318
FXUS63 KIND 091625
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1225 PM EDT Sun Jun 9 2024

.KEY MESSAGES...

- Breezy Today.

- Dry with near to below average temps through Wednesday.

- Warming trend beginning Thursday.

&&

.FORECAST UPDATE...
Issued at 941 AM EDT Sun Jun 9 2024

Central Indiana is under the influence of high pressure but after a
sunny start for the entire region...cirrus associated with the
convective cluster to our southwest has overspread much of the
southern half of the forecast area. 13Z temperatures were largely in
the 60s.

The cirrus shield will make for filtered sunshine near and south of
I-70 in particular for the next several hours but expect cloud
coverage to diminish as the afternoon progresses with the frontal
boundary sagging further south into the Tennessee Valley. Increasing
subsidence will contribute to a decrease in clouds as well...with
breezy conditions again developing as mixing levels surge to above
8kft. Northwest winds will gust up to 25mph with dewpoints falling
back into the 40s over much of the forecast area. The ultimate
result will be another comfortably warm afternoon with highs in the
upper 70s and lower 80s.

Zone and grid updates out.

&&

.SHORT TERM (Today and tonight)...
Issued at 300 AM EDT Sun Jun 9 2024

Today...

Radar and obs data were showing a fine line with diminishing very
light returns from near a Muncie to Indianapolis to Sullivan line at
2 AM. Th fine line was coincident with a cold front that will move
into Kentucky before daybreak. In the mean time, Goes-16 IR loop and
obs were indicating there was a thick stratus deck spreading in from
east central Illinois, in the wake of the front. These clouds will
general sink southeast with the cold front this morning and leave
behind plenty of afternoon sunshine. Would not completely rule out a
shower or two over far south central Indiana, this morning. This
area will be closer to the departed cold front and impulses in fast
northwest flow that was located around the base of a southeastern
Canadian upper low. Otherwise, Hi-Res soundings were showing the low
levels drying as surface high pressure gradually builds in from the
Plains, providing subsidence. This should lead to increasing
afternoon sunshine and allow temperatures to climb back to the upper
70s to around 80 degrees. Last but certainly not least, Hi-Res
soundings are showing the potential for 25 knot northwest winds to
be mixed down from 5K feet, this afternoon. In addition, model winds
look way too low, so raised them. It will once again be a breezy
afternoon as has been the case the past few days.

Tonight...

The upper trough on the back side of the southeastern Canada and
northern New England upper low, will pivot south to the lower Great
Lakes tonight. This will send a surface trough across central
Indiana as well. Hi-Res soundings are showing an increase in sfc-5K
moisture tonight. However, they also were showing dry air aloft.
With forcing weak and only limited low level moisture, skies should
be mostly clear. The gusty winds will quickly die off near sunset as
the diurnal mixing is lost. With northwest winds in place and upper
50s and lower 50s dew points, overnight lows will bottom out well
into the 50s with good confidence.

&&

.LONG TERM (Monday through Saturday)...
Issued at 300 AM EDT Sun Jun 9 2024

A synoptic pattern characterized by flow with a predominantly
northerly component will keep our weather quiet through the long
range. Nevertheless, there are still a few things to talk about.

First, a secondary shot of cold air looks to arrive Monday morning
followed by surface high pressure. Some cloud cover may coincide
with this frontal passage, but the overall dry nature of the
continental air mass in place should limit this. The air flowing
southward behind the front is quite cold. Temperatures at 850mb look
to be between 0 and 5C, which corresponds to surface highs near 70
Monday afternoon. Additionally, as high pressure builds southward
winds should diminish leading to ideal radiational cooling potential
Monday night. Low temperatures by Tuesday morning may dip well into
the 40s outside of urban areas.

Second, a pattern change appears likely towards the end of the week.
While flow aloft retains a northwesterly component, low-level flow
takes on a more southerly component as surface high pressure shifts
southeastward. Modest warm air advection should lead to a gradual
increase in temperatures through Thursday. It is possible that highs
climb into the upper 80s or even near 90 by Friday. However, there
remains some uncertainty regarding this. Some members of guidance
are insistent on bringing a cold front through the region Thursday
night or early Friday. This would act to stunt any significant warm
up, at least for a few days. Some precipitation may accompany the
front depending on how quickly moisture can flow northward Wed and
Thur.

By the weekend, ensemble guidance continues to show substantial
ridge-building over the eastern CONUS. NAEFS/ECMWF situational
tables depict anomalous 250mb heights by Saturday/Sunday (ECMWF
showing 99th percentile heights). In this scenario the polar jet is
displaced well to the north across Canada, with weak flow through
the column across the Midwest. Such a pattern supports above-normal
temperatures with below-average precipitation. However, guidance is
picking up on a plume of tropical moisture developing far to our
south towards the end of the coming week. Should this lift northward
into the ridge, then we may see a few more opportunities for
rainfall than one would expect with such limited synoptic forcing.
CPC`s official outlook echoes this, with above-average temperatures
favored with near-average precipitation.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1225 PM EDT Sun Jun 9 2024

Impacts:

- W/NW winds gusting up to 25kts this afternoon
- MVFR ceilings possible mainly at KIND and KLAF Monday morning

Discussion:

Cirrus shield associated with convection over Kentucky and Tennessee
continues to shift south of the region early this afternoon with
mainly scattered high clouds expected for the rest of the day. Some
diurnal cu development is expected as well with overall cloud
coverage diminishing further into the evening as subsidence expands
across the region. With the mixing layer expected to peak at 7-8kft
this afternoon...winds will remain gusty for most of the rest of the
day.

A sharpening of the upper trough over much of the eastern part of
the country tonight and into Monday will enable lower ceilings
currently over the northern Great Lakes to progress south. MVFR
stratus will make it to KLAF late tonight and KIND shortly after
daybreak. Lower ceilings will gradually lift by Monday  afternoon as
drier air advects in from the north with gusty winds likely resuming
as well.

&&

.IND WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

UPDATE...Ryan
SHORT TERM...MK
LONG TERM...Eckhoff
AVIATION...Ryan