Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 221539
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
839 AM MST SAT NOV 22 2014

.UPDATE...
LEE TROUGH WELL ESTABLISHED WITH STRONG WINDS AT LIVINGSTON
GUSTING AS HIGH AS 68 MPH. HIGHLIGHTS LOOK VERY GOOD. COLD FRONT
SHOULD SWEEP THROUGH THE WEST THIS AFTERNOON AND WILL DECREASE GAP
FLOW AND ALLOW WINDS TO DECREASE SOME. WINDS WILL STILL BE STRONG
AT LIVINGSTON...BUT WILL BE FROM THE WEST AND WILL PROBABLY BE AT
A SLIGHTLY LESSER STRENGTH. GUIDANCE WAS KEEPING WINDS STRONG AT
LIVINGSTON INTO THE EVENING. TYPICALLY WEST WINDS ARE NOT NEARLY
AS STRONG AS GAP WINDS AND AM THUS ANTICIPATING THE WINDS SHOULD
DROP BELOW ADVISORY CRITERIA THIS AFTERNOON. WILL TAKE A CLOSE
LOOK AT THIS FOR THE AFTERNOON PACKAGE. WINDS WILL INCREASE FROM
BIG TIMBER TO JUDITH GAP THIS AFTERNOON AS THE COLD FRONT MARCHES
THROUGH. HIGHLIGHTS LOOK GOOD THERE. RAISED POPS EAST OF BILLINGS
AWAY FROM DOWNSLOPE INFLUENCES AS ENERGY MOVING THROUGH CREATING
SHOWERS ON THE RADAR. ALSO RAISED HIGHS A COUPLE DEGREES IN PLACES
WITH SUCH A WARM START. TWH

&&

.SHORT TERM...VALID FOR TDY AND SUN...

RELATIVELY MINOR CHANGES TO THE SHORT TERM PERIOD...WITH THE
EXCEPTION OF ISSUING WIND HIGHLIGHTS FOR BIG TIMBER TO JUDITH GAP.
OVERALL THE INHERITED FORECAST WAS IN GOOD SHAPE WITH REGARD TO
AND ACTIVE PERIOD OF WEATHER OVER THE NEXT COUPLE OF DAYS...WITH
STRONG GUSTY WINDS IN THE WEST TODAY. GUSTY WINDS WILL SPREAD INTO
THE EAST THIS EVENING AND CONTINUE INTO SUNDAY. MEANWHILE SNOW
WILL IMPACT HIGH TERRAIN TODAY...AND SCATTERED SHOWERS WILL SPREAD
ACROSS THE PLAINS TURNING TO SNOW SHOWERS THIS EVENING.

STRONG GUSTY WINDS HAVE BEEN REPORTED IN AND AROUND LIVINGSTON
THROUGHOUT THE NIGHT...BUT IS STILL EXPECT TO TAPER OFF THIS
AFTERNOON. THE SFC GRADIENT THEN APPEARS BECOME MORE FAVORABLE TO
SEVERE LEVEL WINDS IN HARLOWTON AND BIG TIMBER. LOCAL STUDIES
REMAIN SUPPORTIVE FOR HARLOWTON...BUT LOOKS SOMEWHAT BORDERLINE
FOR BIG TIMBER. CHOSE TO ISSUE HIGH WIND WARNING FOR THIS EVENING
FOR HARLOWTON AND JUDITH GAP ZONES. ALSO ISSUED WIND ADVISORY FOR
BIG TIMBER FOR SAME TIME PERIOD...AS GRADIENT LOOKS GOOD AND COULD
NOT SEE WHAT WAS MISSING FOR BIG TIMBER LOCAL STUDY DATA TO BE
MORE SUPPORTIVE.

AFTER A QUICK SHOT OF SNOW OVERNIGHT...CHANCES APPEAR TO
IMPROVE THIS MORNING AS MAIN TROF IMPACTS THE MOUNTAINS. RAISED
POPS SLIGHTLY FOR THE MORNING. THE TROF COMPLETES PASSAGE THROUGH
THE REGION TONIGHT. STRONGEST IMPACTS WILL BE FELT IN THE
EAST...WITH MORE SIGNIFICANT COOL OFF AND SIGNIFICANT UPTICK IN
WINDS...WITH GUST AROUND 40 MPH COMMON ACROSS CENTRAL AND EAST
ZONES. GUSTS NEAR 50 MPH LOOK POSSIBLE IN EXTREME EASTERN ZONES
SUNDAY EVENING. WINDS DO LOOK LIKE THEY WILL DROP OFF PRETTY
QUICKLY AFTER SUNSET.

MAINLY CONTINUED WITH INHERITED POPS AND TEMPS THROUGH THE SHORT
TERM...WITH MINOR TWEAKS ALONG BORDERS. KEPT POPS RELATIVELY LOW
ACROSS THE PLAINS...AS MODELS APPEAR TO WANT TO SPLIT THE ENERGY A
BIT. AAG

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

MODEL DIFFERENCES CONTINUE TO PLAGUE CONFIDENCE IN THE EXTENDED
FORECAST...EVEN AS EARLY AS TUESDAY.

MODELS ROTATE A SUBTLE RIDGE AXIS ACROSS THE AREA WITH STRONG
NORTHWESTERLY FLOW ALOFT ON MONDAY WITH A WEAKENING FRONT MOVING
THROUGH EASTERN MONTANA. SHOULD BE REASONABLE MIXING SO MOST AREAS
WILL SEE BREEZY NORTHWESTERLY WINDS. SHOWER ACTIVITY WILL BE
LIMITED TO PARTS OF SOUTHEAST MONTANA AND LIKELY ONLY HAVE A
CHANCE TO REACH THE GROUND WHERE UPSLOPE COMPONENT PLAYS A ROLE.

TIGHT PRESSURE GRADIENTS SET UP LATER MONDAY NIGHT INTO TUESDAY
AS AN IMPRESSIVE 150KT JET AT 300 MB MOVES ACROSS NORTHEAST
MONTANA AND DEEPENS A SURFACE LOW WHILE THE FLOW ALOFT OVER
WYOMING AND IDAHO REMAINS ANTICYCLONIC SUPPORTING STRONG HIGH
PRESSURE OVER THE SNAKE RIVER PLAIN. MOISTURE ASSOCIATED WITH THE
JET STREAMS ACROSS THE AREA SO SHOWER ACTIVITY AND CLOUDS WILL
INCREASE. BIGGEST STORY WILL LIKELY BE MOUNTAIN SNOWFALL FOR THE
ABSAROKA MOUNTAINS ON THE WEST ASPECTS WITH GAP FLOW WINDS
BECOMING QUITE STRONG.

CRITICAL DIFFERENCES IN SYSTEM TRACK AND STRENGTH FOR WEDNESDAY
HAVE GENERATED TWO POSSIBLE SOLUTIONS BOTH OF WHICH QUITE EXTREME.
ECMWF HAS FLOPPED BACK TO A COLDER SOLUTION WITH AN ARCTIC HIGH
PUSHING INTO THE AREA GENERATING SNOW POSSIBILITIES. GFS IS NOT AS
STRONG WITH THIS HIGH AND A SECOND STRONG JET BRINGS AN
ADDITIONAL ROUND OF PRESSURE FALLS OVER CENTRAL MONTANA AND
DEVELOPS A VERY IMPRESSIVE WIND SCENARIO.

GIVEN THE SOLUTIONS JUMPING AROUND CONTINUE TO HAVE A COMPROMISE
FORECAST BUT DID DRAMATICALLY INCREASE WINDS FOR WESTERN AREAS ON
WEDNESDAY. THE SPREAD OF HIGH TEMPERATURES FROM THE ENSEMBLE GFS
RANGE FROM 49 TO 18 ON WEDNESDAY AND 51 TO 26 ON THANKSGIVING DAY.
AND THIS IS BEFORE EVEN DISCUSSING THE SUBJECT OF SNOW. WILL WAIT
ANOTHER DAY TO SEE IF MODELS CONVERGE ON A SOLUTION BEFORE
DECIDING WHAT THE BIGGEST WEATHER PROBLEM TO ADVERTISE ON
WEDNESDAY WILL BE. BORSUM
&&

.AVIATION...

VERY WINDY CONDITIONS OVER WESTERN AREAS INCLUDING KLVM. STRONGEST
WINDS AT KLVM WILL PERSIST UNTIL LATE AFTERNOON. STRONGEST WINDS
WILL SHIFT NORTH AND EAST AND WILL IMPACT 6S0 AND 3HT AROUND
MIDDAY. SHOWERS WILL MOVE THROUGH THE AREA AND BE MORE COMMON EAST
OF KBIL...BUT VFR CONDITIONS SHOULD PREVAIL. FOR KBIL...KSHR AND
SOUTHEAST MONTANA MUCH LESS WIND AND ISOLATED SHOWERS EXPECTED
WITH VFR CONDITIONS. WINDS WILL BE INCREASING DURING THIS EVENING
FOR KBIL. THE MOUNTAINS WILL HAVE OCCASIONAL HEAVY SNOW AND WILL
BE OBSCURED ALL DAY. BORSUM/TWH

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY SUN     MON     TUE     WED     THU     FRI
-------------------------------------------------------
BIL 051 030/041 024/040 027/041 028/041 020/037 018/034
    4/W 22/W    21/N    24/W    53/W    21/B    11/B
LVM 049 024/035 020/034 023/038 031/043 024/036 017/035
    6/W 22/J    31/N    24/J    42/W    21/N    11/B
HDN 050 026/041 019/040 021/040 023/039 016/037 014/036
    5/W 22/J    23/W    24/W    43/J    31/B    11/B
MLS 048 025/033 014/033 020/037 019/030 011/030 011/030
    5/W 44/J    21/E    23/W    33/J    21/B    11/B
4BQ 051 026/033 017/033 019/037 021/035 014/032 013/032
    5/W 33/J    22/J    13/W    43/J    21/B    00/B
BHK 048 024/027 010/027 018/033 015/024 007/027 011/027
    4/W 45/J    21/B    12/J    33/J    21/B    10/B
SHR 051 022/037 016/034 017/038 023/042 018/037 013/035
    4/W 33/W    22/J    24/W    43/J    21/B    11/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...HIGH WIND WARNING IN EFFECT UNTIL 2 AM MST SUNDAY FOR ZONES
      28-63.
     WIND ADVISORY IN EFFECT UNTIL 2 AM MST SUNDAY FOR ZONE 41.
     WIND ADVISORY IN EFFECT UNTIL 2 PM MST THIS AFTERNOON FOR
      ZONES 65-66.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



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