Flooding in Illinois, June 27 to 30, 2013

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1138 PM CDT THU JUN 27 2013

.UPDATE...
ISSUED AT 623 PM CDT THU JUN 27 2013

A WEAK SURFACE BOUNDARY WAS EVIDENT ON 88D IMAGERY DROPPING SOUTH
THROUGH THE FORECAST AREA...ROUGHLY ALONG HIGHWAY 30 AT 6 PM.
THUNDERSTORMS HAVE ERUPTED ALONG THIS BOUNDARY FURTHER EAST OVER
THE CHICAGO AREA...WHERE THERE WAS LIKELY BETTER MID LEVEL
MOISTURE AND UPPER LEVEL SUPPORT FROM A SHORTWAVE MOVING INTO THE
GREAT LAKES. OVER THE LOCAL AREA...SURFACE OBSERVATIONS SHOW LOWER
DEWPOINTS ADVECTING INTO THE AREA ON NW WINDS WITH THE VISIBLE
SATELLITE LOOP SHOWING MOSTLY CLEAR SKIES TO THE WEST AND NW INTO
THE NORTHERN PLAINS. A FEW MID LEVEL CLOUDS ASSOCIATED WITH
COMPLEX MOVING INTO KS AND MO WERE MOVING ACROSS THE FAR SOUTH AND
SOUTHWEST.

LACKING A SUFFICIENT TRIGGER AND NO SIGNALS OF ANY CONVECTIVE
ACTIVITY...HAVE REMOVED ALL POPS THE FORECAST FOR THIS EVENING.
THE REST OF SHORT TERM FORECAST IS ON TRACK WITH LOWER
HUMIDITY...CLEAR SKIES AND TEMPERATURES COOLING INTO THE 60S
OVERNIGHT.

&&

.SYNOPSIS...
ISSUED AT 305 PM CDT THU JUN 27 2013

12Z UA ANALYSIS HAD AN 850MB LOW NEAR KLBF WITH A WARM FRONT INTO
NORTHWEST IOWA. SEVERAL SHORTWAVES RAN FROM THE OHIO VALLEY INTO THE
NORTHERN PLAINS WITH A STRONGER UPPER LOW JUST NORTH OF LAKE
SUPERIOR. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON SHOW A WEAKLY
ORGANIZED MCS PRODUCING SHOWERS AND SOME STORMS FROM SOUTHEAST
NEBRASKA EAST ALONG THE IA/MO BORDER TO THE MISSISSIPPI RIVER.

18Z SFC ANALYSIS HAS A LOW NORTH OF KRSL WITH A WARM FRONT INTO
EASTERN KANSAS. OUTFLOW BOUNDARIES RAN FROM NORTHWEST MISSOURI AND
THEN WEST ALONG THE NE/KS BORDER. A SUBSTANTIAL TROF RAN FROM NEAR
KDLH TO KIRK. DEW POINTS WERE IN THE 60S AND 70S ACROSS MUCH OF THE
MIDWEST.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 305 PM CDT THU JUN 27 2013

BASED ON THE EVOLUTION OF CLOUDS THROUGH MID AFTERNOON...THE RAP
TRENDS OF HAVING THE CONVECTIVE TEMPERATURE OF 90 OR ABOVE APPEARS
TO BE CORRECT. THE WEAKLY ORGANIZED BUT DECAYING MCS MOVING FROM
IOWA INTO NORTHERN MISSOURI IS PRODUCING MAINLY SPRINKLES IN THE
SOUTHERN CWFA DUE TO THE DRY AIR ALOFT.

SINCE WE ARE AT PEAK HEATING...IT IS POSSIBLE THAT SOME ISOLATED
LATE AFTERNOON/EARLY EVENING SHOWERS AND A FEW THUNDERSTORMS MAY BE
POSSIBLE. IF NOTHING DEVELOPS BY 23Z...THEN DRY CONDITIONS WILL BE
SEEN ACROSS THE CWFA EXCEPT FOR THE SPRINKLES/LIGHT SHOWERS ACROSS
THE SOUTHERN CWFA.

BY LATE EVENING AND OVERNIGHT...DRY CONDITIONS WILL BE SEEN WITH
CLEARING SKIES. WITH SLIGHTLY LOWER DEW POINTS...MIN TEMPERATURES
SHOULD BE A BIT LOWER TONIGHT.

FRIDAY MORNING WILL BE QUIET AND DRY AS THE UPPER LOW DROPS INTO THE
GREAT LAKES. DIURNAL HEATING AND COLDER AIR ALOFT COMBINED WITH A
VORT MAX DROPPING INTO THE AREA IS EXPECTED TO ALLOW SHOWERS AND
THUNDERSTORMS TO DEVELOP DURING THE AFTERNOON HOURS. THE NORTHEAST
THIRD TO 40 PERCENT OF THE CWFA WILL HAVE THE BETTER CHANCES OF
SEEING CONVECTION BASED ON THE PROJECTED TRACK OF THE VORT MAX. MUCH
COOLER TEMPERATURES ARE EXPECTED ON FRIDAY WITH LOWER HUMIDITY
LEVELS.                             ..08..

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 305 PM CDT THU JUN 27 2013

THE LONG TERM PORTION OF THE FORECAST REMAINS WITH ALL APPEARANCES A
WET WEEK...BUT THIS MAY BE FAR FROM THE CASE FOR RAINFALL. WE HAVE
CHANCE TO LIKELY POPS FOR FRIDAY NIGHT THROUGH SATURDAY EVENING AS
THE UPPER COLD POOL ROTATES DOWN OVER THE REGION...COMBINED WITH THE
NORTH TO SOUTH PASSING OF A SURFACE TROF OF LOW PRESSURE. WHILE 12
HOUR POPS ARE NEEDED TO BE THIS HIGH...THERE SHOULD BE MANY DRY
HOURS...AND OVER ALL RAINFALL AMOUNTS SHOULD BE QUITE LOW.  IT IS
CERTAIN THAT ANY RAIN SHOULD HAVE NO IMPACT ON RIVERS.

ANOTHER CHANCE FOR RAIN WILL ARRIVE TOWARDS TUESDAY...WHEN THE SAME
UPPER LOW AND COLD POOL RETROGRADE WEST AGAIN. IN THE END...THIS MAY
OFFER ONLY A SMALL CHANCE FOR RAIN UNLESS MESOSCALE DETAILS COME
TOGETHER.

THE OVER ALL PATTERN OF HIGHER CONFIDENCE IS COOLER
TEMPERATURES...AND LOWER HUMIDITY. I HAVE STAYED VERY CLOSE TO MODEL
GUIDANCE...BUT IT LOOKS LIKE MANY DAYS WITH HIGHS IN THE 70S ARE
LIKELY THIS WEEKEND AND WEEK AHEAD.  FOR JUNE INTO JULY...THIS
SHOULD REALLY BE AN AMAZINGLY NICE WEEK.
ERVIN

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1138 PM CDT THU JUN 27 2013

CLEAR SKIES AND LIGHT WINDS WILL REMAIN OVER THE AREA THROUGH THE
REST OF TONIGHT INTO FRIDAY MORNING. FRIDAY...AN UPPER LEVEL
DISTURBANCE PASSING THROUGH THE REGION WILL PRODUCE SCATTERED
SHOWERS AND THUNDERSTORMS...MAINLY IN THE AFTERNOON. THIS IS MOST
LIKELY TO IMPACT THE DBQ SITE AND A TEMPO GROUP HAS BEEN ADDED.
CID AND MLI MAY ALSO SEE AFTERNOON THUNDERSTORMS...BUT CONFIDENCE
THAT THESE SITES WILL BE DIRECTLY IMPACTED IS NOT HIGH ENOUGH TO
GO BEYOND PROB30 WORDING. OTHERWISE...CONDITIONS WILL REMAIN VFR
WITH WEST TO NORTHWEST WINDS INCREASING AND BECOMING GUSTY FROM 15
TO 25 KTS FROM LATE MORNING THROUGH AFTERNOON.

&&

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

UPDATE...SHEETS
SYNOPSIS...08
SHORT TERM...08
LONG TERM...ERVIN
AVIATION...SHEETS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
509 PM CDT THU JUN 27 2013

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-282215-
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-
509 PM CDT THU JUN 27 2013

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...TONIGHT

AREA RIVERS ARE EXPERIENCING FLOODING. PLEASE SEE THE LATEST
FLOOD STATEMENTS AND FLOOD WARNINGS FOR DETAILS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THERE IS A CHANCE OF THUNDERSTORMS FRIDAY AFTERNOON AND INTO THE
EVENING ACROSS AREAS NORTHEAST OF A LINE FROM WATERLOO TO MACOMB.
SOME OF THE STRONGER STORMS MAY PRODUCE SMALL HAIL.

SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE SATURDAY.
SEVERE WEATHER IS NOT ANTICIPATED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TONIGHT.