Area Forecast Discussion
Issued by NWS Indianapolis, IN
FXUS63 KIND 170307
Area Forecast Discussion
National Weather Service Indianapolis IN
1010 PM EST Mon Jan 16 2017
The Aviation Section has been updated below.
Issued at 217 PM EST Mon Jan 16 2017
A low pressure system currently moving into the Missouri Valley
will be the main focus early in the forecast period. Rain showers
will continue to spread across the forecast area from the
southwest this evening and tonight. As forcing strengthens, the
threat for isolated thunderstorms will also increase this evening
and tonight. Rain showers will linger through tomorrow, but as the
system pushes farther east, dry conditions will return for
Wednesday. After that, the first of several systems will approach
from the southwest on Thursday, bringing additional rainfall
chances through the end of the week. Further out, additional
systems from the southwest will bring more chances for periodic
rain through the extended period.
.NEAR TERM /Rest of tonight/...
Issued at 916 PM EST Mon Jan 16 2017
A view of the radar mosaic at 9 pm shows another area of showers
overspreading the area from the southwest. Visibilities have
improved across much of the area just ahead of the showers, and
the northwestern counties that previously were experiencing dense
fog have seen significant improvement. Expect similar improvement
at Kokomo as showers are moving in there as well, and then should
be rid of the dense fog at any sites across the area, so cancelled
the remainder of the dense fog advisory. Think some patchy fog
will hang around as showers move out later due to the low level
moisture they leave in their wake but with the warm front moving
north of the area don`t expect fog to be too bad.
The aforementioned area of showers also contains some embedded
thunder, so continued with mention of isolated thunderstorms.
Considered upping to chance or scattered wording for the thunder,
but as echoes are moving east they look less organized and
lightning strikes are decreasing.
With extensive coverage of showers increased pops to categorical
everywhere across the area for a few hours. Showers should
decrease from west to east later during the overnight and by
morning much of the area could be dry or starting to dry out with
the exception of the eastern counties, where likely pops will make
it past 12z. Average rainfall amounts will be around a quarter to
half an inch but some locations could see over an inch.
Temperatures should remain pretty steady through the night with
the rain and southerly flow.
.SHORT TERM /Tuesday through Thursday/...
Issued at 217 PM EST Mon Jan 16 2017
The main focus of the short term period will be rain chances early
in the period as a low pressure system continues its track across
the Great Lakes Region.
Rain showers will continue to linger through Tuesday morning
across all of central Indiana and just across the northern
portions during Tuesday afternoon as the associated cold front
moves through the area. Time cross sections show a rapid loss of
moisture in the mid and upper levels as early as Tue 12Z though,
so will not go any higher than slight chance and chance pops at
any time tomorrow.
Latest Superblend initialization keeps slight chance pops in the
forecast over northern portions of central Indiana into Tuesday
night and will continue with this trend as models hint at another
quick wave in the upper levels between Wed 00-06Z. After that,
models come into agreement in regard to high pressure and dry
conditions on Wednesday. This pattern will be short-lived though
as the first of several systems approaches from the southwest on
Thursday. Rain showers will start spreading across the forecast
area from south to north on Thursday ahead of that system.
Temps will remain above normal through the period with
west/southwesterly flow. Highs will generally be in the 40s and
50s with lows in the 30s, stuck close to a model blend.
.LONG TERM /Thursday night through Monday/...
Issued at 212 PM EST Mon Jan 16 2017
A mild and wet period is on tap this weekend and early next week.
Deterministic models are now in pretty good agreement over 3 main
upper systems that will effect central Indiana. So, with some
confidence, expect the first of these systems to bring widespread
showers to the area Thursday night into Friday. This system is
currently over Mexico and the four corners region and will
eventually become negatively-tilted as it pinwheels northeast
over the Ohio Valley on Friday and spins up a surface low and
occluded front. Instability progs suggest thunder is not out of
Models then pivot another southwestern system northward on Saturday.
However, this one will be west of the first one, across the Plains.
This, should keep the forecast area mostly dry until Saturday night.
Then the final system is progged to wind up over the Ohio Valley
Sunday night into Monday. More widespread showers and possibly
thunderstorms are expected with this system.
Regional blend pops looked good except after coordinating with LMK,
PAH and ILX, pulled small blotchy pops associated with the second
system on Saturday.
With southerly flow off the Gulf, temperatures will be well above
normal with highs in the 50s and possibly 60s per Regional blend.
.AVIATION /Discussion for 170300z TAF issuance/...
Issued at 1010 PM EST Mon Jan 16 2017
Updated to improve ceilings for a few hours as showers move through
the area per observations. Still expect IFR and lower ceilings to
redevelop in a few hours. Previous discussion follows...
Mainly IFR and lower during the period. Could see brief
improvement to cloud ceilings and visibilities as showers move
through the area currently and for the next hour or two, but
after that expect ceilings to drop back down with whatever showers
are still moving through. Low level jet picks up tonight and could
see some LLWS starting around 4z or so at KLAF and KHUF and
arriving at KIND and KBMG by 6z and lasting through around 9-10z.
This could also enhance chance for thunder ahead of it, and may
include a VCTS for a couple hours. Wind gusts around 20 kts are
possible Tuesday afternoon out of the WSW, and ceiling could
briefly improve to MVFR late morning but drop back to IFR during