Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 272118
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
318 PM MDT WED AUG 27 2014

.SHORT TERM...VALID FOR THU AND FRI...

AN UPPER LOW OVER SOUTHERN WYOMING WAS SPREADING CLOUDS NORTHWARD
INTO SOUTHERN MONTANA. A FEW SHOWERS HAVE DEVELOPED OVER THE BIG
HORN MOUNTAINS...WITH MORE CU DEVELOPMENT WORKING NORTHWARD. JET
FORCING SLIDES EAST PRETTY QUICKLY THIS EVENING...SO WOULD
ANTICIPATE THE FORCING TO DO THE SAME. WILL LINGER LOW POPS OVER
THE BIG HORNS AND THAT SHOULD BE IT. WILL HAVE TO WATCH CONVECTION
OVER NORTHEAST WYOMING...AS IT HAS BEEN CREEPING NORTHWARD TOWARD
FAR SOUTHEAST MONTANA. WILL KEEP THAT AREA DRY FOR NOW AND RELY ON
JET ENERGY KEEPING IT SOUTH AND EAST.

THURSDAY WILL BE DRY AND LITTLE WARMER AS MID LEVEL WESTERLY FLOW
INCREASES. WOULD EXPECT MID TO UPPER 80S MOST LOCATIONS. MODELS
SWING A SHORTWAVE INTO WESTERN ZONES THURSDAY EVENING. WEAK
INSTABILITY WILL BE PRESENT AS PRECIPITABLE WATER AMOUNTS INCREASE
TO AROUND .75 INCHES. INTRODUCED POPS FOR THE WEST THURSDAY
EVENING FOR THIS AND SPREAD THEM INTO CENTRAL ZONES AND PART OF
THE SOUTHEAST MONTANA OVERNIGHT AS THE SHORTWAVE SWINGS ACROSS.

WILL LINGER LOW POPS THROUGH DAY FRIDAY AND HIT THE EAST HARDER
AS THE SHORTWAVE DOES NOT CLEAR THE STATE UNTIL LATE FRIDAY
AFTERNOON. CLOUDS AND SHOWERS...ALONG WITH A COLD FRONTAL PASSAGE
AT 850MB...WILL CAUSE A COOLER DAY FOR FRIDAY. SMALL SCALE RIDGE
WILL SLIDE IN BEHIND THE WAVE FRIDAY NIGHT AND THIS WILL CLEAR
THINGS OUT AHEAD OF THE NEXT SYSTEM FOR SATURDAY. TWH

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

THE MAIN FEATURE OF INTEREST DURING THE LONG TERM WILL BE A 500-MB
TROUGH PASSAGE SAT AND SUN. THE SURFACE COLD FRONTAL PASSAGE WHICH
WILL ACCOMPANY THAT TROUGH IS SLATED FOR SAT...AND THE 12 UTC RUNS
OF THE GFS...ECMWF AND NAM ALL SUGGEST THE FRONT WILL PUSH THROUGH
FAR SOUTHEASTERN MT DURING THE PEAK IN DIURNAL HEATING. IF THAT IS
THE CASE...THEN MLCAPE OF 1000-1500 J/KG WITH 0-6-KM BULK SHEAR ON
THE ORDER OF 35 KT WOULD SUPPORT A RISK OF STRONG TO SEVERE STORMS
IN FAR SOUTHEASTERN MT FOR A TIME SAT AFTERNOON OR EVENING. WE ARE
NOT CONFIDENT IN THE FRONTAL TIMING THOUGH /IF IT IS FASTER...THEN
THE STORM RISK WILL BE RELEGATED TO THE DAKOTAS/. SHOWER AND STORM
CHANCES WILL ALSO EXIST IN THE POST-FRONTAL REGIME SAT THROUGH MON
WITH CYCLONIC FLOW ALOFT...BUT THEY WILL BE DROPPING WITH TIME. WE
EXPECT BELOW-NORMAL TEMPERATURES BEHIND THE FRONT...BEGINNING OVER
SOUTH CENTRAL MT ON SAT AND ACROSS THE WHOLE AREA SUN AND MON. THE
HEIGHTS ALOFT ARE EXPECTED TO RISE AGAIN BY TUE AND WED...ALLOWING
FOR A WARMING TREND AGAIN IN THAT TIME FRAME. SCHULTZ

&&

.AVIATION...

A FEW SHOWERS AND POSSIBLY A THUNDERSTORM WILL CONTINUE ACROSS THE
BIGHORN MOUNTAINS INTO THE EVENING WITH LOCALIZED OBSCURATIONS. WE
OTHERWISE EXPECT VFR CONDITIONS OVER THE WHOLE AREA TONIGHT AND ON
THURSDAY. SCHULTZ

&&

.PRELIMINARY POINT TEMP/POPS...

    THU     FRI     SAT     SUN     MON     TUE     WED
-----------------------------------------------------------
BIL 057/087 059/080 056/075 054/071 048/073 050/076 051/080
    00/U    22/T    13/T    32/T    22/T    21/U    12/T
LVM 050/086 051/080 050/073 046/068 043/071 044/076 045/079
    00/U    22/T    13/T    32/T    22/T    21/U    12/T
HDN 056/088 057/082 056/079 054/073 050/075 051/078 052/082
    00/U    22/T    12/T    32/T    22/T    21/U    11/U
MLS 059/087 059/080 058/080 056/073 051/075 052/077 054/080
    00/U    23/T    13/T    32/T    22/T    21/U    12/T
4BQ 058/087 058/081 057/084 055/072 050/074 051/078 053/083
    10/U    03/T    12/T    32/T    22/T    21/U    11/U
BHK 055/083 055/078 055/080 054/071 048/072 050/075 050/080
    00/U    04/T    24/T    43/T    22/T    21/B    12/T
SHR 053/087 053/081 053/081 051/070 046/072 047/077 048/083
    10/U    02/T    12/T    22/T    22/T    21/U    11/B

&&

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

&&

$$
WEATHER.GOV/BILLINGS


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