Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 021746
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1246 PM CDT SUN AUG 2 2015

.UPDATE...
ISSUED AT 1038 AM CDT SUN AUG 2 2015

15Z/10AM SURFACE ANALYSIS SHOWS RIDGE OF HIGH PRESSURE EXTENDING
FROM WEST VIRGINIA SOUTHWESTWARD TO TEXAS. FURTHER NORTH...A COLD
FRONT IS DRAPED ACROSS THE NORTHERN PLAINS. WIDESPREAD CONVECTION
IS CURRENTLY ONGOING ALONG/AHEAD OF THE FRONT ACROSS THE NORTHERN
SECTIONS OF WISCONSIN AND MICHIGAN...AIDED BY A STRONG SHORT-WAVE
TROUGH OVER SOUTHWEST ONTARIO. CLOSER TO HOME...A MUCH WEAKER
WAVE EVIDENT ON LATEST WATER VAPOR IMAGERY OVER SOUTHERN IOWA IS
TRIGGERING A FEW SHOWERS ACROSS WEST-CENTRAL ILLINOIS. AS THIS
FEATURE TRACKS EASTWARD...ISOLATED CONVECTION WILL DEVELOP ACROSS
MUCH OF THE KILX CWA AS THE DAY PROGRESSES. WITH NO FOCUSING
MECHANISM PRESENT...ONLY WEAK UPPER SUPPORT...AND AN OVERALL LACK
OF DEEP LAYER MOISTURE...THINK AREAL COVERAGE OF PRECIP WILL
REMAIN MINIMAL. AS A RESULT...WILL ONLY MENTION ISOLATED
THUNDERSTORMS. OTHERWISE IT WILL BE A BREEZY AND HOT DAY WITH
AFTERNOON HIGHS ONCE AGAIN REACHING THE UPPER 80S AND LOWER 90S.

&&

.SHORT TERM...(TODAY)
ISSUED AT 331 AM CDT SUN AUG 2 2015

HIGH PRESSURE RIDGE IS ORIENTED FROM EASTERN OK...NORTHEASTWARD INTO
THE OHIO RIVER VALLEY...WHILE A COLD FRONT IS LOCATED OVER THE
NORTHERN PLAINS/MISS VALLEY. THIS FRONT WILL DROP SLOWLY SOUTH
TODAY. MODELS POORLY HANDLED THINGS YESTERDAY/LAST EVENING SO HAVE
LOW CONFIDENCE IN ANY MODEL SOLUTION FOR TODAY. HIGH RES MODELS
CONTINUE TO BRING IN SOME SCATTERED CONVECTION INTO THE AREA THIS
MORNING AND THEN HAVE IT MOVING EAST AND THEN DISSIPATING IN THE
AFTERNOON. SOME CONVECTION HAS DEVELOPED WELL AHEAD OF THE FRONT
EXTENDING FROM WI SOUTHWESTWARD THROUGH IA AND INTO NEB. THESE
THUNDERSTORMS ARE IN AN AREA WITH BETTER LOW LEVEL MOISTURE AND WITH
HIGHEST DWPTS IN IOWA...THINKING IS THAT THE PCPN WILL CONTINUE THE
REMAINDER OF THE NIGHT AS IT MOVES EAST/SOUTHEAST. SOME OF THIS
COULD GET INTO THE CWA SO WILL HAVE SLIGHT CHANCE POPS IN THE
NORTHWEST/NORTH FOR THIS MORNING. OUTFLOW FROM THESE STORMS COULD BE
THE FOCUS FOR MORE STORMS FOR THE AFTERNOON/DURING MAX HEATING.
THEREFORE HAVE CHANCE POPS IN THE AFTERNOON IN THE NORTHERN THIRD OF
THE CWA. WITH MORE SOUTHWESTERLY WINDS TODAY AND MOSTLY SUNNY SKIES
INTO THE AFTERNOON...AFTERNOON HIGH TEMPS SHOULD ONCE AGAIN BE IN
THE UPPER 80S TO AROUND 90.

.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 331 AM CDT SUN AUG 2 2015

ISOLATED TO SCATTERED CONVECTION EXPECTED TO DEVELOP OVER NORTHERN
CWA MAINLY NORTH OF I-72 DURING THIS AFTERNOON TO GRADUALLY SHIFT SE
DURING TONIGHT WITH HIGHEST POPS OVER NORTHERN CWA LATE THIS
AFTERNOON AND THIS EVENING. SPC HAS SLIGHT RISK OF SEVERE STORMS
THIS EVENING OVER FROM GALESBURG TO PEORIA TO BLOOMINGTON AND
HOOPESTON NORTH WHERE 15% RISK OF DAMAGING WINDS AND LARGE HAIL
ALONG WITH 2% RISK OF TORNADOES. SPC HAS ENHANCED RISK OF SEVERE
STORMS OVER NE IL CLOSER TO ROCKFORD AND CHICAGO METRO AREA WHERE
STRONGER FORCING WILL BE AND STEEPER LAPSE RATES AS SHORT WAVE
TRACKS ACROSS WI/MI. FRONTAL BOUNDARY TO PUSH SE ACROSS CENTRAL IL
OVERNIGHT INTO MON MORNING AND WEAKEN INTO SOUTHEAST IL MON
AFTERNOON. ISOLATED SHOWERS/THUNDERSTORMS POSSIBLE SOUTH OF I-70
MONDAY AFTERNOON BUT BETTER FORCING WILL HAVE SHIFTED EAST OF SE IL
BY THEN INTO SE PARTS OF OH/IN AND NORTHERN KY. LOWS TONIGHT IN THE
UPPER 60S WITH GALESBURG AROUND 65F. HIGHS MON IN THE MID TO UPPER
80S BUT RANGE FROM LOWER 80S BY GALESBURG TO 90F BY LAWRENCEVILLE
WHERE AFTERNOON HEAT INDICES IN THE MID 90S. GENERALLY DRY
CONDITIONS EXPECTED MONDAY NIGHT AGAIN WITH JUST SLIGHT POPS FAR SW
CWA CLOSER TO FRONTAL BOUNDARY SOUTH OF AREA OVER NORTHERN KY INTO
CENTRAL MO.

00Z FORECAST MODELS SHOW MORE ACTIVE WEATHER PATTERN DURING MID AND
LATE WORK WEEK AS IL IS ESTABLISHED IN A WNW UPPER LEVEL FLOW
WITH LARGE UPPER LEVEL LOW OVER NE CANADA AND UPPER LEVEL RIDGE
OVER THE SOUTHERN ROCKIES. SHORT WAVES TRACKING EAST NEAR FRONTAL
BOUNDARY DURING MIDDLE OF THE WEEK WITH INCREASING CHANCES OF
SHOWERS AND THUNDERSTORMS...MAINLY SW AREAS TUE AND ACROSS AREA BY
WED AND WED NIGHT WITH LIKELY POPS OVER PARTS OF EAST CENTRAL AND
SOUTHEAST IL THEN. BEST CHANCES OF SHOWERS AND THUNDERSTORMS SHIFT
SOUTHWARD BY FRIDAY WITH MOST OF AREA DRY BY NEXT WEEKEND. HIGHS
IN THE LOW TO MID 80S TUE TO COOL INTO THE UPPER 70S/LOWER 80S
FROM WED THRU REST OF THE WEEK WHICH IS BELOW NORMAL FOR EARLY
AUGUST.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1246 PM CDT SUN AUG 2 2015

1730Z RADAR IMAGERY SHOWS ISOLATED CONVECTION IN ADVANCE OF A WEAK
SHORT-WAVE TROUGH EXTENDING FROM NEAR KAAA TO EAST OF KSPI. THIS
ACTIVITY IS TRACKING SLOWLY TO THE E/SE AND WILL IMPACT KDEC OVER
THE NEXT COUPLE OF HOURS. HAVE THEREFORE INCLUDED VCTS AT KDEC BETWEEN
18Z AND 20Z...BUT HAVE GONE WITH A DRY FORECAST THROUGHOUT THE
AFTERNOON AT THE REMAINING TERMINALS. WINDS WILL BE SOUTHWESTERLY
WITH OCCASIONAL GUSTS TO BETWEEN 15 AND 20KT. A COLD FRONT CURRENTLY
ACROSS THE NORTHERN PLAINS WILL SAG SOUTHWARD...POTENTIALLY
TRIGGERING SCATTERED CONVECTION ACROSS NORTH-CENTRAL ILLINOIS
TONIGHT. MOST 12Z MODEL GUIDANCE SUGGESTS THE FOCUS FOR THE MOST
WIDESPREAD CONVECTION WILL BE FURTHER N/NE ACROSS MICHIGAN INTO
NORTHERN INDIANA. FURTHER WEST ALONG THE APPROACHING
BOUNDARY...AREAL COVERAGE OF PRECIP WILL LIKELY BE MUCH LESS. AS A
RESULT...HAVE ONLY INCLUDED VCTS AT KPIA AND KBMI FROM MID-EVENING
THROUGH THE OVERNIGHT HOURS. THINK ANY CONVECTION WILL TEND TO
DISSIPATE AFTER MIDNIGHT DUE TO WANING INSTABILITY. COLD FRONT
WILL DROP SOUTH OF THE AREA BY MONDAY MORNING...WITH NORTHWESTERLY
WINDS DEVELOPING AT KPIA BY 10Z...THEN BY 13Z FURTHER SOUTHEAST AT
KSPI AND KDEC.


&&

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

$$

UPDATE...BARNES
SHORT TERM...AUTEN
LONG TERM...07
AVIATION...BARNES


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