Severe Thunderstorm Warning 47, NWS Louisville, KY

444 
WWUS53 KLMK 290615
SVSLMK

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LOUISVILLE KY
115 AM EST WED FEB 29 2012

INC025-037-117-123-290625-
/O.EXP.KLMK.SV.W.0047.000000T0000Z-120229T0615Z/
PERRY IN-ORANGE IN-CRAWFORD IN-DUBOIS IN-
115 AM EST WED FEB 29 2012

...THE SEVERE THUNDERSTORM WARNING FOR DUBOIS AND NORTHWESTERN PERRY 
COUNTIES HAS EXPIRED...

THE STORMS THAT PROMPTED THE WARNING HAVE MOVED NORTHEAST INTO 
CRAWFORD COUNTY.

TO REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE...CALL TOLL
FREE AT...1...8 7 7...6 3 3...6 7 7 2...WHEN YOU CAN DO SO SAFELY.

LAT...LON 3854 8653 3826 8640 3819 8680 3820 8680
      3820 8702 3820 8707 3821 8708 3834 8708
TIME...MOT...LOC 0615Z 247DEG 62KT 3840 8650

$$

RAS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
952 PM EST TUE FEB 28 2012

.Update...
Update#2
Issued at 945 PM EST Feb 28 2012

A line of thunderstorms has developed across southeast MO and
southern IL. Timing of this line brings it into the western portion
of the forecast area around 05Z. Mesoscale models continue to
develop more convection overnight as the low level jet ramps up.
Have made only minor adjustments to the ongoing forecast.

Update#1
Issued at 630 PM EST Feb 28 2012

The latest runs of the HRRR and the Rapid Refresh are indicating a
bit later start to the precipitation this evening. Currently there
is nothing much on radar close to the forecast area. Will therefore
take out/lower pops before the 05-06Z time frame. Temperatures are
also running quite a bit warmer than hourlies so will update to
bring them in line. Updates will be out soon.

.Short Term (Tonight through Wednesday night)...
Updated at 200 PM EST Feb 28 2012

...Heavy rain/strong storms tonight with potential for severe storms
tomorrow...

The much anticipated storm system that will affect us in the short
term is currently developing over Nebraska, with it's warm front and
60+ dewpoints slowly filtering northward across the southern CONUS,
and it's cold front just downstream of the Rockies. Looks like with
the 12z runs of the mesoscale models, think precipitation will come
in two main waves. First, with the warm-air advection/elevated
showers/storms overnight ahead of the warm front. And second, along
of and just ahead of the cold front tomorrow afternoon.

Tonight, clouds and moisture will be on the increase tonight as the
surface low develops and moves towards the Upper Midwest overnight.
This will help draw the warm front from southwest to northeast
across our County Warning Area (CWA), mainly from the 07-13z time
frame. Showers and thunderstorms should develop along the nose of a
65-70 kt low-level jet, which will overspread north of and ahead of
the warm front from SW to NE across the CWA. However, best moisture
convergence seems to be across our northwest CWA after 06z, so think
convection will be rather scattered from 00-06z tonight, and will
blow up ahead of the warm front, mainly hugging the Ohio River and
into north-central Kentucky from 06-12z. At this time, our far
southwestern CWA could see surface-based warm-sector air, but not
sure any of the convection will be that far south to be rooted in
the boundary layer air. Thus, think the severe chances tonight are
fairly slim. However, if storms do lag into central and even
south-central KY in the morning (4-8am CST), these will likely be
surface-based, and a severe threat would be possible, with damaging
winds and possibly an isolated tornado threat but think that is slim
right now. These storms look more like heavy rainers, possibly
hailers, and ample lightning. And again, think the concentration
will mainly be across the central part of the CWA northward or
northwestward.

Then after daybreak, warm-air advection convection should more north
of the CWA, with the entire CWA getting rooted into the boundary
layer/warm-sector air. Not sure we'll see a break in the low
strato-cu, but it is possible. If breaks occur, much of the
low-level jet winds will mix down, creating ample gusty winds
tomorrow. Think sustained winds of 20-25 mph will be possible with
gusts as high as 40 mph, close to wind advisory criteria. May defer
that to the next forecast tonight. Either way, we'll be sectored in
the warm, moist, gusty air ahead of the quickly approaching cold
front. Progged soundings show ample deep-layer shear, and strong
speed shear in the low-levels. Deep moisture along the cold front
however will be much lower than the overnight moisture, so think a
few storms will erupt along the cold front, but not a large, thick
line of convection. However, any storm that develops along the cold
front has the potential to become quickly supercellular, with
damaging winds, hail and isolated tornadoes being potential threats.
Best chance for this would be east of I-65 after noon tomorrow.
There will still be a severe weather threat along the cold front
west of I-65 as well, but the best heating and longer time to
recover from morning convection will happen over the eastern CWA.

So overall, looks like the best chance for severe weather will be a
small window over our southwestern CWA after 4am CST late tonight,
but a better chance mainly along and east of I-65 tomorrow
afternoon. Behind the cold frontal passage, winds will veer around
to the west and continue to be gusty until Wednesday night where
they will taper off.

Lowered precipitation in the grids to account for the break between
late night/early morning warm frontal convection and the lesser
amount but more significant strong-severe convection tomorrow
midday-afternoon.

Concerning temps, lows will drop off early tonight and then increase
towards 12z with the warm front pushing northward. Tomorrow, despite
mostly cloudy conditions, temperatures will still be able to rise
into the 60s and even lower 70s over the south/southeast.

.Long Term (Thursday - Tuesday)...
Updated at 315 PM EST Feb 28 2012

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

Another potent storm system on Friday is the main concern in the
extended forecast. Before that occurs, however, Thursday will be a
tranquil weather day between systems. Surface high pressure over the
Ohio Valley and Southeast will ensure a mostly sunny day, and
temperatures will remain mild with afternoon highs generally in the
lower and mid 60s.

The high will move off to our east quickly Thursday night as a
deepening trough aloft takes shape over the western United States
and begins moving east. The trough will cause CYCLOGENESIS across
the southern high Plains Thursday night. The surface low pressure
center will then deepen quite rapidly as it moves northeast into the
mid
Mississippi Valley Friday and Great Lakes Friday night. Ahead of
this low, low-level moisture should return rapidly. Last night's and
the newest 12z model runs suggest an area of precipitation will
quickly develop Thursday night over the Tennessee Valley in a warm
advection/isentropic lift zone. Elevated instability returning from
the southern Plains suggests that thunder will be embedded within
the area of rain. This precipitation may make it into south-central
KY by Friday morning, then lift quickly northeast into eastern KY in
the afternoon.

The main concern is Friday afternoon and evening, according to the
latest model timing. Wind fields increase throughout the lower and
mid levels, while actually decent instability is forecast to develop
in the warm sector between the departing warm front and east of a
potent cold front, which will extend south from the low pressure
center. Given cold frontal forcing, wind fields, and instability,
strong to severe storms could develop over parts of the Ohio Valley
extending south into the Tennessee Valley and lower Mississippi
Valley/southeastern United States. This system will need to be
watched closely.

Much cooler weather will move in for the weekend. The strong cyclone
mentioned above will move north of the Great lakes, with possibly a
surface pressure under 980mb. It parent 500mb trough will be
absorbed by a strengthening polar vortex near Hudson's Bay. By early
Sunday, ridging will strengthen over the Rockies with troughing over
the Great Lakes. Expect a partly cloudy sky Saturday with brisk west
winds developing during the afternoon. Highs Saturday will remain in
the lower to mid 50s. A weak clipper will scoot southeast from the
Upper Missouri Valley Saturday and traverse the Commonwealth on
Sunday. Cloud cover will increase Sunday with just a slight chance
of showers. Highs Sunday will have a hard time reaching 50.

In a slowly progressive pattern, 500mb ridging will move east across
the central plains on Monday. After partly cloudy, cool day Monday
with high pressure nearly overhead, southwest winds will commence
Tuesday, beginning a warmup.

&&

.Aviation (00Z TAF Issuance)...
Updated at 612 PM EST Feb 28 2012

A storm system will approach and cross the area through this TAF
period. A warm front will move north across the state through this
evening. Overnight a low level jet will crank up. This will lead to
storm development across the area around 05-06Z, which will spread
east overnight. Have moved back the timing of precip starting at
SDF and BWG, as it looks to be closer to the 05-06Z time frame. Will
continue to mention LLWS from this time on as well as models show
winds around 50 knots out of the SSW at 2 kft.

There looks to be a possible lull in precipitation for a portion of
the morning hours ahead of the cold front. This front will cross the
area through the late morning and afternoon tomorrow. Storms will
redevelop along this front. Ahead of the front, winds will be gusty
out of the southwest through the day, with gusts as high as 30 knots
at times.

Ceilings and visibilities will be a challenge with the
precipitation. MVFR to IFR conditions will be possible with the
storms. Between the two batches of precipitation, skies should
improve for a bit, though there is some uncertainty as to if VFR
conditions will be possible.

&&

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

Update...........EER
Short Term.......AL
Long Term........JSD
Aviation.........EER

HAZARDOUS WEATHER OUTLOOK...CORRECTION
NATIONAL WEATHER SERVICE LOUISVILLE KY
348 PM EST TUE FEB 28 2012

INZ076>079-083-084-089>092-KYZ023>043-045>049-053>057-061>067-
070>078-081-082-292100-
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-
348 PM EST TUE FEB 28 2012 /248 PM CST TUE FEB 28 2012/

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

.DAY ONE...TONIGHT.

A WARM FRONT WILL BRING THUNDERSTORMS TO THE REGION AFTER MIDNIGHT.
THE MAIN THREATS WILL BE FREQUENT LIGHTNING..LOCALLY HEAVY
RAIN...AND POSSIBLY SOME SMALL HAIL.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

A STRONG COLD FRONT WILL PASS THROUGH THE REGION ON WEDNESDAY.
A THIN BROKEN LINE OF THUNDERSTORMS IS EXPECTED TO RAPIDLY
DEVELOP ALONG THIS BOUNDARY DURING THE LATE MORNING HOURS WEST OF
I-65 AND PUSH EAST OF I-65 AFTER NOON EST. STRONG TO SEVERE
STORMS WILL BE POSSIBLE...WITH THE BEST CHANCE OF SEVERE WEATHER
OCCURRING EAST OF I-65 WHERE STORMS COULD PRODUCE DAMAGING
WINDS...HAIL...AND POSSIBLY AN ISOLATED TORNADO OR TWO. BRIEF HEAVY
RAINFALL AND LIGHTNING WILL ACCOMPANY ANY THUNDERSTORM.

OUTSIDE OF THUNDERSTORMS SOUTHWEST WINDS OF 15 TO 25 MPH WITH GUSTS
TO AT LEAST 35 MPH ARE EXPECTED.

ANOTHER LOW PRESSURE SYSTEM WILL DEEPEN RAPIDLY AS IT MOVES FROM
THE SOUTHERN PLAINS TO THE WESTERN GREAT LAKES ON FRIDAY. STRONG
TO SEVERE THUNDERSTORMS MAY DEVELOP FRIDAY AFTERNOON OR EVENING
AHEAD OF A COLD FRONT.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS WILL BE NEEDED ON WEDNESDAY...AND POSSIBLY FRIDAY
EVENING...TO REPORT SEVERE WEATHER TO THE NATIONAL WEATHER
SERVICE.

AL/13/JSD