Area Forecast Discussion
Issued by NWS Indianapolis, IN

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457
FXUS63 KIND 182107 CCA
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
406 PM EST Sat Feb 18 2017

.UPDATE...
The Synopsis...Near Term...and Short Term Sections have been updated
below.

&&

.SYNOPSIS...
Issued at 145 PM EST Sat Feb 18 2017

High pressure to the south and east will control Indiana weather
through Monday. After a weak cold front passes Tuesday, high
pressure should back in charge Wednesday. A large low pressure
system with several associated fronts will affect Hoosierland the
last few days of the week.

&&

.NEAR TERM (Tonight)...

Issued at 145 PM EST Sat Feb 18 2017

The main issue is rain chances.

Orginally we had a dry forecast for this period.  Mostly that still
looks good. However the CONSShort model keeps low POPs for the
extreme south for a few hours after 00Z. Based on latest satellite
observations and rapid refresh model runs that`s reasonable.


As the system associated with the rain slowly moves away, we should
see gradual clearing in the north, but a mostly cloudy night in the
south.

Consensus temperatures have worked well for lows recently and will
be used again tonight.

&&

.SHORT TERM (Sunday through Tuesday)...

Issued at 145 PM EST Sat Feb 18 2017

The forecast problem is how warm we can get tomorrow.

The models agree we should have a lot of sunshine in a continued
southwest flow Sunday.  The consensus forecast has been too cool for
highs recently. Given the situation is basically unchanging, the
SuperBlend will be raised a category.

The models remain consistent with Sunday night mostly clear, clouds
arriving Monday ahead of the next system, then progressively higher
rain chances starting Monday night. Consensus temperatures have been
doing well at night. Clouds and precipitation starting Monday may
end the recent tendency for temperatures to exceed guidance.

All things considered, the forecast for Monday to Tuesday will
mostly reflect SuperBlend.

&&

.LONG TERM.../Tuesday Night through Friday night/
Issued at 238 PM EST Sat Feb 18 2017

Models continue to be in similar agreement with a couple mid-upper
shortwaves moving northeast from the southwest U.S. towards the
Upper Great Lakes. System currently over southern CA will move
northeast into the Plains phasing with one shortwave, while another
develops within active southern stream.

By Thursday, next mid-upper level shortwave will move into the
Rockies with cyclogenesis over the central High Plains region. The
good news here is our mild weather will continue Wednesday and
Thursday, but the bad news is that rain and possibly some
thunderstorms will spread over the region Thursday and Friday. Given
our temperatures have been above normal for this time of year, some
of the rain and storms could be strong Thursday night/Friday
afternoon ahead of an approaching cold front.

Cold front currently projected to move through region late Friday
afternoon dropping temperatures through the 40s into the mid-upper
30s by Saturday morning.

Confidence: moderate through Wednesday.

&&

.AVIATION (Discussion for 182100Z TAF update)...

Issued at 319 PM EST Sat Feb 18 2017

Only minor changes were made based on latest observations  The big
question remains how much IFR will occur tonight. That may not be
fully answered until 00Z observations are available.

Previous discussion follows.

A weak, dissipating, cold front will cause wind to become light
after sundown, promoting fog. Some places may stay VFR, but areas of
visibilities 1-3 miles are possible from midnight through much of
sunday morning. Local ceilings below 1 thousand feet could also
occur. Skies will be mostly clear and visibilities p6SM by
tomorrow afternoon.

The wind should be southwest around 10 knots this afternoon, then
variable less than 5 knots starting this evening.


&&

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

$$
CORRECTED FOR OVERWRITTEN AFDS
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....DWM
AVIATION...JK



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