Hail in Wyoming, August 26, 2002

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
218 PM MDT MON AUG 26 2002

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

TONIGHT AND TUE...AVN AND ETA ARE IN BETTER AGREEMENT WITH EACH OTHER
THROUGH TUE WITH THE TROUGH THAT IS LOCATED OVER OREGON/WASHINGTON.
WILL USE A BLEND OF THE TWO. TROUGH CONTINUES TO DIG AND DROP INTO
SOUTHERN IDAHO AND CLOSES OFF BY TUE EVENING. BOTH MODELS SPIN A WAVE
THROUGH CENTRAL WY UP INTO OUR SOUTHERN AND WESTERN ZONES. ALTHOUGH THE
AVN IS STRONGER WITH THE TROUGH AND WAVE. WEAK CONVECTION HAS BEGUN TO
FIRE OVER CENTRAL AND EASTERN ID AND NORTHWEST WY. THEREFORE...BELIEVE
THE BEST CHANCE OF PRECIP WILL BE ACROSS OUR SOUTHWEST ZONES WITH JUST
ISOLATED CHANCES OUT EAST.

TUE NIGHT & WED...MODELS NOW DIFFER IN HANDLING CLOSED LOW OVER
SOUTHERN IDAHO. AVN SHOWS IT BECOMING ELONGATED FROM WESTERN MT TO
CENTRAL CA WITH THE STRONGEST PIECE OF IT BEING DRAWN NORTHWARD
INTO NORTHWEST MT AND NORTHERN ID BY THE INFLUENCE OF THE NEXT
TROUGH APPROACHING THE PACIFIC NW COAST. ON THE OTHER HAND...THE ETA
WANTS TO CONDENSE THE TROUGH AND MOVE IT BACK WESTWARD WHILE
CONTINUING TO SHOOT A WAVE UP TOWARD SOUTHERN MT. CONFIDENCE IS NOT HIGH
AS TO LOCATION AND AMOUNT OF PRECIP TO BE EXPECTED. HAVE DECIDED TO GO
WITH THE ETA SOLUTION FOR PRECIP SINCE THIS HAS BEEN THE CASE WITH THE
PLACEMENT OF THE LAST COUPLE OF TROUGHS. THEREFORE...WILL PLACE THE
HIGHER POPS ACROSS THE SOUTH AND ADVANCE THEM EAST THROUGH THE PERIOD.
HOOLEY

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

REMNANTS OVER THE PACNW UPPER LOW WILL BE EJECTING ON THURSDAY WHILE
ANOTHER SYSTEM BEGINS TO DIG INTO THE PACIFIC NORTHWEST. THE NEW MODEL
RUNS ARE CONSISTENT WITH DIGGING THE NEXT SYSTEM A BIT MORE SHARPLY
INTO NORTHERN CALIFORNIA THOUGH THE UKMET WANTS TO KEEP A BROADER
TROUGH OVER THE AREA. THURSDAY SYSTEM ACTUALLY EJECTS ON A FAIRLY
NORTHWARD TRACK ACROSS WESTERN MONTANA AND MOST OF SOUTHERN MONTANA
APPEARS TO BE DRY SLOTTED EXCEPT FOR THE SOUTHWEST MOUNTAINS. FRIDAY
AND SATURDAY WILL SEE CONSIDERABLE RIDGING OVER THE AREA IN RESPONSE TO
THE DIGGING OF THE CALIFORNIA SYSTEM WHICH SHOULD KEEP THE AIRMASS
MOSTLY STABLE. STILL LOOKING AT A CHANCE OF PRECIP SATURDAY NIGHT AS
THE HEIGHTS BEGIN TO FALL IN RESPONSE TO THE NORTHERLY BRANCH OVER
CANADA STRENGHTENING IN RESPONSE TO A TROF OVER THE NORTHWEST
TERRITORIES. BY SUNDAY THE NORTHERN TROUGH BEGINS TO DIG INTO ALBERTA
AND ACCELERATES THE FLOW ALOFT OVER THE AREA AND 700 MB PATTERNS LOOK
DOWNSLOPISH FOR SUNDAY AND MONDAY ACROSS THE AREA. BORSUM

    TUE     WED     THU     FRI     SAT     SUN     MON
-----------------------------------------------------------
BIL 056/076 054/076 055/085 054/086 054/079 053/077 053/072
    23/T    32/T    20/E    00/B    00/B    30/B    00/B
LVM 049/073 047/077 048/080 049/083 049/078 046/075 046/070
    44/T    32/T    22/T    20/B    00/B    30/B    00/B
HDN 054/081 050/082 050/087 051/088 052/079 048/079 048/075
    23/T    32/T    20/E    00/B    00/B    30/B    00/B
MLS 058/080 057/080 057/087 057/087 056/080 054/075 054/073
    02/T    33/T    30/E    00/B    00/B    00/B    00/B
4BQ 058/081 054/085 057/086 056/087 055/080 054/075 054/075
    03/T    43/T    30/E    00/B    00/B    00/B    00/B
BHK 055/083 055/082 054/083 054/084 054/078 051/075 051/075
    02/T    33/T    30/E    00/B    00/B    00/B    00/B
SHR 053/075 051/075 053/083 050/084 050/078 050/078 050/076
    24/T    42/T    20/E    00/U    00/B    00/B    00/B

.BYZ...
MT...NONE.
WY...NONE.