Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 020455
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1155 PM CDT SUN MAY 1 2016

...AVIATION UPDATE...

.UPDATE...
ISSUED AT 647 PM CDT SUN MAY 1 2016

HAVE UPDATED THE FORECAST FOR SCATTERED THUNDERSTORMS THAT
DEVELOPED AHEAD OF THE UPPER LEVEL VORT MAX OVER FAR EASTERN
HENRY...BUREAU AND PUTNAM COUNTIES IN IL LATE THIS AFTERNOON.
RADAR LOOPS SHOW THE CENTER OF THIS VORT ROUGHLY OVER THE
MUSCATINE AND LOUISA COUNTY LINE MOVING EAST WITH ITS WING OF
ENHANCED SHOWERS PRODUCING HEAVIER RAINFALL RATES OUT AHEAD FROM
THE QUAD CITIES EAST ALONG THE IL I-80 CORRIDOR.

LATEST TRENDS AND ELEVATED INSTABILITY FIELDS SUGGEST THUNDERSTORM
CHANCES HAVE SINCE PUSHED EAST WITH NO ADDITIONAL STORMS EXPECTED.
OTHERWISE...WIDESPREAD SHOWERS SHOULD DISSIPATE TO PATCHY LIGHT
RAIN OR DRIZZLE WITH THE EXITING UPPER SUPPORT OVER EASTERN IA
AND NW IL THIS EVENING. THE RAIN COOLED BOUNDARY LAYER HAS LEAD TO
FOG JUST ABOVE THRESHOLDS FOR MENTIONING IN THE PUBLIC
FORECAST...BUT WILL BE WATCHING CLOSELY AS FAR SE IA...NE MO AND
ADJACENT W CENTRAL IL WILL BE IN THE ZONE MOST LIKELY TO SEE
FURTHER LOWERING OF VISIBILITIES OVERNIGHT.

&&

.SYNOPSIS...
ISSUED AT 246 PM CDT SUN MAY 1 2016

UPPER LEVEL LOW ACROSS WESTERN IA IS SLOWLY LUMBERING TO THE EAST
TODAY. LIGHT TO MODERATE RAIN SHOWERS WERE OCCURRING ACROSS
WESTERN AND CENTRAL IOWA. SFC FLOW FROM THE NE LEAD TO COOLER
TEMPS AND DRIER AIR ACROSS THE AREA TODAY. THE UPPER LEVEL LOW
LUMBERING TO THE EAST IS THE MAIN FORECAST CONCERN FOR THE SHORT
TERM.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 246 PM CDT SUN MAY 1 2016

QUESTION OF HOW MUCH AND WHEN THE RAIN WILL END EARLY IN THE
PERIOD ARE THE FORECAST CONCERN FOR THIS PERIOD. CONSENSUS ON THE
HIRES GUIDANCE IS A SLOWER PROGRESSION OF THE UPPR LVL LOW AND
SUBSEQUENT LONGER DURATION OF RAIN THAN THE SYNOPTIC MODELS WHICH
MOVES THE RAIN OUT OF THE AREA SHORTLY AFTER 00Z. TEND TO AGREE
WITH THE CAMS AND AS SUCH HAVE SLOWED ON THE PROGRESSION OF THE
LOW AND RAIN LEAVING THE AREA. IT LOOKS AS THOUGH MOST AREA WILL
SEE UP TO 0.3 INCHES OF RAIN WITH SOME AREAS SEEING LOCALLY
HEAVIER AMOUNTS NEAR 0.5 INCHES.

TOMORROW...SLIGHTLY WARMER TEMPS AND SOME SUN RETURNS TO THE AREA.
MODEL GUIDANCE SUGGESTS SYNOPTIC SCALE ASCENT LATER DURING THE
PERIOD AS AN ELONGATED TROF FINALLY STARTS TO MOVE TO THE EAST AS
A HIGH AMPLITUDE RIDGE BUILDS IN. A VORT MAX MOVING SOUTH LATER IN
THE DAY MAY LEAD TO ISOLATED SHOWERS ALONG AND SOUTH OF HIGHWAY 34
LATER IN THE AFTERNOON ON MONDAY.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 246 PM CDT SUN MAY 1 2016

MONDAY NIGHT AND TUESDAY...12Z SUNDAY MODEL RUNS OF THE GFS/ECMWF
SHOW THAT A LONG WAVE RIDGE WILL BUILD OVER THE ROCKY MOUNTAINS
PRODUCING A NORTHERLY FLOW ALOFT OVER THE UPPER MIDWEST. SKIES WILL
BE MAINLY CLEAR AND COOL MONDAY NIGHT WITH LOWS IN THE MID 40S.
MOSTLY SUNNY WEATHER WILL CONTINUE INTO TUESDAY WITH HIGH
TEMPERATURES AROUND 70 AND OVERNIGHT LOWS IN THE MID TO UPPER 40S.

WEDNESDAY AND THURSDAY...A FEW SHOWERS ARE POSSIBLE WEDNESDAY
MORNING AS A STRONG COLD FRONT PUSHES ACROSS THE FORECAST AREA
USHERING IN COOLER TEMPERATURES FOR OUT OF CANADA. WEDNESDAY WILL BE
BREEZY WITH HIGH TEMPERATURES IN THE UPPER 50S NORTH OF INTERSTATE
80 AND THE LOW 60S ACROSS THE SOUTH. LOW TEMPERATURES OVER THE
ENTIRE FORECAST AREA WILL BE IN THE 40S BOTH DAYS.

THURSDAY AND FRIDAY...12Z SUNDAY LONG RANGE BLENDED MODELS SHOW THAT
FAIR AND COOL WEATHER WILL CONTINUE AS AN UPPER LEVEL REX BLOCK
DEVELOPS WITH AN LONGWAVE RIDGE OVER THE MIDDLE OF THE COUNTY AND
DEEP CLOSED LOWS OVER SOUTHERN CALIFORNIA AND THE CAROLINAS.
SPRAWLING SURFACE HIGH PRESSURE WILL EXTEND FROM THE CANADIAN
BORDER ALL THE WAY TO SOUTH TO TEXAS. HIGH TEMPERATURES ON
THURSDAY WILL BE IN THE MID 60S WITH HIGHS CLOSE TO 70 ON FRIDAY.
OVERNIGHT LOWS WILL RANGE IN THE 40S.

SATURDAY AND SUNDAY... THE UPPER LEVEL RIDGE AXIS WILL SHIFT
SLIGHTLY TO THE EAST AS SURFACE HIGH PRESSURE MOVES SOUTHEAST
TOWARDS GEORGIA. SOUTHWEST WINDS AROUND THE BACK SIDE OF THE HIGH
WILL RAISE TEMPERATURES INTO THE UPPER 70S WITH OVERNIGHT LOWS IN
THE 50S. ..KUHL..

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1155 PM CDT SUN MAY 1 2016

DRY AIR ON A WEAK LOW LEVEL NORTHEASTERLY FLOW HAS BROUGHT AN
IMPROVEMENT TO VFR CONDITIONS WITH LIFTING CIGS AND INCREASING
VISIBILITIES AT CID...DBQ AND BRL THIS EVENING. MOIST SURFACE
CONDITIONS AND A POSSIBLE INFLUX OF SLIGHTLY MORE MOIST AIR WILL
CREATE A CHALLENGE FOR THE BALANCE OF THE NIGHT WITH THE POTENTIAL
FOR A RETURN OF MVFR AND POSSIBLE IFR CONDITIONS. FOR NOW...THIS
HAS BEEN INCLUDED AT BRL...WITH LOW CONFIDENCE LOWERING BACK TO
MVFR AT THE OTHER TERMINALS. MONDAY...CONDITIONS ARE EXPECTED TO
BE VFR AT ALL SITES BY NOON. A WEAK SURFACE FRONT MAY TRIGGER
AFTERNOON SHOWERS...WHICH HAS BEEN INCLUDED WITH VICINITY WORDING
AT ALL BUT BRL...WHERE PROB30S WERE INTRODUCED.

&&

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

$$

UPDATE...SHEETS
SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...KUHL
AVIATION...SHEETS



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