Special Weather Statement, NWS Quad Cities, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
651 AM CDT SAT JUL 14 2012

.UPDATE...
THE FCST WILL BE UPDATED SHORTLY TO REFLECT CURRENT TRENDS.

CONVECTION EAST OF THE MISSISSIPPI IS GENERALLY SUPPORTED BY LIFT
AHEAD OF THE FIRST SHORTWAVE CROSSING THE MISSISSIPPI. THIS
CONVECTION IS SLOWLY DISSIPATING AND SHOULD END OR EXIT THE CWFA
AROUND MID MORNING. THE NEXT VORT MAX/SHORTWAVE OVER NORTHERN IOWA
WILL DROP SOUTHEAST DURING THE MORNING AND HELP INITIATE NEW
CONVECTION BY LATE MORNING AND CONTINUING THROUGH THE AFTERNOON.
BASED ON FCST SOUNDINGS...THE DIURNAL CONVECTION SHOULD BE FAIRLY
HIGH BASED WHICH COULD PRODUCE LOCALLY GUSTY WINDS.   ..08..

&&

.AVIATION...
MVFR AND SPOTTY IFR VSBYS WILL IMPROVE TO VFR BY 15Z/14. OTHERWISE
VFR CONDITIONS WILL BE SEEN THROUGH 06Z/15. VCSH WILL SLOWLY END
PRIOR TO 18Z WITH NEW CONVECTION STARTING AROUND 18Z/14 AND
CONTINUING THROUGH SUNSET. VCTS WAS ADDED TO ALL TAF SITES FOR THE
DIURNAL CONVECTION. CIGS WITH CONVECTION SHOULD REMAIN VFR BUT
BRIEF MVFR VSBYS WILL BE POSSIBLE. AFT 06Z/15 LIGHT WINDS SHOULD
ALLOW MVFR AND POSSIBLY IFR CONDITIONS TO DVLP.        ..08..

&&

.PREV DISCUSSION... /ISSUED 319 AM CDT SAT JUL 14 2012/

SYNOPSIS...
06Z SFC ANALYSIS HAS SEVERAL SUBTLE TROFS FROM LAKE MICHIGAN BACK
INTO MINNESOTA WITH A COLLAPSING MESOHIGH NEAR KRST. DEW POINTS WERE
GENERALLY IN THE 60S WITH 70S IN THE DEEP SOUTH AND LOWER OHIO
VALLEY. RADAR TRENDS OVER THE PAST SEVERAL HOURS SHOWS OVERALL
CONVECTION IS SLOWLY DISSIPATING.

SHORT TERM...TODAY AND TONIGHT...
PRECIPITATION SINCE MIDNIGHT HAS EITHER ENDED OR DIMINISHED TO
SPRINKLES/ISOLATED SHRA. EAST OF THE MISSISSIPPI ELEVATED CONVECTION
HAS PERSISTED OR DEVELOPED. RAP TRENDS SHOW THE CONVECTION IS MAINLY
ASSOCIATED WITH SPEED/MOISTURE CONVERGENCE AT 850MB IN RELATIVELY
STRONG LIFT AHEAD OF THE VORT MAX THAT IS ALONG THE MISSISSIPPI. RAP
TRENDS INDICATE THAT THIS ELEVATED CONVECTION WILL PERSIST THE
REMAINDER OF THE NIGHT AND SHOULD DISSIPATE OR EXIT THE CWFA AROUND
MID MORNING.

WEST OF THE MISSISSIPPI SPRINKLES OR ISOLATED ELEVATED CONVECTION
WILL PERSIST OR POSSIBLY DEVELOP AS THE NEXT VORT MAX DROPS INTO THE
TROF FROM NORTHERN IOWA.

FROM LATE MORNING AND CONTINUING INTO THE AFTERNOON...DIURNAL
HEATING WILL ALLOW NEW CONVECTION TO BREAK OUT ACROSS THE CWFA.
BASED ON THE PROJECTED LOCATION OF THE VORT MAXES AND NEGATIVE THETA
E LAPSE RATES...AREAS ALONG/EAST OF THE MISSISSIPPI SHOULD HAVE THE
BETTER CHANCES OF SEEING CONVECTION. THUS THE HIGHER POPS WILL BE
ALONG/EAST OF THE MISSISSIPPI FROM LATE MORNING THROUGH THE
AFTERNOON.

CONVECTION THAT DEVELOPS DURING THE AFTERNOON WILL PERSIST INTO THE
EVENING AND SLOWLY DISSIPATE WITH SUNSET. AFTER MIDNIGHT GENERALLY
DRY CONDITIONS SHOULD BE SEEN WITH SUBSIDENCE BEHIND THE DEPARTING
SHORT WAVE AND BUILDING HEIGHTS.              ..08..

LONG TERM...SUNDAY THROUGH FRIDAY...
HEAT AND MORE HUMID CONDITIONS WILL RETURN TO THE REGION FOR THE
FIRST HALF OF THE WEEK AS THE WESTERN U.S. UPPER RIDGE EDGES EAST
INTO THE PLAINS. THE DEVELOPING UPPER RIDGE WILL KEEP THE AREA DRY
SUNDAY AND MONDAY. WITH INCREASING SOUTHERLY FLOW AND WAA TEMP
WILL TOP OUT IN THE LOW TO MID 90S SUNDAY AND MAINLY MID 90S FOR
MONDAY. HELD DEW POINTS IN THE MID/UPPER 60S BOTH DAYS WHICH WILL
SUPPORT HEAT INDEX VALUES IN THE 95 TO AROUND 100 RANGE BOTH DAYS.

TUESDAY INTO THURSDAY A DEVELOPING TROF OVER GREAT LAKES AND NEW
ENGLAND WILL SENT A COLD FRONT SOUTH THROUGH THE REGION. THE FRONT
WILL TAKE THE EDGE OFF THE EARLY WEEK HEAT AND IT WILL ALSO
PROVIDE A CHANCE OF RAIN FOR THE REGION. THE FORECAST WAS SKEWED
TOWARD THE ECMWF WHICH BRINGS THE FRONT THROUGH SLOWER THAN THE
OTHER MODELS...ESPECIALLY THE GFS. THE SLOWER MOVEMENT SEEMS
REASONABLE WITH THE FRONT MOVING INTO THE UPPER RIDGE. ALSO MODELS
ARE SHOWING WARM MID LEVELS ALONG AND AHEAD OF THE BOUNDARY
SUGGESTING THE WARM SECTOR WILL BE CAPPED. WITH ALL THE PRECIP
EXPECTED TO BE POST FRONTAL HAVE KEPT TUESDAY DRY AND LIMITED POPS
TUESDAY NIGHT TO THE NORTH HALF. LOW CHANCE POP WERE MAINTAINED
OVER THE ENTIRE AREA WEDNESDAY THEN STARTED TO DRY THE FORECAST OUT
FROM NORTH TO SOUTH WEDNESDAY NIGHT INTO FRIDAY AS THE BOUNDARY PUSHES
FAR ENOUGH SOUTH. WITH THE WARM MID LEVEL TEMPERATURES IN PLACE
AND FORCING ALONG AND NORTH OF THE FRONT REMAINING WEAK ANY
SHRA/TSRA OCCURRING WITH THIS SYSTEM SHOULD BE SCATTERED.

THE FRONT WILL ALSO BRING SOME SLIGHTLY COOLER TEMPERATURES TO THE
AREA FOR MID TO LATE WEEK. HEAT INDEX VALUES AROUND 100 ARE
EXPECTED OVER THE ENTIRE AREA TUESDAY BUT SHOULD BE LIMITED TO THE
SOUTH HALF OF THE AREA WEDNESDAY AND THURSDAY.

DLF

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
349 AM CDT SAT JUL 14 2012

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-150900-
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-
349 AM CDT SAT JUL 14 2012

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
THUNDERSTORMS WILL BE POSSIBLE TODAY INTO THIS EVENING. CURRENT
INFORMATION SUGGESTS NO SEVERE STORMS ARE ANTICIPATED.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THERE WILL BE A CHANCE OF THUNDERSTORMS OVER MUCH OF THE AREA FROM
TUESDAY NIGHT THROUGH THURSDAY NIGHT. SEVERE STORMS ARE NOT
EXPECTED AT THIS TIME.

HOT AND HUMID CONDITIONS WILL RETURN TO THE REGION THIS WEEK AS
TEMPERATURES CLIMB BACK INTO THE 90S. SUNDAY AND MONDAY SHOULD BE
THE WARMEST DAYS WITH HIGHS IN THE MIDDLE 90S AND HEAT INDEX VALUES
AROUND 100. A COLD FRONT WILL BRING SLIGHTLY COOLER TEMPERATURES
TO THE REGION BY MID-WEEK. HOWEVER AREAS SOUTH OF INTERSTATE 80
WILL CONTINUE TO SEE HEAT INDEX VALUES IN THE UPPER 90S TO AROUND
100 THROUGH WEDNESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED TODAY OR TONIGHT.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
505 AM CDT SAT JUL 14 2012

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-141115-
KEOKUK-WASHINGTON-LOUISA-JEFFERSON-HENRY IA-DES MOINES-VAN BUREN-
LEE-MERCER-HENDERSON-WARREN-HANCOCK-MCDONOUGH-SCOTLAND-CLARK-
INCLUDING THE CITIES OF...SIGOURNEY...WASHINGTON...WAPELLO...
FAIRFIELD...MOUNT PLEASANT...BURLINGTON...KEOSAUQUA....
FORT MADISON...ALEDO...OQUAWKA...MONMOUTH...CARTHAGE...MACOMB...
MEMPHIS...KAHOKA
505 AM CDT SAT JUL 14 2012

...PATCHY FOG EXPECTED THROUGH SUNRISE...

SPOTTY RAINFALL YESTERDAY COMBINED WITH LIGHT WINDS HAS ALLOWED
PATCHY FOG TO DEVELOP. THE FOG...LOCALLY DENSE IN SPOTS...WAS
GENERALLY IN RIVER VALLEYS AND LOW LYING AREAS.

MOTORISTS SHOULD EXERCISE CAUTION EARLY THIS MORNING AS
VISIBILITIES MAY CHANGE SUDDENLY OVER SHORT DISTANCES.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
605 AM CDT SAT JUL 14 2012

IAZ076>078-087>089-098-099-ILZ024>026-034-035-MOZ009-010-141315-
KEOKUK-WASHINGTON-LOUISA-JEFFERSON-HENRY IA-DES MOINES-VAN BUREN-
LEE-MERCER-HENDERSON-WARREN-HANCOCK-MCDONOUGH-SCOTLAND-CLARK-
INCLUDING THE CITIES OF...SIGOURNEY...WASHINGTON...WAPELLO...
FAIRFIELD...MOUNT PLEASANT...BURLINGTON...KEOSAUQUA....
FORT MADISON...ALEDO...OQUAWKA...MONMOUTH...CARTHAGE...MACOMB...
MEMPHIS...KAHOKA
605 AM CDT SAT JUL 14 2012

...PATCHY FOG WILL CONTINUE PAST SUNRISE...

SPOTTY RAINFALL YESTERDAY COMBINED WITH LIGHT WINDS HAS ALLOWED
PATCHY FOG TO DEVELOP. THE FOG...LOCALLY DENSE IN SPOTS...WAS
GENERALLY IN RIVER VALLEYS AND LOW LYING AREAS.

MOTORISTS SHOULD EXERCISE CAUTION EARLY THIS MORNING AS
VISIBILITIES MAY CHANGE SUDDENLY OVER SHORT DISTANCES.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
824 AM CDT SAT JUL 14 2012

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

0815 AM     HAIL             4 S CUTSHAW BRIDGE STAT 42.47N 92.06W
07/14/2012  E0.75 INCH       BUCHANAN           IA   TRAINED SPOTTER

            SPOTTER REPORTED PEA TO DIME SIZED HAIL FALLING FOR 5 TO
            10 MINUTES.

&&

DC

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
848 AM CDT SAT JUL 14 2012

IAZ040-051-052-141445-
BENTON-BUCHANAN-LINN-
848 AM CDT SAT JUL 14 2012

...LINE OF STRONG THUNDERSTORMS WITH SMALL HAIL AND GUSTY WINDS...

AT 842 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM BRANDON TO 10 MILES
WEST OF MOUNT AUBURN...MOVING SOUTHEAST AT 10 MPH.

* THUNDERSTORMS WILL BE NEAR...
  GARRISON AROUND 920 AM CDT...
  BRANDON AROUND 930 AM CDT...
  MOUNT AUBURN AND BRANDON AROUND 935 AM CDT...
  ROWLEY AROUND 940 AM CDT...
  6 MILES NORTHWEST OF WALKER...8 MILES NORTHWEST OF URBANA...8 MILES
  NORTH OF VINTON AND 8 MILES NORTHWEST OF TROY MILLS AROUND 945 AM
  CDT...

PENNY SIZE HAIL...WINDS GREATER THAN 35 MPH AND HEAVY RAIN CAN BE
EXPECTED WITH THESE STORMS.

SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS PASSED.

LAT...LON 4230 9230 4230 9207 4246 9207 4247 9209
      4249 9207 4231 9163 4204 9219 4213 9231
      4230 9231
TIME...MOT...LOC 1347Z 280DEG 10KT 4239 9197 4226 9228

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
921 AM CDT SAT JUL 14 2012

IAZ040-051-141445-
BENTON-BUCHANAN-
921 AM CDT SAT JUL 14 2012

...STRONG THUNDERSTORM...

AT 917 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 7 MILES WEST OF MOUNT AUBURN...OR 13 MILES
NORTHWEST OF VINTON...MOVING SOUTHEAST AT 10 MPH.

* THE THUNDERSTORM WILL BE NEAR...
  MOUNT AUBURN AROUND 945 AM CDT...

PENNY TO NICKEL SIZE HAIL...WINDS GREATER THAN 35 MPH AND HEAVY
RAIN IS EXPECTED WITH THIS STORM.

SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS PASSED.

LAT...LON 4230 9230 4230 9215 4230 9208 4231 9207
      4232 9206 4229 9201 4212 9217 4221 9231
      4230 9231
TIME...MOT...LOC 1421Z 302DEG 7KT 4228 9221