Alert archive / Iowa / Mesoscale Discussions in 2004
Mesoscale Discussion 2155
The Storm Prediction Center issued this mesoscale discussion at Sep 1, 2004, 3:20 PM CDT for 34 counties in Iowa. It was in force for 115 min.
The area
The outline as issued.
The facts
- Issued
- Sep 1, 2004, 3:20 PM CDT (20:20 UTC)
- Expired
- Sep 1, 2004, 5:15 PM CDT
- In force
- 115 min
- Issued by
- the Storm Prediction Center
All 34 counties
Benton County, IA, Black Hawk County, IA, Boone County, IA, Buchanan County, IA, Butler County, IA, Cedar County, IA, Dallas County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Hamilton County, IA, Hardin County, IA, Humboldt County, IA, Iowa County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Keokuk County, IA, Linn County, IA, Lucas County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Pocahontas County, IA, Polk County, IA, Poweshiek County, IA, Story County, IA, Tama County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Webster County, IA, Wright County, IA
The radar
The Des Moines radar (KDMX), 77 km from the middle of the area, began a volume at 20:17 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.
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 8.3 hours before the alert went out and 208 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1597 m above ground
- 0-6 km bulk shear
- 12 kt
- 0-1 km storm-relative helicity
- 68 m²/s²
- 0-3 km storm-relative helicity
- 99 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
863 ACUS11 KWNS 012023 SWOMCD SPC MCD 012020 IAZ000-012215- MESOSCALE DISCUSSION 2155 NWS STORM PREDICTION CENTER NORMAN OK 0320 PM CDT WED SEP 01 2004 AREAS AFFECTED...PARTS OF CNTRL/ERN IA CONCERNING...CONVECTIVE TRENDS VALID 012020Z - 012215Z POTENTIAL FOR CONVECTIVE DEVELOPMENT APPEARS TO BE INCREASING... WITH PERHAPS ISOLATED/BRIEF SEVERE THREAT. STRONG SURFACE HEATING...FOCUSED ALONG LOW-LEVEL THERMAL RIDGE AXIS EXTENDING OUT OF THE NORTHERN PLAINS...AND EVAPOTRANSPIRATION HAVE CONTRIBUTED TO CONSIDERABLE DESTABILIZATION OF BOUNDARY LAYER ACROSS MUCH OF IOWA AND ADJACENT AREAS OF THE UPPER MISSISSIPPI VALLEY. THIS IS SOUTH OF WEAK FRONTAL ZONE ACROSS SOUTH CENTRAL MINNESOTA/ NORTH CENTRAL WISCONSIN...WHERE LOW-LEVEL FOCUS FOR CONVECTIVE DEVELOPMENT IS UNCERTAIN. HOWEVER...LATEST OBJECTIVE ANALYSIS INDICATES SUBSTANTIAL WEAKENING OF CONVECTIVE INHIBITION IS ONGOING ACROSS IOWA. THIS IS PERHAPS AIDED BY MID-LEVEL FORCING FOR UPWARD VERTICAL MOTION ASSOCIATED WITH ONE OF A SERIES OF WEAK WAVES EVIDENT IN LATEST WATER VAPOR IMAGERY. ADDITIONAL HEATING LATE THIS AFTERNOON IS EXPECTED TO SUPPORT INITIATION OF AT LEAST ISOLATED CONVECTIVE DEVELOPMENT BY 22-23Z...MAINLY EAST OF THE DES MOINES AREA...WHERE MEAN MIXED LAYER CAPE IS ON THE ORDER OF 2000 J/KG. WEAK FLOW FIELDS/SHEAR PROFILES WILL LIMIT OVERALL SEVERE THREAT...BUT THERMODYNAMIC ENVIRONMENT APPEARS SUPPORTIVE OF MARGINALLY SEVERE HAIL...POSSIBLY GUSTY WINDS...IN MOST VIGOROUS CONVECTION. ..KERR.. 09/01/2004 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DVN...ARX...DMX... 43109356 42609177 41879103 41009146 40869307 41449421 42789478
Nearby
Mesoscale Discussions in Iowa, 2004Every mesoscale discussion in 2004
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.