Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 031206
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
706 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 MID-LEVELS, AMPLE SUNSHINE, AND A WEAK SOUTHERLY
COMPONENT TO THE WINDS ON SUNDAY WILL PUSH THE TEMPS UP A FEW MORE
DEGREES FROM SATURDAY`S 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 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 700 AM CDT FRI JUL 3 2015

A WEAK SHORTWAVE WILL MOVE ACROSS ILLINOIS TODAY, TRIGGERING
SPOTTY SHOWERS OR SPRINKLES NEAR THE TERMINAL SITES. VERY FEW
LOCATIONS WILL SEE MEASURABLE RAIN TODAY, BUT WENT WITH VCSH FOR A
FEW HOURS THIS MORNING. UPDATES TO PRECIP MAY BE NEEDED AS THE DAY
PROGRESSES, BUT THE PRIMARY FOCUS FOR SHOWERS AND ISOLATED STORMS
SHOULD REMAIN SOUTH OF I-70 CLOSER TO LOW PRESSURE IN WESTERN
KENTUCKY. OTHERWISE, VFR CLOUDS WILL PERSIST THROUGH THE DAY WITH
NORTHEAST WINDS AT LESS THAN 10KT.

CLEARING SKIES WITH LIGHT AND VARIABLE WINDS TONIGHT COULD ALLOW
FOR SOME MVFR FOG, WITH LOCALIZED IFR FOG.

&&

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

$$

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


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