Heat in Missouri, August 4, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
159 PM CDT SAT AUG 4 2012

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 137 PM CDT SAT AUG 4 2012

THE LATEST SURFACE ANALYSIS DEPICTED A WARM FRONT EXTENDING EAST
FROM A LOW CENTERED OVER SOUTH CENTRAL IA...ACROSS CENTRAL
ILLINOIS TO CENTRAL INDIANA. A COLD FRONT ARCED SOUTHWEST FROM THE
LOW ACROSS KS INTO THE OK PANHANDLE. REGIONAL RADAR LOOP DETECTED
A STRONG LINE OF THUNDERSTORMS EXTENDING FROM SDF TO NEAR BNA AND
MOVING EASTWARD. INFRA RED SATELLITE AND THE LIGHTNING DETECTION
CHART INDICATED THE LINE WAS INTENSIFYING AS TOPS COOLED AND CLOUD
TO GROUND STRIKES INCREASED IN ADDITION TO THE NEGATIVE TO
POSITIVE STRIKE RATIO.

THE AFOREMENTIONED FRONT WILL BE THE FOCUS FOR OUR NEXT ROUND OF
WEATHER WITH A SIGNIFICANT SEVERE THREAT AS WELL. THE FRONT WILL
BE MAKING ITS WAY ACROSS SEMO EARLY MORNING AND SIL LATE MORNING
REACHING INTO SWIN AND WKY IN THE AFTERNOON. THE SEVERE THREAT
EXISTS OVER MOST OF THE QUAD STATE BUT IS MOST ENHANCED OVER WEST
KY. THE MODELS HAVE BEEN HINTING AT THE FRONT HANGING UP OVER WEST
KY IN THE AFTN. IF THIS HOLDS TRUE IT WILL ALLOW THE UPPER LEVEL
SHORT WAVE TO PHASE WITH THE SURFACE FRONT PROVIDING UPPER LEVEL
SUPPORT. IN ADDITION IF DEBRIS CLOUDS HOLD OFF LONG ENOUGH FOR
SUFFICIENT HEATING...WE COULD ENCOUNTER ONE VERY ACTIVE AFTN. BOTH
THE OPERATIONAL GFS AND THE NAM INDICATE CAPES > 2K J/KG IN THE
AFTN...PWATS > 2"...AND LI'S IN THE -5 TO -6 RANGE. WILL TAPER OFF
POPS RAPIDLY AFTER SUNSET AND DRY INTO THE FIRST PART OF NEXT
WEEK. ALSO TEMPS WILL BE ON THE ORDER OF NEARLY 10 DEGREES COOLER
THAN THE PAST WEEK WITH HIGHS AROUND 90 EARLY ON AND DEW POINTS
PLUNGING FOR THIS TIME OF SEASON ESPECIALLY YIELDING MIN RH VALUES
INTO THE LOWER 30S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 137 PM CDT SAT AUG 4 2012

AT THE START OF THE LONG TERM PORTION OF THE FORECAST...WE ARE IN
THE MIDST OF ENJOYING A RELATIVE COOL-DOWN...AT LEAST IN COMPARISION
TO THE EXTREME HEAT/HUMIDITY WE'VE HAD FOR MUCH OF THE SUMMER. TEMPS
WILL BE CLOSER TO SEASONAL NORMS AND HUMIDITY LEVELS WILL ACTUALLY
BE SLIGHTLY DRIER/MAKING FOR A MORE PLEASANT AIRMASS. THIS WILL BE
THE CASE FOR TUE-WED.

THEN DURING THE LATTER PORTION OF THE WEEK...THE NEXT WEATHER SYSTEM
TAKES SHAPE AND WE BECOME WARM SECTORED AHEAD OF IT. THIS MEANS
INCREASED HEAT/HUMIDITY FOR THE WED NIGHT-THU NITE TIME FRAME. THIS WILL
BE COINCIDENT...HOWEVER...WITH INCREASING PCPN CHANCES AS A
DEVELOPING LOW PRESSURE SYSTEM DRIVES A FRONT THRU THE AREA. BOTH
THE GFS/ECMWF SUGGEST FROPA SOMETIME THU NIGHT...WITH A POST FRONTAL
AIRMASS FILTERIN IN FOR FRIDAY. THE GFS IS A LITTLE SHARPER/HIGHER
AMPLITUDE WITH THE FLOW/SYSTEM PASSAGE...THE ECMWF A LITTLE MORE
MUTED...BUT SIMILAR TIMING NONETHLESS.

LOOK FOR A POTENTIAL FOR LINGERING SMALL POPS FRIDAY...THEN A RETURN
TO DRIER/SEASONALLY COOLER (CLOSER TO CLIMO) CONDITIONS AGAIN IN THE
POST FRONTAL ENVIRONS FRI NITE-SAT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 137 PM CDT SAT AUG 4 2012

CONVECTIVE LINE DURING HEAT OF DAY MAY IMPACT OWB...WITH SCT SHOWERS
NEAR EVV...OTHERWISE A LULL IN ACTIVITY TIL THE FRONTAL INTRODUCTION
TONIGHT. GENERALLY VFR CONDITIONS XCP IN STORMS...THEN LATE
TONIGHT-EARLY TOMORROW COLD FRONTAL INTRODUCTION MEANS INCREASING
STORM CHANCES WITH MVFR CIGS/POTENTIAL FOR IFR VSBYS ENTERS THE
FORECAST WINDOW. FRONT SHOULD CLEAR WEST-TO-EAST BY 18Z TOMORROW BUT
MAY BE HANGING UP AS IT TRIES TO CLEAR SO LOW VFR-MVFR CONDITIONS
CAN BE EXPECTED THRU THE BULK OF THE PLANNING PERIOD.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&

SHORT TERM...KH
LONG TERM....DH
AVIATION...DH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PADUCAH KY
100 PM CDT SAT AUG 4 2012

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-051000-
JEFFERSON-WAYNE IL-EDWARDS-WABASH-PERRY IL-FRANKLIN-HAMILTON-
WHITE-JACKSON-WILLIAMSON-SALINE-GALLATIN-UNION IL-JOHNSON-POPE-
HARDIN-ALEXANDER-PULASKI-MASSAC-GIBSON-PIKE-POSEY-VANDERBURGH-
WARRICK-SPENCER-FULTON-HICKMAN-CARLISLE-BALLARD-MCCRACKEN-GRAVES-
LIVINGSTON-MARSHALL-CALLOWAY-CRITTENDEN-LYON-TRIGG-CALDWELL-
UNION KY-WEBSTER-HOPKINS-CHRISTIAN-HENDERSON-DAVIESS-MCLEAN-
MUHLENBERG-TODD-PERRY MO-BOLLINGER-CAPE GIRARDEAU-WAYNE MO-CARTER-
RIPLEY-BUTLER-STODDARD-SCOTT-MISSISSIPPI-NEW MADRID-
100 PM CDT SAT AUG 4 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHERN
ILLINOIS...SOUTHWEST INDIANA...WESTERN KENTUCKY AND SOUTHEAST
MISSOURI.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED THUNDERSTORMS WILL BE POSSIBLE TODAY AND TONIGHT. ISOLATED
SEVERE STORMS CANNOT BE RULED OUT. LARGE HAIL AND DAMAGING WINDS
WILL BE THE PRIMARY CONCERNS...ALONG WITH LOCALLY HEAVY RAINFALL.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THUNDERSTORM CHANCES WILL INCREASE THROUGH DAY SUNDAY...OVER WESTERN
KENTUCKY...SOUTHWEST INDIANA...SOUTHEAST MISSOURI AND SOUTHERN
ILLINOIS. IN FACT...MOST OF THE AREA HAS BEEN OUTLOOKED BY THE STORM
PREDICTION CENTER WITH A SLIGHT RISK OF SEVERE STORMS. LARGE HAIL
AND DAMAGING WINDS WILL BE THE PRIMARY CONCERNS ALONG WITH LOCALLY
HEAVY RAINFALL.

FOR NEXT FRIDAY AFTERNOON AND EVENING...HEAT INDEX VALUES BETWEEN
100 AND 105 DEGREES ARE FORECAST FOR SOUTHERN ILLINOIS AND THE
PURCHASE AREA OF WEST KENTUCKY. HEAT INDEX VALUES BETWEEN 105 TO 115
DEGREES WILL BE POSSIBLE OVER SOUTHEAST MISSOURI.

IN ADDITION...A FEW STORMS MAY APPROACH SEVERE LIMITS WITH ANY
STORMS THAT DEVELOP LATE FRIDAY AFTERNOON AND EVENING. AT THIS
TIME...THE PRIMARY HAZARD WOULD BE DAMAGING WINDS...WITH HAIL A
SECONDARY HAZARD.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE MOST LIKELY ON SUNDAY...BUT CANNOT BE
RULED OUT THIS AFTERNOON...TONIGHT AND AGAIN NEXT FRIDAY.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PADUCAH KY
1219 PM CDT SAT AUG 4 2012

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-042030-
JEFFERSON-WAYNE IL-EDWARDS-WABASH-PERRY IL-FRANKLIN-HAMILTON-
WHITE-JACKSON-WILLIAMSON-SALINE-GALLATIN-UNION IL-JOHNSON-POPE-
HARDIN-ALEXANDER-PULASKI-MASSAC-GIBSON-PIKE-POSEY-VANDERBURGH-
WARRICK-SPENCER-FULTON-HICKMAN-CARLISLE-BALLARD-MCCRACKEN-GRAVES-
LIVINGSTON-MARSHALL-CALLOWAY-CRITTENDEN-LYON-TRIGG-CALDWELL-
UNION KY-WEBSTER-HOPKINS-CHRISTIAN-HENDERSON-DAVIESS-MCLEAN-
MUHLENBERG-TODD-PERRY MO-BOLLINGER-CAPE GIRARDEAU-WAYNE MO-CARTER-
RIPLEY-BUTLER-STODDARD-SCOTT-MISSISSIPPI-NEW MADRID-
INCLUDING THE CITIES OF...MOUNT VERNON...FAIRFIELD...ALBION...
MOUNT CARMEL...PINCKNEYVILLE...WEST FRANKFORT...MCLEANSBORO...
CARMI...CARBONDALE...HERRIN...HARRISBURG...SHAWNEETOWN...
JONESBORO...VIENNA...GOLCONDA...ELIZABETHTOWN...CAIRO...
MOUND CITY...METROPOLIS...FORT BRANCH...PETERSBURG...POSEYVILLE...
EVANSVILLE...BOONVILLE...ROCKPORT...HICKMAN...CLINTON...
BARDWELL...WICKLIFFE...PADUCAH...MAYFIELD...SMITHLAND...BENTON...
MURRAY...MARION...EDDYVILLE...CADIZ...PRINCETON...MORGANFIELD...
DIXON...MADISONVILLE...HOPKINSVILLE...HENDERSON...OWENSBORO...
CALHOUN...GREENVILLE...ELKTON...PERRYVILLE...MARBLE HILL...
CAPE GIRARDEAU...PIEDMONT...VAN BUREN...DONIPHAN...POPLAR BLUFF...
BLOOMFIELD...SIKESTON...CHARLESTON...NEW MADRID
1219 PM CDT SAT AUG 4 2012

...HEAT INDEX POSSIBILITIES...

ABUNDANT CLOUD COVER...SCATTERED SHOWERS...AND ISOLATED
THUNDERSTORMS HAVE KEPT TEMPERATURES BELOW EXPECTED LEVELS TODAY
AND HAVE RESULTED IN CURRENT AND EXPECTED HEAT INDEX VALUES BELOW
ADVISORY CRITERIA. THEREFORE THE HEAT ADVISORY THAT WAS IN EFFECT
HAS BEEN CANCELLED.

HOWEVER...EVEN THOUGH CLOUDS AND PRECIPITATION HAVE KEPT HEAT INDEX
VALUES BELOW ADVISORY CRITERIA TODAY...ANY LOCATIONS THAT BREAK
OUT OF THE CLOUDS WILL INCREASE THE HEAT INDEX TO UNCOMFORTABLE
LEVELS...EVEN IF JUST SHY OF HEAT ADVISORY CRITERIA. IT IS STILL A
GOOD IDEA TO STAY GUARDED ABOUT THE HEAT...TAKE FREQUENT
BREAKS...AND DRINK PLENTY OF WATER...IF YOU MUST BE OUTSIDE FOR AN
EXTENDED PERIOD OF TIME.

THE HEAT ADVISORY CRITERIA THRESHOLD IS A 105 HEAT INDEX.