Hail in Montana, May 3, 2003

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
216 PM MDT SAT MAY 3 2003

.SHORT TERM...VALID FOR SUN AND MON...

THE MODELS AT LAST ARE ARRIVING AT A CONSENSUS WITH A SURFACE LOW OVER
NORTHEAST WYOMING AROUND MIDNIGHT TONIGHT WITH A SURFACE BOUNDARY FROM
THIS LOW INTO NORTHWEST MONTANA. THE LOW WILL NOT BE MOVING EAST THAT
FAST. STRANGELY ENOUGH...TIME HEIGHT SECTIONS FOR BOTH ETA AND AVN
INDICATED WARM AIR ADVECTION OVER THE EASTERN ZONES AT THE OUTSET WITH
COLD AIR ADVECTION COMING IN LATER ON SATURDAY INTO SATURDAY NIGHT.
THIS WOULD TEND TO KEEP THINGS STABLE THERE. HOWEVER...CAPES ARE
FAIRLY GOOD OVER THE EAST. THUS...THUNDERSTORMS THERE AS WELL AS
ELSEWHERE IN THE COUNTY WARNING AREA TO AFTER MIDNIGHT LOOK GOOD. THE
AREA GETS MORE INTO A WRAP-AROUND SITUATION ON THE SURFACE AS TIME
GOES ON. THE LIFT FOR SUNDAY NIGHT INTO MONDAY IS ACTUALLY BETTER THAN
THAT ANTICIPATED FOR TONIGHT. BOTH MODELS SHOW PLENTY OF MOISTURE...AS
WELL AS COLD AIR ADVECTION. THUS PRECIPITATION WOULD SEEM QUITE LIKELY
OVER THE AREA INTO MONDAY. THE HEAVIEST PRECIPITATION SHIFTS TO THE
EASTERN ZONES MONDAY AND THINGS BEGIN TO DWINDLE DOWN FOR
PRECIPITATION OUT WEST. THE LOW PRESSURE AREA SLOWLY PULLS
AWAY DURING THAT TIME AND DRAWS THE SURFACE BOUNDARY WITH
IT. TEMPERATURES SHOULD ALSO COOL DOWN AS THE COLD AIR ADVECTION MAKES
ITS PRESENCE KNOWN. CHB

.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
ACTIVE PATTERN FOR THE DURATION OF THE PERIOD WITH WEST/SOUTHWEST FLOW
DOMINATING NORTHERN ROCKIES. TUESDAY...BOTH ETA AND GFS IN AGREEMENT
THAT UPPER TROUGH ROTATES THROUGH MONTANA AND INTO DAKOTAS BY EVENING.
WILL EXPAND POPS ACROSS ENTIRE CWA...BUT WITH WEAK DYNAMICS AND
THERMODYNAMICS IN PLACE WILL ONLY GO SLIGHT CHANCES. WEDNESDAY SHORT
WAVE RIDGE DEVELOPS ACROSS STATE AS UPPER TROUGH RE-ESTABLISHES ITSELF
ON THE WEST COAST. SOME INSTABILITY PRESENT IN FAR SOUTHWEST AND WILL
ADD CHANCE POPS OVER HIGHER TERRAIN...BUT OVERALL THIS SHOULD BE
DRIEST DAY OF EXTENDED BASED ON CURRENT MODELS. THURSDAY AND BEYOND
ENSEMBLES AGREE THAT SOUTHWEST FLOW SHOULD MAINTAIN ITSELF INTO THE
WEEKEND...BUT DISAGREE ON POSITION OF TROUGH. THIS WILL PLAY ROLE IN
EXTENT OF WARMUP ACROSS THE AREA. BASED ON WARMUP DURING PAST FEW
SOUTHWEST FLOW EVENTS WILL ONLY MAKE A FEW COSMETIC CHANGES WITH
A GENERAL WARMUP INTO END OF THE WEEK. WILL INTRODUCE SATURDAY ONLY
A FEW DEGREES BELOW CLIMATOLOGY WITH LITTLE CONFIDENCE IN EXACT POSITION
OF UPPER TROUGH. UNSETTLED FORECAST FOR END OF THE WEEK LOOKS ON
TRACK WITH UPPER TROUGH IN THE WEST...AND WILL ADD POPS TO SATURDAY
FORECAST WITH SOUTHWEST FLOW CONTINUING. JZ

    SUN     MON     TUE     WED     THU     FRI     SAT
-----------------------------------------------------------
BIL 046/060 040/055 037/056 037/062 040/066 043/065 042/057
    76/T    64/W    32/W    00/B    03/T    33/T    33/W
LVM 040/061 036/054 030/054 030/059 033/061 036/060 036/054
    77/T    64/W    32/W    00/B    03/T    33/T    33/W
HDN 045/061 038/055 035/058 036/063 039/068 042/067 041/059
    76/T    64/W    32/W    00/E    03/T    33/T    33/W
MLS 047/061 042/056 037/060 037/063 040/067 043/067 042/059
    66/T    76/W    42/W    00/E    03/T    33/T    33/W
4BQ 045/059 041/054 038/058 035/063 038/068 041/067 042/060
    66/T    76/W    42/W    00/E    03/T    33/T    33/W
BHK 045/059 040/056 036/058 035/061 038/066 042/066 041/058
    66/T    76/W    42/W    00/E    03/T    33/T    33/W
SHR 041/059 037/050 034/056 034/062 037/067 041/064 042/057
    77/T    64/W    32/W    00/E    03/T    33/T    33/W

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

MTZ028>042-056>058-WYZ098-099-041100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BILLINGS MT
500 AM MDT SAT MAY 3 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL...SOUTHEAST
MONTANA AND NORTH CENTRAL WYOMING.

.DAY ONE...
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

WCJIN-WYNW-WYNE