Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KDVN 241740
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1240 PM CDT FRI APR 24 2015

.SYNOPSIS...
ISSUED AT 335 AM CDT FRI APR 24 2015

LATEST SFC ANALYSIS WAS INDICATING ELONGATED NORTH-TO-SOUTH RIDGE
AXIS STARTING TO SLIDE EAST OF THE AREA BUT STILL PRODUCING LIGHT
TO CALM WINDS ACRS IL...SOUTHEAST RETURN FLOW INCREASING WEST OF
THE MS RVR AS WELL AS THICKENING CLOUD COVER. ELEVATED WARM AIR
ADVECTION WING OF SHOWERS ACRS WEST CENTRAL INTO CENTRAL IA WILL
HAVE TO BE WATCHED IF IT CAN MAINTAIN AND MAKE IT INTO THE
NORTHWESTERN CWA THIS MORNING...MOST HIRES SHORT TERM MODELS NOT
HANDLING IT. ALOFT...WATER VAPOR LOOP SHOWING A RIDGE-RIDING LEAD
VORT LOBE ACRS NORTHEASTERN NEB INTO NW IA WITH SIGNS IT WILL MOVE
ACRS IA THROUGH MIDDAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CDT FRI APR 24 2015

TODAY...WILL LET FROST ADVISORY RIDE ALTHOUGH FOR MUCH OF IT THE
COLDEST TEMPS HAVE ALREADY OCCURRED AND THICKENING CLOUD COVER
FROM THE WEST IS HALTING THE COLD DIP. A COUPLE BOUTS OF ELEVATED
LIFT AND CONVERGENT WARM AIR ADVECTION WINGS TO TRY AND DEVELOP
SCTRD SHOWER ACTIVITY FROM THE WEST TODAY...THE MORNING THROUGH
MIDDAY ACTIVITY WILL HAVE TO BATTLE DRY LOW TO MID LEVEL AIR AS
IT TRIES TO DEVELOP AND MOVE IN...ENOUGH TOP-DOWN SATURATION FOR
THE AFTERNOON AND EVENING FOR MORE PRECIP ACTIVITY. SOME ISOLATED
THUNDER POSSIBLE WEST OF THE MS RVR THIS AFTERNOON WITH MID LAYER
MUCAPES APPROACHING 500 J/KG. WILL KEEP HIGH TEMPS SIMILAR TO
ONGOING PACKAGE...BUT THICKENING CLOUD COVER AND EVAPO-COOLING
PROCESSES MAY MAKE FOR COOLER HIGHS THAN ADVERTISED.

TONIGHT...MOST OF THE 00Z RUN MODEL GUIDANCE IN GENERAL AGREEMENT
OF ROLLING CLOSING OFF UPPER LOW SYSTEM ACRS NORTHWESTERN MO BY
12Z SAT. LEAD PORTION OF DEVELOPING DEF ZONE OF RAIN OFF THIS
SYSTEM TO BUILD ACRS THE AREA AS THE NIGHT PROGRESSES...BECOMING
WIDESPREAD AND MODERATE AFTER MIDNIGHT. PWATS INCREASE TO OVER AN
INCH DURING THIS TIME FRAME FED BY A SOUTHWESTERLY 35-40+ KT H85
MB JET BECOMING RICHER WITH THTA-E...THIS LLJ JET AXIS WILL LOOK
TO CONVERGE JUST SOUTH OF THE CWA MAKING FOR HEAVIER RAIN
POTENTIAL NORTH OF THE CONVERGENT RIBBON INTO THE SOUTHERN THIRD
OF THE DVN CWA AFTER MIDNIGHT. SOME OF THESE AREAS MAY GET AN
INCH OF RAINFALL BY DAWN SAT MORNING. WITH INCREASING SATURATION
AND RISING SFC DPTS...LOWS TO BE HELD UP IN THE 40S IN MOST AREAS
TONIGHT.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 335 AM CDT FRI APR 24 2015

WIDESPREAD RAIN WILL BE ON-GOING SATURDAY AS THE STRONG SURFACE LOW
AND FILLING MID LEVEL SHORTWAVE PASS TO THE SOUTH FROM NORTHERN MO
INTO SOUTHERN IL DURING THE DAY. CATEGORICAL POPS ARE STILL
APPROPRIATE WITH RAINFALL AMOUNTS OF AROUND .25 TO NEAR .75 LIKELY
DURING THE DAY WITH HEAVIEST RAINFALL RATES IN THE MORNING HOURS
WHEN THE STRONGEST FORCING MOVES THROUGH. BRISK EAST TO NORTHEAST
WINDS DRIVEN BY THE TIGHT PRESSURE GRADIENT WILL LEAD TO BRISK WINDS
FROM 20 TO 30 MPH. CLOUDS...RAIN AND BRISK WINDS OUT OF THE GREAT
LAKES WILL RESULT IN A MINIMAL DIURNAL RISE IN THE CENTRAL AND NORTH
WITH HIGHS ONLY REACHING THE MID 40S TO NEAR 50. THE SOUTH WILL TAP
INTO HIGHER DEWPOINTS CLOSER TO THE SURFACE CYCLONE...DRIVING
TEMPERATURES INTO THE 50S TO POSSIBLY NEAR 60. STEEP MID LEVEL LAPSE
RATES AND PROXIMITY TO THE 850 MB WARM FRONT MAY LEAD TO AT LEAST
ISOLATED THUNDER DURING THE MORNING ACROSS THE SOUTH. CURRENT TIMING
SUGGESTS MOST OF THE PRECIPITATION WILL BE OVER BY EARLY TO MID
EVENING AS THE WEAKENING SYSTEM MOVES INTO THE OHIO RIVER VALLEY AND
HAVE CONFINED LOW CHANCE POPS FOR SHOWERS TO THE SOUTH AND SOUTHEAST
BEFORE MIDNIGHT. ADVECTION OF COOL...AND DRIER AIR ON NE WINDS THAT
FOLLOWS OVERNIGHT WILL LEAD TO LOWS IN THE 30S TO AROUND 40.

SUNDAY...INCOMING RIDGING AT THE SURFACE AND ALOFT SHOULD RESULT IN
CLEARING SKIES WITH GUIDANCE HIGHS FROM THE UPPER 50S TO LOWER 60S
REASONABLE AND LIGHT E-NE WINDS. WITH THE HIGH CENTER WELL TO THE
NORTH SUNDAY NIGHT...MODELS AT THIS TIME KEEP E-NE SURFACE WINDS IN
A 5 TO 10 MPH RANGE TO PREVENT A SIGNIFICANT FROST THREAT AS LOWS
DROP INTO THE 30S.

NEXT WEEK...THERE REMAINS LOW CONFIDENCE IN THE DETAILS OF POSSIBLE
WEAK SYSTEMS AROUND LATE TUESDAY AND FRIDAY/SATURDAY. HOWEVER...THE
OVERALL SETUP WITH A SPLIT UPPER LEVEL...MAINLY NW...FLOW SUPPORTS
CONTINUED BELOW NORMAL TEMPERATURES AND LOW CHANCES FOR
PRECIPITATION THROUGHOUT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1231 PM CDT FRI APR 24 2015

18Z TAFS UPDATED TO REFLECT RECENT TRENDS...WITH SOME SHOWERS AT
KDBQ/KCID AND MAINLY DRY THROUGH LATE AFTERNOON AT KMLI/KBRL.
AFTER THE INITIAL SHORT WAVE TROUGH MOVES THROUGH...THERE WILL
LIKELY BE A LULL IN THE SHOWER ACTIVITY THROUGH MUCH OF THE
EVENING WITH SHOWERS SPREADING FROM SOUTH TO NORTH BETWEEN 05Z AND
09Z. EXPECT CIGS TO PROGRESS FROM VFR TO MVFR OVERNIGHT...WITH IFR
MOST FAVORED AT KBRL. MVFR VISIBILITIES IN RAIN AND BR WILL ALSO
BE COMMON WITH PRECIPITATION PERSISTING SATURDAY MORNING AS THE
MAIN UPPER LEVEL LOW ARRIVES. ISOLATED THUNDERSTORMS MOST FAVORED
AT KBRL...BUT LOW PROBABILITY DOES NOT WARRANT INCLUSION IN TAF AT
THIS TIME.

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...SHEETS
AVIATION...RP KINNEY



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.