Area Forecast Discussion
Issued by NWS Billings, MT

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684
FXUS65 KBYZ 051604
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
904 AM MST FRI FEB 5 2016

.UPDATE...

QUIET DAY IN STORE TODAY BEFORE A WINDY PERIOD BEGINS THIS
EVENING CONTINUING FOR MANY AREAS THROUGH THE WEEKEND. SATELLITE
SHOWING SUNNY SKIES ACROSS THE FORECAST AREA THIS MORNING. A DRY
NORTHERLY FLOW ALOFT WILL BE OVER THE AREA AS HIGH PRESSURE
RIDGING BEGINS TO BUILD ONCE AGAIN. LEE-SIDE TROUGHING WILL
DEVELOP ACROSS THE AREA BRINGING ANOTHER ROUND OF STRONG WINDS TO
THE LIVINGSTON AND ADJACENT FOOTHILLS AREAS. A WIND ADVISORY FOR
THAT AREA WILL GO INTO EFFECT AT 5PM TODAY AND CONTINUING THROUGH
SATURDAY NIGHT. ELSEWHERE...A STRONG PACIFIC FRONT WILL BLAST
ACROSS THE AREA SATURDAY INTO SATURDAY NIGHT. STRONG WEST THEN
NORTHWEST WINDS ARE EXPECTED ALONG AND BEHIND THE FRONT. PREVIOUS
SHIFT ISSUED A HIGH WIND WATCH FOR THE LOWER ELEVATIONS. WE ARE
WAITING FOR NEW MODEL DATA TO COME IN THIS MORNING TO FINE TUNE
THESE WIND HIGHLIGHTS. ONLY UPDATE THIS MORNING WAS TO REMOVE SNOW
SHOWER CHANCES THIS MORNING ACROSS SOUTHEAST MONTANA. HOOLEY

&&

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

VIGOROUS SHORT WAVE DIVED SOUTHEAST ACROSS OUR FORECAST AREA
EARLIER TONIGHT PRODUCING SOME INTENSE...ALBEIT BRIEF...SNOW
SHOWERS THROUGH THE CENTRAL ZONES AND DOWN INTO SHERIDAN. SOME
ROADS PICKED UP A QUICK INCH OF SNOW INCLUDING I-90 IN THE
SHERIDAN AREA. MOST OF THIS IS NOW DISSIPATING. RIDGING AT 500MB
WILL QUICKLY BUILD OVER THE REGION TODAY. WE WILL SE SOME BREEZY
CONDITIONS AT TIMES AGAIN BY AFTERNOON AND PUSH US INTO THE 40S
FOR MANY AREAS.

WIND IS THE WORD AS WE HEAD INTO THE WEEKEND. LEE-SIDE TROUGHING
WILL DEVELOP ACROSS OUR FORECAST AREA TODAY AND INCREASE TONIGHT.
THIS IS EXPECTED TO PRODUCE ENHANCED WINDS IN OUR GAP FLOW AREAS
BY EVENING. BUFKIT SOUNDINGS SUGGEST STRONG WINDS DEVELOPING BY
8 PM IN THE BOUNDARY LAYER. AS PACIFIC FRONT COMES THROUGH
SATURDAY THE GRADIENT ORIENTATION TURNS MORE WESTERLY AND THE
WINDS BECOME LESS GAP DRIVEN AND MORE DRIVEN BY MIX DOWN...AND DO
NOT DECREASE UNTIL LATER SATURDAY NIGHT. SO HAVE ISSUED A WIND
ADVISORY DURING THIS TIME FRAME FOR OUR GAP FLOW LOCATIONS FROM
LIVINGSTON TO NEAR NYE.

THE PATTERN ASSOCIATED WITH THE PACIFIC FRONT SATURDAY LOOKS
RATHER FORMIDABLE FOR THE REST OF OUR FORECAST AREA AS WELL.
LATEST PROGS ARE SHOWING MAX WINDS UP TO 70 KTS AT 700 MB BY
SATURDAY AFTERNOON AS LOW LEVEL LAPSE RATES JUMP TO OVER 7C/KM.
THIS SHOULD ALLOW VERY STRONG GUSTS TO MIX DOWN TO SURFACE ALONG
AND BEHIND THE FRONT. MODELS CARRY THIS THREAT FURTHER EAST
OVERNIGHT AND INTO SUNDAY. ALTHOUGH NIGHTTIME IS NOT USUALLY
FAVORABLE FOR STRONG WINDS...AND THERE IS SOME LIFT AS TROUGH
COMES THROUGH NEGATING COLD AIR ADVECTION EFFECTS...MIXING ON
BUFKIT SOUNDINGS SUGGEST AN OUTLIER EVENT IS POSSIBLE ALONG AND
JUST BEHIND FRONT. THEREFORE...WE WILL ISSUE A HIGH WIND WATCH
FOR MUCH OF OUR FORECAST AREA. THE WESTERN LOWER ELEVATIONS TO
ROSEBUD COUNTY FROM 5 AM SATURDAY TO 11 PM SATURDAY...AND FOR THE
EASTERN ZONES FROM 11 AM SATURDAY TO 5 PM SUNDAY. WE ARE GIVING
WIDE BERTH DUE TO LACK OF CONFIDENCE IN MODEL TIMING...AND FEEL
LATER SHIFTS SHOULD BE ABLE TO FINE TUNE THIS SHOULD AN UPGRADE TO
HIGH WIND WARNING BE DEEMED NECESSARY. AT THIS TIME THERE APPEARS
TO BE A POTENTIAL FOR 60 TO 70 MPH GUSTS ALONG AND ABOUT TWO HOURS
BEHIND THE FRONT...WITH A LONGER PERIOD OF GUSTS TO 50 MPH OR
BETTER. BT

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

CONTINUING TO LOOK FOR A MAINLY DRY AND WARM EXTENDED PERIOD WITH GOOD
MODEL AGREEMENT UNTIL LATE IN THE PERIOD. WILL STILL BE DEALING
WITH STRONG WINDS E OF KBIL ON SUN DUE TO A DEPARTING SHORTWAVE. THE
WINDS SHOULD GRADUALLY DIMINISH FROM W TO E DURING THE DAY AS A
SURFACE HIGH BUILDS IN FROM THE W. A HIGH AMPLITUDE RIDGE WILL
BUILD OVER THE WESTERN U.S. THROUGH THE PERIOD. A WARMING TREND
WILL ENSUE WITH HIGHS PEAKING IN THE 50S FOR MUCH OF THE WEEK. THE
GFS SHOWED A POSSIBLE BACKDOOR COLD FRONT THU NIGHT INTO FRI SO
HAD SOME LOW POPS DURING THOSE PERIODS. THE PRESSURE GRADIENT WILL
SUPPORT GUSTY WINDS W OF KBIL FOR MUCH OF THE PERIOD WITH LEE
TROUGHS FORMING DUE TO THE UPPER RIDGE. WILL NEED TO KEEP AN EYE
OUT FOR POSSIBLE WIND HIGHLIGHTS DURING THE WEEK. ARTHUR

&&

.AVIATION...


VFR CONDITIONS WILL THROUGH THE TAF PERIOD. SURFACE WINDS WILL BE
GUSTY FROM THE WEST AT KBIL AND KLVM WITH GUSTS 25 TO 40 KT. GUSTS
INCREASE TO 50 KT IN THE KLVM AREA LATE IN THE DAY. THESE GUSTY
WEST WINDS WILL CONTINUE THROUGH TONIGHT. BY SAT MORNING...EXPECT
GUSTS OF 45 TO 55 KT AT KLVM. EXPECTING LOW-LEVEL WIND SHEAR AT
KMLS TONIGHT. ARTHUR/DOBBS


&&

.PRELIMINARY POINT TEMP/POPS...

    TDY SAT     SUN     MON     TUE     WED     THU
-------------------------------------------------------
BIL 045 032/048 029/044 029/050 034/055 034/057 035/053
    0/N 01/N    10/N    00/B    00/N    00/N    01/N
LVM 041 031/042 025/039 029/047 035/051 035/050 034/049
    1/N 12/W    11/N    10/B    00/N    00/N    11/N
HDN 045 025/048 026/044 022/047 029/052 028/055 029/051
    0/B 02/W    10/N    01/B    00/U    00/U    11/B
MLS 044 030/050 027/042 024/044 030/051 030/051 030/048
    0/B 01/N    11/N    01/B    10/B    00/U    11/B
4BQ 042 025/049 027/039 023/042 028/050 028/052 030/049
    0/B 01/N    11/N    01/B    10/B    00/U    11/B
BHK 040 027/048 025/037 020/038 027/046 027/047 027/042
    0/B 01/N    41/N    01/N    11/B    11/U    11/B
SHR 041 021/048 023/038 022/045 026/053 027/053 027/051
    0/U 01/B    21/N    00/B    10/U    00/U    01/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...HIGH WIND WATCH IN EFFECT FROM SATURDAY MORNING THROUGH
      SATURDAY EVENING FOR ZONES 28>31-34-35-38-39-41-42-56>58-63.
     HIGH WIND WATCH IN EFFECT FROM SATURDAY MORNING THROUGH
      SUNDAY AFTERNOON FOR ZONES 32-33-36-37.
     WIND ADVISORY IN EFFECT FROM 5 PM THIS AFTERNOON TO 5 AM MST
      SUNDAY FOR ZONES 65-66.
WY...HIGH WIND WATCH IN EFFECT FROM SATURDAY MORNING THROUGH
      SATURDAY EVENING FOR ZONE 99.

&&

$$
WEATHER.GOV/BILLINGS



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