Alert archive / Montana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 76, NWS Billings, MT

July 15, 2002Sweet Grass County, Montana

NWS Billings, MT issued this severe thunderstorm warning at Jul 15, 2002, 5:35 PM MDT for Sweet Grass County, Montana. It was in force for 55 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jul 15, 2002, 5:35 PM MDT (23:35 UTC)
Expired
Jul 15, 2002, 6:30 PM MDT
In force
55 min
Issued by
NWS Billings, MT
Area
Whole counties

County Sweet Grass County, MT

The radar

The Billings radar (KBLX), 103 km from the middle of the area, began a volume at 23:38 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Jul 15, 5:45 PM MDTThunderstorm Wind 60 EMc Leod, MT

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 11.6 hours before the alert went out and 190 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Great_falls, MT at 12:00Z on 2002-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 412 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 12:00Z on 2002-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -31 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
412 J/kg
Mixed-layer CIN
-154 J/kg
Mixed-layer LCL
2086 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
-31 m²/s²
0-3 km storm-relative helicity
24 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Billings, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 15, 2:39 PM MDT, 2 hours 56 minutes earlier.

Area forecast discussion, Jul 15, 2:39 PM MDT, 2 hours 56 minutes before
SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
239 PM MDT MON JUL 15 2002

.SHORT TERM...VALID FOR TUE...WED...THU...
ACTIVE PATTERN SETTING UP FOR NEXT COUPLE OF DAYS. EASTERLY LOW LEVEL
FLOW WILL ALLOW MOISTURE TO CREEP INTO EAST OVER NEXT COUPLE OF DAYS
AND SHORTWAVE ENERGY RIDING SOUTHWEST UPPER FLOW PASSES OVER AREA. AVN
AND ETA DIFFERING IN TIMING OF ENERGY...AND WILL LEAN MORE TOWARD ETA
FOR THIS PACKAGE.

TONIGHT THROUGH TUESDAY...CONVECTION ONCE AGAIN UNDERWAY ACROSS THE
MOUNTAINS THIS AFTERNOON. UPPER WAVE WILL PASS ACROSS THE WESTERN PART
OF THE CWA LATE THIS AFTERNOON INTO TONIGHT. SURFACE WINDS WILL TURN
MORE EASTERLY AS SURFACE HIGH DEVELOPS ACROSS SOUTHERN CANADA...
ALLOWING MORE LOW LEVEL MOISTURE TO BEGIN WORKING ITS WAY INTO THE
AREA. WILL HAVE HIGHEST POPS IN THE WEST WITH UPPER SUPPORT...BUT WILL
NOT RULE OUT ISOLATED STORM EAST. AIR STABILIZES SOMEWHAT BEHIND INITIAL
WAVE...SO AREA SHOULD SEE BREAK FROM STORMS AFTER MIDNIGHT. TUESDAY
TEMPS WILL CONTINUE DOWNWARD TREND...BUT WILL STILL BE NEAR 100 FAR
SOUTHEAST. LOW LEVEL MOISTURE WILL CONTINUE TO INCREASE...INCREASING
INSTABILITY. ETA SHOWING AXIS OF GREATEST INSTABILITY CLIPPING NORTHEAST
ZONES TOMORROW AFTERNOON IN AREA WHERE MOISTURE POOLING EXPECTED TO BE
GREATEST. WILL BROADBRUSH CHANCE POPS ACROSS CWA FOR TOMORROW AFTERNOON
AS MORE UPPER ENERGY WORKS NORTHEASTWARD.

TUESDAY NIGHT AND WEDNESDAY...EASTERLY FLOW PROGGED UP THROUGH 700 MB...
WHICH WILL ALLOW AMPLE MOISTURE TO MAKE ITS WAY INTO MUCH OF CWA. THIS
TREND SHOWN WELL IN PRECIPITABLE WATER...WHICH INCREASES TO 1.5 INCHES
ACROSS EAST. WILL BROADBRUSH HIGHER SCATTERED POPS ACROSS ENTIRE CWA...
WITH DECENT SHORTWAVE SLOWLY PUSHING ACROSS SOUTHERN MONTANA THROUGH THE
PERIOD. WILL ALSO GO A FEW DEGREES COOLER THAN PREVIOUS FORECAST...AS
INCREASING MOISTURE AND DEEP EASTERLY FLOW WILL LIMIT WARMING.

WEDNESDAY NIGHT...SOUTHERLY MID LEVEL FLOW CONTINUES WITH SUB-TROPICAL
MOISTURE INTO AREA (PRECP WATER VALUES OVER AN INCH)...WITH FAIRLY MOIST
EASTERLY LOW LEVEL FLOW. AVN FORECASTING SHORTWAVE ENERGY TO MOVE UP
INTO SOUTHERN ZONES OVERNIGHT...THAN ACROSS THE AREA THURSDAY. SURFACE
FRONT ALSO SHOULD BE MOVING ACROSS THE AREA...INTO EASTERN ZONES
THURSDAY AFTERNOON. PRECIPITABLE WATER VALUES REMAIN HIGH WITH
RELATIVELY WEAK UPPER LEVEL WINDS. THIS SHOULD HELP FIRE WEATHER
SITUATION SOMEWHAT WITH HIGHER RELATIVE HUMIDITIES AND WETTER STORMS.
WILL UP POPS INTO HIGHER SCATTERED CATEGORY. JZ/RASCH

.LONG TERM...VALID FOR FRI...SAT...SUN...MON...
FLOW FORECASTED TO BEGIN TURNING MORE WESTERLY THURSDAY NIGHT
INTO EARLY FRIDAY. FLOW LOOKS UNSETTLED EARLY FRIDAY AND WILL KEEP
CURRENT SCATTERED POPS IN. SATURDAY MODELS IN PRETTY GOOD AGREEMENT THAT
CHANCES LOOK LESS WITH DRIER MORE WESTERLY UPPER FLOW OVER AREA AND
ACTUALLY SHORTWAVE RIDGE FORECASTED OVER AREA. OVERALL LOOKS LIKE A
FAIRLY DRY PATTERN AND WILL TAKE CHANCES OUT. SUNDAY...FASTER AND
DRIER WESTERLY FLOW FORECASTED OVER AREA AS FAIRLY STRONG SHORTWAVE
MOVES ACROSS SOUTHERN CANADA...LOOKING MORE WINDY AND WET. EXT-AVN THEN
FORECASTING TROUGHINESS TO MOVE INTO AREA END OF THE EXTENDED FOR COOLER
TEMPS. WILL KEEP A CHANCE IN FOR MONDAY...WITH COOLING TREND. RASCH

    TUE     WED     THU     FRI     SAT     SUN     MON
-----------------------------------------------------------
BIL 066/093 065/088 063/085 060/087 062/090 063/090 065/087
    34/T    44/T    44/T    43/T    00/B    00/B    00/B
LVM 058/090 058/087 056/084 057/086 059/089 060/089 062/086
    44/T    44/T    44/T    43/T    00/B    00/B    00/B
HDN 065/095 066/090 064/087 061/089 063/092 064/092 066/089
    34/T    44/T    43/T    43/T    00/B    00/B    00/B
MLS 070/097 068/091 066/088 063/090 065/091 066/091 068/088
    34/T    44/T    44/T    43/T    00/B    00/B    00/B
4BQ 068/098 067/092 065/089 062/091 064/092 065/092 067/089
    23/T    44/T    44/T    43/T    00/B    00/B    00/B
BHK 065/095 067/088 065/085 062/087 064/090 065/090 067/087
    23/T    44/T    44/T    43/T    00/B    00/B    00/B
SHR 062/096 062/089 060/086 057/088 059/091 060/091 062/088
    23/T    44/T    43/T    43/T    00/B    00/B    00/B

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

The office that day

Everything else NWS Billings, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 14, 7:50 PM MDTSevere Thunderstorm WarningBYZWheatland25 min

Nearby

Severe Thunderstorm Warnings in Montana, 2002Every severe thunderstorm warning in 2002

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.