD SEE SOME
SEVERE THUNDERSTORMS EITHER OF ANY THESE DAYS THANKS TO
INCREASING EFFECTIVE SHEAR. BY THURSDAY AND FRIDAY...ENERGY DIGS
FURTHER SOUTH WHILE OUR MODELS BEGIN TO SHOW INCONSISTENCIES. I
SUSPECT WE WILL HAVE SHOWERS/TSTORMS AROUND...BUT DIFFICULT TO SAY
TO WHAT DEGREE. SOMETHING NEAR CLIMO POPS SEEMS BEST FOR LATER IN
THE WEEK. LOOK FOR TEMPERATURES TO BE ON THE WARM SIDE SUNDAY AND
MONDAY...COOLING TO AROUND SEASONAL NORMS BY MIDWEEK. BT
&&

.AVIATION...

SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THE
EVENING ACROSS MUCH OF THE REGION...WITH THUNDER DECREASING AFTER
03Z. SOME OF THE STORMS WILL PRODUCE HEAVY RAINFALL RESULTING IN
MVFR/IFR CONDITIONS. WE ANTICIPATE AREAS OF MVFR CIGS AND POSSIBLY
FOG AND LOCAL IFR CIGS DEVELOPING BY 12Z...ESPECIALLY IN AREAS
CLOSE TO THE MOUNTAINS AND FOOTHILLS. BT
&&

.PRELIMINARY POINT TEMP/POPS...

    FRI     SAT     SUN     MON     TUE     WED     THU
-----------------------------------------------------------
BIL 048/065 048/078 054/083 056/084 054/075 050/070 049/070
    73/W    22/T    32/T    23/T    23/T    34/T    33/T
LVM 045/066 047/074 050/079 052/079 047/070 045/066 043/067
    74/T    23/T    33/T    35/T    34/T    44/T    43/T
HDN 048/067 045/080 051/084 056/087 054/077 050/073 050/073
    74/W    22/T    32/T    25/T    33/T    33/T    33/T
MLS 048/067 046/077 054/081 058/086 057/077 053/072 051/071
    41/B    12/T    41/B    23/T    52/T    43/T    33/T
4BQ 049/064 045/076 054/080 057/086 057/076 052/071 051/071
    54/W    11/B    32/T    22/T    33/T    43/T    33/T
BHK 044/063 040/069 047/078 052/083 055/076 050/071 049/070
    41/B    01/N    41/N    22/T    42/T    33/T    33/T
SHR 046/062 044/076 050/079 053/083 051/073 047/068 046/069
    86/W    22/T    22/T    23/T    34/T    43/T    44/T

&&

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

&&

$$
WEATHER.GOV/BILLINGS



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