Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 190244
AFDIND

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

.UPDATE...
The NEAR TERM Section has 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 /Overnight/...
Issued at 944 PM EST Sat Feb 18 2017

Light rain near and south of the Ohio River pulling away to the
southeast rather rapidly this evening as the upper wave shifts
away to the east. Scattered mid level clouds remain over the
southern half of the forecast area with pockets of lower stratus
developing as well. 0230Z temps ranged from the upper 40s to mid
50s.

Not much change made to the overnight forecast as questions still
exist as to how extensive the lower stratus and fog will get over
the region late tonight. Hi-res guidance continues to hit both
rather hard over central Indiana towards daybreak...with simulated
satellite data offering some support as well. The stratus will
likely focus more over the southern half of the forecast area with
the entire area susceptible to patchy fog at a minimum. Trends
this evening have suggested more extensive fog will develop to our
west over southern and central Illinois then spread into the
Wabash Valley after 06Z and further east across the forecast area
closer to daybreak. Considering strength of the inversion set to
develop below 2kft...think potential does exist for locally dense
fog but overall confidence is still a bit too low to include at
this time. Will continue to monitor closely into the overnight and
adjust as needed.

Rest of the forecast looked good. Made subtle changes to lows
overnight. Previous discussion follows.

&&

.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 190300Z TAF Update/...
Issued at 944 PM EST Sat Feb 18 2017

Pockets of MVFR stratus continue to lift north and have already
briefly impacted KBMG and KHUF. Expect that to continue over the
next few hours with potential for more expansive stratus to impact
those sites and KIND after 06Z.

Rest unchanged. 00Z discussion follows.

Deteriorating flying conditions are expected late tonight and
Sunday morning in fog and low stratus before returning to VFR
conditions Sunday afternoon.

Light rain showers remain south of the terminals this evening as
an upper level wave tracks across the lower Ohio Valley. The wave
will kick out east into the Mid Atlantic and weaken by Sunday
morning taking any precipitation along with it. Lower stratus and
the potential for fog though however will linger back across the
region and expand to encompass at least to some degree all of the
central Indiana terminals by early Sunday morning. Lower stratus
over western Kentucky and far southern Indiana has been gradually
expanding north over the last few hours and expect that to
continue through the evening.

Model soundings and RH progs with most short range guidance indicating
the development of a shallow but sharp inversion below 2kft after
06Z. While the short range guidance appears overly aggressive with
fog intensity and expansion...do anticipate the potential an
extended period of sub-IFR conditions developing after 06Z and
persisting through mid morning Sunday. The inversion will slowly
weaken through midday with a return to VFR conditions for Sunday
afternoon along with light winds and just scattered mid level
clouds as high pressure passes to the south.

&&

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

&&

$$

SYNOPSIS...JK
NEAR TERM...Ryan
SHORT TERM...JK
LONG TERM....DWM
AVIATION...Ryan



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