Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 030839
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
339 AM CDT SUN MAY 3 2015

.SHORT TERM...(TODAY)
ISSUED AT 338 AM CDT SUN MAY 3 2015

SURFACE TROUGH AND FRONTAL BOUNDARY REMAIN WELL OFF TO THE NORTHWEST
THIS MORNING...DRAPED FROM SD NORTHEAST THROUGH MN. THIS WILL BECOME
THE FOCUS FOR CONVECTIVE ACTIVITY LATER TODAY AS IT MOVES CLOSER TO
CENTRAL IL IN THE LATE AFTERNOON. THIS MORNING A SHORTWAVE EVIDENT
ON WATER VAPOR IMAGERY OVER CENTRAL IL CONTINUES TO PRODUCE A FEW
SHOWERS...EXPECTED TO MOVE EASTWARD AND DISSIPATE LATER THIS MORNING
IN EAST CENTRAL IL ACCORDING TO LATEST HRRR RUN. ANOTHER SHORTWAVE
OVER WEST IA IS EXPECTED TO TRACK ENE AND PASS BY THE CENTRAL IL
FORECAST AREA TO THE NORTH. WITH GENERAL SUBSIDENCE INDICATED ACROSS
THE AREA...HAVE KEPT THE FORECAST DRY LATE MORNING THROUGH LATE
AFTERNOON/EARLY EVENING ONCE THE INITIAL ROUND OF MORNING SHOWERS
PASSES THROUGH. LOW LEVEL SOUTHERLY FLOW WILL KEEP THE WARMING TREND
GOING FOR TODAY WITH HIGHS REACHING AROUND 80 DEGREES. FORECAST
SOUNDINGS INDICATE BOUNDARY LAYER MOMENTUM CAPABLE OF PRODUCING
GUSTS 20-25 MPH FROM I-70 NORTHWARD...WITH SUSTAINED SOUTHERLY WINDS
12-18 MPH.

&&

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 338 AM CDT SUN MAY 3 2015

NOT A LOT OF CHANGES IN THE FORECAST. MAJORITY OF FORECAST REVOLVES
AROUND A SLOWING/STALLED FRONTAL BOUNDARY ACROSS THE REGION FOR
TONIGHT AND THROUGH TOMORROW BEFORE BEING EDGED TO THE NORTH BEFORE
ANOTHER SYSTEM SPINS UP OVER THE PLAINS AND MOVES INTO THE REGION.
FOR TONIGHT, THE FRONTAL BOUNDARY SETTLING IN JUST TO THE NORTHWEST
WILL PROVIDE AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS FOR
THE AREA...SETTLING INTO THE NORTHERN HALF OF THE STATE AND BECOMING
HUNG UP IN QUASI ZONAL FLOW ALOFT.  BEST CHANCES FOR PRECIP REMAIN
IN THE NORTHERN HALF OF THE STATE PROVIDING SOME FOCUS FOR STORM
DEVELOPMENT.  MODELS HAVE TRENDED A LITTLE MORE SCATTERED IN THE QPF
FIELDS, ALTHOUGH THE NORTHERN HALF OF THE STATE STILL SEEMS PRIMED
FOR THE BEST CHANCES OF PRECIP THROUGH MONDAY NIGHT, SPECIFICALLY
THE AREAS WHERE THE BOUNDARY STALLS. SPC HAS KEPT THE NORTHERN HALF
OF THE CWA IN A MARGINAL RISK FOR STORMS INVOF THE BOUNDARY ON
MONDAY. CLUSTERS OF STORMS NEAR A WEAK BOUNDARY LOOKING BORDERLINE
AT THIS POINT, BUT IN AN AREA OF CONTINUING WARM AIR ADVECTION
PROVIDING POTENTIAL INSTABILITY JUST SOUTH OF THE BOUNDARY THAT WILL
SLOWLY BE SETTLING SOUTH INTO THE WARMER AND MORE BUOYANT AIR.

A RIDGE BEGINS TO BUILD INTO THE MIDWEST FROM THE SOUTHEAST...WITH
ENOUGH SUBSIDENCE IN THE REGION OF THE RIDGE AXIS TO ERODE SHOWER
CHANCES AT LEAST TUES NIGHT THROUGH WED NIGHT. ANOTHER PATTERN SHIFT
TAKES HOLD FOR THE LATER HALF OF THE WEEK, SETTING UP MORE OF A
SOUTHWESTERLY FLOW AND AN ACTIVE WEATHER PATTERN AGAIN AS WAVES
CONTINUE TO RIPPLE AROUND THE SWRN LOW AND INTO THE MIDWEST.  A
RATHER WET FORECAST OVERALL, WITH SEVERAL DIFFERENT PATTERNS
ESTABLISHING THEMSELVES...AND KEEPING SHOWERS AND THUNDERSTORMS IN
THE OUTLOOK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1150 PM CDT SAT MAY 2 2015

ISOLATED TO SCATTERED SHOWERS WILL CONTINUE TO MOVE ACROSS THE
AREA OVERNIGHT. SO WILL BE KEEPING VCSH IN OVERNIGHT FOR ALL
SITES. OTHERWISE, VFR AND MID LEVEL CIGS WILL BE HAD AT ALL SITES
OVERNIGHT. HRRR MODEL ENDS THE PCPN TOWARD EARLY MORNING BUT MID
LEVEL CIGS CONTINUE FOR A FEW HOURS. THEN CLOUDS WILL SCATTER OUT.
WILL HAVE HIGH CIRRUS WHICH WILL BE THE BLOW OFF FROM THE STORMS
CURRENTLY WELL WEST OF THE AREA. NOT EXPECTING TO SEE ANY OF THE
PCPN ASSOCIATED WITH THESE STORMS IN THE AREA TOMORROW, BUT MODELS
ADVECT SOME REMNANTS OF THESE STORMS INTO NORTHERN IL. WINDS WILL
BE SOUTH TO SOUTHWEST THROUGH THE PERIOD WITH STILL THINKING OF
SOME GUSTS AROUND 22-25KTS TOMORROW LATE MORNING THROUGH AFTERNOON
AFTER THE CLOUDS CLEAR AND GOOD MIXING TAKES PLACE. MAY SEE SOME
LLWS TOMORROW NIGHT BUT SOME UNCERTAINTY, SO NOT GOING TO PUT IN
TAFS AT THIS POINT.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...ONTON
LONG TERM...HJS
AVIATION...AUTEN



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