Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 312122
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
322 PM MDT MON AUG 31 2015

.SHORT TERM...VALID FOR TUE AND WED...

THE WEATHER WILL TURN VERY WARM AGAIN TUESDAY AND WEDNESDAY. A
WESTERN UPPER TROUGH WILL DEEPEN OVER BRITISH COLUMBIA THROUGH
EARLY WEDNESDAY. THIS SCENARIO WILL DEEPEN THE SOUTHWEST FLOW OVER
SOUTHERN MONTANA AND NORTHERN WYOMING. DEEP MONSOON FLOW WILL BE
DEFLECTED INTO EASTERN WYOMING AND THE WESTERN DAKOTAS...WITH MOST
OF THE AREA HAVING PRECIPITABLE WATERS BELOW SEVEN TENTHS. MIXING
THIS RELATIVELY DRY AIR WILL PRODUCE HIGHS AROUND 90 DEGREES BOTH
TUESDAY AND WEDNESDAY...WITH THE WARMEST POTENTIAL DAY BEING
WEDNESDAY. A COLD FRONT WILL PUSH THROUGH THE AREA WEDNESDAY
EVENING. THIS FRONT IS PROJECTED TO COME THROUGH DRY WITH JUST A
WIND SHIFT...BUT DID INTRODUCE A SLIGHT CHANCE OF CONVECTION
BEHIND THE FRONT OVER THE NORTHWEST ZONES. THE FRONT WILL USHER IN
PROGRESSIVELY COOLER WEATHER THROUGH THE END OF THE WEEK.

FIRE WEATHER...THE NEXT TWO DAYS WILL SEE VERY DRY CONDITIONS
WITH HUMIDITY LEVELS FALLING WELL INTO THE TEENS. WINDS ARE
EXPECTED TO BE LIGHT ON TUESDAY...BUT MIXING WILL INCREASE ON
WEDNESDAY. THE STRONGEST POTENTIAL MIX DOWN WINDS WILL BE WEST OF
COLUMBUS AND ESPECIALLY THROUGH THE UPPER YELLOWSTONE VALLEY.
COULD BE A FIRE WEATHER CONCERN WEDNESDAY AFTERNOON FOR THESE
LOCATIONS...BUT WILL WAIT TO SEE MODEL TRENDS ON THIS BEFORE
ISSUING ANY HIGHLIGHTS. A COLD FRONT WILL PUSH THROUGH WEDNESDAY
EVENING...BUT MODELS WERE NOT ADVERTISING A BIG WIND SHIFT EVENT
FOR THIS FRONT AT THIS POINT. TWH

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

FAIRLY COMPLICATED LONG TERM FORECAST AS MUCH UNCERTAINTY RESIDES
IN THE HANDLING OF AN AMPLIFYING UPPER LOW JUST OFF THE WASHINGTON
COAST. REGARDLESS OF THE THE EVENTUAL SOLUTION, WE SHOULD SEE
BELOW NORMAL TEMPERATURES THROUGHOUT THE EXTENDED WITH ABOVE
NORMAL RAIN CHANCES FRIDAY-SUNDAY.

BOTH MODELS BEGIN THE PERIOD IN GOOD AGREEMENT WITH SOUTHWEST
FLOW OVER THE REGION. WEDNESDAYS COLD FRONT SHOULD COOL CONDITIONS
INTO THE UPPER 70S BUT MODEL TRENDS HAVE KEPT THE SYSTEM SLOWER
WITH EACH SUCCESSIVE RUN SO CAN NOT RULE OUT WARMER TEMPERATURES
THURSDAY. DIFFERENCES IN THE EVOLUTION OF THIS PACIFIC TROUGH
QUICKLY EMERGE FROM FRIDAY ONWARD. THE GFS REMAINS THE FASTER
SOLUTION AND PUSHES A STRONG COLD FRONT THROUGH THE AREA SUNDAY.
THE EURO REMAINS SLOWER AND PUSHES A WEAKER COLD FRONT THROUGH
SOMETIME MONDAY. IN TERMS OF TEMPERATURES THE EURO REFLECTS THIS
TREND WITH MUCH WARMER TEMPERATURES COMPARED TO 00Z RUN. BECAUSE
OF WILDLY DIFFERENT SCENARIOS...HAVE NOT CHANGED MUCH FROM THE
INHERITED FORECAST. FOR THIS UPDATE USED A BLEND OF THE PRIOR
FORECAST AND NEW CONSENSUS GUIDANCE...WITH A LITTLE BIT STRONGER
WEIGHTING OF THE GFS...WHICH HAD BETTER CONSISTENCY.

IN ANY SCENARIO CONFIDENCE REMAINS HIGH THAT TEMPERATURES WILL BE
BELOW AVERAGE THIS WEEKEND WITH THE APPROACHING TROUGH. MOISTURE
CONTENT ALSO WILL BE GOOD WITH ENSEMBLE PWATS AT LEAST 1 STANDARD
DEVIATION ABOVE NORMAL. OCCASIONAL RIPPLES OF ENERGY ROUNDING THE
UPPER LOW...COMBINED WITH THE AFOREMENTIONED PWATS...SHOULD
PROVIDE GOOD CHANCES FOR RAIN THROUGH THE WEEKEND. GIVEN THE
HOLIDAY WEEKEND THIS COULD PUT A DAMPER ON MANY FOLKS OUTDOOR
PLANS SO WILL WAIT FOR BETTER CONSISTENCY BEFORE PUTTING OUT
HIGHLIGHTS ON THIS SYSTEM. DOBBS

&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL THIS EVENING AND INTO THE MORNING WITH
MOSTLY CLEAR SKIES. MROWELL

&&

.PRELIMINARY POINT TEMP/POPS...

    TUE     WED     THU     FRI     SAT     SUN     MON
-----------------------------------------------------------
BIL 055/090 060/091 056/077 050/073 049/064 045/067 043/071
    00/K    00/B    12/T    22/T    34/T    42/T    21/U
LVM 046/091 052/087 048/073 042/071 043/066 039/065 037/071
    00/K    10/N    14/T    43/T    44/T    43/T    31/U
HDN 053/093 057/096 055/082 051/076 051/069 046/069 043/073
    00/U    10/B    02/T    22/T    33/T    33/T    21/U
MLS 055/093 060/098 059/083 055/079 055/072 048/066 043/071
    00/U    00/B    02/T    22/T    44/T    44/T    31/U
4BQ 055/093 059/098 059/088 056/080 056/073 050/067 045/070
    00/U    00/B    01/B    12/T    44/T    33/T    21/U
BHK 053/091 056/098 059/086 056/080 054/071 049/065 044/068
    00/U    00/U    01/B    12/T    44/T    44/T    31/U
SHR 047/092 053/094 053/084 050/078 049/071 045/067 039/071
    00/U    10/B    11/B    12/T    23/T    33/T    21/U

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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