Flooding in Illinois, July 25 to 31, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
258 PM CDT SUN JUL 25 2010

.SYNOPSIS...
VERY QUIET DAY ACROSS THE FORECAST AREA...WITH TEMPERATURES IN THE
LOW TO MID 80S AS OF 2 PM...AND DEWPOINTS DOWN IN THE LOW TO MID
60S.  WE HAVE SOME DIURNALLY DRIVEN CUMULUS...BUT THEY HAVE SHOWN NO
FURTHER DEVELOPMENT AS WE EXPECTED BASED ON THIS MORNINGS SOUNDING.
SURFACE ANALYSIS SHOWING A BROAD SURFACE RIDGE CENTERED OVER
IOWA...WITH THE LIGHT NORTH TO NORTHEAST FLOW HELPING TO KEEP HIGHER
DEWPOINTS SUPPRESSED INTO MISSOURI AND SOUTHERN ILLINOIS. UPPER
LEVEL ANALYSIS ALSO SHOWING THAT DEEPER LAYER MOISTURE HAS BEEN
PUSHED SOUTH INTO TO THESE AREAS ...AND THAT WE ARE INTO SOME WEAK
RIDGING ALOFT BETWEEN TWO FAIRLY STRONG UPPER LEVEL LOWS IN THE
NORTHERN STREAM.
..LE..

&&

.SHORT TERM...TONIGHT AND MONDAY...
QUIET WEATHER TO CONTINUE WITH THE SURFACE RIDGE TO SLOWLY SHIFT
EAST ACROSS THE MIDWEST TONIGHT AND MONDAY.  WE MAY GET SOME FOG
TONIGHT WITH THE LIGHT WINDS AND RADIATIONAL COOLING...BUT DO NOT
EXPECT IT TO BE WIDESPREAD OR DENSE...AND HAVE LEFT IT OUT OF THE
PUBLIC FORECAST FOR NOW.  MIN TEMPS THIS MORNING ONLY DROPPED INTO
THE LOW 70S THIS MORNING ACROSS OUR SOUTH...LIKELY DUE TO THE
LIMITED RADIATIONAL COOLING WITH CIRRUS OVERHEAD.  EXPECT A
DIFFERENT STORY TONIGHT AND DESPITE SLIGHTLY WARMING TEMPERATURES
ALOFT...MIN TEMPS SHOULD RADIATE DOWN INTO THE 60S EVERYWHERE.
MONDAY SHOULD BE RELATIVELY QUIET WITH MAX TEMPS ONLY SLIGHTLY
WARMER THAN TODAY.  A BIT OF MOISTURE OOZES INTO THE SOUTHWEST...AND
WE MAY SEE SOME ISOLATED TO SCATTERED THUNDERSTORMS THERE DURING THE
HEAT OF THE DAY.  THERE IS ALSO A WEAK SHORTWAVE THAT DROPS THROUGH
THE FLOW WHICH MAY ALSO HELP TO INITIATE STORMS.  HOWEVER...NOTHING
VERY STRONG OR ORGANIZED IS ANTICIPATED...AND HAVE ONLY PUT IN A
SLIGHT CHANCE FOR STORMS.
..LE..

.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...
FORECAST FOCUS ON POTENTIAL FOR HEAVY RAIN TOWARDS NEXT WEEKEND.
WILL RELY ON THE MORE CONSISTENT ECM THROUGH THIS EXTENDED PERIOD.

HIGH PRESSURE WILL BE SHIFTING TO THE EAST INTO THE OHIO VALLEY AT
THE START OF THIS PERIOD. THIS SHOULD GRADUALLY BRING THE HEAT AND
HUMIDITY BACK INTO THE DVN CWA ON THE RETURN FLOW. IN THE MEANTIME
A COLD FRONT WILL BE DROPPING SOUTHEAST OUT OF CANADA AND ARRIVING
ABOUT WEDNESDAY. HOT PROD OR THERMAL RIDGE AHEAD OF THE FRONT ON
TUESDAY SHOULD ALLOW MAX TEMPERATURES TO SOAR INTO AT LEAST THE
LOWER 90S WITH DEWPOINTS SURGING INTO THE 70S. WILL PROBABLY
APPROACH OR EXCEED HEAT ADVISORY CRITERIA. WILL CARRY A CHANCE OF
THUNDERSTORMS WITH THE FRONT ON WEDNESDAY.

SOMEWHAT COOLER AND LESS HUMID ON THURSDAY WITH HIGH PRESSURE AGAIN
BRINGING PLENTY OF SUNSHINE. MAX TEMPERATURES SHOULD BE NEAR NORMAL
IN THE LOWER TO MID 80S.

ECM STARTING TO LATCH ONTO THE IDEA OF THE HEAT DOME TO OUR SOUTH
BUILDING A LITTLE MORE NORTHWARD...PUTTING THE CWA IN THE ALL TOO
FAMILIAR EDGE OF THE CAP OR RIM OF THE HEAT DOME. WARM FRONT TO
RETURN TO THE REGION ON FRIDAY AND STALL NEXT WEEKEND. THE ECM
SUGGESTS A COUPLE OF NOCTURNAL HEAVY RAIN EVENTS FRIDAY NIGHT AND
AGAIN SATURDAY NIGHT. WILL CARRY CHANCE POPS FOR NOW BUT AS WE GET
CLOSER TO THE WEEKEND AND CONFIDENCE GROWS THEN POPS CAN BE RAISED.
THIS SCENARIO WILL NEED TO BE MONITORED FOR THE THREAT OF HEAVY
RAINS ONCE AGAIN.

..HAASE..

&&

.AVIATION...
HIGH PRESSURE SLOWLY MOVING ACROSS THE AREA TODAY WILL KEEP WINDS
LIGHT NORTHEAST WITH ONLY SOME DIURNALLY DRIVEN CUMULUS WITH BASES
035-040 KFT APPROXIMATELY 17Z-00Z. TONIGHT THERE IS SOME POTENTIAL
FOR MVFR VSBYS IN RADIATION FOG...BUT HAVE ONLY INCLUDED AT MORE FOG
PRONE SITES OF KCID...KDBQ AND KBRL FOR NOW. SOME DIURNAL CUMULUS
EXPECTED AGAIN MONDAY WHICH SHOULD POP AROUND 16Z WITH BASES AGAIN
IN THE 035-040 KFT RANGE.   ..LE..

&&

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

&&

LE/HAASE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
448 AM CDT SUN JUL 25 2010

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-261000-
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-
448 AM CDT SUN JUL 25 2010

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

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

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE IS A CHANCE OF THUNDERSTORMS EACH DAY ACROSS THE AREA
WEDNESDAY THROUGH SATURDAY. IT IS TOO EARLY TO DETERMINE THE
THREAT FOR SEVERE WEATHER.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

DLS