NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION. Privacy and Cookie policy

FXUS63 KIND 090759 AFDIND

Area Forecast Discussion National Weather Service Indianapolis IN 259 AM EST Sat Dec 9 2023

Key Messages

- Wind gusts to 25-30 MPH through midday.

- Isolated showers this morning.

- More widespread showers and perhaps a thunderstorm this afternoon across Southeastern Central Indiana.

- Much colder on Sunday. Flurries possible, especially during the afternoon.

- Quiet weather conditions expected next week. Below normal temperatures early next week warm back up to near seasonal by mid- week.

Short Term
(Today and tonight)
Issued at 258 AM EST Sat Dec 9 2023

Surface analysis early this morning shows deep low pressure in place over Minnesota. A secondary low was found over Western Illinois. A strong surface front connected these systems, stretching from Central WI, across Western IL, and then south to Central MO, Arkansas and just south of the Red River valley. Indiana was found within the warm sector and a strong pressure gradient was in place.
Warm southerly winds continued to gust near 25-30 mph overnight, providing mixing and not allowing temperature falls. Weak isentropic lift across Central Indiana was allowing for poorly organized showers to develop and push northeast across the forecast area, These showers were moving quickly to the northeast. Farther upstream, radar shows two areas of showers. The first over western and NW IL. A second area of showers and storms were found along the front over west Central Arkansas. Aloft Water vapor showed a closed low over the Dakotas with abroad and deep trough stretching from from Montana, through the Central Plains and then north to the Great Lakes. This put Indiana within a warm southwest flow aloft.

Today...

The dynamic trough aloft will be our main weather player today. The previously mentioned cold front associated with the trough is expected to sweep across Indiana through the course of the day. The two areas of precipitation along the front will be our main precipitation generators. The first area over western IL and eastern MO will generally miss much of Central Indiana, perhaps only sweeping across the northwest areas this morning, as the southwesterly flow in place quickly pushes those dynamics toward the Great Lakes. Models suggest the second area of precipitation, over Arkansas, will push along the frontal boundary and cross southern and eastern Central Indiana mainly this afternoon. Models show mainly dry air across the forecast area this morning, but ahead of the front, they show saturation and forcing with this feature as it crosses our area. Forecast soundings show lapse rates briefly favorable for elevated convection this afternoon, albeit there will be a short window of time for that. Thus will focus best pops across points SE of a HUF-IND-Winchester line. Timing appears to be best during the late morning through mid afternoon period. Will use highest pops at that time across the southeastern parts of the forecast area.

Given the warm southerly flow in place for much of the morning before winds become westerly this afternoon, highs should be reached by mid day Given our warm starting temps in the mid 50s, highs in the upper 50s to lower 60s will be expected.

Tonight...

Models show aloof the best lift and forcing well east of Indiana tonight. However aloft the deep trough will remain in place as northwest flow begins to take hold across Central Indiana. Forecast soundings show dry air and subsidence building across the area overnight as a top down drying is seen developing through the night.
Even the lower levels appear to dry out, leading to partly cloudy skies arriving. Meanwhile within the lower levels strong cold air advection will be in play, as 850mb temps are shown to fall to -4C by 12Z Sunday. Strong surface high pressure over the plains states will be building across Indiana and the Ohio valley. We will expect a 25-30 degree drop in temperatures overnight as lows fall into the lower to middle 30s.

Long Term
(Sunday through Friday)
Issued at 258 AM EST Sat Dec 9 2023

The long term period will start with a large upper trough directly overhead pushing a much colder airmass into the area. At the surface, the cold front associated with the trough will be east of central Indiana. Forecast soundings show low-level moisture remaining trapped beneath a strengthening subsidence inversion on Sunday. This will lead to extensive cloud cover. The saturated layer in the low-levels should also be sufficiently deep to support flurries, especially during the latter half of the day as low-level lapse rates steepen. Flurries will likely taper off during the evening. Look for clouds and CAA to limit diurnal heating significantly with temperatures staying in the 30s.

By Sunday night, surface high pressure will build into the region allowing clouds to clear out. Quiet weather conditions are expected for much of next week as high pressure remains dominant.
Temperatures will warm up during the week with highs generally in the 40s most days. Much of the area could hit the 50F mark again by late next week. While models diverge considerably by the end of the period, there are signals that another system may approach central Indiana late Friday into Saturday supporting low chances for precipitation at this time.

Aviation
(06Z TAF Issuance)
Issued at 1233 AM EST Sat Dec 9 2023

Impacts:

- MVFR Conditions for much of this TAF period

- Gusty winds through this afternoon...highest gusts expected from the predawn hours through midday Saturday

- Low level wind shear possible overnight

- Scattered to isolated, very light showers overnight

- More organized rain expected at HUF, BMG and IND near 18Z

Discussion:

GOES16 shows MVFR stratus over spreading the TAF sites early this morning. MVFR cigs were found upstream across Illinois and MO, ahead of the approaching cold front. Radar shows poorly organized scattered showers across Central Indiana. For now have used a VCSH mention to account for these showers. current showers and CIGs are due to warm air advection and isentropic lift in place across Indiana. Forecast soundings and Time heights show these lower clouds persisting across Central Indiana through much of the day.

Gusty winds will remain in play overnight due to the strong pressure gradient that remains across Central Indiana. This will result in LLWS still being possible through much of the morning hours.

As the cold front passes this afternoon, models suggest shower development across the SE half of Indiana. These showers are suggested to slide SE as the afternoon progresses. Thus have used a prevailing rain shower mention only at HUF, IND and BMG.

A return to VFR is expected tonight as high pressure over the plains begins to build across Central Indiana.



IND WATCHES/WARNINGS/ADVISORIES
None.

toggle option: (graph/table)

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Indianapolis, IN,