Alert archive / Iowa / Special Weather Statements in 2012

Special Weather Statement, NWS Omaha, NE

May 3, 2012Mills County, Pottawattamie County, Iowa

NWS Omaha, NE issued this special weather statement at May 3, 2012, 1:43 AM CDT for Mills County, Pottawattamie County, Iowa. It was in force for 32 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 3, 2012, 1:43 AM CDT (06:43 UTC)
Expired: May 3, 2012, 2:15 AM CDT
In force: 32 min
Issued by: NWS Omaha, NE

Counties Mills County, IA, Pottawattamie County, IA

The radar

The Omaha radar (KOAX), 49 km from the middle of the area, began a volume at 06:47 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, 6.7 hours before the alert went out and 49 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: 2533 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1223 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 46 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.4

Open this sounding in Storm Lab

The text

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

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Omaha, NE wrote its last area forecast discussion before this special weather statement went out at May 3, 1:23 AM CDT, 20 minutes earlier.

Area forecast discussion, May 3, 1:23 AM CDT, 20 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
123 AM CDT THU MAY 3 2012

.AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.

SCATTERED THUNDERSTORMS LIKELY AT KLNK THROUGH 09Z AS LINE OF
CONVECTION BECOMES E-W ORIENTED. ALSO AT KOMA THROUGH 08Z.
OCCASIONAL MVFR CIGS POSSIBLE AT ALL THREE SITES THROUGH
14Z THEN VFR FOR REMAINDER OF FORECAST PERIOD.

&&

.PREV DISCUSSION... /ISSUED 419 PM CDT WED MAY 2 2012/

DISCUSSION...

MAIN FORECAST PROBLEMS TONIGHT ARE CONVECTIVE POTENTIAL AND
SEVERITY. THERE ARE 3 MAIN AREAS FOR CONCERN TONIGHT. THE FIRST
WOULD BE ALONG AN OUTFLOW BOUNDARY FROM LAST NIGHT'S CONVECTION...IN
AN AREA FROM NEAR HEBRON TO SOUTH OF LINCOLN TO WESTERN IOWA.
HOWEVER...AN 18Z SOUNDING REVEALED A CAP THAT HAS TO BE OVERCOME...
AND OVERALL SATELLITE IMAGERY AND VISUAL OBSERVATIONS SUGGESTS
THAT VERTICAL DEVELOPMENT WITHIN THIS CUMULUS FIELD IS
LIMITED...BUT IS AN AREA THAT WE'LL CONTINUE TO MONITOR. THE
SECOND AREA WOULD BE ALONG THE SURFACE TROUGH THAT EXTENDS FROM
NEAR HASTINGS INTO NORTHEAST NEBRASKA. THE DEWPOINT GRADIENT ALONG
THIS FEATURE...COMBINED WITH NEARLY FULL SUNSHINE TODAY HAS
ALLOWED A LINE OF TOWERING CUMULUS CLOUDS TO DEVELOP...AND IT'S
WITHIN THIS AREA THAT SPC IS MONITORING WITH A RECENT MCD THAT
WAS ISSUED. INSTABILITY AND WIND SHEAR WOULD BE SUFFICIENT IN
THIS AREA FOR SEVERE STORMS AND WOULD BE WITHIN THE MODERATE RISK
ENVELOPE GIVEN EFFECTIVE SHEAR AROUND 45 TO 55 KNOTS. ONE CELL
APPEARS TO BE POPPING NEAR CENTRAL CITY...SO WE'LL HAVE TO WATCH
TO SEE IF THIS CAN CONTINUE TO VERTICALLY DEVELOP. AND
FINALLY...THE LAST CONCERN WOULD BE A CONVECTIVE MCS THAT DEVELOPS
ACROSS THE WESTERN HIGH PLAINS THIS EVENING IN RESPONSE TO THE
ADVANCING WAVE FROM THE WEST...THAT WOULD RACE EASTWARD OVERNIGHT
WITH A SUBSTANTIAL WIND THREAT...ALONG WITH HEAVY
RAINFALL...WITHIN AN AXIS ORIENTED NORTH OF INTERSTATE 80. THIS
WOULD MOVE INTO AN AREA THAT RECEIVED THE HEAVY RAINFALL LAST
NIGHT...BUT BECAUSE OF THE FORWARD MOVING PROPAGATION AND NO
TRAINING...ADDITIONAL RAINFALL WOULD PROBABLY NOT CAUSE PROBLEMS.

BEYOND TONIGHT...IF AN MCS DEVELOPS AND ROLLS EASTWARD OVERNIGHT...
THERE COULD BE LINGERING CONVECTION EARLY IN THE MORNING THURSDAY.
THEN THERE SHOULD BE A SEVERAL HOUR PERIOD OF DRY WEATHER...BUT
STORMS COULD REFIRE THURSDAY AFTERNOON...ESPECIALLY ALONG AND
SOUTH OF I80. THE DETAILS BECOME SLIGHTLY DEPENDENT ON HOW FAR
SOUTH THE OVERNIGHT CONVECTION CAN PUSH THE BOUNDARY...BUT
CONVECTION WOULD TEND TO PUSH SOUTH INTO KS/MO BY DAY BREAK FRIDAY.

FRIDAY ACTUALLY MAY BE DRY...WITH AN MCS TO OUR NORTH. HOWEVER
ANOTHER DEVELOPING SURFACE TROUGH IS EXPECTED TO MOVE INTO THE
AREA FRIDAY NIGHT...THUS HAVE ADDED POPS FOR THE NORTHERN HALF OF
THE FORECAST AREA. THIS BOUNDARY THEN APPEARS TO STALL IN SIMILAR
FASHION FROM CENTRAL NEBRASKA THROUGH THE MID MISSOURI VALLEY
REGION. ANOTHER IMPULSE MOVING IN SATURDAY NIGHT SHOULD BRING
ANOTHER ROUND OF THUNDERSTORMS TO THE REGION THAT THEN MOVES
THROUGH THE AREA THE AREA SATURDAY NIGHT...AND COULD LINGER INTO
SUNDAY.

FOR MONDAY THROUGH WEDNESDAY OF NEXT WEEK...OVERALL FORECAST
CONFIDENCE IS SOMEWHAT LOW. MODEL DISCREPANCIES BEGIN TO MAGNIFY
AND DETAILS BECOME UNCLEAR. OVERALL...PREFER A DRIER SOLUTION...
ALTHOUGH THE FORECAST MODEL BLENDS INDICATED 20 TO 30 PERCENT
CHANCE THROUGH THE PERIOD.

DEWALD

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

FOBERT

Hazardous weather outlook, May 2, 4:29 PM CDT, 9 hours 14 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
429 PM CDT WED MAY 2 2012

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-031130-
MONONA-HARRISON-SHELBY-POTTAWATTAMIE-MILLS-MONTGOMERY-FREMONT-
PAGE-KNOX-CEDAR-THURSTON-ANTELOPE-PIERCE-WAYNE-BOONE-MADISON-
STANTON-CUMING-BURT-PLATTE-COLFAX-DODGE-WASHINGTON-BUTLER-
SAUNDERS-DOUGLAS-SARPY-SEWARD-LANCASTER-CASS-OTOE-SALINE-
JEFFERSON-GAGE-JOHNSON-NEMAHA-PAWNEE-RICHARDSON-
429 PM CDT WED MAY 2 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST
IOWA...WEST CENTRAL IOWA...EAST CENTRAL NEBRASKA...NORTHEAST
NEBRASKA AND SOUTHEAST NEBRASKA.

.DAY ONE...TONIGHT AND THURSDAY

THERE IS A CHANCE FOR STRONG TO SEVERE THUNDERSTORMS THIS EVENING...
PRIMARILY IN NORTHEAST NEBRASKA...WITH ADDITIONAL STRONG TO SEVERE
STORMS POSSIBLE BY LATE THIS EVENING INTO THE OVERNIGHT HOURS.

STORMS MAY DEVELOP ACROSS NORTHEAST NEBRASKA THROUGH EARLY EVENING
AND COULD QUICKLY BECOME SEVERE GIVEN INSTABILITY AND WIND SHEAR
IN THE ATMOSPHERE. SUPERCELL STORMS WOULD BE POSSIBLE...WITH LARGE
HAIL...DAMAGING WINDS AND AN ISOLATED ISOLATED TORNADO.

STORMS MAY ALSO DEVELOP EARLY THIS EVENING ACROSS WESTERN NEBRASKA...
THEN SPREAD EASTWARD THROUGH THE LATE EVENING AND OVERNIGHT HOURS
INTO EASTERN NEBRASKA AND WESTERN IOWA. THE MAIN THREAT AREA FOR
SEVERE WEATHER WILL BE ALONG AND NORTH OF INTERSTATE 80. LARGE
HAIL AND ESPECIALLY DAMAGING WINDS WILL BE THE MAIN THREAT WITH
THESE STORMS...AND LOCALLY HEAVY RAINFALL ALSO IS POSSIBLE. THE
HEAVY RAIN THREAT WOULD BE IN THE SAME AREA THAT RECEIVED HEAVY
RAINFALL LAST NIGHT.

ADDITIONAL THUNDERSTORMS COULD DEVELOP ALONG AND SOUTH OF INTERSTATE
80 THURSDAY AFTERNOON WHICH ALSO HAVE A SLIGHT RISK OF BECOMING
SEVERE.

.DAYS TWO THROUGH SEVEN...THURSDAY NIGHT THROUGH TUESDAY

STRONG TO SEVERE THUNDERSTORMS MAY CONTINUE THURSDAY EVENING ALONG
AND SOUTH OF INTERSTATE 80 WITH LARGE HAIL AND DAMAGING WINDS THE
PRIMARY HAZARDS. MORE THUNDERSTORMS COULD DEVELOP FRIDAY NIGHT...THEN
AGAIN SATURDAY NIGHT AND SUNDAY AS ANOTHER SURFACE TROUGH SETTLES
INTO THE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THROUGH THE EVENING IN NORTHEAST
NEBRASKA.

DEWALD

In the hours before

Local storm report, May 3, 12:16 AM CDT, 1 hour 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
1216 AM CDT THU MAY 03 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1212 AM     HAIL             DORCHESTER              40.65N 97.11W
05/03/2012  E0.88 INCH       SALINE             NE   TRAINED SPOTTER

            HAIL UP TO NICKEL SIZE

&&

MILLER

Local storm report, May 3, 1:15 AM CDT, 28 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
115 AM CDT THU MAY 03 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1226 AM     TSTM WND DMG     CRETE                   40.63N 96.96W
05/03/2012                   SALINE             NE   EMERGENCY MNGR

            A FEW TREE LIMBS DOWN BLOCKING A FEW STREETS.

1228 AM     TSTM WND DMG     WILBER                  40.48N 96.96W
05/03/2012                   SALINE             NE   EMERGENCY MNGR

            A FEW TREE LIMBS DOWN BLOCKING A FEW STREETS.

&&

MILLER

Local storm report, May 3, 1:16 AM CDT, 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
116 AM CDT THU MAY 03 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0116 AM     TSTM WND GST     ASHLAND                 41.04N 96.37W
05/03/2012  E60 MPH          SAUNDERS           NE   TRAINED SPOTTER

            WINDS ESTIMATED AT UP TO 60 MPH

&&

MILLER

Local storm report, May 3, 1:19 AM CDT, 24 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
119 AM CDT THU MAY 03 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0115 AM     TSTM WND GST     ASHLAND                 41.04N 96.37W
05/03/2012  E60.00 MPH       SAUNDERS           NE   TRAINED SPOTTER

            WINDS ESTIMATED AT UP TO 60 MPH

&&
CORRECTED TIME

MILLER

Local storm report, May 3, 1:43 AM CDT, 0 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
143 AM CDT THU MAY 03 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0135 AM     HAIL             2 N PAPILLION           41.19N 96.04W
05/03/2012  E0.75 INCH       SARPY              NE   EMERGENCY MNGR

            LAVISTA AREA

0139 AM     HAIL             OMAHA                   41.26N 96.01W
05/03/2012  M0.75 INCH       DOUGLAS            NE   BROADCAST MEDIA

            108TH AND MOCKINGBIRD

&&

MILLER

Special weather statement, May 3, 1:43 AM CDT, 0 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
143 AM CDT THU MAY 3 2012

IAZ069-079-090-NEZ067-030715-
FREMONT IA-MILLS IA-POTTAWATTAMIE IA-CASS NE-
143 AM CDT THU MAY 3 2012

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN FREMONT...MILLS...
POTTAWATTAMIE AND EASTERN CASS COUNTIES UNTIL 215 AM CDT...

AT 142 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS
TRACKING A LINE OF STRONG THUNDERSTORMS ALONG A LINE EXTENDING
FROM FORT CALHOUN TO UNION...OR ALONG A LINE EXTENDING FROM 13
MILES NORTH OF OMAHA TO 37 MILES NORTHWEST OF TARKIO...AND MOVING
NORTHEAST AT 45 MPH.

HAIL UP TO THE SIZE OF DIMES AND WIND GUSTS UP TO 45 MPH WILL BE
POSSIBLE WITH THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
COUNCIL BLUFFS...GLENWOOD...MALVERN...TREYNOR...UNDERWOOD...MINDEN...
PACIFIC JUNCTION...CARTER LAKE...TABOR...NEOLA...CRESCENT...SILVER
CITY...THURMAN...HASTINGS...RANDOLPH AND MCCLELLAND.

THIS INCLUDES THE FOLLOWING HIGHWAYS...
 INTERSTATE 29 BETWEEN MILE MARKERS 20 AND 66.
 INTERSTATE 80 IN IOWA BETWEEN MILE MARKERS 1 AND 34.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THESE STORMS MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO
AND TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR
ADDITIONAL INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL
WEATHER SERVICE.

&&

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 500 AM CDT
THURSDAY MORNING FOR SOUTHWESTERN IOWA AND EASTERN NEBRASKA.

LAT...LON 4088 9544 4080 9584 4114 9589 4117 9587
      4117 9584 4119 9586 4119 9590 4130 9592
      4128 9589 4131 9587 4132 9593 4146 9592
      4149 9596 4150 9542
TIME...MOT...LOC 0642Z 236DEG 38KT 4145 9593 4077 9594

BOUSTEAD

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 2, 7:58 PM CDT	Special Weather Statement	OAX	Boone	32 min
May 2, 8:05 PM CDT	Severe Thunderstorm Warning	OAX	Boone	25 min
May 2, 8:28 PM CDT	Severe Thunderstorm Warning	OAX	Boone	32 min
May 2, 9:11 PM CDT	Severe Thunderstorm Warning	OAX	Platte	34 min
May 2, 9:34 PM CDT	Special Weather Statement	OAX	Pierce	26 min
May 2, 10:08 PM CDT	Special Weather Statement	OAX	Boone	37 min
May 2, 10:17 PM CDT	Severe Thunderstorm Warning	OAX	Boone, Platte	28 min
May 2, 10:26 PM CDT	Severe Thunderstorm Warning	OAX	Boone, Platte	34 min
May 2, 10:45 PM CDT	Severe Thunderstorm Warning	OAX	Platte	45 min
May 2, 11:05 PM CDT	Severe Thunderstorm Warning	OAX	Saline, Seward	40 min
May 2, 11:16 PM CDT	Special Weather Statement	OAX	Wayne	44 min
May 2, 11:26 PM CDT	Severe Thunderstorm Warning	OAX	Madison, Platte, Stanton	49 min
May 2, 11:30 PM CDT	Severe Thunderstorm Warning	OAX	Cedar, Wayne	45 min
May 2, 11:46 PM CDT	Severe Thunderstorm Warning	OAX	Saline, Seward	44 min
May 2, 11:51 PM CDT	Severe Thunderstorm Warning	OAX	Saline	39 min
May 2, 11:57 PM CDT	Severe Thunderstorm Warning	OAX	Colfax, Platte, Stanton	48 min
May 3, 12:22 AM CDT	Severe Thunderstorm Warning	OAX	Gage, Lancaster, Saline, Seward	23 min
May 3, 12:36 AM CDT	Severe Thunderstorm Warning	OAX	Colfax, Dodge	39 min
May 3, 12:47 AM CDT	Severe Thunderstorm Warning	OAX	Cass, Gage, Lancaster, Otoe, Sarpy, Saunders	28 min
May 3, 1:15 AM CDT	Severe Thunderstorm Warning	OAX	Dodge, Saunders, Washington	33 min
May 3, 1:15 AM CDT	Severe Thunderstorm Warning	OAX	Cass, Douglas, Sarpy	30 min
May 3, 1:46 AM CDT	Special Weather Statement	OAX	Douglas, Sarpy	29 min
May 3, 2:08 AM CDT	Flash Flood Warning	OAX	Saline, Seward	6 hr
May 3, 2:11 AM CDT	Severe Thunderstorm Warning	OAX	Fremont, Mills	34 min
May 3, 2:29 AM CDT	Severe Thunderstorm Warning	OAX	Fremont, Page	31 min

Nearby

Special Weather Statements in Iowa, 2012 Every special weather statement in 2012

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.