Hail and Damaging Winds in Iowa, June 24, 2006

AREA FORECAST DISCUSSION...CORRECTION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
545 AM CDT SAT JUN 24 2006

.SYNOPSIS...
UPPER DISTURBANCE OVER MONTANA MOVING SOUTHEAST ON 70 KT JET WITH
WEAK SURFACE LOW DEVELOPING OVER EASTERN SD AT 2 PM.  PRESSURE FALLS
AHEAD OF SYSTEM WITH WIND AND PRESSURE FIELDS SUGGEST STRENGTHENING
OF THIS SYSTEM AS JET ENERGY MOVES INTO LONG WAVE TROUGH.  AREA OF
SHOWER AND STORMS EXTENDS ROUGHLY FROM NW IA INTO KANSAS AHEAD OF
SYSTEM. TIMING OF CLOUDS TO ARRIVE IN NW PORTIONS OF FORECAST AREA
JUST AFTER SUNRISE. 06Z VERIFICATION SUPPORTS UKMET BEST WITH WRF-NMM
AND GFS PROBLEMS PARTIALLY CAUSED BY CONVECTIVE DISCREPANCIES AND
ENERGY TOO FAR NE VERSUS ACTUAL OBS OF LOW AND ALSO BIT TOO WEAK.
UPPER AIR ANALYSIS SUPPORTS SFC ANALYSIS FOR SYSTEM TO DROP INTO
FORECAST AREA THIS AFTERNOON AND INTO EVENING HOURS...SUPPORTIVE OF
AREAS OF STORMS AND SHOWERS. A DOZEN OR MORE LARGE HAIL REPORTS PAST
AFTERNOON AND EVENING WITH SYSTEM IN PLAINS SUPPORT SOME SEVERE
POTENTIAL.

&&

.SHORT TERM...TODAY AND TONIGHT...
BASED FORECAST MAINLY ON USING PRIMARILY UKMET/ECMWF AS WE OFTEN SEE
IT VERIFIES BEST VERSUS GFS AND WRF-NMM AS DESCRIBED ABOVE...
ESPECIALLY WITH PRECIPITATION.  THUS...WENT LIKELY POPS IN PM NW
SECTIONS AS LINE OF STORMS DEVELOP AND MOVE INTO AREA. THERMODYNAMICS
AND UPPER FORCING SUGGEST SOME STORMS TO APPROACH OR REACH SEVERE
LEVELS MID PM INTO EVENING HOURS WITH HAIL THE MAJOR RISK DUE TO LOW
WBZ OF 10-11K AGL AND A MODEST CAPE OF 1000 TO 1200 J/KG. IF SFC
TEMPS REACH NEAR 85F WITH 63F DEWPOINTS THEN ISOLATED GUSTY WINDS UP
TO 60 MPH MAY OCCUR LATE PM INTO EARLY EVENING BASED ON LOCAL
CALCULATIONS USING BLEP AND HELP TOOLS.  KEPT LIKELY POPS NORTH OF I-
80 AS STRONG UPPER TRIGGER CONTINUES AS UPPER LOW SLIDES IN WITH
CHANCE POPS SOUTH.  MAX TEMPS WENT SLIGHTLY ABOVE BLEND TODAY IN SE
2/3 AREA AND SLIGHTLY ABOVE MOST LOCATIONS ON MINS TONIGHT WITH LOTS
OF CLOUDS AND PRECIPITATION.  REGARDING SEVERE...NOT ADDED SVR
VERBIAGE TODAY BUT PASS TO DAY SHIFT TO CONSIDER.  SPC SLIGHT RISK
COVERS NW 1/3 OF FORECAST AREA.  EMPHASIZE THIS RISK IN THE HAZARDOUS
WEATHER OUTLOOK...HWO...PRODUCT WITH HIGHEST SEVERE POTENTIAL NW OF A
STERLING IL TO GENESEO IL TO FAIRFIELD IA LINE.

.LONG TERM...SUNDAY THROUGH MONDAY NIGHT
UPPER LOW TO SLOWLY ROTATE ACROSS AREA SUNDAY BRINGING LOTS OF
POPCORN SHOWERS AND SOME STORMS AND WITH DEFORMATION ZONE CLOUDS
NORTH 1/2 TO 2/3...WENT ON LOW SIDE MAX TEMPS AND CONCERN IS COULD BE
STILL TOO MILD ALONG AND NORTH OF I-80. CHANCE POPS CONTINUED BUT
STRENGTH OF UPPER LOW HIGHER COVERAGE MAY BE NEEDED AND PASS THIS TO
DAY SHIFT. NIGHTFALL SHOULD BRING GRADUAL END TO PRECIPITATION WITH
LOSS OF HEATING.  WITH CLOUDS...KEPT TEMPS NEAR BLEND TO OFFSET NORTH
WINDS. MONDAY...ADDED 20 POPS AND TRIMMED TEMPS MAINLY IN EAST DUE TO
COLD AIR ALOFT AND CLOUDS WITH CONVECTIVE TEMPS TO BE EASILY REACHED
FROM NEARBY UPPER LOW FOR POPCORN PM SHOWERS AND STORMS.  CLEARING
TUESDAY NIGHT WITH MIN TEMPS EASILY INTO 50S MOST LOCATIONS.

TUESDAY THROUGH FRIDAY...NO CHANGES MADE WITH NW UPPER FLOW TO
CONTINUE FOR MAINLY BELOW NORMAL TEMPS.  NEXT SYSTEM/S LATE NEXT WEEK TO
PRODUCE PERIODS OF SHOWERS AND STORMS AND WILL MENTION IN HAZARDOUS
WEATHER OUTLOOK.   ...NICHOLS..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.

&&

NICHOLS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
535 AM CDT SAT JUN 24 2006

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-251000-
BENTON IA-BUCHANAN IA-BUREAU IL-CARROLL IL-CEDAR IA-CLARK MO-CLINTON
IA-DELAWARE IA-DES MOINES IA-DUBUQUE IA-HANCOCK IL-HENDERSON IL-HENRY
IA-HENRY IL-IOWA IA-JACKSON IA-JEFFERSON IA-JO DAVIESS IL-JOHNSON IA-
JONES IA-KEOKUK IA-LEE IA-LINN IA-LOUISA IA-MCDONOUGH IL-MERCER IL-
MUSCATINE IA-PUTNAM IL-ROCK ISLAND IL-SCOTLAND MO-SCOTT IA-
STEPHENSON IL-VAN BUREN IA-WARREN IL-WASHINGTON IA-WHITESIDE IL-
535 AM CDT SAT JUN 24 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
ILLINOIS...NORTHWEST ILLINOIS...WEST CENTRAL ILLINOIS...EAST
CENTRAL IOWA...NORTHEAST IOWA...SOUTHEAST IOWA AND NORTHEAST
MISSOURI.

.DAY ONE...TODAY AND TONIGHT

A SEASONABLY STRONG UPPER LEVEL DISTURBANCE WILL PRODUCE THUNDERSTORMS
BY MID AFTERNOON LASTING INTO THIS EVENING. DESPITE MARGINAL
INSTABILITY...THE RELATIVELY LOW FREEZING LEVELS AND ENOUGH DRY AIR
ALOFT SHOULD ALLOW SOME OF THE STORMS TO BECOME STRONG TO SEVERE BY LATE
AFTERNOON INTO THE MID EVENING HOURS. THE PRIMARY THREAT WILL BE LARGE
HAIL UP TO THE SIZE OF NICKELS. ISOLATED DAMAGING STRAIGHT LINE WINDS OF
50 TO 60 MPH ARE A SECONDARY THREAT LATE THIS AFTERNOON UNTIL SUNSET.

THE AREAS MOST AT RISK OF ANY SEVERE STORMS WILL BE NORTHWEST OF A
STERLING TO GENESEO ILLINOIS TO OTTUMWA IOWA LINE.

THE STORM PREDICTION CENTER HAS A SLIGHT RISK OF SEVERE WEATHER FOR
LOCATIONS NORTHWEST OF A DUBUQUE IOWA TO WILLIAMSBURG IOWA AXIS.

INTERESTED INDIVIDUALS SHOULD MONITOR THEIR FAVORITE MEDIA OUTLET FOR
FURTHER UPDATES.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH FRIDAY

TUESDAY THROUGH FRIDAY...A SERIES OF DISTURBANCES WILL CAUSE EPISODES
OF THUNDERSTORMS ACROSS THE MIDWEST.  ATMOSPHERIC CONDITIONS REMAIN
TOO UNCLEAR TO ASSESS ANY SEVERE THREAT AND POSSIBLE LOCATIONS AT
THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE BY MID AFTERNOON AND INTO THIS EVENING
NORTHWEST OF A STERLING TO GENESEO ILLINOIS TO OTTUMWA IOWA LINE.

NICHOLS