Hail and Damaging Winds in Indiana, July 7, 2017

Area Forecast Discussion
National Weather Service Indianapolis IN
211 PM EDT Fri Jul 7 2017

.UPDATE...
The LONG TERM section has been updated below.

&&

.SYNOPSIS...
Issued at 212 AM EDT Fri Jul 7 2017

Broad low pressure across the Great lakes will sweep a cool front
across Indiana today. This will bring chances for showers and
storms to Central Indiana mainly this afternoon and early this
evening.

High pressure will then settle across the Ohio valley for Tonight
through Sunday...bringing cooler tempertures along with dry
weather through at least Sunday afternoon. Chances for showers and
storms will return on Sunday afternoon as more humid air arrives
on southwesterly winds.

More thunderstorm chances will persist into the next work week as
warm and humid air persists in the Ohio valley along with a
lingering frontal boundary.

&&

.NEAR TERM /Today/...

Issued at 212 AM EDT Fri Jul 7 2017

Surface analysis early this morning shows broad low pressure in
place across the Great lakes. GOES 16 shows strong convection
across Michigan and SE Wisconsin...ahead of a trough within the
flow around the low. Skies across Central Indiana were clear with
dew points in the moist upper 60s.

main forecast challenge today will be pops. GFS and NAm both
suggest the that low to the north will continue its eastward
progression...dragging the cold front/trough across Indian late
this afternoon and evening. Ample moisture appears available with
dew point temps in the 60s and models suggesting a 30 knt llj
ahead of the trough late this afternoon. Furthermore timing
appears quite favorable for daily heating. Thus will trend pops
higher than mavmos...particularly across the SE areas will timing
will be best along with the position of the LLJ. Given the
LLJ...SLIGHT RISK from SPC seems reasonable with main threat
being damaging wind gusts.

Given the expected heating ahead of the front...will trend highs
at or above a MAVMOS blend.

&&

.SHORT TERM /Tonight through Sunday Night/...

Issued at 212 AM EDT Fri Jul 7 2017

Models suggest that the previously mentioned cold front may still
be exiting central Indiana near 00Z. Time heights show deep
moisture and lift available near 00Z. Thus with the previously
discussed favorable dynamics in place...will trend toward higher
pops early this evening...particularly across the southeast parts
of the forecast area where departure will be last. By 06Z
Saturday...Models suggest dry air and subsidence arriving on NW
winds. Thus will trend toward dry overnight...using a blend on
temps.

GFS and NAM suggest strong ridging in place across the western
United States aloft...resulting in lee side...cool NW flow across
the Great Lakes and Ohio valley on Saturday. Models suggest
strong Subsidence across the area on Saturday...Saturday Night and
into Sunday...with large surface high pressure sweeping across
the state. Will trend toward mostly sunny days and mostly clear
nights. By Sunday afternoon...the NAM and GFS suggest the surface
high will be southeast of Central Indiana...and warmer...more
humid air returns on SW winds...however little in the way of upper
supper appears available. Thus at this time...the low pops appear
primarily driven by daytime heating and instability. Thus with
this only factor in place and the strong high in place to the
SE...confidence is low for rain on Sunday afternoon.

GFS keeps NW flow in place across the area on Sunday night and
suggests a short wave moving out of the upper midwest that could
generate more showers.storms overnight. Will stick with a blend
here give the possible dynamics and include precip chances. Given
the expected warm air advection on the backside of the high to the
southeast will trend lows at or above guidance.

&&

.LONG TERM /Monday Night Through Friday/...
Issued at 211 PM EDT Fri Jul 7 2017

Models are close enough that the model blend initialization
was accepted for most items.

The forecast area will remain on the edge of an upper high through
the long term period. A surface front will remain in the vicinity
through much of the period as well. As upper energy moves around the
edge of the high and interacts with the surface front and a warm and
humid atmosphere, thunderstorms should develop from time to time.

There is low confidence in the timing and location of the storms
that far out in the forecast given the variability in upper waves
and potential location of the surface front. Will keep PoPs in
chance category or lower through the period.

&&

.AVIATION /Discussion for the 071800Z TAF Cycle/...

Issued at 157 PM EDT Fri Jul 7 2017

VFR conditions currently will potentially give way to temporarily
deteriorating conditions as TAF sites are possibly impacted by
convection ahead of an advancing cold front. Difficult aviation
forecast for 1800Z TAF Cycle as confidence not high in how current
and near future convection with evolve. Currently, the highest
confidence that showers and thunderstorms will affect any of the
TAF sites exists at LAF and potentially IND. Due to higher
confidence in these locations...a two hour TEMPO group has been
added to account for this possibility. MVFR ceilings and IFR
visibilities are expected under these convective showers and
storms...potentially worse under stronger thunderstorms. With a
Severe Thunderstorm Watch being issued across all TAF sites until
08/0100Z...damaging wind gusts and large hail should also be a
consideration. VCTS has been continued at HUF and BMG with the
possibility that they are impacted from 1900Z to 080100Z.

Expect current SW to WSW winds at 10 to 12 kts...gusting to 20
kts to continue to veer to the W then WNW to NW throughout the
rest of the evening and overnight as a frontal boundary will push
through the area from the northwest.

&&

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

SYNOPSIS...Puma
NEAR TERM...Puma
SHORT TERM...Puma
LONG TERM....50
AVIATION...MRD

Hazardous Weather Outlook
National Weather Service Indianapolis IN
939 AM EDT Fri Jul 7 2017

INZ021-028>031-035>049-051>057-060>065-067>072-081345-
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
939 AM EDT Fri Jul 7 2017

This hazardous weather outlook is for central Indiana.

.DAY ONE...Today and Tonight.

Outlook: Severe thunderstorms are possible across central Indiana
this afternoon and evening.

Hazards: Damaging winds, large hail, isolated tornadoes, heavy rain,
localized flooding.

Timing: Best chances for severe will be between 1200 PM through 900
PM.

Discussion: A cold front will approach from the upper midwest this
afternoon and evening. Thunderstorms, possibly severe, are expected
to develop along and ahead of the front.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Outlook: There is a slight chance for Thunderstorms on Sunday
afternoon and evening. More thunderstorms will be possible from
Monday through Thursday. It is too soon to determine if the storms
will be severe. Lightning is a threat with any thunderstorm.

Discussion: Daily chances for storms returns Sunday onward
as a warm and humid air mass will be in place across Central Indiana
and several upper level weather disturbances arrive from the
northwest.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening.

&&

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
1152 AM EDT FRI JUL 7 2017

INZ041-042-071630-
Randolph IN-Delaware IN-
1152 AM EDT FRI JUL 7 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN RANDOLPH AND NORTHERN
DELAWARE COUNTIES UNTIL 1230 PM EDT...

At 1150 AM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Celina to Redkey. Movement was east at 45
mph.

Half inch hail and wind gusts up to 50 mph will be possible with
these storms.

Locations impacted include...
Winchester, Albany, Union City, Eaton, Ridgeville and Saratoga.

A severe thunderstorm watch remains in effect until 500 PM EDT for
east central Indiana.

LAT...LON 4038 8558 4038 8522 4031 8522 4031 8480
      4012 8481
TIME...MOT...LOC 1550Z 278DEG 40KT 4058 8461 4032 8516

AW/CS

Special Weather Statement
National Weather Service Indianapolis IN
151 PM EDT FRI JUL 7 2017

INZ031-071830-
Howard IN-
151 PM EDT FRI JUL 7 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN HOWARD COUNTY UNTIL
230 PM EDT...

At 151 PM EDT, Doppler radar was tracking a strong thunderstorm near
Bunker Hill, or 7 miles southeast of Grissom Afb, moving east at 25
mph.

Nickel size hail and wind gusts of 50 to 55 mph will be possible with
this storm.

Locations impacted include...
Converse.

A severe thunderstorm watch remains in effect until 900 PM EDT for
central Indiana.

LAT...LON 4046 8586 4056 8618 4057 8602 4057 8587
TIME...MOT...LOC 1751Z 282DEG 23KT 4058 8604

AW/50