Severe Thunderstorm Warning 77, NWS Louisville, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1237 PM EST WED FEB 29 2012

.Update...
Issued at 1235 AM EST Feb 29 2012

After coordination with SPC will be allowing Tornado Watch number 46
to expire at 18Z.  New watch box will be coming shortly to cover
much of central KY.  Updated forecast products and grids will be
coming shortly.

Issued at 1150 AM EST Feb 29 2012

Broken line of convection continues to slowly move across the
central part of the forecast area this afternoon.  Several discrete
cells are moving through central Kentucky.  These storms are
tracking along a boundary that extends from near E-town northeast
toward Lexington.  Discrete supercell is moving northeast through
southern Washington county KY and will likely pass south of the
Lexington metro area over the next hour or so.  Additional storms
are developing in an increasingly unstable airmass across southern
KY.  These storms will affect the Bowling Green area over the next
few hours.  Proximity soundings from the latest data continue to
show large shear values across the region for the afternoon/eve
hours.  These shear profiles are long and turning through the lower
atmosphere which will support severe thunderstorms in a mixed-mode.
Discrete supercells and multicelluar convection are very likely with
the highest threat of severe weather being south of the WK and BG
parkways.  Additional convection may fire along the actual frontal
interface which is still west of the region.  Areas of southern
Indiana and portions of north-central KY north of the current
convection are not out of the woods just yet as this area still
remains in the warm sector.  However, drier air will quickly push in
from the northwest this afternoon...effectively ending the
thunderstorm threat.  From west to east.  Current forecast is in
good shape at the moment.  Will be lowering high temps a bit given
the cloud cover.  Highs for the afternoon will be in the upper 60s
to the lower 70s.

Update issued at 1018 AM EST Feb 29 2012

Scattered convection continues across the forecast area.  Pair of
supercells are crossing the I-65 corridor in southern Hardin and
northern LaRue counties.  These storms are heading northeast and
those located in counties along the Bluegrass Parkway from E-Town to
Lexington should be on the alert for severe weather over the next
few hours.  Additional storms are developing across our far SW just
west of Bowling Green.  Those storms will be moving into an
environment which should result in continued development.
Additional scattered convection continues to develop northwest of
the main line across far NW KY and southern Indiana.  This activity
is not severe, but is capable of producing gusty winds and heavy
rains.  At this time, we still believe the highest threat of severe
weather will be south of the WKY and BG parkways through the
remainder of the morning and the afternoon hours.

Update issued at 903 AM EST Feb 29 2012

Broken line of convection now has cleared the Louisville metro and
all of southern Indiana.  Will be clearing some counties to the
northwest of the convective line after coordinating with SPC.  Line
of storms continue across north-central Kentucky east of the I-65
corridor.  These will affect the Lexington metro area within the
hour.  Main threats with this line will be damaging winds...however
given the bulk shear can not rule out small tornadic spinups within
the line.  Most significant potential for severe weather will remain
across southern Kentucky this morning and into the afternoon hours.
Current indications is that the worst severe weather will likely be
confined to areas south of the Western Kentucky and Bluegrass
parkways...with a strong emphasis on counties across our southern
forecast area.  Airmass destabilization continues and storms across
Ohio/Butler/Grayson county will be moving into an environment that
will continue to support its severe status.  Updated forecast
products will be available shortly...followed by continued mesoscale
updates as this dangerous weather situation unfolds.

Update issued at 810 AM EST Feb 29 2012

Line of convection is now approaching the Ohio River.  This activity
is moving to the east at 50-55 MPH and will be impacting the I-65
corridor and the Louisville Metro over the next hour.  Current
mesoscale analysis reveals a moderately unstable atmosphere across
primarily southern Kentucky.  Pool of 60+ dewpoints is currently
located generally west of I-65.  This combined with a relatively
cooler airmass aloft has resulted in surface based LI's dropping to
around -3 to -4.  While surface winds are generally out of the
southwest...there remains considerable speed shear in the lower
atmosphere that has resulted in long curved hodographs and resulting
in helicity values of 350-500 M2/S2.  The highest helicity values
are across southern KY with lesser values the further north one
goes.  Convection is more linear across the northern part of KY and
southern Indiana...however the better moisture and shear have
supported a long tracked supercell that is moving through southern
Ohio and northern Butler county.  Downstream areas such as Grayson,
Butler, Edmonson, and Hart counties should be on the alert for
severe weather over the next hour.

Update Issued at 650 AM EST Feb 29 2012

Did a subtle update to the grids that will not show up in the zones.
Not seeing much recovery in dewpoints behind the main line still out
to our west. Have dropped pops a little behind this line for the
afternoon. Still cannot rule out some severe storms however, given
strong winds aloft and expected heating. Latest NMM-WRF still shows
discrete cells forming this afternoon and larger scale models still
try and show a line of precip coming through this afternoon.

Update issued at 608 AM EST Feb 29 2012

Line of thunderstorms is west of the area, with airmass quickly
destabilizing out ahead of it.  Have had several tornado warnings
issued out to the west, with some verification. Based on an expected
similar airmass moving into our area, would expect the line to
survive as it heads quickly east. In addition may have some
development out ahead of it that is surface based. Updated products
have already gone out and a tornado watch has been issued.

.Short Term (Today through Thursday)...
Updated at 340 AM EST Feb 29 2012

Warm front a little difficult to find at this hour, but looking at
dewpoints and based on storm cell we issued an earlier warning on,
it would appear to be right along the I-64 corridor. As expected
with the increase in southerly winds across the area, temperatures
and dewpoints are rising slowly at this time. Winds just above the
surface are cranking, with latest area VAD profilers giving winds of
50-55 kts at 3000 feet, 60-70 kts at 4000 feet. Though temperatures
are rising, we still have not seen evidence of any of these cells
becoming surface-based, though winds out ahead of the line are
gusting to 20-30 kts this hour.

Including the current line of storms going through the region, we
might see 3 rounds of storms before the day is over. The second is a
line currently moving through MO/AR. This line may have enough of a
punch to bring some gusty winds just after daybreak to the region,
and will have to watch here again for any type of surface-based
convection as guidance keeps in strong low-level winds and 400-500
0-1 km helicities. However, the line should start breaking up around
daybreak though as it heads into central Kentucky and pulls farther
away from the parent cold front.

Behind that line will be a brief lull in precip as the dry slot gets
over us. Low clouds may stick around through the day, potentially
limiting available instability for the third round of storms just
ahead of the cold front. Still, the southwesterly winds through the
day should make temperatures continue to rise despite the cloud
cover, with highs ranging from the mid 60s to around 70 areawide.
Precipitable waters remain fairly high this afternoon, with readings
around 1.25 inches. Forcing just ahead of the front combined with
any type of heating should be enough to initiate another line around
or just after Noon. Shear profiles associated with this line should
be more unidirectional, but we still will have roughly 70 kts of 0-6
km shear! Thus cannot rule out another damaging wind threat with
this line as well as tornadoes. If I had to pin down an area, would
have to agree with SPC, which has held pretty steady the past couple
of days in their outlook for this region, of along and east of an
SDF to BWG line for having the best chance at seeing severe weather
withing this third line of storms.

Behind this third line, the front will move through with just a
subtle shift in winds to westerly overnight and drier air filtering
in. Expect skies to clear areawide by midnight, with lows falling
into the lower 40s. Given the not that cool air behind this front
and the full sunshine expected Thursday, have gone for highs around
60 over the north and in the upper 60s across the south.

.Long Term (Thursday Night- Tuesday)...
Updated at 320 AM EST Feb 29 2012

...Potential for more strong to severe thunderstorms again Friday
afternoon and night...

Surface low will strengthen as it moves out of the southern Plains
to the middle Mississippi River Valley Thursday night. This will
occur ahead of a positively tilted trough developing over the
central CONUS with 100-120 knot upper level jet rounding the base.
Most of Thursday night will be dry with increasing mid and upper
level clouds ahead of the next system. A warm front will approach
the Tennessee border toward dawn with WAA showers and thunderstorms
possible across the southern tier or two of counties before dawn on
Friday. Warm front will quickly lift north across the CWA during the
late morning on Friday with numerous showers and thunderstorms as
the surface low continues to strengthen on its way to the southern
Great Lakes.

Friday afternoon and evening look to be interesting as the CWA
quickly finds itself in the warm sector and surface based storms
combine with a veering and strong shear profile ahead of a cold
frontal passage. With surface temperatures in the upper 60s and
possibly low 70s, and dew points likely in the 55-60 degree range,
moderate instability appears possible despite heavy cloud cover for
much of the day. Shear profile is also impressive with and increase
to 45-50 knots with h85 jet and enough veering in the low to mid
levels to support supercells. It appears we may have to overcome
some degree of low level inversion through the afternoon hours, and
with heavy cloud cover, the degree of destabilization that models
suggest seems like it could be overdone. That being said, potential
exists for strong and severe storms Friday afternoon and evening and
system will have to be watched. Adding confidence, SPC just included
the entire CWA in a slight risk, with the majority of the CWA in an
enhanced area for severe weather.

Cold front will quickly race from west to east across the CWA Friday
night with thunderstorm chances likely ending by midnight. Trough
will continue to slide east over the eastern CONUS with cooler
airmass in place for the weekend. Highs will drop back to around 50
for Saturday with lows Saturday night around freezing. Saturday and
Saturday night look to be dry as deeper moisture quickly departs
with the system and surface high pressure briefly takes control.

Sunday could be an interesting day as a wave of energy appears to
dive across the northern plains and into the region. Although
surface temperatures will be warming into the mid and upper 40s by
midday, a look at thermal profiles reveals that a rain/snow mix or
even ice pellets will be possible through midday as steep low level
lapse rates combine with some low level moisture. After
collaboration with surrounding offices, will only keep mention of
rain for now as temps will quickly warm and timing/placement of
system is still in question. Should the system arrive, quicker
mention of convective snow showers/ice pellets may be needed with
future forecasts.

Dry weather looks to return Sunday night through Tuesday as surface
high pressure and ridging aloft dominate the weather pattern. Look
for highs back around 60 by Tuesday afternoon with lows around 30
Sunday night warming to the mid 30s by Monday night.

&&

.Aviation (18Z TAF Issuance)...
Updated at 1142 AM EST Feb 29 2012

Surface cold front is still to the west of the region this
afternoon.  Front looks to be crossing into western KY at this
time.  Pre-frontal band of convection continues well ahead of the
approaching front.  Convection will be possible across the region
this afternoon until the front passes on by.  All the terminals are
likely to see showers and storms in the vicinity through the
afternoon hours.  Current thinking is that BWG and KLEX will likely
see the most activity while KSDF probably will see more scattered
convection.  Southwest winds 10 to 20 knots will be common with
gusts of 30kts being possible through the afternoon.  Winds will
shift to the west and eventually northwest after the front goes
through late this afternoon and evening.  Local thunderstorms that
affect the terminals could produce winds in excess of 40kts.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.

Update...........MJ
Short Term.......RJS
Long Term........BJS
Aviation.........MJ

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LOUISVILLE KY
1040 AM EST WED FEB 29 2012

INZ076>079-083-084-089>092-KYZ023>043-045>049-053>057-061>067-
070>078-081-082-010900-
ORANGE IN-WASHINGTON IN-SCOTT IN-JEFFERSON IN-DUBOIS IN-
CRAWFORD IN-PERRY IN-HARRISON IN-FLOYD IN-CLARK IN-HANCOCK KY-
BRECKINRIDGE KY-MEADE KY-OHIO KY-GRAYSON KY-HARDIN KY-BULLITT KY-
JEFFERSON KY-OLDHAM KY-TRIMBLE KY-HENRY KY-SHELBY KY-FRANKLIN KY-
SCOTT KY-HARRISON KY-SPENCER KY-ANDERSON KY-WOODFORD KY-
FAYETTE KY-BOURBON KY-NICHOLAS KY-NELSON KY-WASHINGTON KY-
MERCER KY-JESSAMINE KY-CLARK KY-LARUE KY-MARION KY-BOYLE KY-
GARRARD KY-MADISON KY-BUTLER KY-EDMONSON KY-HART KY-GREEN KY-
TAYLOR KY-CASEY KY-LINCOLN KY-LOGAN KY-WARREN KY-SIMPSON KY-
ALLEN KY-BARREN KY-MONROE KY-METCALFE KY-ADAIR KY-RUSSELL KY-
CUMBERLAND KY-CLINTON KY-
1040 AM EST WED FEB 29 2012 /940 AM CST WED FEB 29 2012/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
INDIANA AND CENTRAL KENTUCKY.

.DAY ONE...TODAY.

A STRONG COLD FRONT WILL MOVE SLOWLY THROUGH THE REGION TODAY.
AHEAD OF THIS COLD FRONT...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP AND MOVE ACROSS THE REGION.  SOME OF THESE STORMS ARE LIKELY
TO BE SEVERE WITH DAMAGING WINDS...TORNADOES...AND LARGE HAIL BEING
THE PRIMARY SEVERE WEATHER THREATS.  AT THIS TIME...THE AREA AT
HIGHEST RISK OF SEVERE WEATHER WILL BE THAT PART OF KENTUCKY LOCATED
SOUTH OF THE WESTERN KENTUCKY AND BLUEGRASS PARKWAYS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

ANOTHER LOW PRESSURE SYSTEM WILL DEEPEN RAPIDLY AS IT MOVES FROM
THE SOUTHERN PLAINS TO THE SOUTHERN GREAT LAKES ON FRIDAY. STRONG TO
SEVERE THUNDERSTORMS MAY DEVELOP FRIDAY AFTERNOON OR EVENING AHEAD
OF A COLD FRONT. AT THIS TIME...THE MAIN THREATS APPEAR TO BE
DAMAGING WINDS...LARGE HAIL...AND DANGEROUS CLOUD TO GROUND
LIGHTNING. A TORNADO THREAT MAY ALSO EXIST THROUGH THE AFTERNOON
AND EARLY EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS REQUESTED TODAY.  WEATHER SPOTTERS AND
EMERGENCY MANAGERS SHOULD REPORT SEVERE WEATHER TO THE NATIONAL
WEATHER SERVICE. SPOTTER ACTIVATION IS LIKELY AGAIN ON FRIDAY.

RJS/BJS/MJ

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOUISVILLE KY
120 PM EST WED FEB 29 2012

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

1244 PM     HAIL             REDHOUSE                37.83N  84.27W
02/29/2012  M1.75 INCH       MADISON            KY   EMERGENCY MNGR

&&

EVENT NUMBER LMK1200145

CMC

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOUISVILLE KY
133 PM EST WED FEB 29 2012

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

0121 PM     HAIL             SMITHS GROVE            37.05N  86.21W
02/29/2012  M0.70 INCH       WARREN             KY   EMERGENCY MNGR

            A LARGE AMOUNT OF DIME SIZED HAIL COVERING THE GROUND.
            ESTIMATED WINDS OF 45 TO 50 MPH.

&&

EVENT NUMBER LMK1200146

EER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOUISVILLE KY
146 PM EST WED FEB 29 2012

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

0111 PM     HAIL             MONROE                  37.23N  85.70W
02/29/2012  M1.00 INCH       HART               KY   TRAINED SPOTTER

&&

EVENT NUMBER LMK1200147

CMC

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOUISVILLE KY
149 PM EST WED FEB 29 2012

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

0148 PM     FLASH FLOOD      BOWLING GREEN           36.97N  86.44W
02/29/2012                   WARREN             KY   BROADCAST MEDIA

            WESTERN AVE AND ASHLEY CIRCLE FLOODED

&&

EVENT NUMBER LMK1200148

CMC

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LOUISVILLE KY
150 PM EST WED FEB 29 2012

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

0145 PM     HAIL             4 SW CENTER             37.09N  85.73W
02/29/2012  M1.00 INCH       METCALFE           KY   TRAINED SPOTTER

&&

EVENT NUMBER LMK1200149

EER

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE LOUISVILLE KY
152 PM EST WED FEB 29 2012

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

0148 PM     FLASH FLOOD      BOWLING GREEN           36.97N  86.44W
02/29/2012                   WARREN             KY   BROADCAST MEDIA

            WESTEN AVE AND ASHLEY CIRCLE FLOODED

&&

CORRECTED REMARKS

EVENT NUMBER LMK1200148

CMC