Severe Thunderstorm Warning 25, NWS Lincoln, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
200 PM CDT SUN APR 16 2000

ETA FAVORED MODEL THIS RUN...THOUGH JUST SLIGHTLY SLOWLY THAN
AVN/NGM AS SYSTEM IS OCCLUDING AS INITIALLY NEGATIVE TILT BUT
BECOMING VERTICALLY STACKED WITH CUTOFF UPPER LEVEL LOW. ALL MODELS
TAKING A BIT FURTHER S COURSE WITH SFC/UPPER LEVEL LOW FROM
SOUTHCENTRAL IA AND TURNING IT SE INTO NE CWA BY MIDNIGHT...S OH MON
AFTN AND TOWARD THE SE ATLANTIC COAST 12Z/TUE. FORECAST CHALLENGE
WILL BE ADDRESSING CHANCE OF SHOWERS AND THUNDERSTORMS TONIGHT AND
ISOLATED SEVERE RISK EARLY. THEN TEMPS AS FAN/FWC ABOUT 5-10 DEGREES
DIFFERENT WITH A BRIEF COOL DOWN MON...THEN BIG MID WEEK WARM UP
WITH UPPER LEVEL RIDGE BUILDING IN CENTRAL/EASTERN PLAINS AHEAD OF
THE NEXT STORM SYSTEM ARRIVING LATE WED/THU.

DIURNALLY INDUCED LINE OF THUNDERSTORMS DEVELOPING ACROSS EAST MO AHEAD
OF A COLD FRONT EXTENDING S FROM A LOW IN SOUTHCENTRAL IA THROUGH
KCOU/CENTRAL MO. ATMOSPHERE MORE UNSTABLE ACROSS E HALF OF MO AND SW
IL WHERE MORE SUNSHINE PEAKED THROUGH CUMULUS FIELD. TEMPS WARMING
TO 70 AND DEWPOINTS IN THE UPPER 50S/60 WITH LIFTED INDICES OF MINUS
3-6C WHILE SBCAPES 1000 J/KG OR LESS. THIS FRONT TO SLIDE E ACROSS
CWA BETWEEN 00-06Z WITH ISOLATED SEVERE THUNDERSTORMS POSSIBLE UNTIL
SUNSET/01Z WITH SMALL-MARGINAL SEVERE HAIL AND GUSTY WINDS. WINDS
UNIDIRECTIONAL WITH HEIGHT SO TORNADOES NOT EXPECTED. WILL HAVE AN
EVENING PERIOD WITH LIKELY CHANCE OF SHOWERS/THUNDERSTORMS WHILE A
CHANCE OF SHOWERS OVERNIGHT.

CYCLONIC FLOW CONTINUES MON AS SFC TROUGH EXTENDS NW INTO IL WITH
AMPLE LOW LEVEL MOISTURE. WILL BE A LOW OVC DAY WITH A FEW SHOWERS
POSSIBLE AS COOL POOL ALOFT MOVES IN. WILL LEAN CLOSER TO COOLER FAN
HIGHS MON WITH EXTENSIVE CLOUDS AND BREEZY NNW FLOW...FWC NEARLY 10
DEGREES WARMER THAN FAN. CLOUDS TO BREAK UP BY LATE DAY W CWA AS
HIGH PRESSURE RIDGE/DRYER AIR APPROCHES WITH CLEARING ACROSS CWA MON
NIGHT AND NNW WINDS DIMINISHING LIGHT. WILL INTRODUCE PATCHY LATE
NIGHT FOG MON NIGHT. AGREE WITH SIMILAR NOS IN THE LOW-MID 40S.

NICE WARM UP TUE AS H85 TEMPS 4-7C MON ELEVATE TO 12-15C PER AVN BY
00Z/WED WITH S FLOW BEING ESTABLISHED AS SFC RIDGE RETREATS TO THE
EAST. STRONG UPPER LEVEL RIDGE BUILDING INTO IL AND TO KEEP SKIES
MOSTLY SUNNY AND LEANING WITH WARMER FWC HIGHS.

MEDIUM RANGE MODELS DIFFER WITH SOLUTION OF STORM SYSTEM OFF THE N
CA COAST WITH NCEP PREFERING FURTHER S POSITION OF SFC LOW
DEVELOPMENT IN THE CENTRAL ROCKIES AND TAKING SFC LOW TO IA BY 12Z
THU AND AREAS S OF I-80 IN WARM SECTOR. TAIL END OF AVN PAINTS QPF
NW OF I-55 ALREADY BY 12Z/WED WITH VORT MAX SUDDENLY APPEARING IN N
IL. LIKE CURRENT WORDING OF LATE DAY CHANCE OF CONVECTION WED WITH
ANY EARLIER CHANCE CONFINED ALONG AND N OF WARM FRONT IN N IL.
SHOWERS/THUNDERSTORMS LIKELY WED NIGHT/THU AS COLD FRONT SWINGS E OF
IL BY SUNSET/THU. FRI LOOKS DRY WITH PARTLY SUNNY SKIES DEVELOPING
AS ANOTHER HIGH PRESSURE NOSES IN WITH A COOLDOWN BACK IN THE 60S.

...PRELIMINARY CCF FOR COORDINATION ONLY...

SPI CA 045/060 044/073 053 07630
PIA CA 045/056 042/071 052 07730
DEC CA 047/059 043/071 051 07730
CMI CB 048/059 041/068 048 07740
MTO CB 050/061 043/070 049 07730
LWV CB 052/063 045/073 051 07740

.ILX...
IL...NONE.

HUETTL