Area Forecast Discussion
Issued by NWS Billings, MT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KBYZ 051541
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
941 AM MDT SUN JUL 5 2015

.UPDATE...
MUCH COOLER AIR HAS POURED INTO THE REGION AND COMBINED WITH SMOKE
AND CLOUDS DO NOT EXPECT TEMPERATURES TO MOVE MUCH TODAY. SHOWER
ACTIVITY WILL BE AROUND DUE TO A COMBINATION OF UPSLOPE FLOW AND
WEAK UPPER LEVEL SUPPORT BUT LOOKING AT GLASGOW SOUNDING LOOKS
PRETTY CLEAR THAT STRONG TO SEVERE THUNDERSTORM POTENTIAL FOR
SOUTHEAST MONTANA HAS ENDED. CURRENT DAYTIME FORECAST APPEARS TO
BE TRENDING A BIT DRIER THAN EARLIER THAT AND OVERNIGHT FORECAST A
BIT WETTER..BUT THATS ONLY BASED ON NAM12 SO WILL WAIT FOR GFS TO
MAKE CHANGES ABOUT TONIGHT FORECAST. UPDATES SENT. BORSUM

&&

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

ACTIVE NIGHT ACROSS NORTHERN MT WHERE STRONG WAVE ROTATING AROUND
CANADIAN UPPER LOW HAS TRIGGERED A LINE OF SEVERE THUNDERSTORMS.
ATTENDANT COLD FRONT HAS COMBINED WITH OUTFLOW BOUNDARIES FROM
THESE STORMS AND WAS THROUGH JUDITH GAP PER STRONG PRESSURE RISES
AND SURFACE OBSERVATIONS AT 08Z. MESOSCALE MODELS HAD A GOOD
HANDLE ON THE CONVECTION AND BROUGHT THUNDERSTORMS INTO FALLON
COUNTY BY 15Z. KBHK SOUNDING FROM THE WRF HAD ABUNDANT ELEVATED
CAPE AND DECENT SHEAR THIS MORNING...SO WILL BE WATCHING FOR
POSSIBLE STRONG TO SEVERE STORMS THERE EARLY.

MODEL CONSENSUS HAD THE COLD FRONT SURGING INTO THE AREA FROM KBIL
W BEFORE 12Z. SE MT WAS FORECAST TO REMAIN IN THE WARM SECTOR FOR
PART OF THE MORNING BEFORE FRONTAL PASSAGE AROUND 15Z. WRF
SOUNDINGS SHOWED THAT SE MT WILL HAVE AROUND 2000 J/KG OF SURFACE
CAPE THIS AFTERNOON...LIKELY AIDED BY THE MORNING PREFRONTAL
CONDITIONS. SREF ALSO HAD DECENT CAPES OVER SE MT...AREAS S OF
KBIL AND THE SW MOUNTAINS. SE MT WILL ALSO BE UNDER FAVORABLE
SHEAR TODAY BASED ON THE SREF. WILL HAVE PLENTY OF LIFT AND
MOISTURE AVAILABLE FOR PRECIPITATION TODAY AS THE RIGHT-REAR
QUADRANT OF THE UPPER JET ROUNDING THE CANADIAN LOW BRINGS UPPER
DIVERGENCE TO THE AREA AND SHORTWAVES PRODUCE Q-VECTOR
CONVERGENCE. IN ADDITION...PRECIPITABLE WATERS CLIMB TO 1-1.5
INCHES BEHIND THE FRONT...AIDED BY MONSOONAL MOISTURE FROM THE S.
ADJUSTED MORNING POPS TO BE MORE IN LINE WITH MESOSCALE
MODELS...THEN INCREASED AFTERNOON POPS DUE TO GOOD SUPPORT FOR
PRECIPITATION. ADDED ISOLATED THUNDER THIS MORNING OVER SE
MT...AREAS S OF KBIL AND THE SW MOUNTAINS. FOR THE
AFTERNOON...WILL FORECAST SHOWERS AND THUNDERSTORMS FOR THESE
LOCATIONS...WITH SHOWERS ELSEWHERE. SOME STORMS COULD BE STRONG TO
SEVERE IN THE SE...BUT DUE TO THE FRONTAL TIMING IN THE E...WILL
LEAVE SEVERE MENTION OUT OF THE FORECAST...BUT WILL PUT OUT AN HWO
AND WEATHER STORY ADVERTISING THIS POSSIBILITY.

TEMPERATURES WILL RANGE FROM THE 60S W AND WILL LIKELY BE FALLING
TODAY. EXPECT HIGHS IN THE 70S E. SOUNDINGS SUGGESTED A BREEZY DAY
WITH 15 TO 25 MPH WINDS SO INCREASED WINDS IN THE FORECAST.

LIFT DECREASES OVER THE AREA TONIGHT AND AIRMASS WILL BE
STABLE...SO HAD DECREASING POPS FOR SHOWERS THROUGH THE NIGHT.
CYCLONIC NW FLOW WILL BE OVER THE REGION MON AND MON NIGHT
BRINGING CONTINUED COOL CONDITIONS AND CHANCES FOR MOUNTAIN
SHOWERS. ARTHUR

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

WE REMAIN CONFIDENT IN A WARMING TREND DURING THE LATTER PARTS OF
THIS WEEK...AND WE ARE STILL ADVERTISING A LOW CHANCE OF STORMS ON
MANY DAYS. THE 00 UTC MODEL SUITE REMAINED IN AGREEMENT SHOWING A
BACKING OF THE FLOW ALOFT FROM NORTHWEST ON TUESDAY AND WEDNESDAY
TO THE SOUTHWEST BY NEXT WEEKEND AS AN UPPER-LEVEL TROUGH MIGRATES
INTO THE WEST COAST AND PACIFIC NORTHWEST. THAT TRANSITION WILL BE
A DRIVING FORCE BEHIND THE WARMING TREND...WHICH WILL PUSH HIGHS
BACK ABOVE 90 F BEGINNING THURSDAY.

THE EVOLUTION OF RIDGING TO THE SOUTH AND EAST OF THE LOCAL AREA
AND RESULTANT PATH OF THE PACIFIC-BASED TROUGH BY NEXT WEEKEND IS
UNCERTAIN. THE 00 UTC ECMWF WOULD SUPPORT MORE ISOLATED...BUT ALSO
STRONGER CONVECTION THAN THE 00 UTC GFS OWING TO STRONGER WINDS
ALOFT IN THE ECMWF SOLUTION. REGARDLESS...AT THIS JUNCTURE BOTH OF
THOSE IDEAS ARE COVERED BY 20 TO 30 PERCENT POPS. SCHULTZ

&&

.AVIATION...

MVFR CEILINGS WILL LIKELY DEVELOP OVER MUCH OF THE AREA TODAY AS A
COOLER AND MORE MOIST AIR MASS FILTERS IN BEHIND AN OVERNIGHT COLD
FRONTAL PASSAGE. SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED WITH
SOME MOUNTAIN OBSCURATIONS AND LOCAL MVFR TO IFR CONDITIONS TOO.
SCHULTZ

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY MON     TUE     WED     THU     FRI     SAT
-------------------------------------------------------
BIL 065 054/076 054/083 059/083 060/092 064/092 063/090
    5/W 31/B    11/B    21/B    11/U    22/T    22/T
LVM 064 048/077 047/081 051/082 052/090 056/089 056/087
    6/W 32/W    13/T    32/T    22/T    22/T    23/T
HDN 068 054/078 053/086 058/086 058/095 061/095 061/092
    5/W 21/B    11/B    11/B    11/U    22/T    22/T
MLS 070 054/075 052/084 058/084 060/093 064/095 065/092
    5/W 21/B    01/B    11/B    11/U    22/T    22/T
4BQ 070 055/075 052/083 058/082 058/090 062/094 064/090
    6/T 71/B    11/B    22/T    11/U    22/T    22/T
BHK 069 053/071 048/079 055/079 055/087 060/091 062/087
    7/T 31/B    01/B    22/T    11/U    12/T    23/T
SHR 070 052/072 049/079 054/078 054/088 057/089 057/087
    5/W 52/W    13/T    32/T    21/B    22/T    22/T

&&

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

&&

$$
WEATHER.GOV/BILLINGS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.