Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 300937
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
337 AM MDT TUE JUN 30 2015

.SHORT TERM...VALID FOR TDY AND WED...

THE UPPER RIDGE THAT HAS PROVIDED SEVERAL DAYS OF HOT
TEMPERATURES TO THE NORTHERN ROCKIES WAS GETTING SUPPRESSED BY A
STRONG PIECE OF ENERGY RIDING OVER SOUTHERN CANADA AND NORTHERN
MONTANA. THIS WILL NOT PROVIDE A GREAT DEAL OF RELIEF FROM THE
HEAT...HOWEVER...AS MID LEVEL HEIGHTS WERE STILL HIGH...BUT THE
FLOW WILL VEER TO THE NORTHWEST OVER TIME AND ALLOW FOR A GRADUAL
COOL DOWN INTO MID WEEK. THAT BEING SAID...HIGHS ARE STILL
PROJECTED TO BE ABOVE NORMAL AS THE UPPER HIGH REMAINS IN TACT
OVER NEVADA WITH MID LEVEL HEIGHTS REMAINING ABOVE 586DM.

A SECONDARY SHORTWAVE WAS SLIDING TO THE SOUTH OF THE MAIN WAVE
AND WAS PROJECTED TO MOVE THROUGH THE NORTHERN HALF OF THE
FORECAST AREA THIS MORNING. SHOWERS WITH A FEW THUNDERSTORMS WERE
APPROACHING WESTERN ZONES AND HAVE THUS CARRIED POPS THIS MORNING.
HIGH RESOLUTION MODELS SWING THE PRECIPITATION ACROSS CENTRAL
ZONES MID MORNING AND SLIDE IT INTO THE EAST BY LATE MORNING. A
SEPARATE AREA OF SHOWERS WAS MOVING INTO EASTERN MUSSELSHELL
COUNTY AT THE MOMENT AND SHOULD CONTINUE TO MOVE EAST/SOUTHEAST
ACROSS THE SOUTHEAST ZONES EARLY THIS MORNING. ACTIVITY SHOULD
WEAKEN SOME AS INSTABILITY WAS NOT GREAT. ANOTHER THING TO
CONSIDER WAS AN AREA OF SMOKE OVER NORTHEAST MONTANA THAT WAS FROM
FIRES IN CANADA. THIS SMOKE HAS BEEN DRIFTING EAST AND SOUTH AND
WITH LOW LEVEL WINDS OUT OF NORTHEAST AT MILES CITY...DO THINK THE
SMOKE SHOULD GET INTO THE NORTHERN PARTS OF SOUTHEAST MONTANA THIS
MORNING...SO WILL MENTION.

THE MAIN ENERGY OVER SOUTHERN CANADA WILL DROP SOUTHEAST TOWARD
WESTERN NORTH DAKOTA EARLY THIS AFTERNOON. DRIER MID LEVEL AIR WAS
RUSHING IN BEHIND THE WAVE...BUT IN FRONT OF IT...PRECIPITABLE
WATER VALUES WERE OVER AN INCH. DEWPOINTS WERE STILL HIGH IN THE
SOUTHEAST AND THIS WILL LEAD TO CAPES NEAR 1000 J/KG EARLY THIS
AFTERNOON ALONG WITH EFFECTIVE BULK SHEAR NEAR 40 KTS. A SURFACE
TROUGH WILL BE STRETCHED OUT OVER SOUTHEAST MONTANA...MAINLY EAST
OF MILES CITY...FOR FOCUS FOR CONVECTION. THERE WILL BE A RISK FOR
STRONG TO POSSIBLY SEVERE THUNDERSTORMS OVER THE FAR EAST THIS
AFTERNOON AND EVENING. THE WINDOW SHOULD BE A SMALL ONE...BUT SPC
DOES PAINT THE AREA IN A SLIGHT RISK...SO WILL MENTION SEVERE IN
THE ZONES EAST OF A MILES CITY TO BROADUS LINE. THIS ACTIVITY
COULD BE HINDERED BY MORNING SHOWERS AND CLOUDS...SO WILL NEED TO
BE MONITORED AS THE DAY WEARS ON.

AS THE SURFACE TROUGH DRIFTS EAST AND DRIER AIR BEHIND THE
SHORTWAVE ARRIVES...NORTHWEST WINDS WILL INCREASE THIS AFTERNOON
FROM BILLINGS EASTWARD. HUMIDITY FORECAST WILL BE TOUGH AS CLOUDS
AND SHOWERS WILL BE AROUND THIS MORNING...BUT CERTAINLY LOOKS LIKE
DEWPOINTS WILL FALL THIS AFTERNOON WITH MIXING. 850 MB WINDS WERE
A LITTLE WEAKER THIS RUN...ONLY AROUND 25 KTS...BUT DO THINK THAT
SOME OF THESE WILL MIX TO THE SURFACE FOR GUSTS. TOUGH CALL ON
EXTENT OF DRYING AND WINDINESS AS THERE WILL BE GENERAL ASCENT IN
THE AREA WITH THE SHORTWAVE ENERGY SLIDING THROUGH. WILL CONTINUE
TO WORD THE FIRE WEATHER FORECAST STRONGLY FOR BREEZY CONDITIONS
AND LOWERING HUMIDITY LEVELS.

THE SHORTWAVE WILL EXIT INTO THE DAKOTAS EARLY THIS EVENING WITH
DRYING ACROSS ALL OF SOUTHERN MONTANA AND NORTHERN WYOMING
TONIGHT. NORTHWEST FLOW WILL PRODUCE ANOTHER SHORTWAVE FOR
WEDNESDAY AFTERNOON AND EVENING. PRECIPITABLE WATERS REMAIN AN
INCH OR HIGHER OVER THE EAST...AND CAPES RETURN TO AROUND 800 J/KG
OVER THE EASTERN FOUR COUNTIES. RAISED THE CHANCE OF THUNDESTORMS
WITH THE MAIN FOCUS FOR STORMS OVER THE EAST. WILL KEEP POPS
CONFINED TO LOCATIONS FROM ROUNDUP TO BILLINGS EASTWARD AND MODELS
PROJECT MUCH DRIER AIR OVER THE WEST. HIGH TEMPERATURES WILL BE
JUST A BIT COOLER WITH NORTHERLY SURFACE WINDS. TWH

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

ONLY A FEW MINOR TWEAKS TO THE EXTENDED FORECAST THIS MORNING.
OVERALL STORY REMAINS THE SAME TO START THE PERIOD...AND MODELS
START TO DIVERGE ABOUT DAY 5...AND JUST CONTINUE TO GET WORSE
THROUGH THE END OF THE PERIOD. NORTHWEST FLOW PERSISTS INTO AT
LEAST SATURDAY...WHEN MODELS BEGIN TO DIVERGE.

SHORTWAVE EXITING THE REGION THURSDAY WILL RESULT IN SOME REMNANT
SHOWER/TSTORM ACTIVITY IN THE EAST. SHORTWAVE WILL DRAG SOME
COOLER AIR WITH IT...BRINGING ONE OF THE COOLER DAYS OF THE
PERIOD...WITH TEMPS IN MID 80S. MODELS ARE INDICATING ANOTHER
PIECE OF ENERGY INTO THE REGION THURSDAY NIGHT...BUT AIRMASS
APPEARS PRETTY DRY...SO HAVE CONTINUED WITH DRY FORECAST AT THIS
TIME.

THE DRY WEATHER SHOULD CONTINUE INTO SATURDAY...AS SHORTWAVE
RIDGING BUILDS OVER THE REGION AHEAD OF THE APPROACHING COLD
FRONT. TEMPS WILL CLIMB QUICKLY TOWARD THE UPPER 90S BY
SATURDAY...WITH RIDGING AND POTENTIAL PRE FRONTAL WARMING. FRONT
SHOULD MORE THROUGH THE REGION SATURDAY
AFTERNOON/EVENING...BRINGING AT LEAST A CHANCE FOR
SHOWERS/TSTORMS. HAVE KEPT POPS LOW AT THIS TIME.

AS MENTIONED...AT THIS POINT MODELS DIVERGE SUCH THAT SIGNIFICANT
CHANGES ARE PROBLEMATIC. THAT SAID...SOME THINGS TO WATCH FOR MAY
BE POTENTIAL FOR SIGNIFICANTLY COOLER THAN FORECAST TEMPS...SUNDAY
THROUGH THE END OF THE PERIOD...IF STRONGER CAA OF ECMWF PANS OUT.
GFS ON THE OTHER HAND POINTS TOWARD DEVELOPING DIRTY RIDGE...AND
WARMER TEMPS. FORECAST LEANS TOWARD MORE UNSETTLED GFS...BASED
PARTIALLY ON PERSISTENCE OF WARMER TEMPS. CONTINUED WITH SLIGHT
POPS AND GRADUALLY INCREASING ABOVE NORMAL TEMPS THROUGH TUESDAY.
AAG

&&

.AVIATION...

ISOLATED SHOWERS AND THUNDERSTORMS WILL AFFECT THE ENTIRE AREA
TODAY...WITH LOCALIZED MVFR/IFR VIS IN HEAVIER PRECIP. EXPECT
LOCALIZED MOUNTAIN OBSCURATION. ADDITIONALLY SMOKE...FROM
CANADIAN FIRES...MAY CAUSE REDUCED VISIBILITY IN EAST AND
NORTHEASTERN ROUTES. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 096 063/091 062/086 061/091 064/098 062/085 062/085
    2/T 12/T    21/B    11/U    12/T    22/T    22/T
LVM 093 053/091 053/087 053/092 055/097 054/087 054/086
    2/T 11/U    11/B    11/U    12/T    22/T    22/T
HDN 098 060/093 061/088 059/093 062/100 060/087 060/087
    2/T 12/T    22/T    11/U    12/T    22/T    22/T
MLS 097 064/089 062/085 060/089 063/099 060/085 059/085
    3/T 13/T    32/T    11/U    12/T    22/T    22/T
4BQ 094 063/087 061/084 059/087 063/097 062/085 061/084
    2/T 13/T    32/T    11/U    12/T    22/T    22/T
BHK 093 060/082 057/080 057/084 059/094 059/081 056/080
    3/T 33/T    42/T    11/U    12/T    22/T    22/T
SHR 093 058/089 058/082 055/086 057/095 058/083 056/083
    2/T 22/T    22/T    11/U    12/T    22/T    22/T

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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