Severe Thunderstorm Warning 129, NWS Paducah, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
ISSUED BY NATIONAL WEATHER SERVICE LOUISVILLE KY
1250 PM CDT Tue Aug 19 2014

.UPDATE...
Issued at 1250 PM CDT TUE AUG 19 2014

The AVIATION section has been updated for the 18Z TAF issuance.

UPDATE Issued at 1121 AM CDT TUE AUG 19 2014

The fog and low clouds have dissipate, leaving behind just a
scattered cu deck late this morning.

An area of convection has weakened significantly since 15Z as it
moved eastward into the KSTL area. However, it did push an outflow
boundary eastward and it is only a county or so northwest of our
area as of 16Z. Not sure whether the boundary will survive as it
moves into the strong mixing in our region or not, but figure it
or just a differential heating boundary may focus thunderstorm
development possibly by 18Z in the KMVN and KMDH areas.

The latest HRRR and 12Z NAM runs develop convection over much of
southern Illinois and push it southeast through southwest Indiana
and much of west Kentucky through the late afternoon and early
evening hours. The southwestward extent of development is in doubt
due to a very strong capping inversion noted on the 12Z KSGF RAOB.

The forecast has been updated to account for these convective
trends. Capped PoPs in the northeast at 50% due to the potential
for the cap to hold even up there. Also, kept a slight chance in
the far west just in case the cap does not hold. The NAM soundings
indicate that there will be some fairly steep mid-level lapse
rates for storms to feed on, if the cap can be broken. Wind fields
will be increasing, but the best winds may lag the convection
through the area. Given the instability alone, figure that a few
storms will reach severe criteria with winds and hail the primary
concerns.

&&

.SHORT TERM...(Today through Thursday night)
Issued at 214 AM CDT TUE AUG 19 2014

Short term weather continues to be somewhat active.

Aside from patchy/areas of dense fog early this morning, only a few
high clouds are expected to track across the region. An MCS located
over north central Kansas at the time of this writing should weaken
considerably on its southeast trek, and should there be anything
left of it later this morning, it should pass by to our south and
west.

Precipitation chances are expected to make their way into the
forecast this afternoon as a short wave pushes a weak cold front
toward the lower Ohio valley. Due to lack of deeper moisture models
not showing much in the way of convection before 18Z, but after that
precipitation chances should begin to increase from the northwest
with the approach of the aforementioned boundary. With decent flow
aloft over a moderately unstable airmass in place, a few storms
could become strong to severe Tuesday afternoon into the evening
hours, especially over most of southern Illinois and northwest
Kentucky, and all of southwest Indiana. Large hail and damaging
winds will be the primary threats.

Models show the short wave outrunning the surface boundary late
Tuesday night, and with H5 heights beginning to increase at that
point, the boundary never quite makes it into our CWA and gets
pushed back to the north and east as a warm front.

Precipitation chances will begin to diminish from southwest to
northeast on Wednesday as an upper ridge over the southern plains
begins to build northeast across our region . This trend will
continue through Thursday as the ridge continues to overspread the
area. At this time it looks like Thursday night will be dry as the
upper ridge takes control.

Unfortunately with the approach of the ridge, the resultant
compression/warming of the air will raise temperatures to near
normal levels (mid 90s) the latter half of the short term period.
This combined with dewpoints around 70 degrees will produce heat
indices near the century mark for most if not all of our CWA both
Wednesday and Thursday afternoon.

.LONG TERM...(Friday through Monday)
Issued at 214 AM CDT TUE AUG 19 2014

The long term will be dominated by an upper level ridge over the
Lower and Middle Mississippi Valley. This will help to stabilize the
atmosphere as the tropospheric profile undergoes a drying trend.
Consequently, any slight chance for showers and thunderstorms will
likely be shunted north and east of the immediate forecast area
through the weekend.

The main concern during this time will be the heat and humidity as
the hottest weather of the year takes hold. Highs in the mid to
upper 90s will combine with relatively high humidity to push heat
index readings to the 100 to 105 degree range each afternoon. Given
the anticipated prolonged nature of this event, I see little reason
why a Heat Advisory will not be issued later this week for peak
afternoon heat indices between 100 and 105 for at least four
consecutive days. Will continue to monitor and adjust forecast as
necessary.

&&

.AVIATION...
Issued at 1250 PM CDT TUE AUG 19 2014

An outflow boundary is expected to provide a focus for
thunderstorm development over southern Illinois this afternoon.
Best guess is that the storms would impact KEVV and KOWB around
00Z. With plentiful low-level moisture, fog development will be
possible again tonight, but with some southwest wind expected,
LIFR/VLIFR conditions are less likely. If they occur it would most
likely be at KCGI. Just a few cu expected by midday Wednesday,
along with modest west southwest to west winds.

&&

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

UPDATE...DRS
SHORT TERM...JP
LONG TERM...RJP
AVIATION...DRS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PADUCAH KY
ISSUED BY NATIONAL WEATHER SERVICE LOUISVILLE KY
1104 AM CDT TUE AUG 19 2014

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-201000-
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-
1104 AM CDT TUE AUG 19 2014

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED STRONG TO SEVERE THUNDERSTORMS MAY DEVELOP ALONG AN
OUTFLOW BOUNDARY ACROSS SOUTHERN ILLINOIS EARLY THIS AFTERNOON.
ANY DEVELOPMENT WILL MOVE SOUTHEAST THROUGH THE EVANSVILLE TRI
STATE LATE THIS AFTERNOON INTO THE EARLY EVENING HOURS. A CAPPING
INVERSION IS EXPECTED TO LIMIT THE SOUTHWESTWARD EXTENT OF THE
DEVELOPMENT. LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY
CONCERNS. LOCALLY HEAVY RAINFALL AND DANGEROUS LIGHTNING SHOULD ALSO
BE EXPECTED.

ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE
OVERNIGHT TONIGHT. LOCALLY HEAVY RAINFALL AND FREQUENT LIGHTNING
WILL BE THE PRIMARY CONCERNS.

A FEW LOCATIONS...MAINLY OVER SOUTHEAST MISSOURI AND THE PURCHASE
AREA OF WEST KENTUCKY MAY SEE HEAT INDEX VALUES CLIMB TO AROUND
100 THIS AFTERNOON.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THUNDERSTORMS ARE ALSO POSSIBLE OVER THE NORTHEAST HALF TO TWO
THIRDS OF THE OUTLOOK AREA WEDNESDAY...WEDNESDAY NIGHT...AND
THURSDAY. WIDESPREAD SEVERE WEATHER IS NOT EXPECTED AT THIS TIME.

A PROLONGED PERIOD OF HEAT AND HUMIDITY IS SHAPING UP FROM MID WEEK
THROUGH THE WEEKEND. PEAK AFTERNOON HEAT INDEX VALUES ARE FORECAST
TO RANGE FROM 100 TO 105 EACH AFTERNOON FROM WEDNESDAY THROUGH
SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ACROSS SOUTHERN ILLINOIS AND THE EVANSVILLE TRI STATE
REGION SHOULD BE PREPARED FOR ACTIVATION THIS AFTERNOON AND EVENING.

DRS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PADUCAH KY
1210 PM CDT TUE AUG 19 2014

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

0449 PM     TORNADO          ROBARDS                 37.69N 87.56W
08/17/2014                   HENDERSON          KY   NWS STORM SURVEY

            CONFIRMED BY NWS STORM DAMAGE SURVEY. EF0-1 WITH PEAK
            WIND 90 MPH. PATH LENGTH 2 MILES. PATH WIDTH 60 YARDS.
            BEGIN 3.5 NE ROBARDS AND END 3.75 MILES ENE ROBARDS.
            DAMAGE TO 3 HOMES AND A MOBILE HOME. NUMEROUS LARGE TREE
            LIMBS BROKEN WITH A COUPLE TREES UPROOTED. CONVERGET
            DAMAGE PATH IN CORN FIELD.

&&

SMITTY