Alert archive / Utah / Mesoscale Discussions in 2003

Mesoscale Discussion 2158

August 15, 2003Coconino County, Arizona; 4 counties in Utah

The Storm Prediction Center issued this mesoscale discussion at Aug 15, 2003, 12:20 PM MST for Coconino County, Arizona; 4 counties in Utah. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: Aug 15, 2003, 12:20 PM MST (19:20 UTC)
Expired: Aug 15, 2003, 2:15 PM MST
In force: 115 min
Issued by: the Storm Prediction Center

Counties Coconino County, AZ, Garfield County, UT, Iron County, UT, Kane County, UT, Piute County, UT

The radar

The Cedar City radar (KICX), 82 km from the middle of the area, began a volume at 19:23 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 nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 7.3 hours before the alert went out and 200 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: 15 J/kg
Mixed-layer CIN: -189 J/kg
Mixed-layer LCL: 1238 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: -38 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

592 
ACUS11 KWNS 151920
SWOMCD
SPC MCD 151920 
UTZ000-AZZ000-152115-

MESOSCALE DISCUSSION 2158
NWS STORM PREDICTION CENTER NORMAN OK
0220 PM CDT FRI AUG 15 2003

AREAS AFFECTED...SRN UT/NRN AZ

CONCERNING...SEVERE THUNDERSTORM POTENTIAL...HEAVY RAINFALL 

VALID 151920Z - 152115Z

CONVECTION CURRENTLY DEVELOPING IN SRN UT AND NRN AZ SHOULD CONTINUE
TO INTENSIFY AND A POTENTIAL WILL EXIST FOR LOCALIZED VERY HEAVY
RAINFALL. ISOLATED DAMAGING WIND GUSTS AND MARGINALLY SEVERE HAIL
WILL ALSO BE POSSIBLE. WW MAY BECOME NECESSARY IN THE NEXT FEW HOURS
IF THE CURRENT TRENDS CONTINUE.

ANALYSIS SHOWS A LOW-LEVEL MOIST AXIS OF MID 50S TO AROUND 60 F SFC
DEWPOINTS EXTENDING NWD THROUGH NCNTRL AZ AND SCNTRL UT. CONVECTION
IS DEVELOPING IN RESPONSE TO SFC HEATING WHERE SBCAPE VALUES HAVE
RISEN TO BETWEEN 2000 AND 3000 J/KG. LARGE-SCALE ASCENT WILL
INCREASE OVER THE NEXT FEW HOURS AS A BAND OF STRONG POSITIVE
VORTICITY ADVECTION MOVES INTO CNTRL UT. THIS WILL LIKELY CAUSE
CONVECTION TO INCREASE IN COVERAGE. SLOW CELL MOTIONS AROUND 10 KT
WILL ENHANCE A POTENTIAL FOR VERY HEAVY RAINFALL. IN ADDITION...DEEP
LAYER SHEAR AROUND 35 KT WILL BE SUFFICIENT FOR ISOLATED ORGANIZED
SEVERE CONVECTION. THE DRY SUBCLOUD LAYER ENVIRONMENT MAY RESULT IN
A FEW MICROBURSTS WITH THE STRONGER CELLS AS THE STORMS MATURE LATER
THIS AFTERNOON.

..BROYLES.. 08/15/2003

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...FGZ...SLC...VEF...

35861306 38131358 38651259 38471133 36181091 35681195

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 14, 7:02 PM MST	Mesoscale Discussion	SPC	Coconino, Gila, Maricopa, Navajo, Pima, Pinal and 1 more	88 min
Aug 14, 8:19 PM MST	Mesoscale Discussion	SPC	Maricopa, Yavapai	56 min

Nearby

Mesoscale Discussions in Utah, 2003 Mesoscale Discussions in Arizona, 2003 Every mesoscale discussion in 2003

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.