Area Forecast Discussion
Issued by NWS Central Illinois

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KILX 160202
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
902 PM CDT WED APR 15 2015

.UPDATE...
ISSUED AT 902 PM CDT WED APR 15 2015

SHORTWAVE TROUGH LIFTING THROUGH SOUTHEAST IL THIS EVENING
BRINGING A FEW SHOWERS TO AREAS SOUTHEAST OF I-72, AND A STEADY
EASTERLY BREEZE. CLOUD COVER AND INCREASING MOISTURE WITH THIS
SYSTEM WILL KEEP TEMPERATURES MILD ACROSS CENTRAL IL TONIGHT,
ESPECIALLY IN THE SOUTHEAST. TEMPERATURES PRIMARILY IN THE UPPER
40S TO MID 50S LOOK REASONABLE. CURRENT FORECASTS ARE GENERALLY ON
TRACK WITH THESE FEATURES, AND ONLY UPDATES WILL BE MINOR
TEMPERATURE ADJUSTMENTS FOR RECENT TRENDS AT THIS TIME.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 229 PM CDT WED APR 15 2015

DEEP UPPER CUT-OFF ACROSS GREAT BASIN IS FORCING A VERY MERIDONAL
PATTERN ACROSS NORTH AMERICA.  A WAVE ROTATING AROUND THE EAST SIDE
OF THE LOW IS PRODUCING SHOWERS AND CLOUDINESS ACROSS THE LOWER
MISSOURI VALLEY. WITH MUCH OF THE WAVES ENERGY WEAKENING AS IT
ENCOUNTERS THE EASTERN U.S. RIDGE AND THE VERY DRY AIR IN PLACE OVER
ILLINOIS PROGRESS INTO THE FORECAST AREA IS SLOW. A SERIES OF
SOUTHERN STREAM JET MAX MOVING ACROSS SOUTHERN TEXAS AND INTO THE
SOUTHEAST U.S. MAY BE ABLE TO PROVIDE ADDITIONAL FORCING AND
MOISTURE TO INTERACT WITH THE NORTHERN STREAM WAVE TO PRODUCE
ABUNDANT CLOUD COVER BUT ONLY LIGHT PRECIP TONIGHT.  THE BEST
CHANCES SHOULD BE ACROSS THE SOUTH AND EAST WHERE THE INTERACTION
BETWEEN THESE TWO FEATURES WILL BE THE MOST PRONOUNCED.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 229 PM CDT WED APR 15 2015

LATEST MODELS SUGGEST SHORT-WAVE RIDGING DEVELOPING OVER ILLINOIS
THURSDAY NIGHT AS THE CUT-OFF LOW OVER WESTERN NORTH AMERICA BEGINS
TO LIFT AND BE ABSORBED BY A STRONG NORTHERN STREAM SYSTEM CURRENTLY
IN THE NORTHEAST PACIFIC. THIS SHOULD KEEP PRECIP MAINLY TO WEST OF
THE FORECAST AREA THROUGH SATURDAY MORNING.  BOTH 12Z ECMWF AND GFS
ARE STRONGER WITH THE SURFACE REFLECTION OF THE SYSTEM SATURDAY
NIGHT AND SUNDAY THEN THEIR PREVIOUS RUNS AND THE LATEST CANADIAN.
WILL INTRODUCE THUNDER INTO SUNDAY AS GFS FORECASTED CAPE REACHES
INTO THE SEVERAL HUNDRED RANGE WITH SOME MID-LEVEL COOLING AND
DRYING EVIDENT IN BUFR SOUNDINGS COMBINED WITH THE PASSAGE OF
THE MAIN SURFACE COLD FRONT.

BY SUNDAY NIGHT AND MONDAY THERE BEGINS TO BE SOME SPREAD ON HOW
FAST THE PRECIP PULLS EAST OF THE AREA.  GIVEN THE STRENGTH OF THE
TROUGH AM FAVORING ECMWF AND ITS SLOWER EVOLUTION.  THIS WILL KEEP
PRECIP CHANCES IN PLACE FOR MONDAY.  STRONG NVA AFTER MONDAY NIGHT
SHOULD PROVIDE SOME CLEARING, BUT WITH MID-LEVEL TEMPS IN THE -20 TO
-30C RANGE DAY TIME DIURNAL CLOUDINESS AND POSSIBLY SOME RW- BY
WEDNESDAY WILL BE POSSIBLE DUE TO STEEP LAPSE RATES.

WITH SHORT-WAVE RIDGING AND RESULTANT HEIGHT RISES EXPECT TEMPS TO
CLIMB WELL ABOVE SEASONAL NORMALS NEXT FEW DAYS WITH AFTERNOON TEMPS
MOSTLY IN THE 70S THROUGH SATURDAY. MORE SEASONAL TEMPERATURES ARE
EXPECTED ON SUNDAY WITH TEMPERATURES 5-10 DEGREES BELOW NORMAL FOR
THE FIRST PART OF THE WORK WEEK.  WILL NEED TO KEEP AN EYE ON LOW
TEMPERATURE FORECASTS AND THE POTENTIAL FOR FROST DURING THIS PERIOD
AS CURRENT PROGS SUGGEST SOME 30S POSSIBLE MAINLY ALONG AND NORTH OF
I-74 AND RELATIVELY LIGHT WINDS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 712 PM CDT WED APR 15 2015

MAINLY VFR CONDITIONS UNTIL 04Z-08Z THEN LOWERING CEILINGS INTO
MVFR CATEGORY AS A SHORTWAVE TROUGH LIFTS NORTHEASTWARD ACROSS
SOUTHEAST ILLINOIS. ISOLATED TO SCATTERED SHOWER ACTIVITY
INCREASING THIS EVENING AS THE SHORTWAVE APPROACHES, WITH MOST
SHOWER ACTIVITY EXPECTED TO BE LIGHT AND NOT PRODUCE ANY MVFR
CIGS/VSBYS UNTIL LATER IN THE EVENING. TOWARD MORNING, COULD SEE
SOME LIGHT FOG PRODUCING MVFR VSBY OR LOCAL IFR VSBY. IMPROVING
CONDITIONS DURING AFTERNOON THURSDAY AS SHORTWAVE TROUGH MOVES
EAST AND RIDGING MOVES IN FROM THE WEST. LOWEST FLIGHT
CATEGORIES/HIGHEST CHANCES FOR PRECIPITATION EXPECTED KSPI-KCMI
SOUTHWARD WHERE INFLUENCE OF SHORTWAVE AND ASSOCIATED MOISTURE
WILL BE GREATEST.


&&

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

$$

UPDATE...ONTON
SHORT TERM...BARKER
LONG TERM...BARKER
AVIATION...ONTON


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.