River Flood Advisory 4, NWS Indianapolis, IN

Area Forecast Discussion
National Weather Service Indianapolis IN
1020 AM EDT Fri Apr 13 2018

.UPDATE...
The Near Term Section has been updated below.

&&

.SYNOPSIS...
Issued at 126 AM EDT Fri Apr 13 2018

Warm spring weather will continue as the work week ends as warm
southerly breezes remain in place ahead of a strong low pressure
across Central Indiana.

A Strong cold front will approach Central Indiana tonight before
passing across the area on Saturday Night. Showers along with a
few thunderstorms will be possible along and ahead of the
front for Friday night through Saturday Night.

Much Colder temperatures will arrive on Sunday an Monday in the
wake of the cold front. Furthermore...deep low pressure looks to
linger across the Great Lakes. This will keep chances for rain
showers in the forecast as the weekend concludes and the new work
week begins.

Dry weather with moderating temperatures look to return early next
week as high pressure builds across the area.

&&

.NEAR TERM /Rest of Today/...

Issued at 1020 AM EDT Fri Apr 13 2018

Low pressure is centered over eastern Kansas/Nebraska this morning
stretching a warm front across northern Illinois and into northern
Indiana. Radar loop shows a line of scattered thunderstorms moving
across eastern parts of central Illinois that will be crossing into
Indiana shortly. The tight pressure gradient across the area
continues to create wind gusts of 25 to 35 mph across the area
currently and could see this increase to around 40 mph for late
morning into the afternoon.

Due to the aforementioned thunderstorms that developed over central
Illinois this morning, have added PoPs and isolated to scattered
thunderstorms over western parts of the forecast area late this
morning into early afternoon. Eastern parts of the area should still
remain dry through the day with increasing chances for showers and
storms not arriving until tonight. Going high temperatures in the
upper 70s still look on track.

&&

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

Issued at 126 AM EDT Fri Apr 13 2018

Active weather poised to begin again tonight. The GFS and NAm
suggest the first short wave aloft will be ejected toward Central
Indiana during the Overnight hours. Forecast soundings show deeper
saturation arriving as do the time heights as strong lift arrives
with the approaching short waves. 300K GFS Isentropic surface
shows some lift tonight ahead of the front...with specific
humidities in excess of 6 g/kg. Thus will trend toward categorical
pops tonight as these features pass...with best forcing expected
after midnight. Indiana will continue to be within the warm sector
tonight...but the rain expected...will trend lows at or above the
forecast builder blends...closer toward wetbulbs.

GFS hints at some dry air arriving across the area in the wake of
the passing short wave on Saturday morning. Forecast soundings
dry out considerably...and the models suggest that the cold front
is still west of the state...over Illinois during the morning.
Thus will trend pops lower at that time before ramping back up on
late saturday afternoon and Saturday night as the cold front
finally passes. Several dry hours within the warm sector on
Saturday could result in a warm day. As the warm air mass will
still be in place for much of the day and good mixing will be
expected...will trend highs at or above forecast builder blends.

The cold front will pass on Saturday night. Forecast soundings
show deep saturation. Excellent upper support will be expected as
the closed upper low passes northwest of Indiana. Thus will again
use categorical pops with the favorable set-up for precipitation.
Given the strong cold air advection in the wake of the
front...will trend lows close to the forecast builder blends.

Sunday showing many signs of colder day. The GFS and NAM allow the
upper low to pass across Northeast Indiana...keeping Broad
cyclonic flow in place across Indiana. Cool NW surface winds will
be expected. Forecast soundings show an initially wet forecast
soundings...drying out mid day...but by afternoon lower level
saturation is seen as convective temps in the mid to upper 50s are
reached. a steep mid level inversion should prevent much
growth...but given the cyclonic flow...shower chances cannot be
ruled out. Thus will stick at or above the forecast builder blends
here. Given the expected clouds and cold air advection...will
trend highs colder then blends.

Shower chances will be expected to persist for at least a few
hours on Sunday Night as forecast soundings again hint toward
lower level saturation as broad cyclonic flow continues around the
deep upper low across the Great lakes. Uncertainty here on
specific timing is high...but a favorable pattern for light
precip remains in place...thus will stick close to the blends
here.

&&

.LONG TERM /Monday Through Thursday Night/...

Issued at 231 AM EDT Fri Apr 13 2018

The ECMWF still depicts Central Indiana under the influence of the
deep upper low over the Great Lakes on Monday. This will continue
to keep some low precipitation chances in the forecast due to the
cyclonic flow around the low. Furthermore...cool NW winds will
continue to provide below normal temperatures to start the work
week.

Dry weather is expected to build across the region on Monday night
in to Tuesday as the ECMWF suggests ridging and High pressure
arriving and the upper low finally departs northeast. This should
start a slow moderation of daily temperatures.

The ECMWF suggest a warm front arriving along with an area of low
pressure on Wednesday. Furthermore...the ECMWF shows a quick
moving short wave passing with this feature on Wednesday.
Curiously the forecast builder fails to insert any pops...which
given these features...a small pop seems warranted.

Dry weather is expected to then return for Thursday and Friday as
ridging returns to the region...temperatures will still remain at
or below seasonal normals.

&&

.AVIATION /Discussion for the 131200Z Tafs/...

Issued at 654 AM EDT Fri Apr 13 2018

Mainly VFR Conditions are expected the next 12-14 hours.
Deterioration to MVFR or worse will be possible after 04Z.

VFR Conditions will remain in place across the TAf sites today as
Central Indiana remains within the warm sector ahead of
strengthening low pressure over the Central Plains states. A
strong pressure gradient in place ahead of the low will result in
some gusty winds today along with some LLWS.

A short wave will arrive in the area after 00Z...as the models
suggest strong lift and moisture arriving across the TAF
sites. Showers and isolated thunderstorms will be expected as the
upper wave passes...mainly after 05Z through the overnight hours.
MVFR along with brief IFR conditions will be expected with any
thunderstorm that strikes a TAF site.

&&

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

SYNOPSIS...Puma
NEAR TERM...CP
SHORT TERM...Puma
LONG TERM....Puma
AVIATION...JP

Hazardous Weather Outlook...UPDATED
National Weather Service Indianapolis IN
1000 AM EDT Fri Apr 13 2018

INZ021-028>031-035>041-043>046-051>054-060-061-141400-
Carroll-Warren-Tippecanoe-Clinton-Howard-Fountain-Montgomery-Boone-
Tipton-Hamilton-Madison-Delaware-Vermillion-Parke-Putnam-Hendricks-
Vigo-Clay-Owen-Morgan-Sullivan-Greene-
Including the cities of Lafayette, Frankfort, Kokomo,
Crawfordsville, Anderson, Muncie, and Terre Haute
1000 AM EDT Fri Apr 13 2018

This hazardous weather outlook is for central Indiana.

.DAY ONE...Today and Tonight.

Outlook: Thunderstorms are possible today and tonight. Southwest
winds may gust to around 35 mph at times.

Hazards: Lightning. Gusty winds.

Timing: Isolated to scattered storms from late morning through the
afternoon. More chances for storms later tonight. Wind gusts
throughout the day.

Discussion: A strong low pressure system approaching central Indiana
will bring gusty winds to the area today and keep chances for
thunderstorms in the forecast today and tonight.

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

Outlook: Thunderstorms are possible at times from Saturday into
Saturday Night. Isolated severe storms are possible on Saturday.
Heavy rainfall is also possible over the weekend.

Discussion: A strong low pressure system is expected to affect the
area over the weekend, with thunderstorm activity and heavy rain
possible. There is a chance for light mixed precipitation Sunday
night into Monday morning. Snow accumulations are not expected at
this time.

.SPOTTER INFORMATION STATEMENT...

Severe storm spotters are encouraged to monitor future statements
regarding the severe threat on Saturday.

&&

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

INZ067-068-141400-
Knox-Daviess-
Including the city of Vincennes
1000 AM EDT Fri Apr 13 2018

This hazardous weather outlook is for central Indiana.

.DAY ONE...Today and Tonight.

Outlook: Thunderstorms are possible today and tonight. Southwest
winds may gust to around 35 mph at times. Moderate flooding will
continue along lower parts of the White River.

Hazards: Lightning. Gusty winds. Strong river currents, flooded roads and low lying
areas.

Timing: Isolated to scattered storms from late morning through the
afternoon. More chances for storms later tonight. Wind gusts
throughout the day. Flooding ongoing.

Discussion: A strong low pressure system approaching central Indiana
will bring gusty winds to the area today and keep chances for
thunderstorms in the forecast today and tonight.

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

Outlook: Thunderstorms are possible at times from Saturday into
Saturday Night. Isolated severe storms are possible on Saturday.
Heavy rainfall is also possible over the weekend.

Discussion: A strong low pressure system is expected to affect the
area over the weekend, with thunderstorm activity and heavy rain
possible. There is a chance for light mixed precipitation Sunday
night into Monday morning. Snow accumulations are not expected at
this time.

.SPOTTER INFORMATION STATEMENT...

Severe storm spotters are encouraged to monitor future statements
regarding the severe threat on Saturday.

&&

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

INZ042-047>049-055>057-062>065-069>072-141400-
Randolph-Marion-Hancock-Henry-Johnson-Shelby-Rush-Monroe-Brown-
Bartholomew-Decatur-Martin-Lawrence-Jackson-Jennings-
Including the cities of Indianapolis, Shelbyville, Bloomington,
Columbus, Bedford, and Seymour
1000 AM EDT Fri Apr 13 2018

This hazardous weather outlook is for central Indiana.

.DAY ONE...Today and Tonight.

Outlook: Thunderstorms are possible after midnight. Southwest winds
may gust to around 35 mph at times.

Hazards: Lightning. Gusty winds.

Timing: Storms after midnight. Gusty winds throughout the day.

Discussion: An upper level weather disturbance may produce some
thunderstorms across Central Indiana overnight.

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

Outlook: Thunderstorms are possible at times from Saturday into
Saturday Night. Present indications suggest isolated severe storms
are possible on Saturday. Heavy rainfall is also possible over the
weekend.

Discussion: A strong low pressure system is expected to affect the
area over the weekend, with thunderstorm activity and heavy rain
possible. There is a chance for light mixed precipitation Sunday
night into Monday morning. Snow accumulations are not expected at
this time.

.SPOTTER INFORMATION STATEMENT...

Severe storm spotters are encouraged to monitor future statements
regarding the severe threat on Saturday.

&&

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