Severe Thunderstorm Warning 110, NWS Billings, MT

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
211 PM MDT SUN AUG 04 2002

.SHORT TERM...VALID FOR MON...TUE...WED...
FORECAST CHALLENGE FOR THIS PACKAGE WILL BE EXTENT AND TIMING OF
CONVECTION AND MAX TEMPERATURES. DRY AIR PUSHING NORTHWARD PER WATER
VAPOR IMAGERY WILL PLAY A ROLE IN LOCATION OF CONVECTION OVER THE NEXT
COUPLE OF DAYS. CONVECTION ALREADY FIRING ACROSS IN IDAHO AND
SOUTHWEST MONTANA. SCATTERED THUNDERSTORMS SHOULD DEVELOP/MOVE INTO
WESTERN ZONES LATE THIS AFTERNOON AND EVENING. MODEST INSTABILITY
SHOULD ALLOW THUNDERSTORMS TO DEVELOP/CONTINUE ACROSS MUCH OF THE CWA
TONIGHT. WILL MENTION SEVERE POSSIBILITY IN WESTERN TWO THIRDS OF CWA.
LOWEST CHANCES WILL BE IN THE SOUTHEAST ZONES AS DRY AIR NOSES IN.
TOMORROW DRY AIRMASS PUSHES FURTHER NORTH INTO SOUTHERN MONTANA. BEST
INSTABILITY IN THE EAST AND NORTH AND WILL PUT BEST CHANCES FOR STORMS
HERE. SEVERE STORMS POSSIBLE IN THE EAST GIVEN GOOD INSTABILITY AND
SHEAR. WILL PUT MENTION OF SEVERE WEATHER IN THESE AREAS.  TEMPS WILL BE
WARM...INTO THE 80S AND 90S.

DRY AIRMASS PUSHES FURTHER NORTH FOR MONDAY NIGHT AND TUESDAY...
KEEPING THUNDERSTORM POTENTIAL CONFINED TO FAR EAST AND NORTH. TEMPS
WILL ONCE AGAIN BE WARM. JZ

THE AVN SWINGS A COLD FRONT TROUGH TUESDAY NIGHT. THE ETA WAS SLOWER
WITH IT AND DOES NOT DRAG IT THROUGH UNTIL WEDNESDAY. HAVE A TENDENCY TO
BELIEVE THE ETA SINCE THE UPPER FLOW SHOULD REMAIN OUT OF THE SOUTHWEST
ON WEDNESDAY...AND THIS WOULD HOLD UP THE SURFACE FRONT. TIMING OF THE
SHORTWAVES WOULD KEEP THE BEST CHANCE OF PRECIPITATION OUT UNTIL
WEDNESDAY NIGHT. CURRENT FORECAST DRY FOR WEDNESDAY. WILL PUT LOW POPS
BACK IN FOR WEDNESDAY WITH FRONTAL PASSAGE AND LEAVE SCATTERED POPS FOR
WEDNESDAY NIGHT. HUMPHREY

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...
EXTENDED MODEL SOLUTIONS DIFFER COMPARED TO YESTERDAY. PROBLEMS STEM
FROM TIMING AND DEPTH OF UPPER TROUGH CURRENTLY OFF THE NORTHWEST COAST.
INSTEAD OF THE TROUGH KICKING NORTHEAST AND ZONAL FLOW DEVELOPING ON
FRIDAY...THE TROUGH CLOSES OFF WITH THE LOW NOT EXITING THE EAST UNTIL
SATURDAY MORNING. THE LATEST AVN WAS STAYING WITH THIS THEME AND IN FACT
MOVING THINGS EVEN SLOWER WITH THE CLOSED LOW FARTHER SOUTH. FLOW DOES
TURN ZONAL...BUT NOT UNTIL SUNDAY. MIDNIGHT CREW INSERTING POPS ON
THURSDAY LOOKS GOOD...AND WILL NEED TO STRETCH POPS INTO FRIDAY AS WELL.
THE ABOVE MENTIONED SCENARIO WOULD ALSO LEAD TO COOLER WEATHER FRIDAY
INTO SATURDAY THEN CURRENT FORECAST HOLDS. HUMPHREY

    MON     TUE     WED     THU     FRI     SAT     SUN
-----------------------------------------------------------
BIL 056/091 062/093 059/087 055/085 052/081 052/084 055/086
    42/T    20/U    02/T    33/T    33/T    30/B    00/U
LVM 052/088 055/086 051/082 049/081 047/077 047/082 050/084
    42/T    20/U    02/T    33/T    33/T    30/B    00/U
HDN 057/093 060/094 057/090 055/087 050/082 050/085 053/087
    40/G    00/G    02/T    33/T    33/T    30/B    00/U
MLS 063/094 065/092 062/093 058/088 055/082 055/085 058/087
    43/T    42/T    22/T    33/T    33/T    30/B    00/U
4BQ 061/095 063/095 061/093 057/088 055/082 055/085 058/087
    42/T    30/G    02/T    33/T    33/T    30/B    00/U
BHK 064/090 064/090 059/091 056/087 053/081 053/084 056/086
    43/T    42/T    22/T    33/T    33/T    30/B    00/U
SHR 058/094 058/094 055/089 051/086 047/081 047/085 050/087
    30/G    00/U    02/T    33/T    33/T    30/B    00/U

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