Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 051031
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
331 AM MST THU MAR 5 2015

.SHORT TERM...VALID FOR TDY AND FRI...

A DRY NORTHWEST FLOW REGIME WILL PREVAIL OVER THE AREA FOR THE
NEXT SEVERAL DAYS...AS AN AMPLIFIED RIDGE BUILDS OVER THE WESTERN
THIRD OF THE COUNTRY. DOWNSLOPE WINDS WILL HELP TEMPERATURES WARM
TO NEAR SEASONAL LEVELS TODAY...AND INTO THE 50S FOR FRIDAY AND
INTO THE WEEKEND. WINDS WILL BE GUSTY AT TIMES THE NEXT FEW
DAYS...ESPECIALLY OVER THE WESTERN VALLEYS WHERE GAP INFLUENCES
WILL DEVELOP. NOT EXPECTING WINDS TO BECOME STRONG AND THIS POINT
FOR AREAS LIKE NYE AND LIVINGSTON...BUT GUSTS 40 TO 50 MPH CAN BE
EXPECTED ESPECIALLY OVERNIGHT INTO THE MORNING HOURS. THE ONLY
SHOT AT ANY PRECIPITATION LOOKS TO BE SLIGHT CHANCES FRIDAY NIGHT
OVER CUSTER AND FALLON COUNTIES WHERE A DISTURBANCE CROSSING NE MT
INTO ND MAY PUSH ENOUGH SURFACE CONVERGENCE SOUTH TO TRIGGER A FEW
SHOWERS. CHAMBERS

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

EXTENDED MODELS WERE IN DECENT AGREEMENT THROUGH TUE...THEN
DISAGREEMENT INCREASED SHARPLY REGARDING WHETHER OR NOT A COLD
TROUGH WOULD AFFECT THE AREA BEGINNING TUE NIGHT.

AREA STARTS OUT UNDER WEAKLY CYCLONIC/NW FLOW ON SAT AND MODELS
BROUGHT A SHORTWAVE S THROUGH THE REGION THROUGH SAT EVENING...
ALONG WITH SOME FRONTOGENESIS AND STEEP LAPSE RATES. THE MODELS
GENERATED LIGHT QPF WITH THIS SYSTEM...SO HAVE ADJUSTED GRIDS TO
ADD A SLIGHT CHANCE IN THE NE PART OF THE AREA. OTHERWISE...LIGHT
QPF IS POSSIBLE OVER THE SOUTHERN MOUNTAINS THROUGH SAT NIGHT. SUN
THROUGH MON NIGHT CONTINUED TO LOOK DRY UNDER A FLATTENING NW
FLOW. HIGH TEMPERATURES WILL CLIMB FROM THE 50S INTO THE 60S
DURING THIS TIME FRAME.

THE EFFECTS OF THE MODEL DIFFERENCES SHOW UP IN TUE/S FORECAST AS
A LEADING SHORTWAVE MOVES E THROUGH THE AREA ON THE GFS BRINGING
SOME QPF TO THE SW MOUNTAINS...WHILE THE ECMWF REMAINS DRY WITH
HIGHER HEIGHTS. THE GFS BRINGS A BROAD TROUGH WITH SHORTWAVE
ENERGY THROUGH THE REGION TUE NIGHT INTO THU...ALONG WITH A COLD
FRONT AND ASSOCIATED UPSLOPE FLOW AND QPF. MEANWHILE THE ECMWF
TRANSITIONS TO WEAK RIDGING AND DOES BRING SOME MOISTURE INTO THE
AREA ON THU. NOTED THAT THE GFS SEEMED MORE CONSISTENT WITH IT/S
SOLUTION THAN THE ECMWF...SO CARRIED PRECIPITATION CHANCES THROUGH
THU IN THE FORECAST. HOWEVER...THIS PERIOD WAS QUITE FAR OUT IN
THE FORECAST TIME FRAME WHICH GIVES THE MODELS PLENTY OF TIME TO
VARY THEIR SOLUTIONS. MODEL SPREADS IN HIGH TEMPERATURES WERE ON
THE ORDER OF 30 TO 40 DEGREES ON WED AND THU SO WENT WITH A BLEND
FOR TEMPERATURES. ARTHUR
&&

.AVIATION...

HIGH CONFIDENCE IN VFR CONDITIONS TODAY AND TONIGHT...ALONG WITH
GUSTY WSW SURFACE WINDS OVER AND NEAR KLVM. EXPECT WIND GUSTS IN
THE 35 TO 40 KT RANGE. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY FRI     SAT     SUN     MON     TUE     WED
-------------------------------------------------------
BIL 046 029/055 030/055 030/056 035/062 035/062 035/048
    0/N 00/N    00/E    10/U    00/U    00/U    22/W
LVM 047 030/054 033/055 030/055 035/059 037/059 038/051
    0/N 00/N    00/B    10/U    00/N    01/N    22/W
HDN 049 025/057 026/055 028/057 031/063 032/064 032/051
    0/B 00/B    00/E    10/U    00/U    00/U    02/W
MLS 048 026/055 027/052 027/053 032/061 033/061 031/047
    0/B 00/B    22/W    20/U    00/U    00/U    02/W
4BQ 043 020/049 021/050 025/052 028/061 030/062 029/051
    0/B 00/B    00/B    10/U    00/U    00/U    02/W
BHK 044 020/052 024/049 024/051 029/059 031/059 029/046
    0/B 00/B    22/W    20/U    00/U    00/U    02/W
SHR 043 022/051 025/050 025/051 027/060 029/061 031/051
    0/B 00/B    00/B    10/U    00/U    00/U    02/W

&&

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

&&

$$
WEATHER.GOV/BILLINGS



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