415
FXUS63 KIND 170702
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
302 AM EDT Wed Jul 17 2024

.KEY MESSAGES...

- Patchy fog this morning...before a few showers and non-severe t-
storms today that could bring localized downpours south of I-70

- Dry weather along with a break from the heat and humidity Thursday
through this weekend

- A return to warm and humid weather with thunderstorm chances next
week.

&&

.SHORT TERM (Today and tonight)...
Issued at 300 AM EDT Wed Jul 17 2024

The short term will oversee central Indiana`s transition into much
needed milder and less humid conditions, following a generally quiet
cold frontal passage through midday today and the subsequent frontal
zone`s crossing through tonight.  Main weather concerns will be
patchy fog early today amid dewpoints still lingering around 70F and
mainly light winds.  Underperforming or a complete lack of rainfall
over the last 18+ hours should prevent organized areas of low
visibility...yet less cloud cover than originally expected will
maintain this concern through 12Z.

Isolated to perhaps briefly scattered convection may accompany the
boundary`s slow passing today as CAMs continue to indicate a few
cells, with perhaps brief heavy downpours later today south/east of
Indianapolis.  At least moderate confidence in no further severe
concerns with only a short late-afternoon window of weaker
instability along/ south of the US-50 corridor, which upstream,
better wind shear will not be able to catch.  Any very localized
flooding threat would be limited to southern zones through afternoon
hours, with precipitable water values falling steadily as the front
crosses today.

Otherwise winds veering to north-northwesterly this afternoon will
begin to usher in more pleasant conditions, with gusts up to 15-20
mph dropping dewpoints through the 60s over all counties by late
day.  This CAA flow should only allow near/slightly below normal
afternoon highs, with 80-85F expected across the region. Slackening
northerly winds under mostly clear skies tonight will promote lows
in the 55-60F range.  Lafayette`s forecast minimum of 57F would be
the city`s first overnight below 61F in over two weeks.

&&

.LONG TERM (Thursday through Tuesday)...
Issued at 300 AM EDT Wed Jul 17 2024

The long term will usher in a much drier and relatively cooler
airmass to central Indiana as surface high pressure moves into the
Missouri Valley, a departing cold front moves south of the Ohio
River and an upper trough pivots eastward bound across the Great
Lakes. The center of the high will move across the lower Great Lakes
Friday and stall out due to a blocking pattern courtesy of a
expansive ridge over the western states.

With 850 millibar temperatures as low as 9 to 11 degrees celsius
Thursday, afternoon highs will only reach the 70s despite Hi-Res
soundings supporting full sunshine. Temperatures will gradually
modify but still stay a few degrees below normal through the weekend
with afternoon highs anywhere from the upper 70s to middle 80s and
lows in the upper 50s and lower 60s.

The next chance of convection is expected to hold off until next
week as the high moves off to the east. This will allow for a
gradual return of southerly flow to potentially interact with an
upstream broad trough as moisture and instability increase and
combine with synoptic forcing.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 116 AM EDT Wed Jul 17 2024

Impacts:

- VCSH through midday Wednesday with isolated TSHRA possible
- MVFR VIS possible from fog 08-12Z late tonight
- Winds veering to NNW by 20Z today...afternoon gusts to 12-16KT

Discussion:

Transition into northerly flow out of Canadian high pressure will
occur during TAF period.  Mainly quiet weather late tonight will
include widely scattered showers and perhaps a passing TSHRA, but
confidence too low for any location/time to include in any TAF.
Overall lower rain chances to slowly decrease from north to south
Wednesday morning and midday where VCSH/stray thunder will
continue to be the rule.

Bigger potential impacts for terminals will be possible MVFR
visibility towards dawn in BR/fog, with overall low confidence
following lack of rainfall during last 12-18 hours. Mainly light
winds late tonight will veer through northwesterly directions
Wednesday morning ahead of NNW flow Wednesday afternoon...
sustained at 6-12KT with gusts to 12-16KT.

&&

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

$$

SHORT TERM...AGM
LONG TERM...MK
AVIATION...AGM