Special Weather Statement, NWS Indianapolis, IN

Area Forecast Discussion
National Weather Service Indianapolis IN
322 AM EST Tue Mar 7 2017

.UPDATE...
The SYNOPSIS...NEAR TERM and SHORT TERM Sections have been updated below.

&&

.SYNOPSIS...
Issued at 239 AM EST Tue Mar 7 2017

A line of showers and thunderstorms will move through central
Indiana early this morning ahead of a cold front. High pressure
will build in behind the front bringing dry weather with it, but
keeping windy conditions over the area through Wednesday. A
quick-moving wave could bring small chances for precipitation
overnight Thursday. Saturday a stronger system could bring cooler
temperatures and chances for accumulating snow to the area.

&&

.NEAR TERM /Early this morning and today/...

Issued at 239 AM EST Tue Mar 7 2017

Scattered showers and thunderstorms have fired in central Indiana, ahead
of a line of prefrontal storms currently over northeast and
central Illinois. A strong low level jet is overhead with winds of
50-60 kts around 2000 ft according to VAD profile at KIND. Gusts
outside of storms across the area are generally running 25 to 45
mph. Lack of any surface based instability and a weak capping
inversion should allow storms to weaken as the aforementioned line
moves into the area. Showers/storms could mix down some of that
low level jet wind though, and thus could see stronger gusts of 50
to 55 mph from these. Can't rule out a severe gust, but the lack
of instability should tend to keep storms from crossing the line
between strong and severe.

Scattered storms ahead of the line are moving ENE through the
area. The line itself is moving into NW Warren county at 310 am,
and should be moving into Lafayette before 4am, Terre Haute around
4 am, Indy and Bloomington just before 5 am, and Muncie to
Columbus around 530 am based on current timing. Expect storms to
continue to weaken as they march across the area.

Rain showers will continue behind the line for a few hours before
ending. Should see dry conditions across all but the far eastern
counties by afternoon, and even there only a slight chance some
showers are still hanging around. Highs for the day will likely be
early this morning and should see dropping temps in the afternoon
behind the front.

&&

.SHORT TERM /Tonight through Thursday night/...

Issued at 239 AM EST Tue Mar 7 2017

High pressure will build in the wake of the frontal passage. A
strong pressure gradient across the area will bring wind gusts on
Wednesday that could approach advisory criteria and will need to
monitor this possibility. Highs in the 50s are expected under full
sunshine but cooler temperatures aloft.

The next system to move through will be Thursday night when a weak
upper wave swings through and a surface frontal system moves
through to the south of the area. This could bring some chances
for rain, and possibly a changeover to snow/rain snow mix late
Thursday night, but no accumulation expected with this one.

&&

.LONG TERM /Friday through Monday/...
Issued at 150 AM EST Tue Mar 7 2017

Primary focus for the extended period is the potential for a late
season winter storm to impact the Ohio Valley late Friday through
Saturday.

Amplified upper flow pattern setting up through the weekend over
much of the eastern U S as a deep upper low dives into New England
and the Canadian Maritimes. Broad northwest flow will reside over
central Indiana on the back side of the progressively deepening
trough aloft in response to the aforementioned upper low.
Multiple waves aloft will quickly track within the northwest flow
and across the Ohio Valley through much of the extended...keeping
the region in an unsettled and chilly weather pattern.

At the surface...bulk of the extended guidance is supporting a
strong Arctic high pressure sliding down from the Canadian
Prairies and into the Great Lakes. This feature will have
influence on how significant of an impact the region will see as
low pressure kicks out to the E/SE from the central Rockies. This
storm will swing east through the Ohio and Tennessee Valleys for
Saturday and with ample cold air in place courtesy of the Arctic
high to the north...stage is set for a late season winter storm
over the Ohio Valley. With that being said though...00Z guidance
including ensemble data continues to shift the threat for
precipitation largely in the form of snow further south due to the
strength of the high to the north. Still plenty to sort out in
the coming days as track shifts will lead to adjustments in
potential snowfall impacts. Will maintain likely pops at a minimum
for Saturday with low level thermals supportive of precipitation
falling as all snow...perhaps mixing with rain at times.

It should be noted that the amount of moisture present certainly
supports the potential for accumulating snow to impact parts of
the region...but details are difficult at this early stage. While
the track of the storm will be critical in determining potential
for snow...the combination of snowfall rates...near surface layer
temperatures and ground temperatures will all be factors in
determining how efficient snowfall will accumulate. In a
nutshell...the potential is certainly there for snow to impact
Saturday activities and possibly accumulate as well. But it
remains far too early to determine specific impacts and amounts at
this time. Stay tuned.

High pressure will bring a dry cool day for Sunday...with
precipitation returning for late Monday and Monday night as a
surface wave tracks into the region with a cold front. Surface
temperatures support a mixture of rain and snow over the region by
Monday night. Temperatures will recover to near normal by Monday
ahead of the cold front but if an accumulating snow is laid down
on Saturday...temperatures would need to be lowered for Sunday and
Monday.

&&

.AVIATION /Discussion for the 07/06Z TAF Issuance/...

Issued at 1153 PM EST Mon Mar 6 2017

Rain showers have ended across the TAF sites, and the area is
currently in a bit of a lull. So, VFR conditions will prevail into
the night. However, as showers and thunderstorms increase in
coverage during the pre-dawn hours with a cold front, there will
be a few hours of MVFR conditions in the Tue 10-14Z time frame.
After that, VFR conditions will return late in the period in the
wake of front. Meanwhile, strong southerly winds with gusts up to
28 kts will create low level wind shear issues through daybreak.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....Ryan
AVIATION...TDUD

Hazardous Weather Outlook
National Weather Service Indianapolis IN
556 PM EST Mon Mar 6 2017

INZ021-028>031-035>049-051>057-060>065-067>072-071100-
Carroll-Warren-Tippecanoe-Clinton-Howard-Fountain-Montgomery-Boone-
Tipton-Hamilton-Madison-Delaware-Randolph-Vermillion-Parke-Putnam-
Hendricks-Marion-Hancock-Henry-Vigo-Clay-Owen-Morgan-Johnson-Shelby-
Rush-Sullivan-Greene-Monroe-Brown-Bartholomew-Decatur-Knox-Daviess-
Martin-Lawrence-Jackson-Jennings-
Including the cities of Lafayette, Frankfort, Kokomo,
Crawfordsville, Anderson, Muncie, Indianapolis, Terre Haute,
Shelbyville, Bloomington, Columbus, Vincennes, Bedford, and Seymour
556 PM EST Mon Mar 6 2017

This hazardous weather outlook is for central Indiana.

.DAY ONE...Tonight.

Outlook: Thunderstorm activity is possible late tonight. Some storms
may contain gusty winds.

Hazards: Cloud to ground Lightning. Gusty winds.

Timing: Thunderstorm activity after 100 am.

Discussion: A low pressure system will move into the area tonight and
bring rain, with embedded thunderstorms possible late tonight. Some
storms after midnight may contain gusty winds.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Outlook: There is a chance for thunderstorms Tuesday morning across
central and eastern parts of the area. Accumulating snows are
possible towards the end of the week, around Friday night through
Saturday night.

Discussion: A cold front moving through the area on Tuesday will
bring an end to thunderstorm chances from west to east during the
morning on Tuesday. Lightning and gusty winds will be the main
threats from these storms. Another low pressure system may affect the
area towards the end of the week, with the potential for accumulating
snow.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

&&

More information, along with other weather, hydrological and climate
information can be found at http://weather.gov/ind

Special Weather Statement
National Weather Service Indianapolis IN
1258 AM EST Tue Mar 7 2017

INZ021-028>031-035>049-051>057-060>065-067>072-071030-
Carroll-Warren-Tippecanoe-Clinton-Howard-Fountain-Montgomery-
Boone-Tipton-Hamilton-Madison-Delaware-Randolph-Vermillion-Parke-
Putnam-Hendricks-Marion-Hancock-Henry-Vigo-Clay-Owen-Morgan-
Johnson-Shelby-Rush-Sullivan-Greene-Monroe-Brown-Bartholomew-
Decatur-Knox-Daviess-Martin-Lawrence-Jackson-Jennings-
Including the cities of Lafayette, Frankfort, Kokomo,
Crawfordsville, Anderson, Muncie, Indianapolis, Terre Haute,
Shelbyville, Bloomington, Columbus, Vincennes, Bedford,
and Seymour
1258 AM EST Tue Mar 7 2017

...Gusty winds through the overnight hours...

Wind gusts of 35 to 45 mph can be expected over the next several
hours out of the south, with a strengthening low level jet mixing
some higher winds down well ahead of a cold front approaching
from the west. Other higher wind gusts may also occur with any
thunderstorms that move through the area tonight as well. High
profile vehicles may experience travel difficulties, and unsecured
outdoor objects may be blown about.

Special Weather Statement
National Weather Service Indianapolis IN
241 AM EST TUE MAR 7 2017

INZ036-044-045-051>053-060-061-070830-
Owen IN-Clay IN-Montgomery IN-Putnam IN-Parke IN-Greene IN-Vigo IN-
Sullivan IN-
241 AM EST TUE MAR 7 2017

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN VIGO...EASTERN
SULLIVAN...CLAY...EASTERN PARKE...WESTERN OWEN...NORTHWESTERN
GREENE...SOUTHERN MONTGOMERY AND PUTNAM COUNTIES UNTIL 330 AM EST...

At 240 AM EST, Doppler radar was tracking strong thunderstorms along
a line extending from near Rockville to 6 miles southwest of Brazil
to near Sullivan. Movement was northeast at 55 mph.

Dime size hail and wind gusts of 50 to 55 mph will be possible with
these storms.

Locations impacted include...
Crawfordsville, Greencastle, Brazil, Rockville, Jasonville,
Cloverdale, Seelyville, Ladoga, Roachdale, Dugger, Knightsville, Clay
City, Hymera, Bainbridge, Rosedale, Carlisle, Harmony, New Market,
Staunton and Fillmore.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3944 8727 3983 8728 4011 8676 3970 8674
      3919 8687 3895 8740
TIME...MOT...LOC 0740Z 238DEG 50KT 3980 8722 3947 8722 3905 8732

Ryan

Special Weather Statement
National Weather Service Indianapolis IN
257 AM EST TUE MAR 7 2017

INZ021-028-029-035-036-043-044-070900-
Montgomery IN-Fountain IN-Parke IN-Warren IN-Vermillion IN-
Tippecanoe IN-Carroll IN-
257 AM EST TUE MAR 7 2017

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN CARROLL...FOUNTAIN...
TIPPECANOE...NORTHWESTERN PARKE...WARREN...VERMILLION AND
NORTHWESTERN MONTGOMERY COUNTIES UNTIL 400 AM EST...

At 256 AM EST, Doppler radar was tracking strong thunderstorms along
a line extending from near Sheldon to near Potomac to near Arthur.
Movement was east at 50 mph.

Wind gusts of 50 to 55 mph will be possible with these storms.

Locations impacted include...
Lafayette, West Lafayette, Delphi, Covington, Veedersburg,
Williamsport, Newport, Attica, Shadeland, Dayton, Battle Ground,
Cayuga, Montezuma, Waynetown, Linden, West Lebanon, Dana, Hillsboro,
Kingman and Perrysville.

LAT...LON 4074 8659 4032 8675 3974 8741 3974 8753
      4048 8753 4048 8709 4056 8709 4056 8677
      4073 8675
TIME...MOT...LOC 0756Z 264DEG 46KT 4073 8764 4032 8788 3975 8848

Ryan

Special Weather Statement
National Weather Service Indianapolis IN
343 AM EST TUE MAR 7 2017

INZ035-036-043>045-051-052-060-061-070930-
Clay IN-Montgomery IN-Putnam IN-Fountain IN-Parke IN-Greene IN-
Vermillion IN-Vigo IN-Sullivan IN-
343 AM EST TUE MAR 7 2017

...SIGNIFICANT WEATHER ADVISORY FOR VIGO...SOUTHERN FOUNTAIN...
SULLIVAN...CLAY...PARKE...WESTERN GREENE...VERMILLION...SOUTHERN
MONTGOMERY AND WESTERN PUTNAM COUNTIES UNTIL 430 AM EST...

At 342 AM EST, Doppler radar was tracking strong thunderstorms along
a line extending from near Ridge Farm to Willow Hill. Movement was
east at 50 mph.

Dime size hail and wind gusts of 50 to 55 mph will be possible with
these storms.

Locations impacted include...
Terre Haute, Crawfordsville, Greencastle, Brazil, Linton, Clinton,
Sullivan, Rockville, Newport, West Terre Haute, Jasonville, Fairview
Park, Shelburn, Prairieton, Prairie Creek, Cayuga, Farmersburg,
Seelyville, Montezuma and Ladoga.

LAT...LON 3922 8757 3925 8757 3925 8760 3931 8762
      3935 8753 3998 8753 4005 8670 3993 8669
      3934 8699 3934 8705 3922 8705 3891 8721
      3891 8753 3896 8751 3899 8758 3899 8756
      3906 8757 3911 8765 3912 8763 3914 8766
TIME...MOT...LOC 0842Z 267DEG 43KT 3991 8760 3901 8802

Ryan

Special Weather Statement
National Weather Service Indianapolis IN
353 AM EST TUE MAR 7 2017

INZ029-035-036-070930-
Montgomery IN-Fountain IN-Tippecanoe IN-
353 AM EST TUE MAR 7 2017

...SIGNIFICANT WEATHER ADVISORY FOR FOUNTAIN...SOUTHERN TIPPECANOE
AND NORTHERN MONTGOMERY COUNTIES UNTIL 430 AM EST...

At 353 AM EST, Doppler radar was tracking strong thunderstorms along
a line extending from near Williamsport to 7 miles northwest of
Newport. Movement was east at 45 mph.

Dime size hail and wind gusts of 50 to 55 mph will be possible with
these storms.

Locations impacted include...
Crawfordsville, Veedersburg, Waynetown, Darlington, Linden, Clarks
Hill, Hillsboro, New Richmond, Wingate, Newtown, Mellott and Yeddo.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4007 8742 4024 8726 4031 8670 4005 8671
      3998 8743 4003 8744
TIME...MOT...LOC 0853Z 263DEG 38KT 4024 8726 3998 8747

Ryan