Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 061230
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
630 AM MDT MON JUL 6 2015

.UPDATE...
NO SIGN OF SMOKE IN THE AREA THIS MORNING SO HAVE REMOVED IT
THROUGH TONIGHT IN ALL AREAS EXCEPT SE MT WHERE N SURFACE FLOW
SHOULD KEEP AREAS OF SMOKE OVER THIS PART OF THE REGION. ALSO
ADDED AREAS OF FOG TO ELEVATIONS ABOVE 4500` WHERE TEMPERATURE/DEW
POINT SPREADS WERE ZERO. ADDED FOG TO A FEW OTHER LOCATIONS AS
WELL...BASED ON WEBCAMS AND OBSERVATIONS. HAVE THE FOG IN THROUGH
15Z. ARTHUR

&&

.SHORT TERM...VALID FOR TDY AND TUE...

SHORTWAVE ASSOCIATED WITH CENTRAL CANADIAN UPPER LOW...WAS SEEN
ON WATER VAPOR IMAGERY EARLY THIS MORNING MOVING THROUGH NE MT.
THIS ENERGY WAS COMBINING WITH LIFT FROM THE RIGHT-REAR QUADRANT
OF AN UPPER JET TO BRING WIDELY SCATTERED SHOWERS TO THE EASTERN
PART OF THE FORECAST AREA. HRRR HAS A DECENT HANDLE ON THE
SHOWERS AND SHOWED THEM INCREASING IN COVERAGE OVER SE MT AROUND
12Z. RAP SOUNDINGS SHOWED SATURATED LOW TO MID LAYERS FROM KBIL S
AND E THIS MORNING...SO WENT WITH SLIGHT CHANCE POPS AROUND KBIL
TO CHANCE POPS FROM ROSEBUD COUNTY E AND OVER SHERIDAN
COUNTY...WHERE THE BEST LIFT FROM THE WAVE IS EXPECTED. EXPECT
STRATUS OVER THE AREA THIS MORNING BASED ON SOUNDINGS...THEN
SOUNDINGS BECOME INVERTED-V IN THE AFTERNOON WITH MIXING TO JUST
BELOW 700 MB. THERE WILL BE LOW CHANCES OF MOUNTAIN THUNDERSTORMS
THIS AFTERNOON WITH SOME INSTABILITY INDICATED BY THE SREF. LIGHT
LOW-LEVEL WINDS WILL KEEP SMOKE IN THE AREA THROUGH THE DAY.
EXPECT HIGHS IN THE UPPER 60S TO MID 70S BASED ON THE ABOVE.

HEIGHTS BEGIN TO LOWER TONIGHT AS THE AREA REMAINS UNDER CYCLONIC
FLOW. MODELS CONTINUED TO SUPPORT SLIGHT CHANCES FOR THUNDERSTORMS
IN THE MOUNTAINS. KEPT SMOKE IN THE GRIDS DUE TO THE CONTINUED
LIGHT LOW-LEVEL FLOW AND DECREASED MIXING.

A WEAK COLD FRONT WILL MOVE S THROUGH THE AREA ON TUE AND AN
INVERTED TROUGH WILL SET UP OVER THE SE ZONES. SHORTWAVES WILL
CONTINUE TO MOVE THROUGH THE CYCLONIC FLOW WITH A STRONG WAVE
MOVING E THROUGH WY. THE WY WAVE WILL HELP PUSH MONSOONAL MOISTURE
N INTO THE FORECAST AREA. AFTER MORNING MOUNTAIN POPS...HAVE
INCREASED COVERAGE OF POPS ACROSS THE AREA IN THE AFTERNOON GIVEN
THE WEAK FRONTAL PASSAGE...INVERTED TROUGH...INCREASING MOISTURE
AND THE SREF SHOWING POSSIBLY 500 J/KG OF SURFACE CAPE. SIMILAR
PATTERN PERSISTS FOR TUE NIGHT AS COOLER AIR CONTINUES TO FILTER S
INTO THE AREA SO INCREASED COVERAGE OF POPS. BETTER MIXING ON TUE
WILL SUPPORT HIGHS IN THE LOWER 80S. SHEAR AND CAPES LOOK TOO WEAK
TUE/TUE NIGHT TO SUPPORT SEVERE WEATHER. ARTHUR

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

THE LONG TERM FORECAST PERIOD WILL BE HIGHLIGHTED BY WARM WEATHER
AND SOME CHANCE OF SHOWERS AND THUNDERSTORMS...ESPECIALLY FRIDAY
INTO SATURDAY. IT/S DURING THAT TIME FRAME THAT MODEL GUIDANCE IS
CONSISTENT IN SHOWING A 500-MB LOW LIFTING OUT OF CALIFORNIA AND
SHEARING INTO AN OPEN WAVE BY THE TIME IT REACHES MONTANA. THE 00
UTC ECMWF TRENDED TOWARD THE LAST SEVERAL GFS SOLUTIONS BY HAVING
THAT WAVE CUT THROUGH BROAD RIDGING ALOFT...CONTRIBUTING TO WEAK
DEEP-LAYER WIND FIELDS DESPITE SOUTHWEST FLOW ALOFT. IF THAT DOES
OCCUR...THE RISK OF SEVERE STORMS WILL BE RELATIVELY LOW.

BY LATE NEXT WEEKEND AND INTO THE FOLLOWING WEEK...GLOBAL MODELS
SUGGEST THE SUB-TROPICAL RIDGE WILL INTENSIFY AND SHIFT WESTWARD
INTO THE SOUTHERN ROCKIES. THAT MAY INCITE A MORE BONAFIDE WARMUP
OVER SOUTHERN MT AND NORTH CENTRAL WY. THE 00 UTC GFS AND ECMWF
SUGGEST THE RIDGE WILL AMPLIFY ENOUGH TO KEEP MOST STORM ACTIVITY
RELEGATED TO NORTHERN MT BY SUNDAY AND MONDAY...THOUGH ANY SUBTLE
SHIFT IN THE RIDGE/S AMPLIFICATION COULD CHANGE THAT. SCHULTZ

&&

.AVIATION...

MVFR TO IFR CONDITIONS IN LOW CLOUDS AND IN SOME CASES FOG WILL
CONTINUE ACROSS SOUTH CENTRAL MT AND NORTH CENTRAL WY UNTIL MID TO
LATE MORNING. MEANWHILE...MVFR CEILINGS ARE POSSIBLE ALONG WITH A
FEW SHOWERS AND LIGHT SMOKE IN SOUTHEASTERN MT THIS MORNING. VFR
CONDITIONS WILL PREVAIL AREA-WIDE BY THIS AFTERNOON AND EVENING...
THOUGH SOME LIGHT SMOKE MAY CONTINUE IN SOUTHEASTERN MT. SCHULTZ

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY TUE     WED     THU     FRI     SAT     SUN
-------------------------------------------------------
BIL 074 056/081 059/080 058/088 062/090 062/088 062/091
    2/W 02/T    22/T    12/T    23/T    32/T    21/B
LVM 075 050/080 051/079 051/085 055/087 056/084 054/088
    0/B 14/T    33/T    23/T    23/T    33/T    31/B
HDN 076 056/084 057/083 057/091 060/093 060/091 060/093
    2/W 03/T    22/T    12/T    23/T    32/T    21/B
MLS 073 055/082 058/082 059/090 063/095 064/091 063/090
    3/W 02/T    22/T    11/U    22/T    23/T    22/T
4BQ 073 055/081 057/082 058/088 063/094 063/090 062/090
    4/W 03/T    42/T    11/U    22/T    22/T    22/T
BHK 070 052/077 055/079 055/085 061/093 061/089 061/087
    3/W 03/T    32/T    11/U    22/T    23/T    22/T
SHR 070 052/078 053/077 054/084 056/087 056/086 056/089
    3/W 13/T    42/T    22/T    23/T    22/T    21/B

&&

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

&&

$$
WEATHER.GOV/BILLINGS



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