Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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422
FXUS63 KDVN 151801
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
101 PM CDT FRI MAY 15 2015

.SYNOPSIS...
ISSUED AT 325 AM CDT FRI MAY 15 2015

SYNOPSIS...A FEW LIGHT SHOWERS HAVE BEEN OCCURRING IN A LINE ACROSS
OUR FAR SE COUNTIES IN AN AXIS OF DEEPER MOISTURE THAT WAS SHIFTING
TO OUR EAST. OTHERWISE...CLOUDY SKIES AND PATCHY FOG WAS NOTED
ACROSS THE CWA EARLY THIS MORNING. 3 AM TEMPERATURES WERE IN THE
UPPER 50S TO LOWER 60S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 325 AM CDT FRI MAY 15 2015

FORECAST FOCUS ON THUNDERSTORM CHANCES.

TODAY...CLOUDY SKIES AND A LACK OF FORCING SHOULD KEEP THE MORNING
HOURS DRY. HOWEVER...THIS AFTERNOON OPERATIONAL MODELS...INCLUDING
THE HRRR/ARW/WRF-NMM...DEVELOP WEAK WARM AIR ADVECTION IN OUR
SOUTHERN CWA. THERE SHOULD BE ENOUGH FORCING TO TRIGGER SCATTERED
SHOWERS AND A FEW THUNDESTORMS AS THE AFTERNOON PROGRESSES AS THE
AIRMASS DESTABILIZES WITH AT LEAST SOME SUNSHINE. NAM INDICATES
CAPES RISING TO 2500 J/KG AT KBRL LATE IN THE AFTERNOON BUT DEEP
LAYER SHEAR REMAINS RATHER WEAK. IN ROUGHLY OUR NORTHERN HALF DRY
WEATHER IS EXPECTED AS THE AIRMASS IS DRIER AND MORE STABLE AND
THERE IS A LACK OF FORCING MUCH OF THE DAY. MORE SUNSHINE THIS
AFTERNOON SHOULD PUSH AFTERNOON TEMPERATURES IN THE 70S TO NEAR 80.
WILL GRADUALLY INCREASE POPS IN OUR SOUTH DURING THE AFTERNOON TO 40
TO 50 PERCENT...OR SCATTERED COVERAGE.

TONIGHT...ZONE OF WEAK WARM AIR ADVECTION/FORCING SPREADS NORTHWARD
OVER ALL THE CWA. OPERATIONAL MODELS STRUGGLING WITH
PLACEMENT/COVERAGE OF CONVECTION WITH THE NAM THE DRIEST AND THE
ECWMF THE WETTEST. FOR NOW WILL CONTINUE THE MIDDLE OF ROAD APPROACH
WITH 40 POPS CWA-WIDE OR SCATTERED COVERAGE. SHOULD BE A MILD NIGHT
WITH CLOUD COVER...INCREASING MOISTURE AND SOUTHERLY WINDS. LOWS
TONIGHT WILL BE IN THE UPPER 50S TO MID 60S.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 325 AM CDT FRI MAY 15 2015

WARM WITH CHANCES FOR SHOWERS AND STORMS THROUGH SUNDAY...THEN BELOW
NORMAL TEMPERATURES AND DRY.

LONG TERM FORECAST CONFIDENCE ASSESSMENT...SLIGHTLY ABOVE OR GOOD
WITH MAIN ISSUE TIMING OF CHANCES FOR SHOWERS AND LIKELY NON-SEVERE
STORMS WITH MOSTLY LIGHT TO MODERATE RAIN AMOUNTS. TEMPERATURES
NEXT WEEK WITH MINS MAY NEED TRIMMING A FEW MORE DEGREES WITH LOW
DEWPOINTS AND FAIR SKIES.

OVERVIEW...INITIALIZATION AND VERIFICATION ARE FAIR OR ABOUT AVERAGE
WITH NORMAL AMERICAN SOLUTIONS A BIT TOO MOIST IN BL RESULTING IN
SLIGHT TOO HIGH POPS THIS WEEKEND. RUN TO RUN CONSISTENCY AND VERIFICATION
TOOLS SUPPORTS A 70/30 MIX OF HI-RES ECMWF TO GFS WITH GFS PROBABLY
TOO HIGH ON POPS MID WEEK WITH WEAK DISTURBANCE.

SATURDAY THROUGH SUNDAY...OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS
WITH BEST CHANCES SUNDAY WITH PASSING FRONT. LIMITED INSTABILITY FROM
CAPE AOB 1500 J/KG AND MODEST WIND SHEAR SUGGEST LOW RISK OF ANY SEVERE.
YET...IF FRONT PASSES IN PM HOURS SOME STRONG STORMS NOT OUT OF QUESTION.
HIGH TEMPERATURES SHOULD BE MOSTLY IN THE LOWER 80S WITH MILD MINS IN
THE LOWER TO MIDDLE 60S SUNDAY AM AND THEN MOSTLY IN THE 5OS WITH ISOLATED
40S FAR NW SECTIONS BEHIND COOL FRONTAL PASSAGE SUNDAY NIGHT. MOST LOCATIONS
OVER THE 36 PLUS HOUR PERIOD SHOULD PICK UP ANOTHER .25 TO .75 INCHES
OF RAIN.

MONDAY THROUGH THURSDAY...COOL...AND DRY WITH FAIR SKIES AS LARGE SURFACE
HIGH FROM CANADA DOMINATES. AREA HIGHS SHOULD BE IN THE 60`S EACH DAY
WITH MINS MOSTLY IN THE 40S WITH ISOLATED UPPER 30S POSSIBLE IN FAVORED
LOW LYING LOCATIONS NORTH OF I-80. LOCAL TECHNIQUES SUGGEST SOME TRIMMING
OF LOWS MAY BE NEEDED WITH ANY BL DECOUPLING AND FAIR SKIES. LIGHT RAIN
CHANCES WEDNESDAY INTO WEDNESDAY NIGHT OF LOW POPS WITH SURFACE HIGH
NEARBY FROM WEAK UPPER DISTURBANCE MAY BE TOO HIGH FOR LATER SHIFTS
TO REASSESS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM CDT FRI MAY 15 2015

CHALLENGING TAF CYCLE WITH THE MAIN ISSUES BEING THE TIMING AND COVERAGE
OF SHOWERS AND STORMS... AND CIGS/VSBYS. SCT-BKN STRATOCU WILL PERSIST
THROUGH THE AFTERNOON WITH POCKETS OF MVFR CIGS BECOMING ALL VFR
BY MID TO LATE AFTERNOON. AN UPPER LEVEL DISTURBANCE WILL LIFT
NORTHWARD FROM EASTERN KS INTO THE UPPER MIDWEST AND WILL BRING AT
LEAST SCATTERED SHOWERS AND STORMS TO THE AREA FROM SOUTH TO NORTH
MID AFTERNOON THROUGH THIS EVENING. HAVE GONE WITH A TEMPO GROUP
AT BRL LATE THIS AFTERNOON WITH ARRIVAL NEAR TO JUST AFTER PEAK
HEATING. AT THE OTHER TAF SITES... LOWER CONFIDENCE DUE TO
LIKELIHOOD OF A BIT LATER ARRIVAL (BARRING ANY ADDITIONAL
DEVELOPMENT OUT AHEAD) AND THUS HAVE OPTED FOR VCTS WORDING ATTIM.
TONIGHT EXPECT WARM FRONT DRAPED IN VICINITY TO LIFT NORTH. WOULD
ANTICIPATE SOME FOG AND LOW CLOUDS DEVELOPING NORTH OF THE
BOUNDARY MOST FAVORING THE NORTHERN SITES. LAMP GUIDANCE HITTING
THE FOG MORE THAN THE STRATUS AND SO FOR NOW FOLLOWING SUIT WITH
GENERAL 2-5SM VSBYS OVERNIGHT INTO EARLY SATURDAY MORNING WITH
SOME MARGINAL MVFR CIGS AT CID...DBQ AND MLI. WILL BE A CHANCE OF
AT LEAST ISOLD TO SCATTERED SHOWERS AND STORMS OVERNIGHT INTO
EARLY SATURDAY MORNING UNTIL THE FRONT LIFTS NORTH... BUT TOO MUCH
UNCERTAINTY ON COVERAGE AND LOCATION TO MENTION IN TAFS ATTIM.
WINDS LIGHT WILL TURN SE/S BY TONIGHT 4-10 KTS THEN INCREASE FROM
SOUTH AT 10-15 KTS ON SATURDAY.

&&

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

$$

SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...NICHOLS
AVIATION...05



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