249 
FXUS63 KIND 100431
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1231 AM EDT Wed Jul 10 2024

.KEY MESSAGES...

- Windy on Wednesday; Beryl remnants exiting.

- Shower and Thunderstorms chances Thursday through Monday.

- Highs in the upper 80s and lower 90s Thursday-Monday.

&&

.FORECAST UPDATE...
1016 PM EDT Tue Jul 9 2024

The surface remnants of Beryl were across the southwestern forecast 
area this evening. A warm front extended from the low northeast to 
near Shelbyville. The dry slot of the system had worked ahead of the 
surface low along and west of a Terre Haute to Bedford line. 

Satellite images show cloud tops warming across central Indiana, and 
convection has been on a general downward trend this evening as 
well. Mesoanalysis still shows some decent effective shear and 0-3km 
CAPE east of the dry slot, but convection is having a hard time 
tapping into that energy.

Will still have to keep an eye on the convection as it moves east as 
850mb winds are still expected to increase some before the line 
exits. However, with diurnally weakening CAPE and storms already 
having trouble using the available energy, feel that odds of severe 
weather will continue to lower this evening. 

With plentiful moisture remaining in place, locally heavy rain will 
remain a threat, especially north of the surface low track. 

Adjusted PoPs and temperatures as needed to reflect current trends. 
Low temperatures look good, so made no changes there. Winds will 
increase in speed late tonight in the far west and the current 
forecast reflects this week.

&&


.SHORT TERM (This evening through Wednesday)...
Issued at 306 PM EDT Tue Jul 9 2024

The remnants of Beryl are in the midst of an extratropical 
transition this afternoon, as indicated by the presence of a robust 
baroclinic leaf on satellite imagery. The remnant circulation is 
centered over far southeastern Missouri at this moment, and looks 
poised to push directly through central Indiana overnight.

More than plentiful moisture and ample forcing continue to be 
expected as this occurs, with precipitable water values at or above 
climatological maximum and strong midlevel deformation just 
northwest of the low track, particularly this evening into early 
overnight.

Storm total rainfall amounts will vary across the area, from near an 
inch to as much as 3 inches with localized higher amounts. The 
highest amounts are likely to be across the far northwestern 
forecast area, including Lafayette metro, and the far 
southern/southeastern forecast area, where a swath of up to 2 inches 
or so appears likely given more opportunity for convection in that 
area. Relatively dry antecedent conditions may limit a more 
widespread flash flood threat and resultant longer term river flood 
threat, though a localized flash flood threat definitely exists 
through tonight. Will forgo a flood watch and continue to message 
through other venues.

Plentiful deep layer and low level effective shear southeast of the 
low track will present a concern for a tornado threat through this 
evening, primarily across the southern/southeastern forecast area. 

Late tonight into Wednesday, as the remnant low continues to 
transition and pulls northeastward, a tightening pressure gradient 
and strong low level flow is likely to result in windy conditions, 
peaking during the daytime hours. Frequent wind gusts of 35-40 MPH 
are likely, with a few gusts of 45-50 MPH possible. CAMs are quite 
aggressive in this respect, but have shown some good skill in such 
situations in the past. This may require a headline tonight, though 
given lingering uncertainty and hydro/tornado threat for this 
evening, will hold off on this.

&&

.LONG TERM (Wednesday night through Tuesday)...
Issued at 306 PM EDT Tue Jul 9 2024

While the remnants of Beryl dominate the short term focus, a trend 
towards hotter and more humid conditions is anticipated through the 
long range.

SYNOPTIC OVERVIEW

The current synoptic setup over the CONUS can be characterized by 
troughing over the Plains. The trough, which is currently capturing 
Beryl, will slowly propagate northeastward with time. It should 
begin to flatten and exit off into the Atlantic by the weekend. 
Thereafter, ensemble guidance shows a strengthening ridge taking 
shape over the intermountain west. Neutral to at times trough-like 
upper flow pattern looks to persist over the midwest and 
northeastern US.

Closer to the surface, high pressure over the Atlantic (The Bermuda 
High) is modeled to build westward into the southeastern US. This 
should allow for a prolonged period of westerly to southwesterly low-
level flow over the Ohio River Valley and lower midwest.

Guidance shows occasional shortwave troughs / vorticity maxima 
diving southeastward after cresting the western ridge. These may 
occasionally bring rain/storm chances through much of the long 
range. Spatial and temporal details still need to be worked out, 
however. Guidance agrees on the first vort max to at least a 
reasonable level, which looks to arrive on Thursday. As such, will 
include a greater chance for showers and storms Thursday compared to 
subsequent days. Upper-level flow looks weak, and CAPE diminishes 
with eastward extent, so and showers and storms may be short-
lived/pulse-like in nature with a low severe risk. The greatest 
likelihood would be west of Indianapolis and the greatest threat 
would be sub-severe gusty winds.

EXPECTED WEATHER

In addition to the rain/storm chances mentioned above, we may see 
occasional fog each morning through Saturday morning. Plenty of 
moisture leftover from Beryl combined with good radiational cooling 
potential should set the stage for this. A limiting factor would be 
cloud cover associated with the Thursday trough.

Despite ridging well to our west, temperatures are expected to 
increase under persistent southwesterly/westerly flow. Additionally 
dew points should increase leading to heat indices into the 90s. 
Temperatures are not anticipated to be excessively hot, but still a 
bit above the climatological norm for this time of the year.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1230 AM EDT Wed Jul 10 2024

Impacts: 

-MVFR to IFR cigs through 17Z
-Brief MVFR vsbys at LAF through 14Z with rain
-Wind shift from the southeast to northwest after 12Z
-Brief wind gusts to 40kts from 15Z to 22Z

Discussion: 

Periodic light rain showers will continue at LAF, but otherwise 
expect mostly dry conditions through the TAF period. Cigs will 
gradually become MVFR to occasionally IFR from 09Z through 17Z with 
a pretty sudden wind shift from the south to northwest towards 09Z-
12Z. Afterwards expect gusty winds through the day with brief gusts 
to 40kts possible.  These stronger winds should relax after 22Z.

&&

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

$$

UPDATE...50
SHORT TERM...Nield
LONG TERM...Eckhoff
AVIATION...White