Area Forecast Discussion
Issued by NWS Central Illinois

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000
FXUS63 KILX 030831
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
331 AM CDT FRI JUL 3 2015

.SHORT TERM...(TODAY)
ISSUED AT 331 AM CDT FRI JUL 3 2015

THE 08Z/3AM SURFACE ANALYSIS SHOWS A STATIONARY FRONT EXTENDING WEST-
EAST JUST SOUTH OF ILLINOIS, WITH A SURFACE LOW MOVING EAST ALONG
THE FRONT NEAR EVANSVILLE. A TROUGH OF LOW PRESSURE EXTENDING NORTH
FROM THE LOW WILL BE A FOCUS FOR SHOWERS AND A FEW STORMS TO DEVELOP
DURING THE DAY TODAY, MAINLY SOUTHEAST OF I-70. ALOFT, A SHORTWAVE
OVER IOWA AND INTO WESTERN ILLINOIS IS TRIGGERING SPOTTY SPRINKLES
ACROSS CENTRAL ILLINOIS. MOST OF THE CLOUD BASES WITH THAT FEATURE
ARE AT OR ABOVE 12K FEET, WHICH IS USUALLY HIGH ENOUGH THAT THE RAIN
DOESN`T REACH THE GROUND. HRRR AND RAP OUTPUT WERE NOT HANDLING THAT
WAVE AT ALL EARLIER. THE HRRR FINALLY ACKNOWLEDGED IT LAST HOUR, AND
SHOWS ALL SPRINKLES DISSIPATING IN A COUPLE HOURS. BASED ON
SATELLITE IMAGERY, AND FORECAST MOVEMENT OF THE UPPER TROUGH AXIS
ACROSS ILLINOIS THE REST OF THE DAY, WILL KEEP SPRINKLES IN THE
FORECAST ACROSS OUR NORTHERN AND CENTRAL COUNTIES INTO THE
AFTERNOON.

INSTABILITY PARAMS SHOW A MORE FAVORABLE ENVIRONMENT FOR A FEW
STORMS WILL REMAIN CLOSER TO THE LOW PRESSURE IN OUR SE COUNTIES. NO
STRONG STORMS ARE EXPECTED, AS SEVERE POTENTIAL WILL REMAIN ALONG
THE STATIONARY FRONT WELL SOUTH OF OUR AREA.

CLOUD COVER WILL REMAIN HIGH DUE TO MOISTURE CONTENT AT MULTIPLE
LEVELS. LOW CLOUDS ARE PROJECTED TO AFFECT OUR EASTERN COUNTIES AS
THE WEAK SURFACE TROUGH LINGERS NEAR THE IL-IN BORDER. HIGH CLOUDS
WILL AFFECT THE WESTERN COUNTIES AS THE UPPER SHORTWAVE PASSES
ACROSS IL. THE CLOUDS WILL KEEP HIGHS A FEW DEGREES COOLER, WITH
HIGHS IN THE UPPER 70S. PREVAILING WINDS WILL BE NORTHEAST DUE TO
LOW SURFACE PRESSURE SOUTHEAST OF OUR AREA.

&&

.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 331 AM CDT FRI JUL 3 2015

NOT MUCH OF A SHIFT OVERALL IN THE FORECAST RUNS THIS TIME
AROUND...SO THE NEXT COUPLE OF DAYS ARE STILL DRY FOR THE MOST PART
IN THE FORECAST.  AS THE FLOW SHIFTS FROM NWRLY TO VERY WEAK AND
DIFFUSE, MODELS ARE ALREADY MISSING SOME WEAK RETURNS THIS MORNING
ON RADAR WITH A WEAK OPEN WAVE ALOFT.  ALTHOUGH THERE WILL REMAIN
THE CONCERN FOR WEAK WAVES PROVIDING SOME LIFT...FORECAST IS DRY
THROUGH THE WEEKEND.  COOLER THAN NORMAL TEMPS FOR SATURDAY WITH
INCREASINGLY CLEARER SKIES...ALTHOUGH SOME HAZE STILL AN ISSUE.
WARMING MIDLEVELS, AMPLE SUNSHINE, AND A WEAK SOUTHERLY COMPONENT TO
THE WINDS ON SUNDAY WILL PUSH THE TEMPS UP A FEW MORE DEGREES FROM
SATURDAYS HIGHS...CLOSER TO SEASONAL NORMS FOR THE BEGINNING OF
JULY.  UPPER TROF DIGS INTO THE NRN PLAINS LATE IN THE WEEKEND,
DRIVING A FRONT THROUGH THE MIDWEST FOR MON NIGHT AND INTO TUESDAY,
WITH THE NEXT BIG CHANCE FOR PRECIP. AND LOWER TEMPS FOR TUESDAY AND
WEDNESDAY IN THE WAKE OF THE BOUNDARY. HOWEVER, THIS IS WHERE THE
FORECAST BECOMES FAMILIAR AGAIN. WITH WEAK QUASI-ZONAL FLOW ALOFT,
THE FRONT LAYS OUT INVOF THE OHIO RIVER VALLEY AND STARTS TO STALL
OUT.  HOW FAR SOUTH THE BOUNDARY GETS WHILE INTERACTING WITH
SHORTWAVES RIDING OUT OF THE PLAINS AND THROUGH THE MID MISS RIVER
VALLEY WILL ULTIMATELY END UP CONTROLLING THE POPS IN THE LONG TERM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1125 PM CDT THU JUL 2 2015

LOW PRESSURE PUSHING SLOWLY EAST ACROSS KENTUCKY WITH A EASTERLY
FLOW AROUND THE SURFACE WAVE SENDING LOW AND MID LEVEL MOISTURE
BACK TO THE WEST. WILL HAVE TO WATCH FOR THE POSSIBILITY FOR SOME
LOW VFR TO MVFR CIGS EDGING BACK INTO CMI AND DEC OVER THE NEXT
SEVERAL HOURS WITH THE MAIN CONCERN BEING HOW FAR WEST WILL THE
MOISTURE PUSH OVERNIGHT. STILL THINKING MOST AREAS WILL SEE CIGS
LOWER TO BETWEEN 2000-3000 FEET OVERNIGHT WITH PIA THE LAST TO SEE
THE CHANGE IN THEIR CIG. A FEW SHOWERS WERE TRYING TO DEVELOP OVER
WEST CENTRAL INDIANA AND WERE EDGING WEST OVER THE PAST HALF HOUR
TO HOUR. COVERAGE IS STILL VERY LIMITED BUT WILL KEEP AN EYE ON IT
TO SEE IF WE WANT TO COVER IT WITH AT LEAST VCSH AT CMI AND DEC
LATE TONIGHT. FORECAST SOUNDINGS CONTINUE WITH THE PREVIOUS TREND
OF CIGS LIFTING BY MID TO LATE MORNING FRIDAY WITH VFR CONDITIONS
EXPECTED THEREAFTER. SURFACE WINDS WILL CONTINUE FROM AND EAST TO
NORTHEAST DIRECTION THRU THE PERIOD WITH SPEEDS IN THE 8 TO 13 KT
RANGE.


&&

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

$$

SHORT TERM...SHIMON
LONG TERM...HJS
AVIATION...SMITH


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