AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1230 PM CDT WED JUN 19 2013
.DISCUSSION...
ISSUED 1038 AM CDT WED JUN 19 2013
ONLY MINOR GRID EDITS WERE NEEDED TO THE GOING FORECAST. SKIES
LARGELY SUNNY ASIDE FROM SOME CIRRUS SPREADING IN FROM THE
WEST...AND TEMPERATURES WERE ON TRACK TO REACH THE LOWER 80S
ACROSS THE FORECAST AREA.
GEELHART
&&
.AVIATION...
ISSUED 1230 PM CDT WED JUN 19 2013
QUIET WEATHER EXPECTED THE NEXT 24 HOURS. HAVE HAD SOME DIURNAL
CUMULUS DEVELOP OVER MOST OF THE TAF SITES OVER THE LAST HOUR OR
TWO...AND THESE MAY BRIEFLY FORM CEILINGS AROUND 4000 FEET EARLY
THIS AFTERNOON BEFORE DIMINISHING AGAIN. LIGHT NORTHEAST WINDS
SHOULD GRADUALLY TURN SOUTHEAST DURING THE NIGHT...BEFORE TAKING A
MORE SUSTAINED SOUTHERLY DIRECTION THURSDAY MORNING AS HIGH
PRESSURE PULLS EASTWARD FROM THE GREAT LAKES.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 251 AM CDT WED JUN 19 2013
SHORT TERM...TODAY THROUGH FRIDAY
COLD FRONT THAT BROUGHT A FEW STRONG THUNDERSTORMS TO PORTIONS OF
EAST-CENTRAL AND SOUTHEAST ILLINOIS YESTERDAY AFTERNOON/EVENING
HAS NOW SAGGED SOUTHWARD TO NEAR THE OHIO RIVER. COOL/DRY
NORTHEASTERLY FLOW BEHIND THE FRONT HAS SPREAD ACROSS CENTRAL
ILLINOIS EARLY THIS MORNING...WITH 07Z/2AM DEWPOINTS DIPPING INTO
THE UPPER 40S ACROSS THE FAR NORTHERN KILX CWA. THIS DRY AIR MASS
WILL LEAD TO MOSTLY SUNNY AND PLEASANT CONDITIONS TODAY...WITH
AFTERNOON HIGHS ONLY REACHING THE LOWER 80S. THE ONLY POTENTIAL
FLY IN THE OINTMENT WILL BE FURTHER SOUTH IN CLOSER PROXIMITY TO
THE FRONTAL BOUNDARY...WHERE SEVERAL ITERATIONS OF THE WRF MODEL
ARE SUGGESTING ISOLATED CONVECTION ALONG THE I-64 CORRIDOR LATE
THIS AFTERNOON. BASED ON STRONG PUSH OF DRY AIR FROM THE
NORTHEAST...THINK IF ANY CONVECTION DEVELOPS...IT WILL REMAIN
JUST S/SW OF THE KILX CWA.
DRY WEATHER WILL CONTINUE THROUGH THURSDAY MORNING...BEFORE WARM
FRONT LIFTING NORTHWARD INTO THE AREA POTENTIALLY TRIGGERS ISOLATED
SHOWERS/THUNDER ACROSS WEST-CENTRAL ILLINOIS THURSDAY AFTERNOON.
WEAKENING UPPER WAVE APPROACHING FROM THE PLAINS WILL PROVIDE
LIMITED SYNOPTIC LIFT ALONG THE BOUNDARY...HOWEVER THINK AIR MASS
WILL BE TOO DRY TO SUPPORT MUCH IN THE WAY OF PRECIP. WILL CARRY
JUST A 20 POP ALONG/WEST OF THE ILLINOIS RIVER THURSDAY
AFTERNOON...AND EVEN THAT MAY BE OVERDOING IT. ANY SHOWERS THAT
DEVELOP IN ADVANCE OF THE FRONT WILL QUICKLY DISSIPATE THURSDAY
EVENING AS MEAGER DAYTIME INSTABILITY IS LOST.
UPPER RIDGE BEGINS TO BUILD ACROSS THE MIDWEST ON FRIDAY...IN
RESPONSE TO UPSTREAM DEEP TROUGH WEST OF THE ROCKIES. MODELS ARE
STILL HAVING DIFFICULTY DETERMINING THE EXACT STRENGTH OF THE
RIDGE AND WHETHER OR NOT ANY POTENTIAL MCS ACTIVITY COULD IMPACT
PARTS OF CENTRAL ILLINOIS. GFS HAS SHOWN A CONSISTENT SIGNAL OVER
THE PAST SEVERAL RUNS...KEEPING BULK OF PRECIP WELL TO THE NORTH
ACROSS THE UPPER MIDWEST INTO THE GREAT LAKES. WILL CONTINUE TO
FOLLOW THIS SOLUTION...WHICH LEADS TO A VERY WARM/DRY DAY ON
FRIDAY WITH HIGHS WELL INTO THE 80S.
LONG TERM...SATURDAY THROUGH TUESDAY
HOT AND GENERALLY DRY WEATHER WILL PERSIST OVER THE WEEKEND...WITH
UPPER RIDGING FIRMLY IN PLACE AND ANY SIGNIFICANT CONVECTION
STAYING NORTH OF CENTRAL ILLINOIS. MAY SEE SOME ISOLATED
SHOWERS/STORMS AROUND THE AREA SATURDAY AFTERNOON DEPENDING ON
STRENGTH OF MID-LEVEL CAPPING...BUT NOT ENOUGH TO MENTION IN THE
FORECAST AT THIS TIME. MAIN STORY FOR THE WEEKEND WILL BE THE
HOT/HUMID WEATHER...WITH HIGHS IN THE UPPER 80S/LOWER 90S AND HEAT
INDEX VALUES APPROACHING 100 ON BOTH SATURDAY AND SUNDAY. RIDGE
BEGINS TO FLATTEN EARLY NEXT WEEK...GRADUALLY ALLOWING A FRONTAL
BOUNDARY TO SETTLE SOUTHWARD INTO CENTRAL ILLINOIS. SPEED IN WHICH
THIS PROCESS OCCURS IS STILL IN QUESTION...AS MODEL SOLUTIONS VARY
FROM RUN TO RUN. BOTTOM LINE WITH BOTH THE GFS AND ECMWF IS THAT
RIDGE AXIS WILL SHIFT INTO THE ROCKIES BY THE MIDDLE/END OF NEXT
WEEK...RESULTING IN A COOLER NORTHWESTERLY FLOW ACROSS THE
MIDWEST. AT THIS POINT...WILL BRING LOW CHANCE POPS INTO THE
NORTHERN CWA ON MONDAY...HOWEVER WIDESPREAD PRECIP WILL LIKELY
HOLD OFF UNTIL WEDNESDAY/THURSDAY WHEN RIDGE RE-POSITIONS ITSELF
FURTHER WEST.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
