Alert archive / Montana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 89, NWS Great Falls, MT

August 5, 2002Lewis and Clark County, Montana

NWS Great Falls, MT issued this severe thunderstorm warning at Aug 5, 2002, 5:16 PM MDT for Lewis and Clark County, Montana. It was in force for 44 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 5, 2002, 5:16 PM MDT (23:16 UTC)
Expired
Aug 5, 2002, 6:00 PM MDT
In force
44 min
Issued by
NWS Great Falls, MT
Area
Counties, with a storm outline in the text

County Lewis and Clark County, MT

The radar

The Great Falls radar (KTFX), 87 km from the middle of the area, began a volume at 23:17 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 5, 3:55 PM MDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 11.3 hours before the alert went out and 146 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 2002-08-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2002-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 135 square meters per square second.1939587897117Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
992 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
135 m²/s²
0-3 km storm-relative helicity
308 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

173 
WUUS55 KTFX 052316
SVRTFX
MTC049-060000-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
515 PM MDT MON AUG 5 2002

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL LEWIS AND CLARK COUNTY IN WEST CENTRAL MONTANA

* UNTIL 600 PM MDT

* AT 512 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 15 MILES SOUTHWEST OF AUGUSTA...OR ABOUT 39
  MILES WEST OF CASCADE...MOVING NORTHEAST AT 25PH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  4 MILES SOUTHEAST OF AUGUSTA AT 540 PM MDT

THIS STORM IS CAPABLE OF PRODUCING HAIL TO ONE INCH IN 
DIAMETER...AND WIND GUSTS TO 60 MPH.

REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY
WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE IN GREAT FALLS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 PM MDT
MONDAY EVENING FOR WESTERN MONTANA.

LAT...LON 4730 11270 4718 11251 4741 11213 4762 11265

$$

BRUSDA

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 Great Falls, MT wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 5, 3:00 PM MDT, 2 hours 16 minutes earlier.

Area forecast discussion, Aug 5, 3:00 PM MDT, 2 hours 16 minutes before
SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
300 PM MDT MON AUG 5 2002

.SHORT TERM...SOUTHWEST PORTION OF CWA HAS SEEN AMPLE SUNSHINE
THIS AFTERNOON AND INITIAL CONVECTION SHOULD BEGIN THERE. THESE
STORMS WILL ADVANCE IN SWIFT SOUTHWEST FLOW ALOFT INTO SHEAR
ENVIRONMENT OVER THE NORTHERN PART OF THE CWA WHICH IS PROGGED TO BE
QUITE HIGH THIS EVENING. HELICITY...CAPE AND LI VALUES INDICATE THE
BEST POTENTIAL FOR SEVERE WEATHER IS EAST OF A LINE FROM NEAR GREAT
FALLS TO CHESTER.  SPC MODERATE RISK CALLS FOR LONG LIVED SUPERCELLS
WITH GREATEST THREAT FROM LARGE HAIL. HELICITY VALUES AND INSTABILITY
SUGGEST ROTATING UPDRAFTS ARE LIKELY. WILL PLAY THIS SCENARIO UP IN
AFTERNOON PACKAGE. SPS ISSUED EARLIER TODAY AS A HAZARDOUS WEATHER
OUTLOOK TO ATTRACT MEDIA ATTENTION FOR POSSIBLE SEVERE WEATHER
OUTBREAK.

MAIN UPPER LOW STILL OVER PACNW AND WILL CONTINUE TO SEND SHORT WAVE
ENERGY THROUGH A MOIST SOUTHWEST FLOW THROUGH WEDNESDAY. MODELS
CONTINUE ADVANCING PARENT LOW EAST AND WILL CONTINUE TO PLAY IT A BIT
SLOWER THAN PROGGED. BOTTOM LINE...WILL KEEP SCATTERED POPS IN FOR
MOST OF CWA THROUGH MOST OF PERIOD. DITTMANN

.EXTENDED...AVN/ECMWF ARE IN PRETTY GOOD AGREEMENT FOR FRI AND SAT
BUT DIVERGE SIGNIFICANTLY BY SUN. 12Z UKMET LEANS TOWARDS THE
00Z/12Z AVN. FOR FRI AND SAT LOOKS LIKE DRY W TO NW FLOW ALOFT WILL
BE OVER THE AREA. SUN AVN BRINGS AN UPPER TROUGH INTO THE AREA
WHILE THE ECMWF HAS AN UPPER RIDGE. ON MON 00Z AVN RUN DUG THE UPPER
TROUGH INTO ERN MT WITH COOL THICKNESSES FOR THE AREA. NCEP
DISCUSSION FAVORS A SLOWER AND LESS AMPLIFIED UPPER TROUGH THAN WHAT
THE 00Z/12Z AVN HAVE. SO WHEREAS THE 00Z AVN BROUGHT A COLD FRONT
THROUGH THE AREA ON SUN WILL HOLD OFF ON COLD FRONTAL PASSAGE UNTIL
MON. HARD TO SAY AT THIS POINT HOW MUCH MOISTURE AND WHETHER
THERE WILL BE MUCH IF ANY UPSLOPE FLOW WITH THE UPPER TROUGH.
WILL GO WITH A SLIGHT CHANCE OF SHOWERS FOR NOW. BLANK

.CCF NUMBERS
GTF BB 052/077 050/074 048 02533
    EBNNB 075/052 077/050 083/053 083/050 078 33321111112
CTB BB 048/070 047/069 045 02433
    BBNNB 071/048 076/048 080/050 077/046 072 22221111122
HLN BB 052/078 050/076 050 02533
    EBBNB 076/050 076/050 085/054 085/053 080 33421111112
BZN BB 048/080 046/078 048 02533
    EBBBB 078/044 074/045 082/048 084/047 080 33431111112
WEY BB 040/072 038/070 040 02333
    EBBBB 070/038 068/036 075/038 077/039 075 34541111112
DLN BB 048/078 046/076 046 02333
    BBBNB 075/044 075/044 080/047 082/049 080 33431111112
HVR BB 056/082 053/078 050 02633
    BBBNB 079/050 078/050 085/054 084/054 077 33311111122
LWT BB 052/080 050/076 047 02633
    EBBNB 074/047 073/045 081/050 081/050 077 33321111112=

.TFX...

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 4, 7:02 PM MDTSevere Thunderstorm WarningTFXFergus, Judith Basin58 min
Aug 5, 5:36 PM MDTSevere Thunderstorm WarningTFXLewis and Clark54 min
Aug 5, 5:52 PM MDTSevere Thunderstorm WarningTFXJudith Basin38 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.