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 260245
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
845 PM MDT SAT JUL 25 2015

.UPDATE...

QUICK UPDATE TONIGHT TO ADDRESS ISOLATED SHOWER AND THUNDER
POTENTIAL ACROSS THE REGION. FIRST...EXPANDED POPS IN THE WEST
THROUGH MIDNIGHT TO ACCOUNT FOR MORE EXTENSIVE ACTIVITY MOVING
INTO WESTERN ZONES...AS FAR SOUTH AS LIVINGSTON. THE BIGGER CHANGE
WAS TO ADD ISOLATED THUNDERSTORMS IN THE EASTERN ZONES AFTER
MIDNIGHT EVEN THOUGH MOISTURE AVAILABILITY IS SOMEWHAT
LIMITED AND THE CAP LOOKS FAIRLY STRONG. CONCERNS STARTED WITH
NOTICING THE DEVELOPMENT OF A LOW LEVEL JET ACROSS THE EAST AFTER
MIDNIGHT...WITH 1000-2000 J/KG OF CAPE ABOVE THE INVERSION.
CLOSER INSPECTION SHOWED SOME INDICATION THAT THE TAIL END OF THE
WAVE CROSSING THE NORTHWEST ZONES AND MAINLY NORTH OF US WOULD
SLIDE THROUGH THE EAST IN THAT GENERAL TIME RANGE.
ADDITIONALLY...IT APPEARS THAT THERE WILL BE SOME WEAK THETA-E
ADVECTION AT 850-700MB. FINALLY...NOTICED THAT THE HRRR MODEL IS
INDICATING DEVELOPMENT IN THE EAST FOR THE SAME APPROXIMATE TIME
PERIOD. ALTHOUGH NOT CONFIDENT ENOUGH FOR HIGH POPS...COULD NOT
IGNORE POTENTIAL FOR THE EAST OVERNIGHT. OTHERWISE...THE INHERITED
FORECAST APPEARS TO BE IN GOOD SHAPE. AAG

&&

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

TONIGHT AND SUNDAY...SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE
TO BE POSSIBLE THIS AFTERNOON AND EVENING. A WEAK DISTURBANCE IN
THE SOUTHWESTERLY FLOW WILL PROVIDE ENOUGH INSTABILITY OVER THE
HIGHER TERRAIN AND IN THE FAR EASTERN ZONES TO CREATE SCATTERED
ACTIVITY. A FEW STORMS IN THE EASTERN ZONES SHOULD BE STRONG THIS
AFTERNOON AND EARLY EVENING. FOLLOWING THIS AFTERNOON
DISTURBANCE...THINGS WILL DRY OUT OVERNIGHT. AS THE MAIN TROUGH
OVER THE PACIFIC NORTHWEST BEGINS TO APPROACH THE AREA
TOMORROW...THE FLOW WILL BECOME MORE UNSETTLED. THIS WILL
INCREASE RAIN CHANCES OVER THE WESTERN MOUNTAINS. SOME INSTABILITY
EXISTS SO A FEW THUNDERSTORMS COULD BE STRONG AGAIN.

MONDAY...AN UNSEASONABLY DEEP UPPER TROUGH IS PROGGED TO SLICE
THROUGH THE AREA. THIS WILL CAUSE QUICKLY CYCLOGENESIS OVER
EASTERN MONTANA MONDAY AFTERNOON AND DRAG AND STRONG COLD FRONT
THROUGH THE AREA. THE FRONTAL TIMING HAS SPED UP OVER PAST FEW
RUNS WITH THE FRONTAL GETTING INTO THE WEST SUNDAY NIGHT AND
THROUGH BILLINGS BY LATE MONDAY MORNING. THE FRONT SHOULD CLEAR
THE EAST FRIDAY AFTERNOON. STRONG WINDS WILL ACCOMPANY THE FRONTAL
PASSAGE WITH COOLER TEMPERATURES. HIGHS IN THE WESTERN ZONES WILL
STRUGGLE TO GET INTO THE LOWER 70S. THE EAST WILL BE MUCH WARMER
AHEAD OF THE FRONT WITH HIGHS REACHING THE LOWER 90S. THE EAST
WILL ALSO EXPERIENCE THE LOWEST HUMIDITY AND THUS COULD HAVE
CRITICAL FIRE WEATHER CONDITIONS AS THE FRONT ROLLS IN MONDAY
AFTERNOON AND EVENING. HAVE ISSUED A FIRE WEATHER WATCH FOR MONDAY
AFTERNOON AND EVENING OVER THE EAST BASED ON THIS. WESTERN AND
CENTRAL ZONES WILL BE WINDY TOO BEHIND THE FRONT...BUT WILL BE
COOLER WITH A DECENT SHOWERS OF SHOWERS AND THUNDERSTORMS AND THUS
HAVE HIGHER HUMIDITY LEVELS...ALONG WITH MORE CLOUD COVER.

REIMER/TWH

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


TUESDAY...WILL BE A COOL AND WINDY DAY. 850MB WINDS WERE STILL
PEGGED AT 40KTS ACROSS MOST OF THE AREA. CYCLONIC FLOW AND SOME
WRAP AROUND MOISTURE AND CLOUDS WILL PREVENT SOME OF THIS FROM
REACHING THE SURFACE...BUT THE SURFACE PRESSURE GRADIENT WILL BE
STRONG ENOUGH TO PRODUCE WIND GUSTS TO 45 MPH. THE UPPER LOW WAS
POSITIONED A LITTLE FARTHER NORTH...SO THE TREND LOOKS TO BE
DRIER. THERE IS STILL SOME QUESTION ON HOW LOW HUMIDITY LEVELS
WILL FALL TOO...GIVEN SOME WRAP AROUND MOISTURE AND ASCENT IN
CYCLONIC FLOW. WILL KEEP ADVERTISING POTENTIAL FIRE WEATHER
CONCERNS FOR TUESDAY. HIGHS WILL BE HELD INTO THE 70S WITH GUSTY
WINDS THROUGH THE DAY. WINDS SHOULD FALL OFF TUESDAY EVENING AS
THE SURFACE LOW PUSHES EAST.

WEDNESDAY THROUGH SATURDAY...WEATHER WILL QUICKLY TRANSITION TO A
QUIETER PATTERN. BEHIND THE DEPARTING TROUGH...A RIDGE BEGINS TO
BUILD IN BUT REMAINS SOMEWHAT FLATTENED. THE AREA WILL SEE A DRY
AND WARMING TREND THROUGH THE REMAINDER OF THE WEEK. SATURDAY A
WEAK SHORTWAVE WILL MOVE OVER THE RIDGE BRINGING A SLIGHT RAIN
CHANCE TO THE MOUNTAINS ON SATURDAY.

TWH/REIMER

&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL ACROSS THE REGION TONIGHT. ISOLATED
SHOWERS AND TSTORMS ARE POSSIBLE...WEST AND NORTH OF KBIL THROUGH
06Z. ISOLATED SHOWERS AND TSTORMS ARE POSSIBLE EAST OF KBIL AFTER
06Z...WITH BEST POTENTIAL FROM KMLS EAST AFTER 09Z. LOCALIZED
MVFR CONDITIONS ARE POSSIBLE WITH HEAVIER PRECIP. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    SUN     MON     TUE     WED     THU     FRI     SAT
-----------------------------------------------------------
BIL 061/091 061/076 052/075 053/086 058/092 061/093 062/092
    11/B    24/T    42/W    11/U    11/U    11/U    11/B
LVM 054/090 055/070 047/073 047/084 052/090 054/091 056/089
    23/T    35/T    53/T    11/U    11/U    11/U    11/B
HDN 058/095 058/082 051/077 051/088 056/094 058/095 061/094
    11/B    23/T    42/W    11/U    11/U    11/U    11/B
MLS 063/096 064/089 054/075 053/087 059/094 062/096 063/094
    21/B    22/T    42/T    21/U    11/U    11/U    11/B
4BQ 062/096 063/092 054/076 053/086 058/093 060/095 062/092
    21/B    22/T    32/W    11/U    11/U    11/U    11/B
BHK 060/094 062/091 054/074 052/083 056/090 058/092 060/089
    22/T    22/T    42/T    21/U    11/U    11/U    11/B
SHR 055/094 056/086 049/073 047/083 052/090 055/091 057/089
    12/T    22/T    22/W    01/U    11/U    11/U    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...FIRE WEATHER WATCH IN EFFECT FROM MONDAY AFTERNOON THROUGH
      MONDAY EVENING FOR ZONES 30>33-36>38-57-58.
WY...FIRE WEATHER WATCH IN EFFECT FROM MONDAY AFTERNOON THROUGH
      MONDAY EVENING FOR ZONES 98-99.

&&

$$
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.