Alert archive / Iowa / Winter Storm Warnings in 2009

Winter Storm Warning 5, NWS Quad Cities, IA

December 7, 200921 counties in Iowa; 13 counties in Illinois; Clark County, Scotland County, Missouri

NWS Quad Cities, IA issued this winter storm warning at Dec 7, 2009, 3:45 PM CST for 21 counties in Iowa; 13 counties in Illinois; Clark County, Scotland County, Missouri. It took effect at Dec 8, 2009, 6:00 AM CST. It was in force for 36 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Dec 7, 2009, 3:45 PM CST (21:45 UTC)
In effect from
Dec 8, 2009, 6:00 AM CST
Expired
Dec 9, 2009, 6:00 PM CST
In force
36 hr
Issued by
NWS Quad Cities, IA
All 36 counties

Benton County, IA, Buchanan County, IA, Cedar County, IA, Clinton County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Washington County, IA, Bureau County, IL, Carroll County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, McDonough County, IL, Mercer County, IL, Putnam County, IL, Rock Island County, IL, Stephenson County, IL, Warren County, IL, Whiteside County, IL, Clark County, MO, Scotland County, MO

The radar

The Quad Cities radar (KDVN), 41 km from the middle of the area, began a volume at 21:47 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

Davenport, (KDVN), launched 12:00Z, 9.8 hours before the alert went out and 47 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-pSkew-T log-p diagram, Davenport, at 12:00Z on 2009-12-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Davenport, at 12:00Z on 2009-12-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -33 square meters per square second.1939587897117136Sfc1 km3 km6 km9 kmRMLM
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
541 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
-33 m²/s²
0-3 km storm-relative helicity
87 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Quad Cities, IA wrote its last area forecast discussion before this winter storm warning went out at Dec 7, 3:30 AM CST, 12 hours 15 minutes earlier.

Area forecast discussion, Dec 7, 3:30 AM CST, 12 hours 15 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
330 AM CST MON DEC 7 2009

.SYNOPSIS...
00Z UA ANALYSIS HAS A RESPECTABLE SHORTWAVE OVER NORTHEAST KANSAS
WITH A LLJ OF 30-40 KTS RUNNING FROM EASTERN TEXAS INTO MISSOURI.
SATELLITE TRENDS SHOW PLENTY OF LOW CLOUDS RUNNING FROM THE WESTERN
GREAT LAKES INTO THE LOWER MISSISSIPPI VALLEY WITH RADAR INDICATING
LIGHT SNOW FROM THE WESTERN SHORES OF LAKE MICHIGAN BACK TO THE
MISSOURI RIVER. 06Z SFC ANALYSIS HAS THE LOW BETWEEN KCDJ AND KDMO
WITH A STATIONARY FRONT RUNNING NORTHEAST ACROSS NORTHERN ILLINOIS
INTO LOWER MICHIGAN. A COLD FRONT RAN FROM THE LOW SOUTHWEST INTO
CENTRAL TEXAS. DEW POINTS WERE GENERALLY IN THE 20S AHEAD OF THE LOW
WITH 30 DEW POINTS FROM CENTRAL MISSOURI INTO THE LOWER MISSISSIPPI
VALLEY.

&&

.SHORT TERM...TODAY AND TONIGHT...
CURRENT SYSTEM IS MOVING THROUGH THE AREA WITH GEM DOING THE BEST OF
ANY MODEL REGARDING SFC LOW POSITION AT 06Z. GEM AND 08Z RUC SHOW
LOW CONDENSATION PRESSURE DEFICITS THROUGH MID MORNING BEFORE
INCREASING SUGGESTING MINIMALLY LIKELY POPS EARLY THIS MORNING.
RADAR TRENDS THROUGH 09Z SUGGEST THAT THIS IS THE WAY TO GO.
SO...HIGH CHC TO LIKELY POPS THROUGH MID MORNING WITH PRECIP
SHUTTING DOWN QUICKLY BY MID DAY. SATURATED LOW LEVELS SHOULD LEAVE
THE ATMOSPHERE PRIMED FOR --SN IN THE AFTERNOON WITH ANY PASSING
RIPPLE ALOFT.

FLURRIES SHOULD BE SEEN THIS EVENING AS THE LOWER ATMOSPHERE REMAINS
SATURATED. AFT 06Z THINGS GET MORE INTERESTING. CONDENSATION
PRESSURE DEFICITS BEGIN TO LOWER QUICKLY AGAIN PER THE GEM/ECMWF AND
FORCING INCREASES. THUS EXPECT -SN TO BREAK OUT AS A DEFORMATION
ZONE BEGINS TO DEVELOP WITH THE FIRST VORT MAX. PARTS OF THE
SOUTHWEST TO WEST AREAS OF THE CWFA SHOULD SEE SOME NEW ACCUMULATION
PRIOR TO SUNRISE. ..08..

.LONG TERM...TUESDAY THROUGH NEXT SATURDAY...
...HIGH IMPACT...POTENTIALLY CRIPPLING WINTER STORM TUE/WED REMAINS
THE FORECAST CHALLENGE...

OVERALL INITIALIZATION AND VERIFICATION GOOD. AGAIN...HI-RES ECMWF
THE GEM-NHEM AND NOW UKMET ARE MOST ACCURATE...CONSISTENT AND
RELIABLE. THE GFS AND NAM CONTINUE TO SHOW LATENT HEAT FEEDBACK
ISSUES..THE 06Z NAM FORCING IS SLOWLY GETTING BETTER.  THE HI-RES
ECMWF SHOWS THE DEFORMATION ZONE NICELY WEDNESDAY AM WHICH MOST OR
ALL SOLUTIONS SHOULD CAPTURE BY TONIGHT/S RUNS.

OVERVIEW...MINOR CHANGES TO CURRENT PACKAGE EXCEPT UPGRADED WNW 1/2
TO 2/3 ARE FOR BLIZZARD WATCH AS BLIZZARD CONDITIONS WILL OVERSPREAD
AT LEAST ALL THIS REGION AFTER MIDNIGHT TUESDAY NIGHT AND THROUGH
MOST TO ALL OF THE DAY WEDNESDAY.  THUNDER-SNOW ALSO EVIDENT MOVING
INTO AREA TUESDAY NIGHT OVER MOST OR ALL THE REGION. SNOW EVENT
AMOUNTS OF 6 TO 12 INCHES REMAIN ON TAP WITH LOCALLY HIGHER AMOUNTS
OF 12+ INCHES...LOCALLY UP TO 15 INCHES SUGGESTED +/- 40 MILES OF A
FREEPORT TO IOWA CITY TO OTTUMWA LINE. THIS SYSTEM REMAINS ON TRACK
TO BE ONE OF THE MOST SIGNIFICANT HIGH IMPACT EVENTS IN THIS AREA FOR
SEVERAL YEARS...IF NOT LONGER.

TUESDAY...HAVE UPPED POPS WITH SNOW OVERSPREADING ALL AREA WITH SNOW
AMOUNTS OF 1 TO 4 PLUS INCHES BY EVENING.  HEAVIER SNOW MAY ARRIVE
IN FAR SW SECTION LATE PM THAT LATER SHIFTS MAY NEED TO UP TOTALS
AS LEAD VORT MAX MAY BE STRONGER THAN CURRENT SOLUTIONS INDICATE. NE
WINDS OF 10 TO 20 MPH SHOULD LIMIT SNOW TO JUST MINOR DRIFTING
UNTIL LATER.  ALONG AND SOUTH OF HIGHWAY 34 STILL SUGGESTS SNOW...
MIXED AT TIMES WITH SLEET.  LOCAL ANALYSIS SUGGEST MOST PRECIPITATION
SHOULD STILL BE SNOW.

TUESDAY NIGHT...A WILD NIGHT WITH SNOW...HEAVY AT TIMES WITH THUNDER-
SNOW AND WINDS INCREASING FROM NW TO SE. LOCAL TOOLS SHOW 1 TO 2
INCH SNOWFALL RATES REMAIN PLAUSIBLE.  SOME SUGGESTION OF INTERNAL
GRAVITY WAVES MAY RESULT IN GUSTS AOA 40-45 MPH THAT WOULD CREATE
BRIEF WHITEOUT CONDITIONS FOR LATER SHIFTS TO CONSIDER. BLOWING SNOW
AND AREAS OF BLOWING SNOW TO OCCUR OVER ALL BUT FAR EAST SECTIONS
THAT WILL RENDER TRAVEL CONDITIONS DIFFICULT IF NOT IMPOSSIBLE BY
DAYBREAK. MOST OF THE HEAVIEST SNOW WILL OCCUR IN THIS PERIOD.

WEDNESDAY...EXTREME WINTER STORM WILL RESULT IN LARGE PERIODS AND
AREAS OF BLIZZARD CONDITIONS...POTENTIALLY CRIPPLING THE AREA. OVER A
DOZEN TOOLS INDICATE SUSTAINED WINDS AT LEAST OF 25 TO 40+ MPH WITH
GUSTS OF 50 MPH OR MORE.  SUSTAINED WINDS OF 30 TO 45 MPH APPEAR
QUITE PROBABLE WITH SOME GUSTS TO 55-60 MPH.  A VIGOROUS DEFORMATION
ZONE SHOULD REMAIN FROM DBQ TO NEAR BRL THAT WILL LIFT NE TOWARD MID
DAY. WIDESPREAD AND PROLONGED POWER OUTAGES BASED ON PAST SNOW
AMOUNTS AND WIND SPEEDS APPEAR LIKELY. TEMPERATURES WILL FALL
THROUGHOUT THE DAY INTO THE SINGLE DIGITS TO LOWER TEENS BY DUSK.
SNOW TO DIMINISH TO FLURRIES BUT WITH BLOWING SNOW WILL BE HARD TO
ASCERTAIN THE DIFFERENCE UNTIL LATE AFTERNOON MANY LOCATIONS. SNOW
DRIFTS OF 3 TO OVER 6 FEET DEEP WILL BE COMMON BY LATE AFTERNOON.
COMBINE THIS WITH PERIODS OF WHITEOUT CONDITIONS WILL MAKE TRAVEL
CONDITIONS DIFFICULT AT BEST TO IMPOSSIBLE WITH LIFE THREATENING
CONDITIONS POSSIBLE DUE TO VERY LOW WIND CHILLS BELOW ZERO BY
AFTERNOON.

WEDNESDAY NIGHT...WINDS TO DECREASE TO 15 TO 20 MPH BY MIDNIGHT BUT
DEEP DRIFTS MAY KEEP MOST ROADS CLOSED.  HAVE TRIMMED LOWS TO NEAR
TO BELOW ZERO AS SKIES CLEAR AND IMPACTS OF A FRESH..DEEP SNOW
COVER.  MINS MAY NEED LOWER SEVERAL MORE DEGREES.

THURSDAY AND FRIDAY...FAIR AND COLD.  LOWERED TEMPERATURES WITH
SUGGESTION A FURTHER LOWERING OF 2 TO 5 DEGREES APPEARS REASONABLE.
FLURRIES MAY BE POSSIBLE WITH WEAK DISTURBANCES FOR DAY SHIFT TO
CONSIDER.

SATURDAY AND SUNDAY..NO CHANGES MADE.  EVIDENCE OF LARGE NEGATIVE
FEEDBACK FROM SNOW COVER WITH CHANGES THAT SHOULD BE BETTER
CLARIFIED TODAY.  SUGGESTION OF LIGHT SNOWFALL WITH SLOWLY
MODERATING TEMPERATURES.   WINTER HAS ARRIVED.  ..NICHOLS..

&&

.AVIATION...
LOW CONDENSATION PRESSURE DEFICITS AND RESPECTABLE FORCING SHOULD
KEEP -SN GOING THROUGH 15Z BEFORE TAPERING TO FLURRIES AND POSSIBLY
ENDING. 1-2SM VSBYS WITH POCKETS OF 3-5SM WILL CONTINUE THROUGH 15Z
BEFORE IMPROVING TO 6SM. FCST SOUNDINGS SUGGEST A TRAPPING INVERSION
KEEPING CIGS GENERALLY IN THE 1-2KFT RANGE. AFT 06Z/08 INCREASED
FORCING AND LOWERING CONDENSATION PRESSURE DEFICITS TO INITIATE THE
NEXT ROUND OF -SN BY 09Z/08. KCID MAY SEE CIGS BLO 1KFT PRIOR TO
12Z/08. KBRL/KMLI/KDBQ CIGS/VSBYS TO QUICKLY DETERIORATE AFT 12Z/08.
..08..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...BLIZZARD WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY AFTERNOON
     FOR BENTON-BUCHANAN-CEDAR-CLINTON-DELAWARE-DES MOINES-
     DUBUQUE-HENRY IA-IOWA-JACKSON-JEFFERSON-JOHNSON-JONES-
     KEOKUK-LEE-LINN-LOUISA-MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.

IL...BLIZZARD WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY AFTERNOON
     FOR CARROLL-JO DAVIESS-ROCK ISLAND-STEPHENSON.

     WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
     AFTERNOON FOR BUREAU-HANCOCK-HENDERSON-HENRY IL-MCDONOUGH-
     MERCER-PUTNAM-WARREN-WHITESIDE.

MO...BLIZZARD WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY AFTERNOON
     FOR CLARK-SCOTLAND.

&&

08/NICHOLS/08
Hazardous weather outlook, Dec 7, 4:44 AM CST, 11 hours 1 minute before
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In the hours before

Local storm report, Dec 7, 9:51 AM CST, 5 hours 54 minutes before
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Local storm report, Dec 7, 10:00 AM CST, 5 hours 45 minutes before
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The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 7, 3:46 AM CSTBlizzard WatchDVNBenton, Buchanan, Cedar, Clinton, Delaware, Des Moines and 15 more34 hr

Nearby

Winter Storm Warnings in Iowa, 2009Winter Storm Warnings in Illinois, 2009Winter Storm Warnings in Missouri, 2009Every winter storm warning in 2009

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.