Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 291652
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1052 AM MDT TUE JUL 29 2014

.UPDATE...
BAND OF SHOWERS NEAR MILES CITY AND COLSTRIP GRADUALLY DISSIPATING
AS UPPER SUPPORT WANES THIS MORNING. DEEPEST MOISTURE WILL REMAIN
OVER OUR SOUTH TODAY...ON NORTHERN FRINGES OF DEEPER MONSOONAL
PLUME IN THE CENTRAL ROCKIES...AND WOULD EXPECT SOME UNORGANIZED
DIURNAL DEVELOPMENT OVER OUR MTNS AND FOOTHILLS THIS AFTN AND
EARLY EVENING. WE MAY ALSO SEE A FEW SHOWERS OR TSTMS DEVELOP IN
SOUTHEAST MT BETWEEN NOW AND MID AFTN...A SHORT WINDOW HERE...BUT
OTHERWISE WE WILL BEGIN MIXING DRIER AIR FROM THE NORTH AS THE
WAVE MOVING TOWARD THE DAKOTAS PASSES. HAVE MADE A FEW MORE POP
ADJUSTMENTS BASED ON CURRENT ACTIVITY. JKL

&&

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

A SERIES OF MONSOONAL IMPULSES ARE MOVING THROUGH AN UPPER LEVEL
RIDGE ACROSS THE ROCKIES. THESE ARE PRODUCING SOME SHOWERS AND
ISOLATED THUNDER ACROSS THE MONTANA/WYOMING BORDER REGION EARLY
THIS MORNING...WHILE A SHORTWAVE ROUNDS THE RIDGE TO THE NORTH
AND HAS BEEN PRODUCING SOME LIGHTNING NORTH OF OUR FORECAST
AREA...JUST EAST OF LEWISTOWN. ALL OF THIS ACTIVITY IS TRACKING
SOUTHEAST. THE HRRR IS HANDLING THE NORTHERN CONVECTION BEST AND
HAS IT TRACKING SOUTHEAST INTO ROSEBUD COUNTY THIS MORNING.
THEREFORE...HAVE ADDED LOW POPS ACROSS THIS SECTION OF THE
FORECAST AREA. REST OF POPS OVER THE SOUTHERN TIER OF OUR FORECAST
AREA INTO NORTH CENTRAL WYOMING LOOK GOOD. THE SHORTWAVE ROUNDING
THE RIDGE WILL PUSH SOUTH/SOUTHEAST TODAY AND CAUSE A SHIFT IN THE
MONSOONAL PLUME...SUPPRESSING IT SOUTHWARD. THUS...FORCING BY
TOMORROW WILL BE WEAKER WITH DRIER MID LEVELS...SO THE POPS WILL
BE MAINLY SITUATED OVER THE SOUTHERN BORDER ZONES FOR WEDNESDAY.
AS FOR TEMPS...YESTERDAYS HIGHS AROUND 90F SHOULD FALL A FEW
DEGREES FOR TODAY WITH WEAK COLD ADVECTION/EASTERLY FLOW...THEN
CLIMB BACK A FEW DEGREES AGAIN WEDNESDAY. OVERALL...SEASONAL
TEMPERATURES AND A LIMITED CHANCE OF PRECIPITATION THE NEXT COUPLE
OF DAYS. BT

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

MADE SEVERAL CHANGES TO THE EXTENDED FORECAST PERIOD...AS IS
BEGINNING TO SHOW SIGNS OF INCREASE WEATHER POTENTIAL. THE UPPER
LEVEL RIDGE REMAINS IN CONTROL OVER THE REGION TO BEGIN THE
PERIOD...AND MONSOONAL MOISTURE CONTINUES TO STREAM INTO THE
REGION.

MAINLY DRY CONDITIONS WILL PERSIST THURSDAY AND FRIDAY...WITH
ISOLATED SHOWER/THUNDERSTORM POTENTIAL CONFINED MAINLY TO THE HIGH
TERRAIN. MODELS INDICATE A SHORTWAVE ROTATING THROUGH THE REGION
BEGINNING AS EARLY AS FRIDAY EVENING...DEPENDING ON THE MODEL.
IMPACTED AREA ALSO VARIES CONSIDERABLY...BUT TEND BE A LITTLE MORE
CONSERVATIVE THAN BROADER COVERAGE OF THE ECMWF...BASED ON THE DRY
CONDITIONS IN THE EASTERN THIRD OF THE CWA. AT THIS POINT THE
PATTERN TRANSITIONS TO A MORE ACTIVE FLOW...WITH SOMEWHAT ZONAL
ACROSS THE REGION...WITH SEVERAL SHORTWAVES AND ACROSS THE REGION
THROUGH THE REMAINDER OF THE PERIOD. THIS SHOULD RESULT IN MORE
WIDESPREAD SHOWER AND THUNDERSTORM POTENTIAL...AND SHOULD BE
PRETTY WET SYSTEMS WITH THE TAP TO MONSOONAL FLOW. HAVE OPTED TO
KEEP POPS ISOLATED TO SCATTERED ACROSS THE REGION AT THIS
TIME...JUST TO GET MENTION IN THE FORECAST IS CASE PATTERN TURNS
DRY AGAIN.

AS FOR TEMPS WE ARE STILL LOOKING AT HIGHS AROUND 90
EACH DAY TO START THE EXTENDED PERIOD. THIS CHANGE IN OVERALL
PATTERN HOWEVER SHOULD ALSO RESULT IN A COOLER STRETCH OF WEATHER
THROUGH THE LATTER HALF OF THE PERIOD. THEREFORE COOLED INHERITED
TEMPS A FEW DEGREES FOR THE WEEKEND AND EARLY NEXT WEEK. THIS
STILL PUTS FORECAST TEMPS IN MID TO UPPER 80S. AAG

&&

.AVIATION...

ISOLATED SHOWERS /AND PERHAPS A THUNDERSTORM/ WILL AFFECT PORTIONS
OF THE AREA THIS MORNING...ESPECIALLY AROUND KSHR. WE BELIEVE MUCH
OF THE CONVECTIVE ACTIVITY WILL BE RELEGATED TO NEAR THE MOUNTAINS
AND FOOTHILLS AFTER 18 UTC. MVFR CONDITIONS ARE POSSIBLE WITH THAT
ACTIVITY...BUT VFR WEATHER WILL GENERALLY PREVAIL TODAY. SCHULTZ

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY WED     THU     FRI     SAT     SUN     MON
-------------------------------------------------------
BIL 087 060/089 062/089 062/091 064/089 060/087 062/088
    1/B 00/U    01/B    12/T    22/T    22/T    22/T
LVM 088 051/087 053/089 055/091 055/087 053/083 055/085
    2/T 11/U    12/T    22/T    22/T    22/T    22/T
HDN 089 057/091 057/091 061/093 061/090 059/088 062/091
    2/T 00/U    01/U    11/U    22/T    22/T    22/T
MLS 089 060/091 061/089 064/093 064/091 062/087 064/089
    1/B 00/U    01/U    11/U    12/T    22/T    12/T
4BQ 087 058/088 058/088 060/092 062/089 060/086 063/089
    2/T 11/U    01/U    11/U    12/T    22/T    22/T
BHK 085 054/086 055/086 059/089 059/086 057/083 060/086
    1/U 00/U    01/U    11/U    12/T    22/T    12/T
SHR 085 052/086 053/086 057/089 057/085 055/083 057/086
    2/T 21/U    02/T    12/T    22/T    23/T    32/T

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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