Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 242355
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
655 PM CDT TUE MAR 24 2015

.SYNOPSIS...
ISSUED AT 332 PM CDT TUE MAR 24 2015

LATEST SFC ANALYSIS WAS INDICATING THE MAIN UPSTREAM LOW PRESSURE
ACRS SOUTHEAST KS ATTM...WITH THE GREATEST LEE-SIDE PRESSURE FALLS
POINTING TO THE SOUTH STL AREA. SEVERAL OF THE LATEST MODEL RUNS
WANT TO PULL THIS LOW NORTHEASTWARD ACRS THE SOUTHERN CWA BY
MIDNIGHT...BUT CURRENT TRENDS SUGGEST THE MAIN CIRCULATION TO TRACK
FURTHER TO THE SOUTH. MAIN UPPER TROF COMPLEX WAS SEEN ON CURRENT
WATER VAPOR LOOP PULLING EAST ACRS THE PLAINS...WITH MID/UPPER
MOISTURE CHANNELS SUGGESTING THIS FEATURE TAKING ON A SLIGHT NEG
TILT ALREADY. ANOTHER DAY WHERE CLOUD COVER AND UNFAVORABLE EAST-
SOUTHEAST FETCH HAS KEPT A LID ON TEMPS...ESPECIALLY IN NW IL WITH
FETCH OFF THE SNOW FIELDS OF NORTH CENTRAL IL. FIRST WING OF LIGHT
RAIN CURRENTLY LIFTING NORTH THROUGH THE NW TO CENTRAL CWA ATTM.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 332 PM CDT TUE MAR 24 2015

TONIGHT...WILL RAMP UP THE POPS/OR KEEP THE ALREADY HIGH POPS
ADVERTISED FOR THIS EVENING AS ELEVATED THTA-E FEED TO LEE OF THE NEG
TILTING UPPER TROF ORGANIZES ON THE NOSE OF A 40+ KT H85 SOUTHERLY
JET. WITH THE MAIN LLVL CYCLONE PROBABLY TRACKING FURTHER TO THE
SOUTH THEN MOST MODELS SUGGEST...MID LEVEL LAPSE RATES AND MUCAPES
NOT LOOKING AS HIGH AS THIS TIME YESTERDAY. BETTER FORCING UNDER
MAIN UPPER JET DIFFLUENCE PLUME OVER MO THIS EVENING...AS WELL AS
THERMODYNAMICS IN THAT AREA SUPPORT MORE SUBSTANTIAL STORMS TO THE
SOUTH OF THE LOCAL AREA OF CONCERN. BUT ELEVATED CONVERGENT FORCING
WING AND SECONDARY MOISTURE FEED TO STILL FUEL A FEW TO SCTRD
ELEVATED THUNDERSTORMS EMBEDDED IN RAIN BANDS ACRS THE SOUTH HALF TO
SOUTHEAST HALF OF THE DVN CWA...STREAMING UP FROM THE SOUTH AS THE
EVENING PROGRESSES. A FEW OF THESE MAY BE ABLE TO PRODUCE AT LEAST
SMALL HAIL. STILL APPEARS TO BE A VERY STRONG LLVL SHEAR BUT LOW CAPE
SCENARIO FOR THE LOCAL AREA...AGAIN WITH AN ELEVATED CONVECTIVE
SCENARIO NOT TAKING ADVANTAGE OF THE LLVL WIND FIELDS. BULK
OF THE RAIN COVERAGE AND QPF TO OCCUR FROM 00Z-06Z...WITH MOST AREAS
GETTING FROM 0.20 OF AN INCH OF RAIN...TO AROUND A HALF INCH.
LOCALIZED HIGHER SWATHS POSSIBLE IN AREAS THAT CAN GET IN ON A FEW
PASSING THUNDERSTORM BANDS WHICH WOULD LIKELY BE MORE IN IN THE
SOUTHEASTERN THIRD TO HALF OF THE DVN CWA. BULK OF THE PRECIP MAY
MIGRATE EAST AND NORTHEAST OF THE CWA BY 08Z TONIGHT. TEMPS TO
CONTINUE TO TREND STEADY OR SLOW RISE AHEAD OF APPROACHING LOW AND
ASSOCIATED INVERTED SFC TROF THAT WILL NUDGE ACRS THE CWA FOR A WIND
SHIFT ACRS THE MS RVR BY 12AM-1AM.

OF MORE OF A CHALLENGE WILL BE THE FAR NORTHERN CWA ESPECIALLY THE
HWY 20 CORRIDOR NORTH WHERE PRECIP TYPE MAY BE AN ISSUE. FIRST IN
THE FAR NORTHWESTERN CWA AFTER 9 PM WHERE SOME TOP DOWN COOLING MAY
ALLOW FOR A RAIN TO SNOW MIX TO OCCUR...BUT THINK WITH MARGINAL SFC
TEMPS IT WOULD BE HARD TO ACCUMULATE MUCH OF ANYTHING...WET DUSTING
TO A FEW TENTHS OF AN INCH OF SLUSH. FURTHER TO THE EAST IN DRIER SFC
DPT FETCH AND FLOW OFF THE SNOW FIELDS OF NORTHERN IL...MORE CONCERN
THAT EVAPO-COOLING MAY TEMPORARY DRIVE SFC TEMPS BELOW FREEZING FOR
A FEW HRS AT LEAST FROM 7 PM-9PM OR SO FROM JUST WEST OF DBQ IA...
TO FREEPORT IL. WILL PUT IN THIS POTENTIAL IN THE GRIDS...BUT WITH
SFC/PAVEMENT TEMPS WELL ABOVE FREEZING IN THESE AREAS...HOPEFULLY
WILL KEEP ANY LIGHT ICE GLAZE TO ELEVATED SFCS AND NO REAL NEED FOR
A HEADLINE AT THIS POINT. THE SCENARIO WILL HAVE TO BE MET-WATCHED
HOWEVER ON THE NEXT SHIFT.   ..12..

.LONG TERM...(WEDNESDAY THROUGH NEXT TUESDAY)
ISSUED AT 332 PM CDT TUE MAR 24 2015

THE OVERALL WEATHER PATTERN WILL REMAIN QUITE ACTIVE WITH NUMEROUS
WEAK DISTURBANCES MOVING THROUGH IN THE FLOW ALOFT.

A WEAK FRONT WILL SLIP THROUGH THE AREA ON WEDNESDAY. ATMOSPHERIC
PROFILES SHOW A LAYER OF SATURATION ALOFT BUT THE FORCING IS OVERALL
WEAK. THE MORNING HOURS SHOULD REMAIN DRY WITH THE POSSIBILITY OF
SPRINKLES OVER VERY LIGHT RAIN ALONG/BEHIND THE FRONT DURING THE
AFTERNOON. THERE SHOULD BE A 15 DEGREE TEMPERATURE GRADIENT ACROSS
THE AREA WITH THE WARMEST TEMPERATURES IN THE FAR SOUTH.

WEDNESDAY NIGHT A STORM SYSTEM WILL PASS TO THE SOUTH OF THE AREA.
MOISTURE FROM THIS SYSTEM WILL COMBINE WITH THE FORCING BEHIND THE
DEPARTING FRONT TO HELP GENERATE A MORE GENERAL LIGHT RAIN ACROSS
THE SOUTH HALF OF THE AREA. AFTER MIDNIGHT THE RAIN WILL SLOWLY END
ACROSS THE SOUTH HALF OF THE AREA WHICH MIGHT BRIEFLY MIX WITH A
LITTLE SNOW BEFORE ENDING.

THURSDAY...DRY CONDITIONS WILL BE SEEN ACROSS THE AREA AS HIGH
PRESSURE QUICKLY MOVES THROUGH THE MIDWEST. TEMPERATURES SHOULD
AVERAGE SLIGHTLY BELOW NORMAL.

THURSDAY NIGHT ANOTHER WEAK UPPER LEVEL DISTURBANCE WILL DROP INTO
THE WESTERN GREAT LAKES. MOISTURE IS LIMITED BUT THE OVERALL FORCING
MAY DEVELOP SOME ISOLATED RAIN/SNOW SHOWERS AFTER MIDNIGHT ACROSS
BUREAU/PUTNAM COUNTIES.

DRY CONDITIONS WILL BE SEEN ON FRIDAY AS ANOTHER HIGH PRESSURE
QUICKLY MOVES THROUGH THE MIDWEST. TEMPERATURES WILL AVERAGE BELOW
NORMAL.

FRIDAY NIGHT ON...
YET ANOTHER WEAK DISTURBANCE WILL DROP SOUTHEAST FROM THE NORTHERN
PLAINS. HIGH PRESSURE OVER THE GREAT LAKES WILL KEEP DRY AIR ACROSS
THE AREA SO THERE ARE QUESTIONS AS TO THE POSSIBILITY OF
PRECIPITATION. THE MODEL CONSENSUS HAS SLIGHT CHANCE POPS JUST TO
THE WEST OF VAN BUREN COUNTY IOWA AND SCOTLAND COUNTY MISSOURI. IF
THE DRY AIR IS NOT AS DEEP AS SUGGESTED BY THE MODELS...THEN THESE
SLIGHT CHANCE POPS FOR SNOW COULD BE JUST A LITTLE FURTHER EAST.

DRY CONDITIONS WILL BE SEEN ACROSS THE AREA ON SATURDAY AS HIGH
PRESSURE QUICKLY MOVES THROUGH THE MIDWEST. TEMPERATURES SHOULD BE A
LITTLE BELOW NORMAL.

SATURDAY NIGHT/SUNDAY ANOTHER COLD FRONT SWEEPS THROUGH THE AREA.
MOISTURE WILL BE SOMEWHAT LIMITED BUT THE POTENTIAL IS THERE FOR
SOME PRECIPITATION TO OCCUR. AS SUCH THE MODEL CONSENSUS HAS SLIGHT
CHANCE TO VERY LOW CHANCE POPS. THERMAL PROFILES ARE SUCH THAT THE
PRECIPITATION MAY BE A RAIN/SNOW MIX BEFORE TURNING BACK TO ALL RAIN
ON SUNDAY. TEMPERATURES SHOULD AVERAGE ABOVE NORMAL.

SUNDAY NIGHT THROUGH TUESDAY THE MODEL CONSENSUS CURRENTLY HAS DRY
CONDITIONS FOR THE AREA. HOWEVER...THERE ARE TWO AND POSSIBLY THREE
VERY WEAK DISTURBANCES THAT WILL MOVE THROUGH THE AREA IN THE FLOW
ALOFT. A NEGATIVE FOR PRECIPITATION IS THE VERY SPARSE NATURE OF THE
MOISTURE. TEMPERATURES SHOULD AVERAGE ABOVE NORMAL.   ..08..

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 644 PM CDT TUE MAR 24 2015

PERIODS OF RAIN WITH CONDITIONS LOWERING TO MVFR AND IFR EXPECTED
THIS EVENING INTO THE EARLY OVERNIGHT BEFORE STORM SYSTEM PASSES
THROUGH THE MID MISSISSIPPI VALLEY. TEMPS MARGINAL FOR MIX OF SLEET
AND FREEZING RAIN AND POSSIBLY SOME SNOW NEAR HWY 20 CORRIDOR
INCLUDING DBQ. MEANWHILE...A FEW THUNDERSTORMS ARE POSSIBLE MOSTLY
SOUTH OF I-80 INCLUDING BRL. AS THE RAIN DIMINISHES LOW CLOUDS
WILL LINGER WITH TERMINALS SUBJECT TO IFR TO LIFR CONDITIONS
OVERNIGHT THROUGH WEDNESDAY MORNING BEFORE CIGS START TO LIFT AGAIN
AND SURFACE WINDS SWING TO WEST AND SOUTHWEST AND INCREASE AOA 10 KTS.

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...08
AVIATION...05





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