Alert archive / Illinois / Special Weather Statements in 2012

Special Weather Statement, NWS Lincoln, IL

May 20, 2012Sangamon County, Illinois

NWS Lincoln, IL issued this special weather statement at May 20, 2012, 4:54 PM CDT for Sangamon County, Illinois. It was in force for 51 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 20, 2012, 4:54 PM CDT (21:54 UTC)
Expired
May 20, 2012, 5:45 PM CDT
In force
51 min
Issued by
NWS Lincoln, IL

County Sangamon County, IL

The radar

The Lincoln radar (KILX), 40 km from the middle of the area, began a volume at 21:53 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 9.9 hours before the alert went out and 97 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2012-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 616 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2012-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -67 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
616 J/kg
Mixed-layer CIN
-119 J/kg
Mixed-layer LCL
1773 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-67 m²/s²
0-3 km storm-relative helicity
-55 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Lincoln, IL wrote its last area forecast discussion before this special weather statement went out at May 20, 2:35 PM CDT, 2 hours 19 minutes earlier.

Area forecast discussion, May 20, 2:35 PM CDT, 2 hours 19 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
235 PM CDT SUN MAY 20 2012

.DISCUSSION...
ISSUED 235 PM CDT SUN MAY 20 2012

LATEST SURFACE ANALYSIS HAD AN AREA OF LOW PRESSURE CENTERED OVER
NORTH CENTRAL WISCONSIN/EXTREME WESTERN UPPER MICHIGAN...WITH AN
ASSOCIATED COLD FRONT EXTENDING SOUTH SOUTHWEST THROUGH IOWA AND
MISSOURI INTO THE SOUTHERN PLAINS. THE PASSAGE OF THIS COLD FRONT
TONIGHT SHOULD BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE
FORECAST AREA TONIGHT...VERY POSSIBLY THE ONLY RAINFALL FOR AT
LEAST THE NEXT WEEK. ASIDE FROM PRECIPITATION CHANCES/TIMING
TONIGHT...PRIMARY FORECAST CONCERN TODAY IN THIS RATHER QUIET
WEATHER PERIOD REVOLVES AROUND TEMPERATURES.

12Z MODELS IN REASONABLE AGREEMENT OVER THE NEXT FEW DAYS IN THE
PREDOMINANTLY BENIGN WEATHER PERIOD EXPECTED. HOWEVER...
MODEL/ENSEMBLE SPREAD INCREASES SIGNIFICANTLY BY THE END OF THE
WEEK...AND RUN-TO-RUN CONSISTENCY HAS BEEN POOR. THE DISAGREEMENT
LOCALLY REVOLVES AROUND HOW STRONG THE EASTERN U.S. RIDGE WILL BE
AND IF A STRONG ENOUGH IMPULSE FLATTENS TO THE TOP OF THE RIDGE TO
DROP A FRONTAL BOUNDARY INTO THE FORECAST AREA. FOR NOW...
PRIMARILY TO MINIMIZE FORECAST FLIP-FLOP...HAVE LEANED TOWARD THE
STRONGER RIDGE/DRIER SOLUTION OF THE ECMWF. HOWEVER...EVEN THE
ECMWF IS LITTLE WEAKER WITH THE RIDGE FOR FRIDAY/SATURDAY THAN IT
HAS BEEN. SO...THE LATE WEEK FORECAST IS CERTAINLY SUBJECT TO
CHANGE.

SHORT TERM...TONIGHT THROUGH WEDNESDAY...THE UPSTREAM COLD FRONT
WILL CLEAR THE FORECAST AREA TONIGHT. MUCH AS ANTICIPATED THE PAST
FEW DAYS...PRE FRONTAL SURFACE BASED CAPE VALUES HAVE CLIMBED INTO
THE 1500-2000 J/KG RANGE...BUT DEEP LAYER SHEAR IS ONLY ON THE
ORDER OF 25 KTS. THE CONVERGENCE ALONG THE COLD FRONT IS ALSO
RATHER WEAK. FOR THESE REASONS...STILL DO NOT EXPECT ORGANIZED
SEVERE WEATHER. HOWEVER...A FEW PULSE SEVERE STORMS WITH DAMAGING
WINDS AND LARGE HAIL CAN NOT BE RULED OUT GIVEN THE INSTABILITY
AND VERY STEEP LOW LEVEL LAPSE RATES. THE MOST INTENSE STORMS
SHOULD FADE BY EARLY EVENING AS DIURNAL INSTABILITY WANES.

MUCH COOLER...BUT CLOSER TO NORMAL...TEMPERATURES ARE ANTICIPATED
IN THE WAKE OF THE COLD FRONT FOR TOMORROW. THIS COOL DOWN WILL BE
SHORT LIVE HOWEVER AS AN AREA OF HIGH PRESSURE MOVES ACROSS THE
AREA AND SOUTHERLY FLOW RETURNS BY TUESDAY NIGHT. THIS WILL RESULT
IN WARMING...BUT STILL QUIET WEATHER FOR THE REST OF THE PERIOD.

LONG TERM...THURSDAY THROUGH SUNDAY...SOUTHERLY LOW LEVEL FLOW AND
BUILDING UPPER HEIGHTS SUPPORT MOSTLY QUIET AND INCREASINGLY WARM
WEATHER THROUGH THE EXTENDED RANGE OF THE FORECAST. AS MENTIONED
IN THE MODEL DISCUSSION ABOVE...STILL NEED TO KEEP AN EYE ON HOW
FAR SOUTH A MOSTLY EAST/WEST ORIENTED FRONTAL BOUNDARY TO OUR
NORTH WILL SINK AS DISTURBANCES TOP THE RIDGE. IF MODELS TREND ANY
FURTHER SOUTH WITH THE FRONT...WE WILL NEED TO INTRODUCE POPS TO
AT LEAST NORTHERN SECTIONS OF THE FORECAST AREA AND CUT
TEMPERATURES A BIT.

BAK
&&

.AVIATION...
ISSUED 1245 PM CDT SUN MAY 20 2012
GREAT AMOUNT OF MODEL VARIANCE IN THE FACE OF BLOSSOMING CU FIELD
OVER ILX TERMINALS. SWRLY WINDS BECOMING BLUSTERY...WITH GUSTS
25-30KTS. SOME MINOR RETURNS POPPING UP ON RADAR...BUT WIDESPREAD
EFFECTIVE CONVECTION HOLDING A BIT. PLENTY OF INSTABILITY OUT
THERE...BUT LIMITED MOISTURE. STILL CONCERNED ABOUT EXTENT OF
AFTERNOON CONVECTION...BUT WANT MORE THAN VCTS IN THE TAFS. HAVE
PLACED TEMPOS FOR BEST CHANCES OF TS IN PIA AND BMI...AND RA FOR
SPI AND CMI. WILL LIKELY BE A LAST MINUTE CALL WITH SCT TS THIS
EVENING. BEHIND THE FRONT...NWRLY WINDS AND THEN A QUESTION OF HOW
QUICKLY THE MVFR CIGS CONTINUE. ONCE AGAIN...LIMITED MOISTURE IS A
CONCERN...WITH MAJORITY OF MVFR CIGS MOVING WELL NORTH...CLOSER TO
THE LOW.

HJS
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
Hazardous weather outlook, May 20, 3:09 PM CDT, 1 hour 45 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LINCOLN IL
309 PM CDT SUN MAY 20 2012

ILZ027>031-036>038-040>042-047-048-211100-
CASS-FULTON-KNOX-LOGAN-MARSHALL-MASON-MCLEAN-MENARD-PEORIA-
SCHUYLER-STARK-TAZEWELL-WOODFORD-
309 PM CDT SUN MAY 20 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
ILLINOIS.

.DAY ONE...TONIGHT

A COLD FRONT APPROACHING FROM THE WEST WILL BRING SCATTERED
THUNDERSTORMS TO PARTS OF CENTRAL ILLINOIS THIS AFTERNOON INTO
EARLY THIS EVENING. THERE IS A SLIGHT RISK THAT A FEW OF THE
THUNDERSTORMS FROM MID AFTERNOON THROUGH EARLY THIS EVENING MAY
BECOME SEVERE...CONTAINING GUSTY WINDS AND LARGE HAIL BEFORE THE
STORMS WEAKEN AFTER SUNSET.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED FROM MID AFTERNOON THROUGH EARLY
THIS EVENING. THE PRIMARY TIME FRAME FOR THUNDERSTORMS AND POSSIBLE
SPOTTER ACTIVATION TODAY WOULD BE FROM 300 PM UNTIL 700 PM THIS
EVENING.

ILZ043>046-049>057-061>063-066>068-071>073-211100-
CHAMPAIGN-CHRISTIAN-CLARK-CLAY-COLES-CRAWFORD-CUMBERLAND-DE WITT-
DOUGLAS-EDGAR-EFFINGHAM-JASPER-LAWRENCE-MACON-MORGAN-MOULTRIE-
PIATT-RICHLAND-SANGAMON-SCOTT-SHELBY-VERMILION-
309 PM CDT SUN MAY 20 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
ILLINOIS...EAST CENTRAL ILLINOIS AND SOUTHEAST ILLINOIS.

.DAY ONE...TONIGHT

A COLD FRONT APPROACHING FROM THE WEST LATE TODAY WILL BRING SCATTERED
THUNDERSTORMS TO PARTS OF CENTRAL ILLINOIS THIS AFTERNOON INTO EARLY
THIS EVENING. ALTHOUGH NO ORGANIZED SEVERE WEATHER IS ANTICIPATED
AT THIS TIME...A FEW OF THE THUNDERSTORMS FROM LATE THIS AFTERNOON
THROUGH THIS EVENING MAY CONTAIN GUSTY WINDS AND HAIL BEFORE THE
STORMS WEAKEN AFTER SUNSET.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT.

HJS

In the hours before

Local storm report, May 20, 4:31 PM CDT, 23 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LINCOLN IL
431 PM CDT SUN MAY 20 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0428 PM     HAIL             TRIVOLI                 40.69N 89.88W
05/20/2012  M0.50 INCH       PEORIA             IL   LAW ENFORCEMENT

&&

TIMTE
Special weather statement, May 20, 4:54 PM CDT, 0 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE LINCOLN IL
454 PM CDT SUN MAY 20 2012

ILZ048-051-202245-
MENARD-SANGAMON-
454 PM CDT SUN MAY 20 2012

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN SANGAMON AND
SOUTHEASTERN MENARD COUNTIES UNTIL 545 PM CDT...

AT 449 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 6 MILES SOUTHEAST OF PLEASANT PLAINS...OR 10
MILES WEST OF SPRINGFIELD...MOVING NORTHEAST AT 30 MPH.

PENNY SIZE HAIL IS EXPECTED WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
  ATHENS...
  SHERMAN...
  RIVERTON...
  WILLIAMSVILLE...

OTHER LOCATIONS AFFECTED INCLUDE...FARMINGDALE...SALISBURY...CAPITAL
AIRPORT...CANTRALL AND FANCY PRAIRIE.

PEOPLE NEAR THESE LOCATIONS SHOULD MONITOR THE WEATHER SITUATION
CLOSELY. LISTEN FOR POSSIBLE WARNINGS...AND BE PREPARED TO TAKE
APPROPRIATE ACTION SHOULD SEVERE WEATHER THREATEN.

LAT...LON 4006 8967 3986 8943 3975 8984 3987 8991
TIME...MOT...LOC 2154Z 235DEG 32KT 3986 8978

BARNES

The office that day

Everything else NWS Lincoln, IL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 20, 4:00 PM CDTFlash Flood WarningILXEffingham6 hr
May 20, 5:04 PM CDTSpecial Weather StatementILXLogan41 min
May 20, 5:36 PM CDTSpecial Weather StatementILXLogan54 min
May 20, 5:38 PM CDTSevere Thunderstorm WarningILXLogan, Sangamon37 min
May 20, 5:46 PM CDTSevere Thunderstorm WarningILXMorgan, Sangamon44 min
May 20, 6:11 PM CDTSevere Thunderstorm WarningILXLogan, Mason, Tazewell49 min
May 20, 6:56 PM CDTSpecial Weather StatementILXChampaign64 min

Nearby

Special Weather Statements in Illinois, 2012Every special weather statement in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.