Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 171134

Area Forecast Discussion
National Weather Service Indianapolis IN
734 AM EDT Tue Apr 17 2018

The AVIATION Section has been updated below.


Issued at 202 AM EDT Tue Apr 17 2018

Pesky and cold low pressure northeast of Indiana will exit the
area Today. This will allow High pressure in place over the
Central Plains to build across the Ohio Valley. The HIgh pressure
system will bring gradual clearing for Indiana today...along with
dry weather and moderating temperatures.

A warm front is expected to approach Indiana on Wednesday. As this
system passes quickly during the afternoon and evening chances for
some light rain will return.

A Large High pressure system is then expected to begin to build across
the region on Thursday. This will result in dry and warmer
temperatures this weekend.


.NEAR TERM /Today/...

Issued at 202 AM EDT Tue Apr 17 2018

Surface analysis early this morning shows deep low pressure in
place across Ontario and New England...with broad cyclonic flow in
place across Indiana. High pressure was found across Missouri and
the Dakotas. Water vapor imagery showed a strong ridge over the
Central Plains...building east in the wake of the departing low to
the northeast.

GFS and Nam both suggest the low pressure system to the northeast
will continue to lift Northeast and away from central Indiana.
This should allow the high pressure system to the west to fill in
behind. Plenty of cloud still lingering across the area per
GOES16. Forecast soundings and Time heights...showing a saturated
layer early this drying and subsidence arriving
late this morning and afternoon. Thus will trend skies toward
partly cloudy as some ridge riding high cloud could arrive from
the west late in the day. As for temps will stick close to the
forecast builder blends.


.SHORT TERM /Tonight through Thursday Night/...

Issued at 202 AM EDT Tue Apr 17 2018

Models suggest warm air advection tonight as the quick moving
surface high quickly exits to the east. The GFS and NAM then show
a low pressure system developing over Kansas with a warm front
extending east to the Ohio Valley. Forecast soundings show
saturating arriving within the lower levels overnight and
lingering in the area on Wednesday. Aloft...this system fails the
dynamics test as the model suggest ridging in place aloft and
overall a lack of strong forcing. Thus will trend toward
increasing clouds tonight...mainly late. As for Wednesday as this
warm front arrives in the area...lower level convergence and good
saturation could lead to some light precip amounts. Thus will
include some low chance pops for Wednesday. Again will stick with
a blend of the forecast builder temps.

The GFS and NAM show the low pressure system quickly exiting on
Wednesday night...continuing this trend of two weak and fast
paced systems. Cold air advection resumes and lower level flow is
expected to become northwesterly Wednesday night into Thursday.
Forecast soundings suggest trapped stratocu on Wednesday Night and
Thursday as the lower level flow remains rather cyclonic with the
departing low. Given the cold air advection will trend
temperatures here at or below the forecast builder blends.

Finally on Thursday night the lower level flow becomes more anti-
cyclonic and forecast soundings respond with a dry column as a
large...well-organized area of high pressure builds across
Indiana from the upper midwest. Thus will trend toward becoming
partly cloudy here.


.LONG TERM /Friday through Sunday Night/...

Issued at 322 AM EDT Tue Apr 17 2018

Latest blended initialization is trending toward a dry forecast
for the duration of the extended period as a large ridge of high
pressure dominates the central U.S.  Even the precipitation
chances associated with a low pressure system over the southern
Mississippi Valley have subsided as latest model runs show it
taking more of a southeast path. Meanwhile, temperatures through
the period will start out below normal with a warming trend
throughout the period back to normal.


.AVIATION /Discussion for the 17/12Z TAF Issuance/...

Issued at 709 AM EDT Tue Apr 17 2018

Some MVFR ceilings early in the period at KIND and KHUF, but VFR
elsewhere. And, VFR will become the prevailing flight category at
all sites by mid morning. Expect VFR conditions for the duration
of the TAF period. The only exception will be at the very end of
the TAF period at KIND when MVFR ceilings return ahead of a warm
front. Winds will start out northwesterly then veer to the
northeast and finally southeast through the course of the TAF
period. Winds will be strong this morning and afternoon with
sustained speeds of 10 to 12 kts and gusts up to 22 kts.


Freeze Warning until 10 AM EDT this morning for INZ045>048-



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