Severe Thunderstorm Warning 79, NWS Billings, MT

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
226 PM MDT TUE JUL 16 2002

.SHORT TERM...VALID FOR WED...THU...FRI...

ACTIVE AND MOIST SOUTHWEST FLOW AT MID LEVEL TONIGHT. FAIRLY DEEP
EASTERLY FLOW ACROSS THE AREA TODAY ALLOWING DEWPOINTS TO REMAIN IN
UPPER 50S MOST AREAS...WITH 60S IN SOUTHEAST ZONES. EXPECT ACTIVITY TO
FIRE IN SOUTHWEST ZONES THIS AFTERNOON AND MOVE TO THE NORTHEAST NORTH
OF +12C 700 MB ISOTHERM...SIMILAR TO LAST NIGHTS. WILL KEEP CHANCE OF
SEVERE IN TONIGHT WITH SURFACE BASED CONVECTION TAPPING INTO CAPES
AROUND 2000 J/KG.

WEDNESDAY...BOTH ETA AND AVN DRAGGING COOLER AIR AT LOW AND MID LEVELS
INTO SOUTHERN MONTANA. INSTABILITY STILL AROUND AS MOISTURE GETS
WRAPPED AROUND BACK SIDE OF LOW PRESSURE CURRENTLY IN S.D. RIDGE GETS
FLATTEN A BIT TOMORROW WHICH ACTUALLY TURNS MID LEVEL WINDS MORE
WESTERLY. THIS SHOULD SHUNT SUB-TROPICAL MOISTURE FETCH FURTHER SOUTH
INTO WYOMING. NOT MUCH CAP TOMORROW SO WILL BLANKET AREA WITH 20 TO 30
PERCENT CHANCES...HIGHEST IN THE SOUTH. TEMPERATURES SHOULD BE WARM BUT
COOLER THAN TODAY.

THURSDAY...UPPER RIDGE REBOUNDS A BIT WITH MORE SOUTHWEST FLOW INTO
SOUTHWEST ZONES. HOWEVER...MAIN MOISTURE REMAINS SOUTH IN WYOMING.
AGAIN WILL TREND POPS NORTH-SOUTH ACROSS AREA. DIMPLE IN TEMPERATURE
FIELDS REMAINS IN CENTRAL AND EASTERN ZONES...WITH TEMPERATURES A FEW
DEGREES WARMER. TEMPERATURE RIDGE DOES REBOUND IN WESTERN ZONES. RASCH

FRIDAY...UPPER RIDGE BEGINS TO BUILD AHEAD OF LIFTING WEST COAST TROUGH
PER NEWER AVN RUNS. WILL BUMP TEMPS UP A FEW DEGREES WITH WARMING
OCCURRING UNDER BUILDING RIDGE. WITH RIDGE AXIS OVER WESTERN DAKOTAS
BEST INSTABILITY WILL BE IN PLACE OVER THE WEST...WITH SHORTWAVE
APPROACHING BY 00Z...SO WILL TRIM BACK POPS TO INCLUDE WESTERN ZONES
ONLY ATTM. JZ

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

UPPER TROUGH CURRENTLY OVER WEST COAST PROGGED TO LIFT OVER THE RIDGE
FOR THE WEEKEND. THIS BRINGS SUBSTANTIAL SHORTWAVE ENERGY ACROSS THE
AREA LATE FRIDAY INTO SATURDAY. WILL BACK TEMPS OFF A FEW DEGREES FOR
SATURDAY WITH TROUGH BREAKING DOWN RIDGE AND INTRODUCE CHANCE OF
STORMS...WITH ENERGY ALOFT AND LOWER LEVEL INSTABILITY IN PLACE. THE
REST OF THE EXTENDED WILL BE MAINLY DRY AS FLOW SHIFTS FROM THE
SOUTHWEST TO MORE WEST/NORTHWEST. SOME ENERGY MOVING THROUGH FLOW MAY
SET OFF A FEW STORMS DURING THE PERIOD BUT NOT ENOUGH TO WARRANT
MENTION...WITH TEMPS AROUND OR SLIGHTLY ABOVE SEASONAL AVERAGES. JZ

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 065/089 063/089 063/091 064/087 063/090 063/087 063/087
    63/T    32/T    22/C    33/T    30/B    00/B    00/B
LVM 058/087 056/091 057/088 056/085 056/089 056/086 056/085
    63/T    33/T    33/T    33/T    30/B    00/B    00/B
HDN 063/091 061/092 063/093 065/087 064/092 064/089 064/088
    63/T    32/T    20/B    33/T    30/B    00/B    00/B
MLS 070/091 068/092 065/094 066/088 066/091 066/088 066/087
    62/T    22/T    20/B    33/T    30/B    00/B    00/B
4BQ 068/092 066/093 064/094 065/088 065/092 064/089 065/087
    23/T    33/T    30/B    33/T    30/B    00/B    00/B
BHK 066/090 064/091 064/090 064/085 065/090 063/087 063/085
    32/T    22/T    20/B    33/T    30/B    00/B    00/B
SHR 066/091 064/092 060/090 059/087 060/091 060/088 061/087
    43/T    34/T    40/B    33/T    30/B    00/B    00/B

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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS, MT
121 PM MDT TUE JUL 16 2002

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0545 PM    MC LEOD                   MT   60 MPH WIND GUST
07/15/02   SWEET GRASS

0915 PM    10  W SUMATRA             MT   1.75 INCH HAIL
07/15/02   ROSEBUD

JZ