Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 250817

Area Forecast Discussion
National Weather Service Indianapolis IN
417 AM EDT Sat Mar 25 2017

Aviation section updated


Issued at 300 AM EDT Sat Mar 25 2017

A series of low pressure systems will provide frequent chances for
rain across central Indiana for the next week. Temperatures will
remain above average through the period.


.NEAR TERM.../Today/
Issued at 300 AM EDT Sat Mar 25 2017

Early this morning a surface front was stalled just northwest of
central Indiana, and the front stretched back to an area of low
pressure in Missouri. An upper low was back in Oklahoma. The bulk of
rainfall was back near the Mississippi River and moving north

The surface front shouldn`t make any more progress southeast as the
surface low continues to move northeast. Meanwhile, expect the bulk
of the rain across Illinois to continue to move more north than east
given the expected forcing and upper flow. Thus will start the day
off with chance PoPs west to slight chance or dry east.

Forcing will only slowly work its way east today as the system moves
slowly toward the area. Thus will only gradually increase PoPs from
west to east today. By 18Z will have likely PoPs extreme west with
PoPs lowering to the east.

By the end of the Today period will have likely PoPs west half and
chance east half as better forcing finally arrives.

Instability will increase today allowing for thunderstorms to spread
east during the day. Storm Prediction Center has the far southwest
counties in a Marginal Risk for the potential of an isolated severe
storm with damaging winds this afternoon.

Again today some of the stronger winds aloft could mix down and
bring surface gusts around 30 MPH.

For temperatures, generally went above the model blend for highs
given the blend`s performance on Friday. Once again if cloud cover
is less than expected temperatures will exceed the forecast and
could get closer to the warm MET MOS numbers in the mid 70s.


.SHORT TERM.../Tonight through Monday night/
Issued at 300 AM EDT Sat Mar 25 2017

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

Tonight the upper and surface lows will move to near the Mississippi
River. Thus expect continued forcing across central Indiana as the
system moves closer to the area. Will continue likely category or
higher PoPs through the night.

As the upper low moves into Indiana Sunday high PoPs will continue,
especially during the first half of the day. During Sunday evening,
only the east half of the area will see some low PoPs as the system

The brief dry period overnight Sunday night will give way to more
chances for rain Monday and Monday night as another system moves in.
The upper system doesn`t look as strong as the first one, but
forcing and moisture look sufficient for likely PoPs Monday night.


.LONG TERM /Tuesday through Friday/...

Issued at 219 AM EDT Sat Mar 25 2017

ECMWF suggests mainly quiet weather in place on Tuesday and
Wednesday across Central Indiana as strong ridging aloft is
expected to be building and pushing across the region during that
that time. Have trended grids toward a dry forecast for now even
through the ECMWF still suggests a weak lingering boundary across

ECMWF suggests a much more wet period for Thursday and Friday as a
strong negatively tilted upper trough is poised to push into the
Ohio Valley. Further support is seen with the a surface low
trekking through Illinois to Michigan...placing Indiana within the
warm sector. Forecast Builder responded with likely or better
pops on Thursday through Friday...and although rain will be
expected at some time during this period...confidence for high
pops at specific times is much lower. Given the SW flow in
place...look for temps at or above normals through the period.


.AVIATION /Discussion for the 2509000Z IND Taf/...

VFR Conditions will continue. No significant changes to the
ongoing tafs as VFR Conditions continue as low pressure continues
to approach from the west. Radar trends continue to suggest
mainly a northward propagation of the the showers to the west
through the next 3-6 hours...with little advance toward the TAF

Previous Discussion Below

/Discussion for 250600Z TAF Issuance/...
Issued at 1201 AM EDT Sat Mar 25 2017

VFR conditions expected through midday...with restrictions
developing during the afternoon in showers and embedded
thunderstorms. Lower ceilings arriving this evening.

Upper ridge giving way as upper low and associated surface wave loft
out of the southern Plains. Despite the presence of a frontal
boundary sagging south slowly over the lower Great Lakes...hi-res
guidance continues to slow the arrival of the initial surge of
showers until after daybreak at the earliest with a greater impact
to the terminals coming for the afternoon as a low level jet
overspreads the area and forcing aloft increases. Expect expanded
precip coverage for the afternoon as a result and considering the
presence of weak instability...expect a few thunderstorms as well.
Restrictions are expected within heavier rain and storms...but
ceilings should remain VFR for the most part through the afternoon.
Model soundings and RH progs indicate the boundary layer becoming
saturated this evening and into the overnight...with more extensive
MVFR to possibly IFR stratus developing.

South-southeast winds are expected through the period...with higher
gusts approaching 25kts once again developing during the afternoon.




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