Alert archive / Iowa / Severe Thunderstorm Warnings in 2006

Severe Thunderstorm Warning 160, NWS Des Moines, IA

May 23, 2006Crawford County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at May 23, 2006, 9:56 PM CDT for Crawford County, Iowa. 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: May 23, 2006, 9:56 PM CDT (02:56 UTC)
Expired: May 23, 2006, 10:45 PM CDT
In force: 49 min
Issued by: NWS Des Moines, IA
Area: Counties, with a storm outline in the text

County Crawford County, IA

The radar

The Omaha radar (KOAX), 114 km from the middle of the area, began a volume at 02:56 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

Omaha, NE (KOAX), launched 00:00Z, 2.9 hours before the alert went out and 114 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: 827 J/kg
Mixed-layer CIN: -22 J/kg
Mixed-layer LCL: 1972 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 51 m²/s²
0-3 km storm-relative helicity: 124 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.9

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 Des Moines, IA wrote its last area forecast discussion before this severe thunderstorm warning went out at May 23, 3:30 PM CDT, 6 hours 26 minutes earlier.

Area forecast discussion, May 23, 3:30 PM CDT, 6 hours 26 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
330 PM CDT TUE MAY 23 2006

.DISCUSSION...

COMPLICATED FORECAST THIS ISSUANCE.  WE HAD SOME ISOLATED
THUNDERSTORMS DEVELOP THIS MORNING ALONG A NARROW AXIS OF 850
THETA-E ADVECTION. THIS WAS ALSO AIDED BY A WEAK SURFACE WAVE AS
DEPICTED IN SFC ANALYSIS.  AS SOON AS THE STORMS MOVED INTO DRIER
AIR THEY FELL APART.  CAP OUT WEST NOW IS RAPIDLY ERODING AS A
RIBBON OF MID TO UPPER 60S DEWPOINTS GETS DRAWN NORTHWARD.  CAPE
VALUES (ESPECIALLY 0-3 KM) ARE INCREASING AS WELL BUT THERE IS NO
REAL TRIGGER YET.  THE BETTER CAPE AND DEEPER MOISTURE REMAIN WEST
CLOSER TO THE UPPER SYSTEM OVER SDKTA.  THE UPPER SYSTEM WILL MOVE
EAST OVER THE NEXT FEW HOURS AND A LLJ WILL DEVELOP AFT 00Z WHICH
HAS AIDED IN THE DEVELOPMENT OF STORMS OVER NEB/SDKTA.  THESE STORMS
WILL BE SLOW TO MOVE BUT EVENTUALLY (BETWEEN 00Z AND 03Z) WILL MAKE
IT INTO THE WESTERN CWA.  THE LINE SHOULD THEN MOVE ACROSS THE CWA
OVERNIGHT.

WEDNESDAY AND THURSDAY PRESENT EQUALLY TOUGH CHALLENGES AS THE UPPER
LOW WILL SLOW AS IT PUSHES EAST LEAVING A TROUGH SOMEWHERE OVER THE
CWA.  I HAVE SPENT EXTRA TIME ON WEDNESDAYS PRECIP GRIDS AS THERE
WILL LIKELY BE SOME LINGERING STORMS/SHOWERS FROM TONIGHT/S
CONVECTIVE LINE IN THE MORNING.  WE SHOULD SEE A BREAK MID TO LATE
MORNING AND IF WE SEE SOME SUN...A RELOADING OF THE ATMOSPHERE FOR
CONVECTION LATER IN THE AFTERNOON AND EVENING.  THE EXTENT OF THE
CONVECTION WILL DEPEND ON WHERE THE TROUGH SETS UP.  THE EASTERN CWA
WILL HAVE THE BEST CHANCE FOR THUNDER BUT HOW FAR NORTHWEST TO TAKE
THE HIGHER POPS IS DIFFICULT TO SAY.  FOR NOW I HAVE IT BACK AS FAR
AS ALGONA BUT THE MAY BE TOO FAR NORTHWEST.  THE MID SHIFT CAN
DECIDE THIS ONCE THINGS COME INTO PLAY.  THEN FOR THURSDAY WE GET
WRAP AROUND PRECIP AS THE SURFACE LOW SINKS SOUTHEAST BUT
AGAIN...THE EXTENT OF THIS IS HIGHLY QUESTIONABLE AT THIS POINT.
THE WEEKEND STILL LOOKS WARM BUT I DONT KNOW HOW DRY.  DEFINITELY A
SUMMER PATTERN BUT ECMWF AND GFS ARE HINTING AT WEAK WAVES MOVING
ACROSS THE FRONT GIVING SOME LATE DAY/OVERNIGHT PRECIP
CHANCES...ESPECIALLY MONDAY WHEN THE FRONT STARTS TO MOVE.  I COULD
SEE A COUPLE DIFFERENT SOLUTIONS HERE...AND IF THERE ARE MORE CLOUDS
THAN THE MODELS ARE ELUDING TO THEN TEMPS WILL NEED TO BE LOOKED AT
AS WELL.  FOR NOW WILL LEAVE AS IS BUT THIS WILL BE SOMETHING TO
CONSIDER IN A FEW MORE RUNS.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

FAB

Hazardous weather outlook, May 23, 2:55 PM CDT, 7 hours 1 minute before

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The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 23, 11:31 PM CDT	Severe Thunderstorm Warning	DMX	Cass	44 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2006 Every severe thunderstorm warning in 2006

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.