Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 040835
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
235 AM MDT WED MAY 4 2016

.SHORT TERM...VALID FOR TDY AND THU...

ELONGATED SHORTWAVE...SEEN ON WATER VAPOR IMAGERY FROM ALBERTA
SOUTH THROUGH ID...WILL MOVE INTO THE UPPER RIDGE THIS AFTERNOON.
THE WAVE COULD TRIGGER A FEW MOUNTAIN THUNDERSTORMS THIS AFTERNOON
AS SOUNDINGS WILL HAVE STEEP LAPSE RATES. HAVE ADDED THESE TO THE
FORECAST. OTHERWISE...LOOKING AT A MOSTLY SUNNY AND VERY WARM DAY
TODAY WITH TEMPERATURES IN THE LOWER TO MID 80S DUE TO MIXING TO
ABOVE 700 MB WHERE TEMPERATURES WILL BE AT LEAST +6 DEGREES C.
TONIGHT WILL BE ANOTHER WARM NIGHT WITH LOWS IN THE 40S TO MID
50S.

UPPER RIDGE REMAINS IN THE PLACE ON THU AND STARTS SHIFTING E THU
NIGHT. EXPECT HIGHER MIXING HEIGHTS THAN TODAY WHICH WILL PUSH
TEMPERATURES WELL INTO THE 80S TO RECORD OR NEAR-RECORD LEVELS.
UPSLOPE FLOW AND STEEP LAPSE RATES WILL AID CONVECTION BREAKING
OUT OVER THE NE SLOPES OF THE BEARTOOTHS/ABSAROKAS IN THE
AFTERNOON. UPPER DIFFLUENCE WILL MOVE OVER THE WESTERN ZONES THU
NIGHT. THIS WILL COMBINE WITH A COLD FRONT MOVING IN FROM THE NW
TO BRING LOW CHANCES FOR EVENING THUNDERSTORMS AND OVERNIGHT
SHOWERS TO THE NW PART OF THE AREA. MOISTURE INCREASES AFTER 06Z
SUPPORTING CHANCE POPS IN THE WESTERN MOUNTAINS. GUSTY N WINDS MAY
ACCOMPANY THE FRONTAL PASSAGE IN THE NW LATE AT NIGHT. ARTHUR

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

FRIDAY BRINGS A COOLER WEATHER REGIME AS A COLD FRONT PUSHES
THROUGH THE AREA DURING THE MORNING HOURS. SURFACE HIGH PRESSURE
BEHIND THE FRONT SETS UP UPSLOPE FOR PART OF SOUTHERN MONTANA BUT
THE UPPER LOW OVER THE GREAT BASIN IS NOT PROVIDING A SIGNIFICANT
AMOUNT OF SUPPORT AS THE INITIAL PUSH IS UNDER UPPER LEVEL
RIDGING. THIS IS REPLACED FRIDAY NIGHT WITH SOME WEAK DIFFLUENCE
SO THAT IS THE PERIOD WITH THE BEST CHANCE FOR MOISTURE. CIPS
ANALOGS HIGHLIGHT A CASE FROM MAY OF 1996 WHICH LOOKS SIMILAR
EXCEPT THERE WAS NOT STRONG RIDGING IN ADVANCE OF THE SYSTEM SO
THIS EPISODE DOES NOT HAVE NEARLY AS MUCH MOISTURE TO WORK WITH.
SOUTHEAST MONTANA WILL HAVE A CHANCE TO WARMUP A BIT AHEAD OF THE
FRONT HAVE HAVE DEPICTED NEARLY A 20 DEGREE GRADIENT ACROSS THE
AREA. THUNDER THREAT IS PRESENT BUT SIGNIFICANT CONVECTION NOT
EXPECTED DUE TO THE FAVORED NOCTURNAL TIMING FOR THE BEST LIFT.

AS THE UPPER DIFFLUENCE WEAKENS ON SATURDAY DRY AIR PUSHING IN
FROM THE NORTH CUTS OFF MUCH OF THE CHANCE FOR PRECIPITATION.
SUNDAY THE UPPER LOW TRANSITIONS INTO THE PLAINS AND ANOTHER COLD
FRONT MOVES INTO WESTERN MONTANA DRIVEN BY A MUCH STRONGER
WESTERLY FLOW MOVING THROUGH CANADA. SATURDAY WILL STILL BE COOL
BUT A REBOUND CAN BE EXPECTED ON SUNDAY DUE TO COMPRESSIONAL
WARMING AHEAD OF THE FRONT.

MONDAY THROUGH WEDNESDAY LOOK LIKE SHOWER ACTIVITY CANNOT BE RULED
OUT BUT NO MECHANISMS FOR SIGNIFICANT WIDESPREAD MOISTURE EXIST.
TEMPERATURES WILL BE CLOSE TO NORMAL FOR THIS TIME OF YEAR. BORSUM

&&

.AVIATION...

VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS. BORSUM

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY THU     FRI     SAT     SUN     MON     TUE
-------------------------------------------------------
BIL 084 052/088 054/067 048/063 045/069 047/066 043/063
    1/U 00/U    13/T    54/W    22/W    22/W    33/W
LVM 081 046/084 046/062 043/061 039/070 041/063 039/062
    1/U 01/B    24/T    54/T    33/W    33/W    33/W
HDN 084 044/089 047/070 043/065 041/069 041/068 041/063
    1/U 00/U    13/T    45/W    11/B    23/W    33/W
MLS 085 051/090 054/075 047/070 046/072 047/068 044/062
    1/U 00/U    12/T    32/W    11/B    12/W    33/W
4BQ 083 046/090 050/080 045/065 043/068 043/066 041/063
    1/U 00/U    13/T    44/T    22/W    22/W    22/W
BHK 082 046/089 050/077 043/069 041/069 043/066 040/060
    1/U 00/U    11/N    31/B    11/B    22/W    33/W
SHR 079 042/084 043/067 042/061 039/065 039/063 038/060
    1/U 00/U    14/T    66/T    43/W    23/W    33/W

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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