Alert archive / Montana / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 2, NWS Billings, MT

May 21, 2002Yellowstone County, Montana

NWS Billings, MT issued this severe thunderstorm warning at May 21, 2002, 4:37 PM MDT for Yellowstone County, Montana. It was in force for 53 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: May 21, 2002, 4:37 PM MDT (22:37 UTC)
Expired: May 21, 2002, 5:30 PM MDT
In force: 53 min
Issued by: NWS Billings, MT
Area: Counties, with a storm outline in the text

County Yellowstone County, MT

What was reported inside it

Time	Report	Where	Remark
May 21, 4:39 PM MDT	Thunderstorm Wind 61 M	Billings, MT	61 mph wind gust at the Billings National Weather Service
May 21, 4:46 PM MDT	Thunderstorm Wind 63 M	Billings Logan Arpt, 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.

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.

Issued	Product	Office	Lasted
May 21, 3:00 PM MDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Great_falls, MT (KTFX), launched 12:00Z, 10.6 hours before the alert went out and 221 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1038 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 7 m²/s²
0-3 km storm-relative helicity: 189 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

000 
WUUS55 KBYZ 212237
SVRBIL
MTC111-212330-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BILLINGS MT
436 PM MDT TUE MAY 21 2002

THE NATIONAL WEATHER SERVICE IN BILLINGS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WEST CENTRAL YELLOWSTONE COUNTY IN SOUTH CENTRAL MONTANA
  THIS INCLUDES THE CITY OF BILLINGS

* UNTIL 530 PM MDT

* AT 436 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A SEVERE THUNDERSTORM WITH DAMAGING WINDS 5 MILES SOUTHWEST OF     
  BILLINGS...MOVING NORTHWEST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL AFFECT WEST BILLINGS BY 440 PM.

LAT...LON 4613 10892 4613 10861 4573 10844 4565 10864
          4584 10888

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 May 21, 2:09 PM MDT, 2 hours 28 minutes earlier.

Area forecast discussion, May 21, 2:09 PM MDT, 2 hours 28 minutes before

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
209 PM MDT TUE MAY 21 2002

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

COMPLICATED PATTERN SETTING UP FOR TONIGHT THROUGH THURSDAY MORNING AS
UPPER LEVEL SYSTEM MOVES INTO MONTANA. AVN AND ETA BOTH HANDLING THE
SYNOPTIC PATTERN SIMILARLY WITH THE AVN BEING ABOUT 200 MILES FARTHER
NORTH WITH LOW LEVEL FEATURES THAN THE ETA. LIKE THE ETA/META
SOLUTION WITH A BIT SLOWER TIMING AND MORE SOUTHERLY TRACK PER 15Z
ANALYSIS WITH SURFACE LOW PRESSURE CENTERED IN SOUTHWEST WYOMING WITH
A SECONDARY LOW DEVELOPING IN SOUTH CENTRAL MONTANA. ETA IS PUTTING OUT
VERY HIGH QPF OVER THE WESTERN HALF OF MY CWA OVER THE NEXT 24 TO 36
HOURS WITH SOME VALUES OVER TWO INCHES FOR THE STORM TOTALS. AS
PRECIPITATION TURNS TO SNOW EARLY WEDNESDAY MORNING HEAVY SNOW
ACCUMULATIONS CAN BE EXPECTED ABOVE 6000 FEET SO WILL ISSUE A WINTER
STORM WARNING FOR THE AREAS CURRENTLY UNDER A WATCH. PRECIPITATION MAY
CHANGE OVER TO SNOW AT LOWER ELEVATIONS AROUND SUNRISE IN THE WARNED
LOCATIONS BUT 850 MB TEMPS AROUND +2C SHOULD PREVENT ADVISORY
ACCUMULATIONS. STRONG WRAP AROUND WILL DRIVE COLD FRONT INTO THE AREA
EARLY WEDNESDAY...MODELS INDICATING 12 MB PRESSURE RISES BEHIND
THIS FEATURE WITH WINDS APPROACHING WARNING CRITERIA FOR THE
WESTERN 2/3 OF MY CWA...THINK STRONG UPWARD MOTION WILL LIMIT TRANSFER
OF 60KT WINDS FROM 800-700MB LAYER TO SURFACE SO WILL HOLD OFF ON
ISSUING A WARNING.

SYSTEM BEGINS TO EXIT THE STATE THURSDAY MORNING WITH SOME WRAP AROUND
PRECIPITATION HOLDING ON IN THE EAST UNTIL LATE AFTERNOON. TEMPERATURES
WILL GET CLOSE TO RECORD LEVELS FOR THURSDAY AND FRIDAY WITH RECORD LOWS
AROUND 31 DEGREES...ESPECIALLY FRIDAY MORNING AS CANADIAN HIGH PRESSURE
BUILDS IN AND SKIES CLEAR OUT. SKIES CONTINUE TO CLEAR OUT FRIDAY BUT
TEMPS WILL BE SLOW TO WARM WITH GENERAL ZONAL FLOW ALOFT WARM WITH A FEW
INSTABILITY SHOWERS IN THE AFTERNOON. CHAMBERS

.LONG TERM...VALID FOR SAT...SUN...MON...TUE...
LONG RANGE MODELS IN GOOD AGREEMENT WITH A BROAD RIDGE AND NEARLY ZONAL
FLOW ACROSS THE AREA SATURDAY. ECMWF THEN BECOMES THE OUTLIER AS UKMET
AND AVN/MRF BOTH TURN FLOW SOUTHWEST WITH ANOTHER UPPER LEVEL LOW OFF
THE SOUTHERN BRITISH COLUMBIA COAST. MRF HAS A SURFACE TROUGH AND
PACIFIC COLD FRONT MOVING ACROSS MONTANA SATURDAY AND SUNDAY WITH COOLER
TEMPERATURES TRAILING BEHIND. WILL MODERATE GUIDANCE TEMPERATURE FALLS
WITH THIS SYSTEM TO INDICATE SLIGHT COOLING TREND THROUGH SUNDAY...AND
INSERT SLIGHT CHANCE POPS FOR SATURDAY/SATURDAY NIGHT IN THE WEST...AND
SATURDAY NIGHT/SUNDAY IN THE EAST. SURFACE HIGH MOVES INTO THE AREA
BEHIND THE FRONT BEGINNING MONDAY...WHILE UPPER FLOW BECOMES MORE ZONAL
BY MONDAY/NIGHT TUESDAY. TEMPERATURES SLOWLY REBOUND TO NEAR NORMAL
VALUES FOR DAYS 6 AND 7. CARPENTER

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 045/051 034/054 033/060 044/065 046/064 045/068 045/071
    8+/R    42/W    22/W    02/B    20/E    00/B    00/B
LVM 041/045 029/052 028/060 038/065 044/064 041/067 043/071
    ++/0    62/0    22/W    02/B    20/E    00/B    00/B
HDN 045/052 035/055 034/061 043/066 045/065 044/069 044/072
    88/R    42/W    22/W    02/B    20/E    00/B    00/B
MLS 050/055 037/056 035/060 045/065 047/064 046/068 046/071
    66/W    64/W    22/W    02/B    20/E    00/B    00/B
4BQ 048/055 038/057 035/060 042/065 045/064 044/068 045/071
    66/W    64/W    22/W    00/B    22/E    00/B    00/B
BHK 049/054 038/055 035/061 042/066 045/065 044/069 045/071
    64/W    64/W    22/W    00/B    22/E    00/B    00/B
SHR 046/055 037/055 034/058 040/064 045/063 044/066 044/069
    67/W    64/W    22/W    00/B    22/E    00/B    00/B

.BYZ...WINTER STORM WARNING FOR LATE TONIGHT AND WEDNESDAY FOR MOUNTAIN
ZONES...

The office that day

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

Issued	Product	Office	Counties	Lasted
May 21, 5:03 PM MDT	Severe Thunderstorm Warning	BYZ	Yellowstone	57 min
May 21, 5:54 PM MDT	Severe Thunderstorm Warning	BYZ	Musselshell	66 min

Nearby

Severe Thunderstorm Warnings in Montana, 2002 Every 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.