Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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308
FXUS63 KDVN 301222
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
722 AM CDT SAT APR 30 2016

.UPDATE...
ISSUED AT 718 AM CDT SAT APR 30 2016

DRY SLOT IS NOW QUITE PROMINENT FROM MISSOURI INTO EASTERN IOWA.
TRENDS IN PRESSURE FALLS AND RADAR INDICATE WIDESPREAD RAINFALL
WILL BE ENDING EARLIER. TRENDS IN THE RAP MODEL CONTINUE TO
INDICATE NEGATIVE THETA E LAPSE RATES DEVELOPING THIS AFTERNOON
WHICH MAY BE ENOUGH TO ALLOW REDEVELOPMENT IN THE FORM OF RAIN
SHOWERS. HOWEVER...AN ISOLATED THUNDERSTORM CANNOT BE FULLY RULED
OUT SOUTH OF I-80.

UPDATE ISSUED AT 506 AM CDT SAT APR 30 2016

TRENDS IN RADAR DATA SHOW A PRONOUNCED DRY SLOT ACROSS MISSOURI
THAT IS SLOWLY MOVING NORTH. RADAR RETURNS HAVE ALSO BEEN TRENDING
DOWNWARD SOMEWHAT AS DRY AIR CONTINUES TO BE ADVECTED INTO THE
AREA.

A WHOLESALE CHANGE TO THE FORECAST IS BEING DONE BASED ON RADAR
TRENDS WHAT WHAT IS BEING SUGGESTED BY TRENDS IN THE RAP. ALL
THUNDER HAS BEEN PULLED FROM THE MORNING HOURS. QPF HAS BEEN
LOWERED AND MAY STILL BE TOO HIGH. THE RAP IS SUGGESTING THE
POTENTIAL FOR PRECIPITATION TO SHUT DOWN FROM SOUTH TO NORTH THIS
AFTERNOON. THIS SCENARIO MAY OR MAY NOT OCCUR AS RAP TRENDS DO
SHOW NEGATIVE THETA E LAPSE RATES WHICH MAY PROMOTE DEVELOPMENT OF
SHOWERS THIS AFTERNOON. SAID LAPSE RATES MAY ALSO ALLOW SOME
ISOLATED THUNDER TO OCCUR AS WELL.

AN UPDATE TO THE FORECAST WILL BE AVAILABLE SHORTLY.

&&

.SYNOPSIS...
ISSUED AT 251 AM CDT SAT APR 30 2016

06Z SFC DATA HAS AN INFERRED LOW NEAR KEMP IN EASTERN KANSAS. AN
INVERTED TROF RAN FROM THE LOW NORTHWEST TO THE KS/NE BORDER. DEW
POINTS WERE IN THE 30S FROM THE GREAT LAKES INTO THE NORTHERN PLAINS
WITH 40S AND 50S FROM THE OHIO VALLEY INTO THE CENTRAL PLAINS. DEW
POINTS IN THE 60S WERE IN THE LOWER MISSISSIPPI VALLEY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 251 AM CDT SAT APR 30 2016

THROUGH SUNRISE...A NARROW BAND OF LIGHT RAIN WILL CONTINUE MAKING
SLOW PROGRESS NORTH THROUGH THE AREA. SOUTH OF I-80...PATCHY LIGHT
RAIN WILL CONSOLIDATE INTO A MUCH LARGER AREA OF LIGHT RAIN.

ON SATURDAY...A LARGE AREA OF LIGHT TO MODERATE RAINFALL WILL SLOWLY
MOVE NORTH ACROSS THE AREA DURING THE DAY. THE COMBINATION OF RAIN
AND EASTERLY WINDS WILL HOLD TEMPERATURES 15 TO POSSIBLY 20 DEGREES
BELOW NORMAL. AREAS ALONG/NORTH OF HIGHWAY 30 MAY STAY IN THE 40S.

BASED ON OVERALL FORCING AND MOISTURE PROFILES...ISOLATED EMBEDDED
THUNDERSTORMS MAY OCCUR SOUTH OF I-80 FROM LATE MORNING THROUGH THE
AFTERNOON WITH THE BETTER CHANCES ALONG AND SOUTH OF A KOTM TO KGBG
LINE.

TONIGHT...THE WIDESPREAD RAIN WILL SLOWLY FALL APART AS THE BETTER
FORCING SHIFTS INTO THE OHIO VALLEY. WIDESPREAD RAIN DURING THE
EVENING WILL SLOWLY BECOME MORE SHOWERY...ESPECIALLY AFTER MIDNIGHT.
A FEW ISOLATED THUNDERSTORMS MAY STILL BE POSSIBLE THE FIRST PART OF
SATURDAY EVENING...ESPECIALLY ALONG AND SOUTH OF A KOTM TO KGBG
LINE.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 251 AM CDT SAT APR 30 2016

GENERALLY QUIET WEATHER AND MOSTLY DRY AND TENDING CLOSE TO NORMAL TEMPERATURES.

LONG TERM FORECAST CONFIDENCE ASSESSMENT...FAIR OR AVERAGE WITH TOO
MOIST BL SUGGESTING ANY LINGERING LIGHT PRECIPITATION AMOUNTS ON SUNDAY
TO TEND TO BE LIGHTER WITH LOWER POPS. THEN TYPICAL DIURNAL RANGE ISSUES
OF A BIT UNDERDONE WITH FAIR SKIES.

SUNDAY...HAVE CHANCE POPS AND COOL WITH AREAS OF LIGHT RAIN OR RAIN
SHOWERS AS UPPER LOW PASSES. IF BL MOISTURE IS OVERDONE THEN HIGHS MAY
BE A FEW DEGREES TOO LOW WITH MOSTLY UPPER 50S TO AROUND 60 DEGREES
POSSIBLE. SOME CLEARING ALSO IN THE PM WITH HEATING AND LIGHT POPCORN
SHOWERS SUGGESTED FOR LATER SHIFTS. SUNDAY NIGHT...CLEARING WITH LIGHT
NORTHERLY WINDS SUGGESTING MINS IN THE UPPER 30S TO LOWER 40S SOUTH.
PATCHY FROST NOT OUT OF THE QUESTION BUT MINS NEED TO BE A COUPLE OF
DEGREES LOWER FOR CONSIDERATION OF HEADLINES. WILL PASS THIS ON AS ISSUE
FOR LATER SHIFTS. MINS SOUTH 1/3 TO 1/2 SHOULD BE MOSTLY IN THE LOWER
40S. OVERALL...RAIN AMOUNTS ON SUNDAY SHOULD BE A TENTH OF AN INCH OR
LESS.

MONDAY THROUGH SATURDAY...NW FLOW WITH REINFORCING SHOT OF CANADIAN
AIR WEDNESDAY. HIGHS SHOULD BE CONSISTENTLY IN THE MID 60S TO LOWER
70S OR NEAR NORMAL OVERALL. LOWS MOSTLY IN THE 40S WITH SOME UPPER
30S SUGGESTED FOR THURSDAY MORNING FOR LATER SHIFTS TO CONSIDER.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 627 AM CDT SAT APR 30 2016

WIDESPREAD IFR CONDITIONS WITH RAIN WILL DEVELOP ACROSS EASTERN
IOWA AND NORTHERN ILLINOIS THROUGH 18Z/30 AS A STORM SYSTEM MOVES
THROUGH SOUTHERN MISSOURI. ALTHOUGH NOT INCLUDED IN THE 12Z
TAFS...THERE IS A 10 PERCENT CHANCE OF A TSRA THAT MAY APPROACH KBRL
18Z/30 TO 02Z/01. AFT 00Z/30 WIDESPREAD IFR CONDITIONS WILL
CONTINUE WITH ISOLATED TO SCATTERED RAIN SHOWERS.


&&

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

$$

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



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