Alert archive / Illinois / Special Weather Statements in 2017

Special Weather Statement, NWS St. Louis, MO

April 10, 2017Fayette County, Illinois

NWS St. Louis, MO issued this special weather statement at Apr 10, 2017, 1:34 PM CDT for Fayette County, Illinois. It was in force for 41 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: Apr 10, 2017, 1:34 PM CDT (18:34 UTC)
Expired: Apr 10, 2017, 2:15 PM CDT
In force: 41 min
Issued by: NWS St. Louis, MO

County Fayette County, IL

The radar

The Lincoln radar (KILX), 120 km from the middle of the area, began a volume at 18:34 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, 6.6 hours before the alert went out and 116 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1373 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: -63 m²/s²
0-3 km storm-relative helicity: 3 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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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 St. Louis, MO wrote its last area forecast discussion before this special weather statement went out at Apr 10, 5:39 AM CDT, 7 hours 55 minutes earlier.

Area forecast discussion, Apr 10, 5:39 AM CDT, 7 hours 55 minutes before

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
539 AM CDT Mon Apr 10 2017

.SHORT TERM...  (Through Late Tonight)
Issued at 332 AM CDT Mon Apr 10 2017

A weakening MCS will move eastward through northeast MO and west
central IL early this morning.  Additional, more scattered
convection will develop late this morning and this afternoon as an
upper level low over northwest Nebraska early this morning moves
east-northeastward into the Great Lakes region tonight and sends a
cold front southeastward through our forecast area today and
tonight. There may be isolated severe storms this afternoon across
east central and southeast MO and southwest IL as the atmosphere
destabilizes ahead of the front. High temperatures will be slightly
cooler today than the previous day due to the increased cloud cover,
albeit still well above normal. Most of the convection should shift
southeast of our forecast area by late tonight as a surface ridge
over the northern Plains builds southeastward into the region behind
the cold front. Low level cold air advection behind the cold front
along with a clearing sky and lowering surface dew points will lead
to much colder low temperatures tonight, close to seasonal normals.

GKS

.LONG TERM...  (Tuesday through Sunday)
Issued at 332 AM CDT Mon Apr 10 2017

This period will open with a rare quiet stretch of wx until
Wednesday evening.

The surface cold front should be southeast of the CWA by 12z/Tue
with high pressure dominating the remainder of Tuesday.  This high
pressure will represent the outer fringe of a Canadian airmass
centered much further to the north and therefore will only be able
to cool us to near normal for one day.

Clear skies on Tuesday night along with a light east wind should
give us the coolest night of the week with min temps in many
locations in the lower 40s.  A few favored valley areas should drop
into the 30s and this will need to be watched for any need to
mention frost, but for now, it looks like any potential will be
very isolated.

High pressure will begin losing its influence on Wednesday with
winds returning from the southeast and daytime temps creeping back
into the 70s for most locations.

From Wednesday night onward, it looks to be a more typical active
springtime pattern with the chance for showers and storms each day.

An upper level disturbance ahead of a surface front will provide the
next round of storms Wednesday night and this will continue into
Thursday as the surface front sinks into the CWA and stalls.  At
this point, there is some model spread concerning mid level flow
which will determine how long the front stalls before retreating
northward as a warm front.  The GFS lingers the front the longest
over our region (into Friday) while the EC and CMC are quick to yank
it back north by Friday morning.  Went conservative on reducing PoPs
Friday, instead leaning toward more of a hedge climo value, which is
30% this time of year.

For Friday night and Saturday, there is better agreement on a warm
sector setup for much of the CWA, and went for a brief period of dry
wx for most locations save northern MO and central IL.

The spread increases further between the CMC/EC/GFS concerning on
whether or not to bring a cold front thru the region next weekend,
with the GFS not even dropping it thru at all.  Again leaned towards
a climo PoP approach when some models were bringing the front thru
Saturday night and into early Sunday until confidence can increase.

Concerning temps, after Tuesday, southerly surface flow is expected
to prevail for virtually the remainder of the week and into next
weekend.  So a prolonged stretch of above average temps continues to
be forecast, highlighted by what should be the warmest day on
Saturday with decent consensus on the warm sector setup, with highs
reaching into the 80s again in some areas.

TES

&&

.AVIATION...  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 522 AM CDT Mon Apr 10 2017

Cluster of showers and thunderstorms moving eastward through UIN
early this morning. Most of this activity will shift east of UIN
by 12Z Monday, and most of it will remain north of the St Louis
metro area taf locations. A cold front will move southeastward
through the taf sites today and this evening. Scattered showers
and storms will develop along and ahead of the front this
afternoon as the atmosphere destabilizes. The convection should
shift southeast of the St Louis metro area by early evening.
South-southwesterly surface winds will veer around to a
northwesterly direction tonight after the passage of the cold
front.

SPECIFICS FOR KSTL: Cluster of showers and thunderstorms moving
eastward through northeast MO and west central IL early this
morning. Most of this activity will remain north of the STL area
this morning. A cold front will move southeastward through the STL
area this afternoon and this evening. Scattered showers and
storms will develop along and ahead of the front this afternoon as
the atmosphere destabilizes. The convection should shift
southeast of the STL area by early evening. South-southwesterly
surface winds will veer around to a northwesterly direction by
late tonight after the passage of the cold front.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

WFO LSX

Hazardous weather outlook, Apr 10, 4:05 AM CDT, 9 hours 29 minutes before

Hazardous Weather Outlook
National Weather Service Saint Louis MO
405 AM CDT Mon Apr 10 2017

ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027-
034>036-041-042-047>052-059>065-072>075-084-085-099-111200-
Greene IL-Macoupin IL-Montgomery IL-Bond IL-Fayette IL-Clinton IL-
Marion IL-Washington IL-Randolph IL-Adams IL-Brown IL-Pike IL-
Calhoun IL-Jersey IL-Madison IL-Saint Clair IL-Monroe IL-Knox MO-
Lewis MO-Shelby MO-Marion MO-Monroe MO-Ralls MO-Pike MO-Boone MO-
Audrain MO-Moniteau MO-Cole MO-Osage MO-Callaway MO-Montgomery MO-
Lincoln MO-Gasconade MO-Warren MO-Saint Charles MO-Franklin MO-
Saint Louis MO-Saint Louis City MO-Jefferson MO-Crawford MO-
Washington MO-Saint Francois MO-Sainte Genevieve MO-Iron MO-
Madison MO-Reynolds MO-
405 AM CDT Mon Apr 10 2017

This hazardous weather outlook is for portions of eastern and
central Missouri as well as west central and southwest Illinois.

.DAY ONE...Today and Tonight

Isolated severe thunderstorms are possible this afternoon and
early this evening for the Saint Louis metro area and areas to the
south and east as a cold front moves through. Large hail and
damaging winds are the main severe threats.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is possible this afternoon and early this
evening for the Saint Louis metro area and areas to the south and
east.

TES

In the hours before

Local storm report, Apr 10, 10:17 AM CDT, 3 hours 17 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
1017 AM CDT MON APR 10 2017

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

1014 AM     HAIL             2 WNW O'FALLON          38.80N 90.74W
04/10/2017  E0.75 INCH       ST. CHARLES        MO   PUBLIC

            SPOTTERNETWORK.

&&

CVKING

Local storm report, Apr 10, 10:27 AM CDT, 3 hours 7 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
1027 AM CDT MON APR 10 2017

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

1025 AM     HAIL             2 WSW WELDON SPRING     38.70N 90.68W
04/10/2017  E1.00 INCH       ST. CHARLES        MO   NWS EMPLOYEE

            AT WFO ST. LOUIS.

&&

CVKING

Local storm report, Apr 10, 10:39 AM CDT, 2 hours 55 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
1039 AM CDT MON APR 10 2017

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

1039 AM     HAIL             SAINT CLAIR             38.36N 90.98W
04/10/2017  E0.25 INCH       FRANKLIN           MO   TRAINED SPOTTER

&&

CVKING

Local storm report, Apr 10, 10:40 AM CDT, 2 hours 54 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
1040 AM CDT MON APR 10 2017

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

1035 AM     HAIL             SAINT CHARLES           38.79N 90.52W
04/10/2017  E0.88 INCH       ST. CHARLES        MO   TRAINED SPOTTER

&&

Local storm report, Apr 10, 12:29 PM CDT, 1 hour 5 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
1229 PM CDT MON APR 10 2017

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

1030 AM     HAIL             2 NE WELDON SPRING      38.74N 90.62W
04/10/2017  M1.00 INCH       ST. CHARLES        MO   PUBLIC

            VIA FACEBOOK. KISKER AND HIGHWAY 94.

&&

BYRD

Special weather statement, Apr 10, 1:34 PM CDT, 0 minutes before

Special Weather Statement
National Weather Service St Louis MO
134 PM CDT MON APR 10 2017

ILZ065-101915-
Fayette IL-
134 PM CDT MON APR 10 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN FAYETTE COUNTY UNTIL
215 PM CDT...

At 133 PM CDT, Doppler radar was tracking a strong thunderstorm over
Wrights Corner, moving east at 50 mph.

Nickel size hail will be possible with this storm.

Locations impacted include...
St. Elmo and Wrights Corner.

LAT...LON 3902 8893 3920 8898 3922 8891 3922 8881
      3920 8880 3904 8881
TIME...MOT...LOC 1833Z 256DEG 42KT 3913 8886

Glass

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 10, 3:57 AM CDT	Special Weather Statement	LSX	Shelby	48 min
Apr 10, 7:11 AM CDT	Special Weather Statement	LSX	Franklin, Gasconade, Osage, Warren	49 min
Apr 10, 9:55 AM CDT	Special Weather Statement	LSX	Saint Charles	50 min
Apr 10, 9:58 AM CDT	Severe Thunderstorm Warning	LSX	Franklin, Saint Charles, Saint Louis, Warren	47 min
Apr 10, 10:29 AM CDT	Severe Thunderstorm Warning	LSX	Saint Charles, Saint Louis	26 min
Apr 10, 5:51 PM CDT	Special Weather Statement	LSX	Crawford, Washington	39 min
Apr 10, 5:56 PM CDT	Severe Thunderstorm Warning	LSX	Crawford, Washington	36 min
Apr 10, 4:55 AM CDT	Special Weather Statement	LSX	Pike	50 min
Apr 10, 1:51 PM CDT	Special Weather Statement	LSX	Marion	39 min
Apr 10, 4:02 PM CDT	Severe Thunderstorm Warning	LSX	Calhoun, Jersey	43 min
Apr 10, 6:46 PM CDT	Special Weather Statement	LSX	Montgomery	44 min

Nearby

Special Weather Statements in Illinois, 2017 Every special weather statement in 2017

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.