Alert archive / Iowa / Mesoscale Discussions in 2011

Mesoscale Discussion 23

January 17, 201120 counties in Iowa; 7 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Jan 17, 2011, 2:50 AM CST for 20 counties in Iowa; 7 counties in Missouri. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Jan 17, 2011, 2:50 AM CST (08:50 UTC)
Expired: Jan 17, 2011, 7:15 AM CST
In force: 4 hr
Issued by: the Storm Prediction Center

All 27 counties

Appanoose County, IA, Clarke County, IA, Davis County, IA, Decatur County, IA, Henry County, IA, Jasper County, IA, Jefferson County, IA, Keokuk County, IA, Lee County, IA, Lucas County, IA, Mahaska County, IA, Marion County, IA, Monroe County, IA, Polk County, IA, Poweshiek County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Adair County, MO, Clark County, MO, Mercer County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Sullivan County, MO

The radar

The Des Moines radar (KDMX), 121 km from the middle of the area, began a volume at 08:51 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 00:00Z, 8.8 hours before the alert went out and 201 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: 951 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 112 m²/s²
0-3 km storm-relative helicity: 165 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.

742 
ACUS11 KWNS 170850
SWOMCD
SPC MCD 170850 
ILZ000-IAZ000-MOZ000-171315-

MESOSCALE DISCUSSION 0023
NWS STORM PREDICTION CENTER NORMAN OK
0250 AM CST MON JAN 17 2011

AREAS AFFECTED...SOUTH CENTRAL AND SERN IA/FAR NORTH CENTRAL AND
NERN MO

CONCERNING...FREEZING RAIN 

VALID 170850Z - 171315Z

LIGHT SNOW WILL CONTINUE TO DEVELOP FROM W-E ACROSS THE DISCUSSION
AREA.  WINTRY PRECIPITATION IS EXPECTED TO TRANSITION TO SLEET BY
09-10Z ACROSS S CENTRAL IA/FAR N CENTRAL MO...AND THEN TO FREEZING
RAIN BY 12Z.  SLEET AND EVENTUALLY FREEZING RAIN SHOULD DEVELOP OVER
SERN IA AND FAR NERN MO BETWEEN 12-15Z.  FREEZING RAIN RATES ACROSS
THE ENTIRE DISCUSSION AREA WILL BE AT LEAST 0.05 IN/3 HR WITH VALUES
UP TO 0.1 IN/3 HR POSSIBLE.  

A MIDLEVEL SHORTWAVE TROUGH...CURRENTLY TRACKING SEWD ACROSS SWRN
MN/NWRN IA...WILL MOVE INTO CENTRAL IA BY 12Z...BEFORE MOVING MORE
ENEWD LATER THIS MORNING.  WIND PROFILERS/WSR-88D VADS SHOWED A 40
KT SWLY LLJ EXTENDING FROM KS INTO WRN IA.  AT THE SURFACE...
TEMPERATURES ACROSS SRN IA/FAR NRN MO ARE EXPECTED TO REMAIN
SUB-FREEZING INTO THE EARLY MORNING.  MEANWHILE...TEMPERATURES IN
THE 850-900 MB LAYER WILL CONTINUE TO INCREASE TO ABOVE 0 C THROUGH
15Z ACROSS THE DISCUSSION AREA AS THE AFOREMENTIONED LLJ TRANSLATES
EWD INTO IA/NRN MO.  THIS ABOVE GROUND WARM LAYER WILL SUPPORT THE
TRANSITION IN PRECIP TYPES TO SLEET AND THEN FREEZING RAIN.  UPWARD
VERTICAL MOTION ATTENDANT TO THE SHORTWAVE TROUGH/VORT AND STRONG
LOW LEVEL WAA AS THE LLJ STRENGTHENS TO 50 KT BY 12Z SHOULD SUPPORT
AN INCREASE IN PRECIPITATION COVERAGE...AS INDICATED BY RECENT
TRENDS IN REGIONAL RADAR IMAGERY OVER WRN/CENTRAL IA.

..PETERS.. 01/17/2011

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

ATTN...WFO...LSX...DVN...DMX...EAX...

LAT...LON   41919348 41719242 41339172 40989135 40509130 40299179
            40139269 40249358 40379397 40959420 41919348

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 17, 6:35 AM CST	Mesoscale Discussion	SPC	Appanoose, Davis, Des Moines, Henry, Jefferson, Keokuk and 9 more	4 hr

Nearby

Mesoscale Discussions in Iowa, 2011 Mesoscale Discussions in Missouri, 2011 Every mesoscale discussion in 2011

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.