Severe Thunderstorm Warning 1, NWS Quad Cities, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1044 AM CST THU FEB 26 2009

.UPDATE...
WIDESPREAD DENSE FOG HAS OVERSPREAD THE SOUTHERN THIRD OF THE CWFA
IN THE LOW LEVEL CONVERGENCE AHEAD OF THE WARM FRONT. AT
15Z...SURFACE ANALYSIS INDICATED THIS FRONT REACHING FROM THE
DEVELOPING LOW NEAR KICT ACROSS NRN MO TO NEAR KUIN. SCATTERED
SHOWERS AND THUNDERSTORMS WHERE OCCURRING IN THE ELEVATED WARM
AIR ADVECTION AND H8 SPEED CONVERGENCE ALONG AND WELL NORTH OF
THIS BOUNDARY THIS MORNING. STORMS ROOTED CLOSER TO THE BOUNDARY
HAVE PRODUCED PRIMARILY SMALL HAIL ACCORDING TO UPSTREAM STORM
REPORTS. ELEVATED CORES BEGINNING TO STRENGTHEN OVER DVN CWFA IN
THE SOUTH...WHILE IN THE NORTH SOME ENHANCED REFLECTIVITY LIKELY
INDICATING SLEET ALONG HWY 20 CORRIDOR INCLUDING DBQ AREA.

DENSE FOG WILL LIKELY CONTINUE TO EXPAND W AND N THIS MORNING AS
THE FRONT APPROACHES AND WITH WIDESPREAD 1/4SM VISIBILITIES...HAVE
ISSUED AN ADVISORY. THE FAR SOUTH SHOULD SEE RAPID IMPROVEMENT
ONCE THE BOUNDARY PUSHES THROUGH. SPC HAS EXPANDED THE SLIGHT RISK
NORTH TO I-80 CORRIDOR AND WILL HAVE TO MONITOR APPROACHING STORMS
IN THIS AREA THIS AFTERNOON FOR PRIMARY THREAT OF 1 INCH HAIL. HAVE
UPDATED THE HAZARDOUS WEATHER OUTLOOK TO HIGHLIGHT THIS THREAT.

&&

.AVIATION...
WIDESPREAD IFR CONDITIONS WILL PREVAIL TODAY DUE TO FOG AND LOW
CIGS. DENSE FOG WILL KEEP CONDITIONS IN LIFR AT BRL THROUGH
NOON...AND POSSIBLY IMPACT MLI AND CID THROUGH EARLY AFTERNOON.
ISOLATED SHOWERS AND THUNDERSTORMS WILL BECOME MORE NUMEROUS THIS
AFTERNOON. WITH LOW PROBABILITY OF IMPACTING FORECAST SITES...WILL
CONTINUE TO HANDLE THUNDERSTORM THREAT WITH CB MENTION AND VCTS.
WINTER STORM SYSTEM WILL SWEEP A COLD FRONT THROUGH TONIGHT...
CHANGING PRECIPITATION THREAT FROM RAIN TO POSSIBLY SOME FREEZING
PRECIPITATION BEFORE CHANGEOVER TO SNOW LATE TONIGHT. WITH THE
FRONTAL PASSAGE...DRIER AIR WILL IMPROVE CIGS AND VISBYS WELL INTO
MVFR CRITERIA FRI MORNING. THIS WILL ALSO BRING A WIND SHIFT TO NW
WITH SPEEDS OF 15 TO 25 KTS.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR DES MOINES-
     HENRY IA-JEFFERSON-LOUISA-MUSCATINE-SCOTT-WASHINGTON.

     DENSE FOG ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR LEE-VAN
     BUREN.

IL...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR BUREAU-
     HENDERSON-HENRY IL-MERCER-PUTNAM-ROCK ISLAND-WARREN-
     WHITESIDE.

     DENSE FOG ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR HANCOCK-
     MCDONOUGH.

MO...DENSE FOG ADVISORY UNTIL 1 PM CST THIS AFTERNOON FOR CLARK-
     SCOTLAND.

&&

SHEETS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
931 AM CST THU FEB 26 2009

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-271545-
BUCHANAN-DELAWARE-DUBUQUE-BENTON-LINN-JONES-JACKSON-IOWA-JOHNSON-
CEDAR-CLINTON-MUSCATINE-SCOTT-KEOKUK-WASHINGTON-LOUISA-JEFFERSON-
HENRY IA-DES MOINES-VAN BUREN-LEE-JO DAVIESS-STEPHENSON-CARROLL-
WHITESIDE-ROCK ISLAND-HENRY IL-BUREAU-PUTNAM-MERCER-HENDERSON-
WARREN-HANCOCK-MCDONOUGH-SCOTLAND-CLARK-
931 AM CST THU FEB 26 2009

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

THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS LATE THIS MORNING
AND AFTERNOON ACROSS THE OUTLOOK AREA SOUTH OF A LINE FROM BELLE
PLAINE TO CLINTON IN IOWA...AND SOUTH OF INTERSTATE 80 IN
ILLINOIS. THE PRIMARY THREAT WILL HAIL UP TO 1 INCH IN DIAMETER
WITH THUNDERSTORMS OCCURRING AHEAD OF A WARM FRONT THAT WILL LIFT
NORTH INTO THE AREA LATE THIS MORNING AND AFTERNOON.

DENSE FOG WILL CONTINUE TO OVERSPREAD AREAS SOUTH OF INTERSTATE 80
THIS MORNING AND MAY EXTEND NORTH TO THE HIGHWAY 20 CORRIDOR BY
AFTERNOON. WIDESPREAD VISIBILITIES BELOW A QUARTER MILE ARE
POSSIBLE.

WITH THE WIDESPREAD RAIN AND THUNDERSTORMS TODAY WILL BE THE
POTENTIAL FOR SEASONALLY SIGNIFICANT RAINFALL. RAINFALL AMOUNTS OF
A HALF INCH...AND LOCALLY UP TO AROUND ONE INCH ARE EXPECTED. THIS
COULD LEAD TO MINOR URBAN AND SMALL STREAM TYPE FLOODING...AS
WELL AS RISES ON AREA RIVERS.

TONIGHT...THE RAIN IS EXPECTED TO CHANGE OVER TO SNOW BEFORE
ENDING. AS IT DOES SO...THERE MAY BE A SHORT PERIOD OF FREEZING
RAIN AS COLD AIR UNDERCUTS THE WARMER AIR ALOFT. AS MORE COLD AIR
MOVES IN...THE PRECIPITATION WILL BECOME ALL SNOW. SNOW AMOUNTS OF
LESS THAN A QUARTER INCH ARE EXPECTED. IF THE FREEZING RAIN DOES
OCCUR...IT IS EXPECTED TO ONLY PRODUCE A THIN GLAZE OF ICE ON
ELEVATED SURFACES.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

A WEATHER DISTURBANCE WILL BRING THE CHANCE FOR LIGHT SNOW TO
PORTIONS OF THE OUTLOOK AREA LATE FRIDAY NIGHT AND SATURDAY MORNING.
LATEST INDICATIONS SUGGEST MINOR SNOW ACCUMULATIONS WILL BE POSSIBLE
SOUTHWEST OF A LINE FROM IOWA CITY TO GALESBURG.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED FOR SEVERE THUNDERSTORMS TODAY
PRIMARILY SOUTH OF INTERSTATE 80.

DLS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
737 AM CST THU FEB 26 2009

IAZ089-099-ILZ025-026-034-035-MOZ010-261545-
DES MOINES-LEE-HENDERSON-WARREN-HANCOCK-MCDONOUGH-CLARK-
INCLUDING THE CITIES OF...BURLINGTON...FORT MADISON...OQUAWKA...
MONMOUTH...CARTHAGE...MACOMB...KAHOKA
737 AM CST THU FEB 26 2009

...AREAS OF DENSE FOG AND LOW CLOUDS AFFECTING THE AREA THIS
MORNING...

AN AREA OF FOG AND LOW CLOUDS HAS MOVED OVER THE AREA FROM THE
SOUTHEAST THIS MORNING. IN SOME AREAS THE VISIBILITY HAS BEEN
REDUCED TO A QUARTER MILE OR LESS. THIS FOG HAS FORMED ON THE
NORTH SIDE OF A WARM FRONT...AND THIS FRONT WILL LIFT NORTH THIS
MORNING...CAUSING THE FOG TO DISSIPATE BY 10 AM THIS MORNING. IF
YOU WILL BE OUT DRIVING THIS MORNING...SLOW DOWN...USE YOUR
HEADLIGHTS...AND LEAVE PLENTY OF DISTANCE AHEAD OF YOU.

LE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
916 AM CST THU FEB 26 2009

IAZ087>089-098-099-ILZ025-026-034-035-MOZ009-010-261715-
JEFFERSON-HENRY IA-DES MOINES-VAN BUREN-LEE-HENDERSON-WARREN-
HANCOCK-MCDONOUGH-SCOTLAND-CLARK-
INCLUDING THE CITIES OF...FAIRFIELD...MOUNT PLEASANT...
BURLINGTON...KEOSAUQUA....FORT MADISON...OQUAWKA...MONMOUTH...
CARTHAGE...MACOMB...MEMPHIS...KAHOKA
916 AM CST THU FEB 26 2009

...DENSE FOG AND THUNDERSTORMS WITH HAIL THIS MORNING...

DENSE FOG WILL REMAIN OVER MUCH OF NORTHEAST MISSOURI...SOUTHEAST
IOWA...AND WEST CENTRAL ILLINOIS THIS MORNING. THE FOG WILL REDUCE
VISIBILITIES TO LESS THAN A QUARTER MILE AT TIMES.

A LINE OF SHOWERS AND THUNDERSTORMS...ASSOCIATED WITH AN
APPROACHING WARM FRONT...WILL MOVE INTO THE REGION BETWEEN 10 AM
AND NOON. SOME THUNDERSTORMS MAY BE CAPABLE OF PRODUCING HAIL UP TO A
HALF INCH IN DIAMETER.

MOTORISTS SHOULD PREPARE FOR DENSE FOG THIS MORNING AND ALLOW
EXTRA TRAVEL TIME. REMEMBER TO TURN ON YOUR HEADLIGHTS WHEN
DRIVING IN FOG.

SHEETS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1053 AM CST THU FEB 26 2009

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

1052 AM     HAIL             MACOMB                  40.47N 90.68W
02/26/2009  M0.25 INCH       MCDONOUGH          IL   FIRE DEPT/RESCUE

            FALLING RIGHT NOW. MINOR ACCUMULATIONS.

&&

WE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1056 AM CST THU FEB 26 2009

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

1053 AM     HAIL             MACOMB                  40.47N 90.68W
02/26/2009  E0.25 INCH       MCDONOUGH          IL   LAW ENFORCEMENT

&&

DLF