748 
FXUS63 KILX 161114
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
614 AM CDT TUE JUL 16 2013

.DISCUSSION...
ISSUED 330 AM CDT TUE JUL 16 2013

SHORT TERM...TODAY THROUGH FRIDAY

FORECAST CONCERN IS THE HEAT WAVE THROUGH FRIDAY AND HOW HIGH
AFTERNOON HEAT INDICES WILL GET. THEN LOOKING AT INCREASING
CONVECTION CHANCES LATE THIS WEEK AS A COLD FRONT MOVES SOUTH
THROUGH IL FRI NIGHT/SAT. 00Z MODELS ARE IN GOOD AGREEMENT INTO
THIS WEEKEND...THEN DIVERGE EARLY NEXT WEEK. LEANED ON THE ECMWF
MODEL FOR THE WX FORECAST EARLY NEXT WEEK. 

STRONG 600 DM 500 MB HIGH PRESSURE THE NEAR IN/OH/KY BORDER TO
RETROGRADE WESTWARD INTO CENTRAL/SE IL DURING MID WEEK AND BRING
THE LONGEST HEAT WAVE OF THE SUMMER TO THE REGION. HIGHS IN THE
LOWER 90S TODAY AND LOW TO MID 90S WED THRU FRI COMBINED WITH
DEWPOINTS OF 70-75F TO GIVE HEAT INDICES OF IN THE UPPER 90S TO 
NEAR 100F THIS AFTERNOON...98-103F WED AFTERNOON AND 100-106F
THU/FRI AFTERNOON. THIS IS BELOW HEAT ADVISORY CRITERIA OF 105F
BUT WILL ISSUE A SPECIAL WEATHER STATEMENT TO ADDRESS THIS HEAT
WAVE. OUR HOTTEST DAY OF THE YEAR SO FAR WAS JUNE 12 WITH LOW TO
MID 90S BUT THAT ONLY LATEST ONE DAY. THIS HEAT WAVE WILL BE 4 
DAYS LONG.

A SUTTLE SHORT WAVE TRACKS NW ACROSS MO/SW IL THIS AFTERNOON AND
COULD DEVELOP ISOLATED CONVECTION SW OF JACKSONVILLE DURING THE
AFTERNOON AS AIRMASS IS UNSTABLE WITH CAPES OF 2000-3000 J/KG.
SCATTERED TO BROKEN CUMULUS CLOUDS TO DEVELOP AGAIN THIS AFTERNOON
BUT MOST AREAS WILL STAY DRY TODAY WITH LITTLE OR NO LIFTING
MECHISMS AROUND AND SOME CAP DEVELOPING WITH APPROACHING STRONG
UPPER LEVEL HIGH PRESSURE RIDGE.

SIMILAR WEATHER EXPECTED WED THROUGH THU NIGHT AS GENERALLY DRY...
HOT AND HUMID CONDITIONS PREVAIL WITH STRONG UPPER LEVEL HIGH
PRESSURE NEARLY OVERHEAD. BROUGHT IN 20-30% CHANCE OF CONVECTION
OVER NORTHERN AND EASTERN AREAS FRI AFTERNOON WITH COLD FRONT
PUSHING SOUTH THROUGH SOUTHERN WI TOWARD NORTHERN IL. FRIDAY COULD
BE EVEN HOTTER AND MORE HUMID WITH COMPRESSIONAL HEATING AHEAD OF
COLD FRONT TO OUR NORTH IF WE SEE ENOUGH SUNSHINE ESPECIALLY FROM
I-72 SOUTH. 

LONG TERM...FRIDAY NIGHT THROUGH TUESDAY

BEST CHANCES OF THUNDERSTORMS WILL BE FRIDAY NIGHT AND SAT AS COLD
FRONT PUSHES SOUTHWARD THROUGH IL WITH UPPER LEVEL RIDGE WEAKENING
AND SHIFTING SOUTHWARD INTO TN VALLEY. FAIRLY STRONG UPPER LEVEL
LOW/TROF DIGS SE FROM CANADA INTO THE GREAT LAKES REGION LATE THIS
WEEK AND THIS TO BRING SOME RELIEF FROM THE HIGH HEAT THIS
WEEKEND. CONVECTION CHANCES MAINLY SHIFT SOUTH OF CENTRAL IL
DURING SAT NIGHT AND SUNDAY AS COLD FRONT PUSHES SLOWLY THROUGH
THE OHIO VALLEY. A NORTHERN STREAM SHORT WAVE/TROF TO TRACK INTO
THE WESTERN GREAT LAKES REGION EARLY NEXT WORK WEEK AND RETURN A
CHANCE OF SHOWERS AND THUNDERSTORMS TO CENTRAL IL MON OR TUE.

07


&&

.AVIATION...
ISSUED 605 AM CDT TUE JUL 16 2013

OTHER THAN SOME PATCHY FOG EARLY THIS MORNING AND AGAIN AFTR 08Z
WEDNESDAY...VFR CONDITONS WILL PREVAIL. HIGH PRESSURE AT THE SFC
AND ALOFT WILL DOMINATE THE WEATHER ACROSS THE FORECAST AREA 
OVER THE NEXT COUPLE OF DAYS. FORECAST SOUNDINGS CONTINUE TO 
INDICATE A RAPID INCREASE IN THE CU FIELD AGAIN TODAY...HOWEVER
WITH THE LACK OF ANY FORCING/LIFT...ANY TSRA WILL BE ISOLATED
AT BEST SO WILL CONTINUE TO KEEP OUT OF ANY TAF SITE. WITH
THE ABUNDANT LOW LEVEL MOISTURE AND INSTABILITY PRESENT...IT
APPEARS WE MAY SEE A PERIOD OF BROKEN CU WITH BASES FROM
4000-5000 FEET. ONCE AGAIN...ANY BKN CIGS SHOULD SCATTER OUT
AFTR 23Z WITH A MAINLY CLEAR SKY OVERNIGHT...WHICH AGAIN WILL
LEAD TO SOME PATCHY GROUND FOG BY WED MORNING. WINDS WILL BE
QUITE LIGHT AGAIN TODAY OUT OF THE SOUTH WIND SPEEDS OF 10KTS
OR LESS. A SOUTHERLY WIND AT OR LESS THAN 5 KT CAN BE EXPECTED
TONIGHT. 

SMITH
&&

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

$$