Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 071521
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
921 AM MDT TUE JUL 7 2015

.UPDATE...

FORECAST LOOKS TO BE IN GOOD SHAPE WITH JUST A COUPLE MINOR
ADJUSTMENTS WITH THIS UPDATE. SATELLITE SHOWING MOSTLY SUNNY SKIES
ACROSS THE FORECAST AREA ALONG WITH AREAS OF SMOKE BEING PUSHED
SOUTH OUT OF CANADA. NOT SEEING ANY SHOWER ACTIVITY THIS MORNING
SO CHANCES WERE REMOVED FROM THE MOUNTAINS AND FOOTHILLS. A WEAK
COOL FRONT WILL MOVE ACROSS THE FORECAST AREA THIS AFTERNOON AND
EVENING BRINGING A SLIGHT CHANCE FOR A SHOWER OR THUNDERSTORM.
BEST DYNAMICS FOR A STRONGER STORM WILL BE ACROSS FAR SOUTHEAST
MONTANA WHERE AN INVERTED TROUGH HAS SET UP AND WHERE THE BETTER
DYNAMICS WILL BE LOCATED. UPDATED FORECAST HAS BEEN SENT. HOOLEY

&&

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

THERE WAS NOT A LOT OF FORCING FOR PRECIPITATION TODAY OUTSIDE OF
WEAK SHORTWAVES MOVING THROUGH CYCLONIC FLOW ALOFT AND A WEAK COLD
FRONT THAT DROPS S INTO THE AREA LATE THIS MORNING THROUGH THE
AFTERNOON. AS NOTED YESTERDAY...A WEAK INVERTED TROUGH ALSO SETS
UP OVER SE MT. THE SREF SHOWED SURFACE CAPES OF 500-1000 J/KG
OVER SE MT INTO BIG HORN COUNTY THIS AFTERNOON AND EVENING...WITH
LESSER PROBABILITIES OF 500 J/KG OF CAPE ELSEWHERE. THERE WAS ALSO
A CHANCE OF 40 KT OF SHEAR OVER SE MT THIS AFTERNOON. IN
ADDITION...PRECIPITABLE WATERS WERE FORECAST TO CLIMB ABOVE 1 INCH
OVER THE SE TODAY THROUGH TONIGHT. THE RAP LINED UP WELL WITH THE
SREF WITH IT/S INSTABILITY PARAMETERS. NOTED THE WRF SOUNDINGS
GENERALLY HAD HIGHER CAPES THAN THE OTHER MODELS...WITH KBHK
PEAKING OUT AT 1600 J/KG BY 00Z WED. SO...CONSENSUS SUGGESTS THAT
STRONG THUNDERSTORMS ARE POSSIBLE OVER SE MT THIS AFTERNOON AND
EVENING. AFTER SOME MORNING MOUNTAIN POPS...GENERALLY WENT WITH
SLIGHT CHANCE POPS THIS AFTERNOON AND EVENING...WITH HIGHER POPS
IN SE MT...AND OVER THE MOUNTAINS WHERE NNE FLOW WILL PROVIDE
UPSLOPE.

MIXING TODAY WILL BE BETWEEN 700 AND 600 MB SUPPORTING HIGHS IN
THE UPPER 70S TO MID 80S. SHOULD SEE A RESURGENCE IN THE SMOKE
THIS AFTERNOON AS LOW-LEVEL WINDS BECOME NORTHERLY.

A COOLER PUSH OF AIR WILL DRIVE S THROUGH THE REGION TONIGHT
KEEPING LOW CHANCES FOR CONVECTION ACROSS THE ENTIRE AREA
OVERNIGHT...AS WELL AS AREAS OF SMOKE.

SHORTWAVE ENERGY LOOKED EVEN WEAKER OVER THE AREA ON WED IN A WEAK
FLOW ALOFT. INSTABILITY WILL BE WEAKER THAN TODAY WITH A DRIER
AIRMASS. WENT WITH SLIGHT CHANCE POPS IN THE MORNING...THEN
RESTRICTED POPS TO THE SOUTHERN TIER AND WESTERN ZONES IN THE
AFTERNOON AS DRIER AIR MOVES IN FROM THE N. MIXING TO 700 MB WILL
MAKE FOR A MARGINALLY COOLER DAY WITH HIGHS IN THE UPPER 70S TO
LOWER 80S. KEPT SOME POPS OVER AND NEAR THE SOUTHERN MOUNTAINS WED
EVENING...THEN WENT MAINLY DRY AFTER 06Z DUE TO WANING
INSTABILITY. ARTHUR

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

WARM WEATHER IS EXPECTED DURING THE LONG TERM FORECAST PERIOD AND
BY EARLY NEXT WEEK WIDESPREAD 90+ F HIGHS ARE FORECAST. THE CHANCE
OF SHOWERS AND THUNDERSTORMS WILL BE GREATEST ON FRIDAY AND FRIDAY
NIGHT AS A SHORTWAVE TROUGH CROSSES THE REGION. THE LAST FEW MODEL
CYCLES HAVE OFFERED UP SOME SUBTLE DIFFERENCES IN THE HANDLING OF
THAT WAVE...BUT IN GENERAL THERE/S AGREEMENT THAT DEEP-LAYER
VERTICAL WIND SHEAR WILL BE LACKING AND THUS THE SEVERE STORM RISK
WILL BE LIMITED...ALBEIT NON-ZERO. HEAVY RAIN MAY BE THE GREATER
STORM HAZARD FRIDAY AND FRIDAY NIGHT.

GUIDANCE REMAINS CONSISTENT IN CALLING FOR THE SUBTROPICAL RIDGE
TO INTENSIFY AND BUILD WESTWARD INTO THE SOUTHERN ROCKIES AND
SOUTHERN PLAINS BY EARLY NEXT WEEK. HOTTER WEATHER WILL DEVELOP
ACROSS SOUTHERN MT AND NORTHERN WY ON THE EDGE OF THE RIDGE TOO.
CONVECTION WILL LIKELY BE LIMITED INITIALLY ON SUNDAY AND MONDAY
IN THIS PATTERN IF THE RIDGE AMPLIFIES LIKE THE 00 UTC GFS AND
ECMWF SUGGEST. HOWEVER...BY NEXT TUESDAY THERE ARE SIGNS THAT
IMPULSES ROUNDING THE TOP OF THE LARGE DOME OF HIGH PRESSURE ALOFT
COULD YIELD SOME THUNDERSTORM ACTIVITY ACROSS OUR AREA. SCHULTZ

&&

.AVIATION...

VFR CONDITIONS WILL GENERALLY PREVAIL TODAY AND TONIGHT. THERE MAY
BE LOCALIZED MVFR CONDITIONS WITH A FEW SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EVENING...AND WE DID INCLUDE A VCTS IN THE TAFS
TO COVER THAT POTENTIAL EVEN THOUGH CONFIDENCE IN IMPACTS AT ANY
ONE TERMINAL IS LOW. FINALLY...SMOKE MAY RETURN AT THE SURFACE BY
EVENING THANKS TO NORTHERLY FLOW BEHIND A WEAK COLD FRONT. SCHULTZ

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 083 056/080 058/086 061/090 062/087 062/092 063/092
    2/T 22/T    11/B    23/T    32/T    21/B    11/U
LVM 081 049/077 051/084 054/085 055/083 055/089 055/090
    3/T 33/T    23/T    24/T    33/T    21/B    12/T
HDN 085 055/082 057/089 060/094 060/090 060/095 060/095
    2/T 22/T    11/B    23/T    42/T    21/B    11/U
MLS 084 056/082 058/089 063/094 064/092 063/094 064/093
    2/T 22/T    11/B    13/T    33/T    21/B    11/U
4BQ 083 055/080 057/087 061/093 062/091 062/093 062/091
    3/T 22/T    12/T    13/T    32/T    11/B    11/U
BHK 079 053/079 055/085 060/090 062/090 061/090 061/089
    3/T 22/T    11/U    12/T    33/T    22/T    11/B
SHR 079 052/074 053/083 056/087 056/086 056/089 056/089
    2/T 33/T    33/T    23/T    32/T    11/B    11/U

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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