Severe Thunderstorm Warning 48, NWS Billings, MT

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
220 PM MDT TUE JUL 04 2000

.WED AND THU...

LOOKS LIKE CHANCE OF THUNDERSTORMS WILL REMAIN IN THE FORECAST THROUGH
THE PERIOD AS A BROAD SOUTHWEST FLOW ALOFT REMAINS OVER MONTANA. THE
ETA/AVN PROGS THE CLOSED LOW OVER EXTREME SOUTHERN ALBERTA TO MOVE TO
THE NORTHEAST WITH A LONGWAVE TROF EXTENDING FROM THE LOW TO NEAR
CALIFORNIA. THE MODELS SHOW A SERIES OF SHORTWAVES BEING EJECTED
OUT OF THIS TROF OVER THE NEXT 48 HOURS WITH THE FIRST ONE MOVING ACROSS
MONTANA TUESDAY AFTERNOON.

THE NEXT SHORTWAVE MOVES ACROSS WESTERN MONTANA DURING THE MORNING ON
WEDNESDAY...BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS. THE
ETA ALSO INDICATES THE BEST CAPES OVER EXTREME EASTERN MONTANA AT 00Z
WED AND MOVES THIS ENERGY EAST TO THE DAKOTAS DURING THE DAY TOMORROW.
WITH A SOUTHWEST FLOW ALOFT AND SHORTWAVES PROGGED TO EXIT THE LONGWAVE
TROF ALONG THE CALIFORNIA COAST...I WILL GO WITH 40 POP FOR THUNDER
STORMS THIS EVENING AND TONIGHT. I WILL ALSO KEEP 30 A POP FOR ALL
ZONES DURING THE DAY ON WED AND THU...EXCEPT FOR LVM WHICH MAY BE
INFLUENCED BY THE SHORTWAVE MOVING ACROSS WESTERN MONTANA WHERE I WILL
GO WITH A 40 POP. MACHINE TEMPS LOOK REASONABLE SO HAVEN'T STRAYED FAR
FROM GUIDANCE. KUHL

.FRI...SAT...AND SUN...
MODELS SIMILAR IN TREND OF DROPPING AN UPPER LOW OFF THE NORTHERN
CALIFORNIA COAST FRIDAY THEN WEAKENING AND LIFTING THE LOW NORTHEAST
INTO SUNDAY. ECMWF IS THE PREFERRED MODEL FOR POSITION AS MRF WANTS
TO RETROGRADE PACIFIC RIDGE TOO MUCH. THE RIDGE SLOWLY BUILDS HEIGHTS
OVER THE NORTHERN ROCKIES THROUGH THE PERIOD WITH TEMPERATURES WARMING.
THE DISTURBANCES IN THE FLOW ALOFT WILL AID IN THUNDERSTORM DEVELOPMENT
THROUGH THE PERIOD AND WILL BROADBRUSH FOR THUNDERSTORMS THROUGH THE
EXTENDED PERIOD. THORICHT

BIL TTBBB 054/083 058/085 057/086 058/089 059/092 514333 58
LVM TTBBB 052/079 055/084 055/084 056/087 058/089 514433 58
HDN TTBBB 054/084 058/087 055/088 057/091 057/093 514333 58
MLS TTBBB 059/085 062/090 060/088 059/090 059/092 514333 58
4BQ TTBBB 058/085 060/089 060/089 060/091 060/093 514333 58
BHK TTBBB 058/084 060/091 059/087 059/088 059/091 514333 58
SHR TTBBB 052/083 054/089 055/087 056/090 056/091 514333 58