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fxus63 kind 192351 
afdind

Area forecast discussion
National Weather Service Indianapolis in
751 PM EDT Thu Sep 19 2019

Update...
the aviation section has been updated below.

&&

Synopsis...
issued at 325 PM EDT Thu Sep 19 2019

Warm and dry weather will continue into the first part of the
weekend as ridging aloft remains over the Ohio Valley. A cold front
will slide into the region late in the weekend bringing the best
chance for rain and thunderstorms that central Indiana has seen in a
couple weeks. Cooler and drier weather will return for the first
half of next week.

&&

Near term /tonight/...
issued at 325 PM EDT Thu Sep 19 2019

The upper ridge remains anchored across central Indiana and the Ohio
Valley this afternoon...providing another warm and dry day for the
region. A boundary lifting north into the area in the form of an
inverted trough is gradually shifting low level flow to the S/southeast and
enabling deeper moisture to advect north out of the Tennessee
Valley. Dewpoints have been steadily creeping up in the the 60s
since late morning. 19z temperatures were in the 80s.

Despite heights aloft gradually falling as the ridge slowly
suppresses...the presence of continued dry air and high pressure
over central Indiana will maintain quiet weather through tonight. Cu
field is a bit more developed this afternoon over previous day in
response to the increasing low level moisture spreading into the
region. While the bulk of the cu will diminish with sunset...model
soundings and relative humidity progs do hint at more in the way of mid and high
level cloud debris lingering across the region tonight from the
convection to our northwest and the moisture plume to our southeast.

As for the convection ongoing over Iowa and northwest Illinois...
activity has been associated with an upper level wave rounding the
ridge. The wave will remain to the northwest of the forecast area
tonight with model soundings indicating the well developed cap
holding firm. Have no concern for any isolated convection meandering
into the northern Wabash valley and will continue with a dry
forecast.

Temps...leaned closer to the warmer mav guidance as lows should
remain generally in the lower to middle 60s.

&&

Short term /Friday through Sunday/...
issued at 325 PM EDT Thu Sep 19 2019

Forecast challenges focus on rain and storm chances developing
especially by Sunday and temperatures throughout the weekend.

The core of the upper ridge will continue to shift south and refocus
over the mid south this weekend as a deep trough tracks from the
northern rockies to the upper Midwest by late weekend. The Ohio
Valley will remain on the periphery of the surface ridge into Sunday
before a cold front approaches from the northwest. This should keep
the region in a continue dry and warm pattern for much of the short
term before rain chances increase Sunday with the approach of the
front.

The namnest and other hi-res guidance continues to hint at a
slightly better threat for isolated convection Friday afternoon that
appears to be generating along the remnants of any outflow
boundaries that develop with the storms over the upper Mississippi
Valley tonight. While a stray shower or storm probably cannot be
ruled out...bulk of the forcing aloft will remain well north of the
region Friday. In addition...model soundings suggest the cap will
hold with just limited instability above the inversion. Have elected
to maintain a dry forecast at this time for Friday afternoon and
evening.

A slightly drier airmass will advect into the region from the
southeast Saturday and Saturday night which should limit cu
formation during peak heating. Potential exists however for an
increasing amount of mid and high level clouds over the weekend as
the frontal boundary and associated convection align to the
northwest of the forecast area. While the front will ingest remnant
moisture from Imelda...overall model trends have slowed the primary
impacts to central Indiana to Sunday afternoon and night as the
ridge holds firm over the southeast states. While a few stray
showers are possible over the northern Wabash valley late Saturday
night...will focus primary pops Sunday with a gradual increase from
northwest to southeast through the day. Primary concerns from
convection will be locally torrential rainfall as precip water
values surge to values in excess of 2 inches by late day Sunday.
Potential certainly is there to get some badly needed rainfall.

Temps...model blends have not been handling temperatures well the
last few days and appear to be struggling considering low level
thermals and the drier ground. Went above guidance for highs Friday
through Sunday as mid to possibly upper 80s appear achievable all
three days. Lows will remain in the 60s.

&&

Long term (sunday night through thursday)...
issued at 233 PM EDT Thu Sep 19 2019

Models are close enough that the National blend of models
initialization was accepted for most items.

A cold front will move through Sunday night/early Monday. The front
will have plenty of moisture with it, thanks to some lingering
tropical moisture. Precipitable water values approach 2 inches. Thus
some locally heavy rain is possible. However, potentially limiting
any flooding threat, the ground will still be pretty dry, and the
speed of the system will help limit rainfall totals. Will continue
to monitor.

The area should be dry by Monday afternoon, and high pressure will
keep the area dry through Tuesday. Afterward, another front will
move into the area for Wednesday into Thursday, along with
potentially more upper energy.

Models differ though on strength and timing of the system, so
confidence is quite low. Will keep most of the nbm's low chances of
rain for now, and hopefully will be able to refine as we get closer.

&&

Aviation /discussion for the 20/00z taf issuance/...

Issued at 738 PM EDT Thu Sep 19 2019

VFR conditions will prevail for the duration of the taf period
with light, southerly winds.

&&

Ind watches/warnings/advisories...none.

&&

$$

Synopsis...Ryan

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