Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 191152
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
552 AM MDT FRI SEP 19 2014

.UPDATE...

RADAR TRENDS WERE REFLECTING THE LAST FEW HRRR RUNS IN MOVING
PRECIPITATION RAPIDLY OUT OF THE AREA WITH JUST A HINT OF SOME
PRECIPITATION POSSIBLE OVER SE MT. SO WILL UPDATE TO REDUCE POPS
THIS MORNING. ARTHUR

&&

.SHORT TERM...VALID FOR TDY AND SAT...

AREAS OF SHOWERS AND THUNDERSTORMS WERE MOVING NE THROUGH MT IN A
POST-FRONTAL ENVIRONMENT AND AHEAD OF AN APPROACHING UPPER TROUGH.
MOST OF THE ACTIVITY WAS OVER SE MT EARLY THIS MORNING. THE
RIGHT-REAR QUADRANT OF AN UPPER JET WAS ALSO SUPPORTING THE
PRECIPITATION.

MODELS WERE SIMILAR IN MOVING THE UPPER TROUGH INTO E MT TODAY.
WHILE THE SSEO DID NOT HAVE A GOOD HANDLE ON THE PRECIPITATION
EARLY THIS MORNING...THE HRRR WAS DOING WELL AND MOVED EVERYTHING
OUT OF THE AREA AROUND 12Z. CONCERNED THIS MOVEMENT MAY BE A
LITTLE FAST GIVEN RADAR TRENDS...SO HAVE KEPT POPS OVER THE AREA
THIS MORNING...MAINLY E AND S OF KBIL. ALSO RAISED POPS TO CHANCE
IN SE MT. GIVEN STEEP MID AND UPPER LEVEL LAPSE RATES ON FORECAST
SOUNDINGS...WILL KEEP THUNDER IN THE FORECAST THIS MORNING. FOR
THE AFTERNOON...REMOVED POPS OVER KSHR DUE TO DOWNSLOPING AND KEPT
A LOW POP OVER THE NE BIG HORNS. MODELS AGREED THAT AIRMASS WILL
STABILIZE THIS AFTERNOON AS IT DRIES OUT. BASED ON MODEL
SOUNDINGS...WILL HAVE A BREEZY TO WINDY DAY OVER MOST AREAS WITH
THE FAST FLOW ALOFT. LOWERED TEMPERATURES A COUPLE OF DEGREES
BASED ON MIXING PROFILES AND WENT CLOSE TO CONSALL GUIDANCE.

WILL HAVE A FLAT NW FLOW OVER THE AREA TONIGHT...THEN UPPER
RIDGING AND DRY WEATHER BUILDS IN FOR THE REMAINDER OF THE
PERIOD. HAVE DRIED OUT THE EVENING WITH LIFT AND MOISTURE
CONTINUING TO EXIT THE REGION.

SAT WILL BE LESS WINDY THAN TODAY...AS FAST FLOW ALOFT SHIFTS E
WITH THE UPPER TROUGH. HOWEVER IT WILL STILL BE WINDY OVER PLACES
LIKE KBHK AND EKALAKA. EASTERLY WINDS ON SAT WILL INHIBIT MIXING
OVER THE AREA SO LOWERED TEMPERATURES SLIGHTLY TOWARD THE
SUPERBLEND GUIDANCE. ARTHUR

.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...

MADE A FEW CHANGES TO THE EXTENDED FORECAST PACKAGE FOR A COUPLE
OF REASONS. THE FIRST CHANGE WAS TO RAISE POPS A BIT FOR THE
SUNDAY NIGHT THROUGH MONDAY NIGHT PERIOD. THIS IS IN RESPONSE TO
THE UPPER LOW CURRENTLY SITTING OVER CENTRAL CALIFORNIA. MODELS
PULL THIS SYSTEM INTO NORTHERN WYOMING AND SOUTHERN MONTANA SUNDAY
NIGHT AND EARLY MONDAY. MODELS HAVE TRENDED FARTHER NORTH WITH
THIS FEATURE AND BECAUSE OF SUCH PULL PRECIPITABLE WATERS AS HIGH
AS 1.5 INCHES INTO THE EASTERN HALF OF MONTANA...WHICH IS QUITE
HIGH FOR THIS TIME OF YEAR. JET FORCING WITH THE UPPER LOW IS
MINIMAL...BUT GIVEN THE AMOUNT OF PWAT AVAILABLE...SHOULD NOT BE
TERRIBLY DIFFICULT TO GET SHOWERS TO FORM.

THE SYSTEM KICKS OUT TUESDAY AFTERNOON AND NIGHT. THIS WILL DRY
THINGS OUT FROM WEST TO EAST. RIDGING FOLLOWS FOR WEDNESDAY. THIS
RIDING WILL QUICKLY BE REPLACED BY STRONG SOUTHWEST FLOW FOR A
STRONG DOWNSLOPE PATTERN. THIS IS THE SECOND CHANGE TO THE
FORECAST PACKAGE MADE...A CHANGE TO RAISE TEMPERATURES WEDNESDAY
INTO FRIDAY WITH THIS STRONG DOWNSLOPE PATTERN. WOULD EXPECT DRY
AIR TO GET PULLED UP FROM THE DESERT SOUTHWEST AND BECAUSE OF
THAT...MID 80S ARE QUITE POSSIBLE WEDNESDAY AND THURSDAY. THE FLY
IN THE OINTMENT OF WARMER TEMPERATURES COULD BE SOME CLOUD COVER
AS MID TO HIGH LEVEL MOISTURE TRIES TO INCREASE AHEAD OF AN
ADVANCING COLD FRONT. THIS FRONT APPROACHES THE WEST THURSDAY
EVENING AND WILL LEAD TO COOLER TEMPERATURES FRIDAY ALONG WITH AN
INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. TWH
&&

.AVIATION...

A FEW SHOWERS AND THUNDERSTORMS WILL LINGER OVER SOUTHEAST
MONTANA THIS MORNING. THIS PRECIPITATION WILL QUICKLY EXIT THE
AREA EARLY THIS MORNING. THE REST OF THE DAY WILL BE DRY AS WEST
TO NORTHWEST WINDS INCREASE. EXPECT GUSTS TO 20KTS ACROSS MOST OF
THE AREA TODAY. TWH

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY SAT     SUN     MON     TUE     WED     THU
-------------------------------------------------------
BIL 078 052/074 049/076 053/076 054/080 054/082 054/080
    3/B 00/U    00/U    13/T    31/B    11/U    11/B
LVM 075 043/076 041/076 047/074 049/078 048/080 049/078
    3/N 10/U    00/U    23/T    21/B    11/B    12/T
HDN 080 050/076 045/078 052/078 052/080 052/084 052/082
    4/B 00/U    00/U    13/T    31/B    11/U    11/B
MLS 080 051/075 045/076 052/079 054/078 053/083 053/084
    4/N 00/U    00/U    02/T    21/B    11/U    11/B
4BQ 081 051/076 046/076 053/079 054/077 052/082 052/084
    4/T 00/U    00/U    12/T    32/T    11/B    11/B
BHK 078 049/073 041/073 047/077 051/073 049/079 050/081
    4/N 00/N    00/U    02/T    22/T    11/U    11/B
SHR 077 048/075 045/077 051/075 049/076 049/080 050/080
    5/B 10/U    00/U    24/T    42/T    10/U    11/B

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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