Severe Thunderstorm Warning 146, NWS Lincoln, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
213 PM CDT SUN JUL 21 2002

PLENTY OF CONCERNS WITH FOCUS ON CURRENT HEAT ADVISORY AND POSSIBLE
SEVERE THUNDERSTORMS ON MONDAY.

LATEST 17Z SURFACE ANALYSIS PLACES SURFACE LOW PRESSURES ACROSS
NORTHERN GREAT LAKES REGION AND ANOTHER ACROSS WESTERN PLAINS
STATES. A SURFACE COLD FRONT WAS ACROSS UPPER MIDWEST SOUTHWEST TO
NORTH CENTRAL PLAINS STATES.  A BOUNDARY WAS ASSOCIATED WITH LINE OF
CONVECTION ACROSS SOUTHERN LOWER MICHIGAN. LATEST 1745Z IR SATELLITE
IMAGE PLACES PLENTY OF CLOUDS ACROSS MICHIGAN...AND ACROSS NORTHERN
PLAINS STATES ALONG THE COLD FRONT. SOME CU CLOUDS WERE ACROSS
ILLINOIS. LATEST 1745Z W/V IMAGE PLACES S/W ACROSS UPPER
MICHIGAN...OTHER SW/S WERE ACROSS NORTHERN MINNESOTA SOUTHWEST INTO
SOUTH DAKOTA AND SOUTHWEST INTO MOUNTAIN WEST.  LATEST 1830Z KILX
RADAR INDICATES ISOLATED THUNDERSTORMS JUST SOUTH OF ILX EAST TO
NORTH OF DEC. LATEST 1820 KDVN RADAR INDICATES NO PRECIPITATION.

MODELS DEMONSTRATING SEVERAL DIFFERENCES ON FEATURES AND HANDLING
SW/S. CONTINUE TO PREFER MAINLY AN ETA OVERALL SOLUTION.

ETA MODEL MOVES H50 RIDGE ACROSS THE REGION BUILDING BACK ACROSS THE
WESTERN U.S BY 00Z WED.  A H50 TROUGH IS ACROSS GREAT LAKES/MID MS
VALLEY BY 06Z TUE-12Z TUE THEN SHIFTS EAST INTO OHIO VALLEY.  MODELS
DIFFER ON TIMING OF COLD FRONT AND PREFER MAINLY THE SLOWER ETA
SOLUTION. COLD FRONT MOVES EAST FROM UPPER MIDWEST AND NORTHERN
PLAINS STATES INTO NORTHERN GREAT LAKES REGION SOUTHWEST INTO
CENTRAL PLAINS STATES BY 12Z MON.  THE COLD FRONT IS EXPECTED TO BE
ACROSS FAR NORTHWEST CWA BY 18Z MON AND MOVE SOUTHEAST ACROSS CWA ON
MONDAY AND EXPECTED TO BE ACROSS SOUTHEAST CWA BY 06Z TUE. ETA MOVES
SURFACE LOW ACROSS SOUTHERN CANADA/ FAR NORTHEAST U.S. AND WITH A
WAVE ACROSS SOUTHEAST MISSOURI BY 00Z TUE.  SURFACE HIGH PRESSURE
BUILDS ACROSS SOUTHERN CANADA/NORTHERN PLAINS STATES BY 00Z TUE.
THIS HIGH PRESSURE STRENGTHENS AND MOVES SOUTHEAST ACROSS UPPER
MIDWEST AND EASTERN NORTHERN PLAINS STATES BY 12Z TUE.  IT CONTINUES
EAST ACROSS GREAT LAKES REGION AND UPPER MIDWEST BY 00Z WED.  850MB
TEMPERATURES PLACE +20C TO +23C ACROSS CWA BY 12Z MON...+19C TO +22C
ACROSS CWA BY 00Z TUE...+16C TO +18C 850MB TEMPS BY 12Z TUE...+15C
TO +16C 850 TEMPS BY 00Z WED.  LATEST ETA 310K ISENTROPIC SURFACE
INDICATES SOME COND PRES DEF AND ISENTROPIC LIFT ACROSS CWA BY 12Z
MON-00Z TUE.  ETA 310K ISENTROPIC SURFACE ALSO INDICATING SOME
DECENT COND PRES DEF ACROSS EAST CENTRAL AND SOUTHEAST ILLINOIS BY
06Z TUE.  T/H CROSS SECTIONS PROVIDE HIGH RELATIVE HUMIDITY AT ALL
LEVELS BY 03Z TUE-09Z TUE...THEN MAINTAINS FAIRLY HIGH RH AT LOWER
LEVELS THROUGH 21Z TUE. LATEST MODEL SOUNDINGS INDICATE SOME DECENT
LAPSE RATES...HIGH INSTABILITY LI/S AROUND -10 WITH PW/S OVER 2.0
INCHES AND CAPES 4000-5000 J/KG BY 18Z MON-06Z TUE.  AGREE WITH SPC
DAY 2 OUTLOOK AS SEVERE STORMS ARE POSSIBLE MONDAY AFTERNOON INTO
MONDAY NIGHT AS COLD FRONT MOVES THROUGH CWA. WITH COLD FRONT NOT
REACHING SOUTHEAST CWA UNTIL EARLY EVENING...ELECTING TO GO WITH
HEAT ADVISORY CONTINUING PARTS OF CENTRAL AND SOUTHEAST CWA TONIGHT
INTO MONDAY.

EXTENDED...LOOKS ON TRACK AND WILL ADD CHANCE OF THUNDERSTORMS ON
SUNDAY.

TEMPERATURES HAVING DIFFERENCES AND WILL LEAN ON WARMER TEMPERATURES.

THANKS FOR COORDINATION ON HEAT ADVISORY CHI...PAH...IND...LSX...AND
DVN.

...PRELIMINARY CCF FOR COORDINATION PURPOSES...

SPI BB 077/092 067/082 062 13244
PIA BB 077/090 066/081 061 13243
DEC BB 076/093 067/082 062 13244
CMI BB 075/093 065/081 061 13246
MTO BB 076/094 068/083 063 13246
LWV BB 077/095 070/085 064 13246

.ILX...HEAT ADVISORY THIS EVENING NORTHWEST CWA.
.ILX...HEAT ADVISORY TONIGHT AND MONDAY MAINLY NEAR A SPI-CMI LINE
AND SOUTHEAST.

EH

ILZ027>031-036>038-040>057-061>063-066>068-071>073-211700-

HAZARDOUS WEATHER OUTLOOK FOR CENTRAL ILLINOIS
NATIONAL WEATHER SERVICE LINCOLN IL
1100 AM CDT SUN JUL 21 2002

...A HEAT ADVISORY IS IN EFFECT THROUGH THIS EVENING...

A DANGEROUS COMBINATION OF HEAT AND HUMIDITY CAN BE EXPECTED
THROUGH THIS EVENING. TEMPERATURES RISING INTO THE MIDDLE 90S TODAY
WILL COMBINE WITH HIGH HUMIDITY TO PRODUCE HEAT INDEX VALUES OF 105
TO 110. THE HUMID CONDITIONS WILL BEGIN TO IMPROVE THIS EVENING AS
THE TEMPERATURE BEGINS TO FALL AROUND SUNSET.

IF YOU MUST BE OUTSIDE TODAY...TAKE FREQUENT BREAKS...DRINK PLENTY
OF WATER AND WEAR LIGHT COLORED CLOTHING. MAKE SURE OUTDOOR PETS
HAVE FRESH WATER AND A SHADY SPOT TO REST. IF YOU DO NOT HAVE AIR
CONDITIONING...CONSIDER GOING TO THE MALL OR TAKE IN A MOVIE.
CHILDREN AND THE ELDERLY ARE ESPECIALLY VULNERABLE TO THE EFFECTS OF
EXTREME HEAT.