River Flood Warning 18, NWS Quad Cities, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
640 AM CDT SUN APR 20 2014

.UPDATE...
ISSUED AT 634 AM CDT SUN APR 20 2014

THE NOCTURNAL CONVECTION THAT DEVELOPED ACROSS CENTRAL IOWA IS
SLOWLY DISSIPATING BUT WILL CATCH THE FAR NORTHWEST PARTS OF THE
AREA EARLY THIS MORNING. INTERESTINGLY...THE FEW SITES THAT HAVE
REPORTED RAIN INDICATE IT IS FALLING OUT OF CLOUD DECKS ABOVE 7
KFT AGL. RADAR TRENDS INDICATE THIS ELEVATED CONVECTION IS SLOWLY
DISSIPATING AND IT SHOULD BE GONE BY MID MORNING.

&&

.SYNOPSIS...
ISSUED AT 257 AM CDT SUN APR 20 2014

06Z SFC ANALYSIS HAS WEAK LOWS IN NORTHWEST IOWA...SOUTH CENTRAL
NEBRASKA...AND SOUTHEAST COLORADO. A FRONT CONNECTS THE LOWS AND
EXTENDS NORTHEAST INTO WESTERN LAKE SUPERIOR. DEW POINTS WERE IN THE
30S ACROSS THE GREAT LAKES AND NORTHERN PLAINS WITH 40S ALONG THE
FRONT. DEW POINTS IN THE 50S WERE ACROSS THE SOUTHERN PLAINS AND
LOWER MISSISSIPPI VALLEY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 257 AM CDT SUN APR 20 2014

MAINLY DRY CONDITIONS WILL BE SEEN TODAY AS MOISTURE AND THE BETTER
FORCING REMAIN RIGHT ALONG THE FRONTAL BOUNDARY. THE FRONT WILL MOVE
VERY SLOWLY EASTWARD TODAY BUT REMAIN WELL WEST OF THE AREA THROUGH
SUNSET. ALTHOUGH CLOUDS WILL BE ON THE INCREASE...TEMPERATURES WILL
BE WELL ABOVE NORMAL.

MAINLY DRY CONDITIONS WILL CONTINUE ACROSS THE AREA DURING THE
EVENING HOURS AS THE BETTER MOISTURE/FORCING STILL REMAIN WEST OF
THE AREA ALONG WITH THE FRONT. AFTER MIDNIGHT...THE CLOSER PROXIMITY
OF THE FRONT COMBINED WITH INCREASED MOISTURE AND SOME FORCING
SHOULD ALLOW SHOWERS TO DEVELOP OVER ROUGHLY THE NORTHWEST THIRD OF
THE AREA.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 257 AM CDT SUN APR 20 2014

THERE IS GOOD AGREEMENT THAT THE COLD FRONT WILL MOVE THROUGH THE
CWA DURING THE EARLY TO MID AFTERNOON HOURS MONDAY...AND THIS LEADS
TO ONLY A SMALL CHANGE IN OUR FORECAST. FOR MONDAY...THE SLOWER
FRONTAL PROGRESSION AND LESS MORNING RAIN CHANCE SHOULD ALLOW FOR A
SLIGHTLY MORE AGGRESSIVE WARM UP MONDAY...WITH WIDESPREAD LOWER 70S
LIKELY. THE EAST...WHICH COULD SEE SOME HOURS OF FILTERED
SUNSHINE...COULD TOP OUT IN THE MID 70S IF THE FRONT IS ANY FURTHER
DELAYED. THE LATER FRONTAL TIMING SHOULD ALLOW ENOUGH MODEST CAPE TO
BUILD FOR AT LEAST A SCATTERED TO BROKEN LINE TO FORM ALONG THE
FRONT. WHILE WIDESPREAD RAIN AMOUNTS CONTINUE TO LOOK LIGHT...THE
MOVEMENT OF STORMS DOES NOT LOOK OVERLY FAST...AND COULD LEAD TO
SOME ISOLATED AREAS OF MODERATE AMOUNTS ESPECIALLY ALONG AND EAST OF
THE MISSISSIPPI RIVER.

TUESDAY THROUGH EARLY WEDNESDAY CONTINUE TO APPEAR COOLER AND
DRY...WITH NORTH WINDS GRADUALLY VEERING TO THE EAST. TUESDAY AND
WEDNESDAYS HIGHS SEEM DESTINED FOR THE UPPER 50S NORTH TO MID 60S
SOUTH...WHICH COMPARED TO RECENT WEEKS SHOULD STILL SEEM QUITE
RESPECTABLE. WEDNESDAY ITSELF SEEMS A DAY IN QUESTION...AS SEVERAL
MODELS INCLUDING THE GFS AND NAM PLACE MOST OF THE WARM FRONTAL
FORCING WELL NORTH OF THE CWA WITH LITTLE CAPE OR FORCING THIS FAR
EAST. THE UKMET...GEM...AND MORE EXPLICITLY THE ECMWF CONTINUES TO
SHOW A BETTER POTENTIAL FOR ELEVATED SHOWERS AND STORMS THROUGH THE
DAY. I HAVE CHOSEN TO BLEND THIS POTENTIAL BY GOING TO MORE OF A
SHOWERS AND ISOLATED THUNDER RATHER THAN STRAIGHT SHOWERS AND
THUNDER.

WEDNESDAY NIGHT THROUGH EARLY THURSDAY EVENING DOES APPEAR SOMEWHAT
MORE INTERESTING AS BOTH THE GFS AND ECMWF BRING A STRONG UPPER WAVE
OUT ACROSS IOWA AND THE GREAT LAKES. MOISTURE APPEARS ADEQUATE AND
THE PROGRESSIVE STRONG WAVE SUGGESTS MODERATE RAINFALL AMOUNTS WITH
POTENTIALLY SOME STRONG THUNDER IF OTHER MESOSCALE FACTORS COME
TOGETHER TO SUPPORT IT.

FRIDAY INTO SATURDAY...WE SHOULD BE SUBSTANTIALLY COOLER...WITH HIGHS
IN THE MID 50S TO LOWER 60S. BY SATURDAY...THERE IS A VERY WIDE
MODEL SPREAD...WITH THE GFS DRY AND THE ECMWF CONSISTENTLY VERY WET.
THE DIFFERENCE BETWEEN SOLUTIONS IS MAINLY ON THE LOCATION OF THE
BAROCLINIC ZONE/ELEVATED WARM FRONT AT THAT TIME. THE GFS HAS IT
WELL SOUTH...WHILE THE ECMWF HAS IT OVER NORTHERN MO. TIME WILL TELL
IF EITHER MODELS HAS SKILL ON THIS FEATURE.
ERVIN

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 634 AM CDT SUN APR 20 2014

NOCTURNAL CONVECTION THAT DEVELOPED ACROSS CENTRAL IOWA IS
EXPECTED TO REMAIN TO THE NORTH AND WEST OF KCID/KDBQ AS IT SLOWLY
DISSIPATES. OTHERWISE...EXPECT VFR CONDITIONS THROUGH 06Z/21 AS
HIGH PRESSURE MOVES INTO THE EASTERN GREAT LAKES. AFT 06Z/21 THE
POTENTIAL EXISTS FOR MVFR VSBYS TO DEVELOP. KCID/KDBQ MAY SEE A
SHRA PRIOR TO SUNRISE MONDAY AND A TSRA CANNOT BE RULED OUT.

&&

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

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
316 AM CDT SUN APR 20 2014

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-210830-
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-
316 AM CDT SUN APR 20 2014

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

A COLD FRONT WILL BRING A CHANCE FOR THUNDERSTORMS TO THE OUTLOOK
AREA MONDAY...WITH NO SEVERE STORMS EXPECTED. ANOTHER CHANCE FOR
THUNDERSTORMS APPEARS SET FOR WEDNESDAY AND THURSDAY THIS WEEK. IT
IS TOO EARLY TO DETERMINE THE SEVERE WEATHER THREAT WITH THIS MID
WEEK CHANCE OF STORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

ERVIN