Area Forecast Discussion
Issued by NWS Indianapolis, IN

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923
FXUS63 KIND 250857
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
357 AM EST Sat Feb 25 2017

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

&&

.SYNOPSIS...
Issued at 256 AM EST Sat Feb 25 2017

The fluctuating pattern will continue as cooler temperatures
prevail through the weekend, quickly followed by a warm-up early
next week. First, light snow showers will persist this morning in
wraparound moisture on the back side of yesterday`s system.
However, high pressure will quickly strengthen over the region by
this afternoon, resulting in dry conditions through Sunday. At
that point, precipitation chances will increase again as the first
of several disturbances enters central Indiana.

&&

.NEAR TERM /Today/...

Issued at 256 AM EST Sat Feb 25 2017

The main focus of the near term period will be any lingering
wraparound moisture with yesterday`s system.

Currently, yesterday`s system has moved into the eastern Great
Lakes Region, putting central Indiana in a dry slot. However,
satellite imagery is indicating wraparound moisture over Wisconsin
and Illinois. As a result, anticipate light snow showers and rain
showers to filter into the forecast area around daybreak. No
accumulations are expected though, and they will quickly taper off
by early afternoon as high pressure strengthens to the west.

Much colder temperatures today will make it feel like a return to
winter with projected highs only in the 30s. This was handled best
with a model blend.

&&

.SHORT TERM /Tonight through Monday Night/...

Issued at 256 AM EST Sat Feb 25 2017

The main focus of the short term period will be 2 rounds of
precipitation, the first starting Sunday night and the second
beginning on Monday night.

High pressure/zonal flow will result in dry conditions tonight
through tomorrow. However, moisture will start increasing from the
south on Sunday night ahead of the next upper trough.
Precipitation will initially start out as rain tomorrow evening
across the southern counties, but it could transition to a wintry
mix overnight as temperatures drop. This wintry mix will spread
into the central and northeast counties by daybreak Monday and
quickly transition back to all rain before ending early Monday
afternoon.  No snow accumulations are expected.

After a short period of dry conditions on Monday afternoon, rain
will quickly re-develop on Monday evening ahead of the next
system approaching from the west. Latest Superblend initialization
is trending toward likely pops by Monday night, which seem
reasonable as the system moves closer.

A gradual warming trend will prevail through the period with highs
in the low to upper 40s on Sunday and low/mid 50s by Monday.
Meanwhile, overnight lows will jump from the 30s on Sunday night
to 40s on Monday night. Did not need to deviate from latest
Superblend initialization.

&&

.LONG TERM /Tuesday through Friday/... Issued at 245 AM EST Sat
Feb 25 2017

Forecast confidence will start off good as models agree that a cold
front will move east across central Indiana Wednesday. Deep moisture
advected in off the Gulf ahead of the system, along with waves
moving along the front, suggest high pops per the Superblend are a
good bet. In addition, operational 00z GFS and ECMWF both have
decent instability Tuesday through Wednesday. So, have thunder in
the grids in that time period. Kept shower chances in through
Wednesday night, as a trailing upper trough moves through. Could see
some snow mix in overnight across our northern counties as the
roller coaster weather continues.

Less confidence the remainder of the long term as models handle the
next system differently. The 00z has a well defined frontal system
moving through the area Thursday night. The 00z ECMWF has much less
of a surface reflection. However, both have an cyclonic flow over
the area, so small superblend pops are justified Thursday night.
Left small pops in the extreme northeast Friday morning as the
system moves out. Could once again see some snow mix in, mainly over
the northeastern half. Accumulation is not expected at this time.

Superblend looks to be handling the temperature trends well, so no
reason to make any changes. Highs could once again reach the 60s on
Monday with highs in the 40s to follow late week.

&&

.AVIATION /Discussion for the 25/09Z TAF Update/...

Issued at 256 AM EST Sat Feb 25 2017

UPDATE...
Increased sustained winds at KIND and inserted gusts up to 27 kts
as well.  No flight category changes though.

PREVIOUS DISCUSSION...
MVFR ceilings at times late tonight and Saturday morning.
Otherwise...VFR.

Strong low pressure centered over lake Huron will move to the
northeast as high pressure over the central plains moves to
Tennessee by Saturday evening.

A dry slot was spreading east across the Ohio valley and may
cause clouds to scatter out for a few hours central and south
sections.  Wrap around clouds over the middle and upper Mississippi
valley will push across central Indiana towards morning and scattered
sprinkles or flurries are possible over northern sections.  Main
impact will be a period of MVFR ceilings.   These clouds will
break up late Saturday as high pressure builds eastward.

West winds up to 15 knots and gusts up to 25 knots will occur
overnight and Saturday.  Winds will decrease to 10 to 15 knots
Saturday evening and 8 knots or less by end of forecast period.

&&

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

&&

$$

SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....MK
AVIATION...JH/TDUD



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