Alert archive / Colorado / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 44, NWS Grand Junction, CO

September 29, 2002Mesa County, Colorado

NWS Grand Junction, CO issued this severe thunderstorm warning at Sep 29, 2002, 4:41 PM MDT for Mesa County, Colorado. It was in force for 49 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Sep 29, 2002, 4:41 PM MDT (22:41 UTC)
Expired: Sep 29, 2002, 5:30 PM MDT
In force: 49 min
Issued by: NWS Grand Junction, CO
Area: Whole counties

County Mesa County, CO

The radar

The Grand Junction radar (KGJX), 22 km from the middle of the area, began a volume at 22:41 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.

The watch it was issued in

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

Issued	Product	Office	Lasted
Sep 29, 1:10 PM MDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Grand Junction, CO (KGJT), launched 12:00Z, 10.7 hours before the alert went out and 13 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: 77 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 1002 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 56 m²/s²
0-3 km storm-relative helicity: 183 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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 Grand Junction, CO wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 29, 3:53 PM MDT, 48 minutes earlier.

Area forecast discussion, Sep 29, 3:53 PM MDT, 48 minutes before

WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
353 PM MDT SUN SEP 29 2002

STRONG TROUGH OVER SE NV/NW AZ BEGINNING TO LIFT NE INTO SWRN
UTAH. PLENTY OF DIVERGANCE ALOFT/PVA/UVV AHEAD OF IT OVER
CENTRAL UTAH. MINOR SHORTWAVE AND JET SPEED MAX SPAWNING TSTMS
OVER XTRM ERN UT AND NW CO. LONG-LIVED CELLS APPEAR TO BE JUST
BELOW SEVERE STORM STRENGTH. MOIST SOUNDING COULD HELP PRODUCE WET
MICROBURST TYPE WINDS...BUT BASES AND TOPS ARE LOW SO MAY NOT BE
ENOUGH VERTICAL FALL TO ALLOW SEVERE WIND GUSTS TO DVLP. TWO STRONG
CELLS THAT HAVE DEVELOPED DID SHOW BOWING ECHO CHARACTERISTICS...BUT
VILS HAVE REMAINED LOW. FREEZING LEVEL FROM 12Z SOUNDING JUST ABOVE
10,000 FT...AT LEAST SMALL HAIL EXPECTED ESPECIALLY OVER HIGHER
TERRAIN.

STRONG THUNDERSTORMS SHOULD CLEAR CWA THIS EVENING TO NORTHEAST WITH
STABILIZATION TO FOLLOW.  MODELS SHOW THIS FRONT BECOMING STATIONARY
WITH INCREASING MOISTURE CONVERGENCE THROUGH THE FIRST PART OF THIS
WEEK. FRONT WILL INITIALLY STALL NORTHWEST OF OUR FORECAST AREA
TUESDAY...THEN SLOWLY SLIDE SOUTHEAST WED. CJC

EXTENDED...(THU-SUN) MODELS STILL SHOW PRETTY GOOD CONSISTENCY WITH
OVERALL PATTERN OF HIGH PRESSURE OVER THE EASTERN PACIFIC WITH A
LONG WAVE TROUGH OVER WRN/CNTRL UNITED STATES. EMBEDDED WAVES WILL
PRODUCE AREAS OF PRECIPITATION AND TEMPERATURES WILL BE NEAR TO A
LITTLE BELOW NORMAL. A STRONG UPPER LEVEL LOW PRESSURE SYSTEM WILL
BE NEAR THE 4 CORNERS THURSDAY MORNING AND THEN MOVE EASTWARD DURING
THE DAY. THIS SHOULD BRING FAIRLY WIDESPREAD PCPN TO MOST OF THE CWA
INCLUDING THE NORTH...WHERE THE FLOW BECOMES UPSLOPE NORTHWESTERLY
BY AFTERNOON. FRIDAY WE WILL BE BETWEEN STORMS AS THE NEXT SYSTEM
DROPS INTO THE NORTHERN ROCKIES AND THE FLOW BACKS TO THE SOUTHWEST.
THE UPPER LOW DRIFTS EASTWARD INTO THE AREA SATURDAY AND SUNDAY
PRODUCING SCATTERED SHOWERS.

.GJT...NONE.

In the hours before

Local storm report, Sep 29, 1:01 PM MDT, 3 hours 40 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION, CO
101 PM MDT SUN SEP 29 2002

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

1115 AM    1 N FRUITA                CO   .75 INCH HAIL
09/29/02   MESA                           REPORTED BY
                                          NWS EMPLOYEE

DJN

The office that day

Everything else NWS Grand Junction, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 29, 11:15 AM MDT	Severe Thunderstorm Warning	GJT	Garfield, Mesa	45 min
Sep 29, 11:54 AM MDT	Severe Thunderstorm Warning	GJT	Garfield, Mesa	51 min
Sep 29, 3:30 PM MDT	Flash Flood Warning	GJT	Garfield	3 hr
Sep 29, 4:41 PM MDT	Severe Thunderstorm Warning	GJT	Mesa	49 min
Sep 29, 2:44 PM MDT	Severe Thunderstorm Warning	GJT	Grand	46 min

Nearby

Severe Thunderstorm Warnings in Colorado, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.