Severe Thunderstorm Warning 26, NWS Billings, MT

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
203 PM MDT MON JUL 07 2003

.SHORT TERM...VALID FOR TUE AND WED...
POTENTIALLY ACTIVE NEXT 36 HOURS SHAPING UP AS UPPER FLOW TRANSITIONS TO
SOUTHWESTERLY TONIGHT INTO TUESDAY. FIRST WAVE LIFTS INTO NORTHERN
WYOMING THIS EVENING AND STRADDLES MT/WY BORDER OVERNIGHT. BOTH MODELS
HINTING AT CONVECTION OVERNIGHT AHEAD OF THIS WAVE...ESPECIALLY ACROSS
EASTERN MONTANA...AND WILL UP POPS HERE WITH LOW LEVEL JET AND THETA E
RIDGE IN PLACE. FLOW WILL TURN MORE SOUTHEASTERLY OVERNIGHT AS SURFACE
HIGH SLIPS SOUTH AND EAST...WITH RETURN OF LOW LEVEL MOISTURE. WILL
BUMP LOWS UP GIVEN INCREASING SURFACE MOISTURE AND CONTINUED SOUTHEAST
WIND.

TUESDAY...WILL KEEP SOME POPS IN EASTERN ZONES IN THE MORNING WITH
POSSIBILITY OF LINGERING SHOWERS. JET STREAK PUSHES ACROSS STATE BY
MIDDAY WITH LEFT EXIT REGION OVER EASTERN MONTANA DURING AFTERNOON
HOURS. WITH SURFACE MOISTURE INCREASING CAPES RISE ABOVE 1500 IN MUCH
OF EAST WITH GOOD SPEED SHEAR UNDER JET STREAK. THETA E RIDGE
ACROSS EAST DURING THIS TIME AS WELL. SPC HAS EAST PAINTED IN SLIGHT
RISK FOR TOMORROW AND GIVEN ABOVE A FEW SEVERE STORMS LOOK LIKE A GOOD
BET. HOWEVER...EARLY TIMING OF JET STREAK MAY PUSH BEST DYNAMICS INTO
DAKOTAS BY LATE AFTERNOON WHEN STRONGEST INSTABILITY PRESENT. MORNING
CONVECTION MAY ALSO KEEP CLOUD COVER HANGING OVER AREA AND KEEP SURFACE
TEMPS FROM WARMING ENOUGH TO OVERCOME CAP AND ALLOW CONVECTION TO
BECOME SURFACE BASED. FOR NOW WILL NOT MENTION SEVERE IN ZONES BUT MAY
NEED TO BE ADDED OVER NEXT COUPLE SHIFTS AS SCENARIO COMES INTO FOCUS.
ANOTHER WAVE TRAILING JET STREAK SHOULD RESULT IN A CHANCE OF AFTERNOON
AND EVENING THUNDERSTORMS IN THE WEST AND POPS HERE LOOK ON TRACK.
BEHIND SURFACE TROUGH ATMOSPHERE SHOULD MIX WELL...AND TEMPS IN THE
UPPER 80S/LOWER 90S LOOK ON TRACK. WILL ADJUST EASTERN AREAS DOWN A FEW
BASED ON SOUTHEAST FLOW AND POSSIBLE CLOUD COVER. WINDS SHOULD BE AT
LEAST BREEZY IN THE FAR EAST WITH DECENT GRADIENT SETTING UP...AND WILL
BUMP WINDS UP HERE.

TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. SYSTEM PUSHES EAST DURING
TUESDAY NIGHT AND WILL DRY THINGS OUT FROM WEST TO EAST OVERNIGHT...AND
KEEP SLIGHT CHANCE POPS LINGERING ON FAR EAST WEDNESDAY MORNING.
DRY WESTERLY FLOW DEVELOPS ACROSS ENTIRE FORECAST AREA BY WEDNESDAY
AFTERNOON SO DRY FORECAST LOOKS ON TRACK. WITH WESTERLY FLOW
ATMOSPHERE SHOULD MIX WELL...AND WITH COMPARABLE THERMAL PROFILE TO
TUESDAY CURRENT FORECAST OF MID 80S TO AROUND 90 LOOKS ON TRACK. JZ

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
THE EXTENDED PERIOD WILL BE DRY AND WARM. UKMET/GFS/ECMWF ALL HAD HIGH
PRESSURE CENTERED OVER THE FOUR CORNERS REGION ON THU. WEST TO
NORTHWEST FLOW WAS OVER MONTANA N OF THE HIGH. THIS PATTERN
WILL PERSIST INTO SAT AS A LOW PRESSURE SYSTEM LINGERS OFF THE
PACIFIC COAST AND A TROUGH SETTLES OVER THE EASTERN U.S.. GFS AND UKMET
BROUGHT A SHORTWAVE AND A JET THROUGH THE RIDGE N OF THE FORECAST AREA
ON THU WHILE ECMWF DID NOT SHOW A WAVE. WHILE A SMALL RIPPLE IN THE
FLOW COULD TRIGGER AN AFTERNOON THUNDERSTORM ON THU...CHANCES WILL NOT
BE HIGH ENOUGH TO INCLUDE A MENTION OF PRECIPITATION IN THE FORECAST.
TEMPERATURES WILL BE SEASONABLE ON THU. ON FRI...THE RIDGE WILL BUILD
EAST INTO THE REGION AND 700 MB TEMPS WILL RECOVER TO BETWEEN +8 AND +12
DEGREES C. SKIES SHOULD BE MOSTLY SUNNY AS ANY RIPPLES IN THE FLOW WILL
BE WEAK. PREVIOUS FORECAST OF ABOVE NORMAL TEMPS LOOKED FINE. ON
DAY 7 (MON) UPPER RIDGE PROGGED TO SLIDE E OF THE REGION. A SHORTWAVE
WILL MOVE INTO WESTERN MT ACCOMPANIED BY A COLD FRONT AND SOME MOISTURE.
CHANCE OF THUNDERSTORMS FROM PREVIOUS FORECAST LOOKED FINE. ONLY CHANGE
TO BEYOND DAYS 3 AND 4 WAS TO RAISE TEMPERATURES IN SE ZONES ADJACENT TO
UNR/S AREA IN VICINITY OF THERMAL RIDGE. ARTHUR

    TUE     WED     THU     FRI     SAT     SUN     MON
-----------------------------------------------------------
BIL 058/088 057/087 056/084 056/088 056/088 055/090 057/086
    03/T    30/U    00/U    00/U    00/U    00/G    00/B
LVM 052/086 049/086 049/082 048/086 048/087 047/089 050/085
    23/T    20/U    00/U    00/U    00/U    00/U    03/T
HDN 058/090 058/089 056/085 056/089 059/089 055/090 057/089
    23/T    30/U    00/U    00/U    00/U    00/G    00/U
MLS 058/086 059/088 056/084 056/088 059/088 055/089 057/089
    34/T    40/B    00/U    00/U    00/U    00/U    00/B
4BQ 058/087 058/088 055/084 056/088 059/088 055/090 057/089
    34/T    40/B    00/U    00/U    00/U    00/G    00/U
BHK 055/082 060/086 055/084 055/086 058/086 054/088 056/086
    34/T    42/T    00/U    00/U    00/U    00/U    00/B
SHR 055/090 055/088 053/084 054/088 057/088 053/090 053/086
    33/T    30/U    00/U    00/U    00/U    00/G    00/U

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

MTZ028>042-056>058-WYZ098-099-081100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BILLINGS MT
500 AM MDT MON JUL 7 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.

.DAY TWO THROUGH SEVEN...
AN UPPER LEVEL DISTURBANCE WILL PUSH ACROSS SOUTHERN MONTANA AND
NORTH CENTRAL WYOMING TUESDAY AFTERNOON INTO TUESDAY NIGHT.
THUNDERSTORMS WILL BE POSSIBLE WITH THE DISTURBANCE. A FEW
THUNDERSTORMS MAY BECOME SEVERE...PRODUCING LARGE HAIL AND DAMAGING
WINDS.

.SPOTTER INFORMATION STATEMENT...
WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

JZ