Severe Thunderstorm Warning 87, NWS Des Moines, IA

000 
WWUS53 KDMX 222039
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
339 PM CDT SUN APR 22 2007

IAC161-222100-
/O.CON.KDMX.SV.W.0087.000000T0000Z-070422T2100Z/
SAC IA-
339 PM CDT SUN APR 22 2007

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR SAC COUNTY
UNTIL 400 PM CDT...

AT 337 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING NICKEL
SIZE HAIL...AND DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THESE STORMS
WERE LOCATED ALONG A LINE EXTENDING FROM 9 MILES SOUTH OF LAKESIDE TO
SAC CITY TO LAKE VIEW...MOVING NORTHEAST AT 50 MPH.

THIS LINE OF SEVERE THUNDERSTORMS WILL AFFECT MAINLY RURAL AREAS OF
SAC COUNTY...INCLUDING THE TOWNS OF SAC CITY...EARLY...LAKE VIEW AND
NEMAHA.

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. SEVERE
THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO WARNING.
ALTHOUGH NOT IMMEDIATELY LIKELY...IF A TORNADO IS SPOTTED ACT QUICKLY
AND MOVE TO A PLACE OF SAFETY INSIDE A STURDY STRUCTURE...SUCH AS A
BASEMENT OR SMALL INTERIOR ROOM.

PREPARE FOR DAMAGING WINDS...FALLING TREES AND FLYING DEBRIS. MOVE
INDOORS AND STAY AWAY FROM WINDOWS. IF YOU LIVE IN A MOBILE HOME...
SEEK SHELTER IN A STURDY BUILDING.

LAT...LON 4222 9533 4221 9496 4256 9492 4256 9534

$$

VACHALEK

000 
WWUS53 KDMX 222059
SVSDMX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
359 PM CDT SUN APR 22 2007

IAC161-222109-
/O.EXP.KDMX.SV.W.0087.000000T0000Z-070422T2100Z/
SAC IA-
359 PM CDT SUN APR 22 2007

...THE SEVERE THUNDERSTORM WARNING FOR SAC COUNTY HAS BEEN ALLOWED TO
EXPIRE...

AT 358 PM CDT...WEATHER SERVICE DOPPLER RADAR INDICATED THAT THE
THUNDERSTORMS WHICH PROMPTED THE WARNING HAVE MOVED OUT OF THE AREA.
THEREFORE...THE SEVERE THUNDERSTORM WARNING HAS BEEN ALLOWED TO
EXPIRE.

LAT...LON 4222 9533 4221 9496 4256 9492 4256 9534

$$

VACHALEK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
409 AM CDT SUN APR 22 2007

.SHORT TERM (TODAY AND TONIGHT)...

CATEGORICAL POPS IN FORECAST FOR THIS AFTERNOON AS ALL MODELS
INDICATING PCPN WITH ADVANCING DYNAMIC STORM SYSTEM. LARGE AREA OF
CONVECTION ACROSS THE NORTHERN GREAT PLAINS SEEING WARMING OF CLOUD
TOPS ON IR IMAGERY DUE TO DYING MCS. AT THE SAME TIME...AREA OF
CONVECTION RAPIDLY DEVELOPING ACROSS WESTERN KANSAS THIS MORNING
WILL AID IN DEEPENING SURFACE LOW.  FROM GFS/WRF APPEARS ANOTHER
LINE OF CONVECTION SHOULD FORM ALONG A NW TO SE LINE ACROSS EASTERN
NEBRASKA LATER TO DAY AND ADVECT INTO THE SOUTHWEST. LITTLE CHANGE
IN THINKING FOR THE HWO AS FAR AS THREATS GO...EXPECTING INITIAL
BAND OF CONVECTION TO EXPAND ACROSS WESTERN IOWA BY NOON SHIFTING
RAPIDLY NORTH...WITH ANOTHER COUPLE OF ROUNDS DEVELOPING IN THE LATE
AFTERNOON INTO THE EARLY EVENING ACROSS THE ENTIRE CWA.

.LONG TERM (MONDAY THROUGH THURSDAY)

MONDAY  WILL SEE NORTHERLY RETURN FLOW WINDS BEHIND THE SYSTEM AND
WEAK COLD DRY ADVECTION IN THE LOW LEVELS WITH WEAK SUBSIDENCE AS
REMNANTS OF LOW PRESSURE LIFT FARTHER INTO THE EASTERN GREAT LAKES.
LIGHT AND VARIABLE WINDS SHOULD QUICKLY BECOME ESTABLISHED BY THE
EVENING AS SIGNIFICANT HIGHT FALLS ACROSS THE  CENTRAL PLAINS WILL
REESTABLISH A STRONG SOUTHEAST SURFACE FLOW  AND WARM ADVECTION
PATTERN BY EARLY TUESDAY. THE SETUP OD ANOTHER STRONG BAROCLINIC
ZONE ACROSS IOWA WILL BE OF THE  FOCAL POINT FOR A COUPLE OF ROUNDS
OF THUNDERSTORM WITH HEAVY RAIN PRODUCING MCS. WITH MODELS ARE
PRODUCING 2 TO 3 INCHES OF QPF ACROSS SOUTHWEST SECTION OF THE CWA
DURING THIS PERIOD. RIVERS ACROSS THE HSA AT THIS TIME ARE WELL
WITHIN BANKS AND APPEARS THE DRAWN OUT TIMEFRAME OF THE MODERATE
RAINFALL TO HEAVY SHOULD BE ABLE TO RUNOFF WITHOUT A SIGNIFICANT
FLOOD THREAT AT THIS TIME...LARGEST 12 HOUR QPFS AROUND 1.5-2 INCHES
LATE TUESDAY THROUGH TUESDAY NIGHT.

&&

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

&&

RUSSELL/SMALL

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
544 AM CDT SUN APR 22 2007

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-231100-
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-
POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-
WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE-
BOONE-STORY-MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-
POWESHIEK-CASS-ADAIR-MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION-
CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-
APPANOOSE-DAVIS-
544 AM CDT SUN APR 22 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS ARE EXPECTED OVER WEST CENTRAL IOWA BY LATE THIS
MORNING...EXPANDING RAPIDLY INTO NORTH CENTRAL IOWA BY EARLY
AFTERNOON. MORE THUNDERSTORMS WILL ENTER SOUTHWEST IOWA BY AFTERNOON
AND SPREAD ACROSS CENTRAL IOWA DURING THE LATE AFTERNOON AND
EVENING HOURS. LARGE HAIL AND DAMAGING WINDS ARE POSSIBLE WITH THE
THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING. A FEW ISOLATED
TORNADOES ARE POSSIBLE...PRIMARILY SOUTHEAST OF A WATERLOO TO DES
MOINES TO ATLANTIC LINE BETWEEN 5 AND 9 PM.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

MULTIPLE ROUNDS OF THUNDERSTORM PRODUCING HEAVY RAIN ARE FORECAST
LATE TUESDAY THROUGH TUESDAY NIGHT. SOME OF THE STORMS MAY PRODUCE
LARGE HAIL AND DAMAGING WINDS...BUT AT THIS TIME HEAVY RAIN AND
LIGHTNING APPEAR TO BE THE MAIN THREATS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE NEEDED THIS AFTERNOON AND EVENING.

SPOTTER ACTIVATION MAY BE NEEDED AGAIN LATE TUESDAY AND TUESDAY
NIGHT.

RUSSELL