Area Forecast Discussion
Issued by NWS Indianapolis, IN
Issued by NWS Indianapolis, IN
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672 FXUS63 KIND 101653 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 1253 PM EDT Fri May 10 2024 .KEY MESSAGES... - Isolated showers/sprinkles possible today - Rain returns tonight, dry and breezy Saturday - Showers and storms return Monday into Monday night - Near normal temperatures for next week && .FORECAST UPDATE... Issued at 936 AM EDT Fri May 10 2024 Forecast is in good shape this morning. Areas of stratus are breaking up across central Indiana, but cumulus will develop as heating continues. Will keep skies partly cloudy overall today. Still cannot rule out a brief shower this afternoon, but coverage is expected to be low enough not to mention at this time. High temperatures look good, so only adjusted hourly forecasts to match trends seen in observations. && .SHORT TERM (Today and tonight)... Issued at 243 AM EDT Fri May 10 2024 Noticeably cooler air has advected into central Indiana early this morning as the cold front has shifted off to the south. Still seeing plenty of low stratus persisting across much of the forecast area and as the upper trough axis pivots through...light showers continue to linger across northeast counties but coverage was diminishing. 06Z temperatures were generally in the 50s. The passage of the cold front late Thursday has finally shifted the warmer and more humid airmass well south of the area...with a transition to a cooler regime aided by a broad upper level trough positioned over the Great Lakes and northwest flow aloft. A quick moving wave aloft traversing through the broad trough tonight in tandem with a surface frontal boundary will bring a chance for showers during the predawn hours Saturday. Drier air continues to gradually expand into the forecast area from the north and that will lead to a continued decrease in coverage to the light rain showers over the next couple hours. Stratus however is likely to remain in abundance through daybreak over much of the forecast area as moisture remains trapped beneath a boundary layer inversion. Model soundings show that not giving way until later this morning as the progressively drier airmass advecting into the area slowly infiltrates the boundary layer. Expect increasing sunshine through late morning and midday as a result but a healthy cu field will develop for the afternoon as lapse rates steepen beneath colder air in the mid levels. Model soundings show dry adiabatic conditions up through nearly 700mb by mid to late afternoon which might be just enough to generate a few very light showers with the subtle forcing present in the mid levels. Any light showers that do develop will be isolated and diminish quickly towards sunset with the loss of heating. Quiet weather this evening as the Ohio Valley remains under the influence of weak surface ridging. The ridge will shift east tonight as a quick moving front dives southeast in tandem with a wave aloft poised to reinforced the upper trough over the region. Short range ensemble guidance remains consistent with a band of showers along the boundary moving across the northeast half of the forecast area in particular after 06Z through shortly after daybreak Saturday. Rainfall amounts will be generally a tenth of an inch or less with the precipitation late tonight. While winds will drop off and become light and variable this evening and into the overnight...there is potential for a burst of wind gusts to near 25mph as the front passes late. Temps...breezy northerly flow today will keep temperatures below normal with low level thermals supportive of mid and upper 60s across the forecast area. Temperatures tonight will fall into the low and mid 50s. && .LONG TERM (Saturday through Thursday)... Issued at 243 AM EDT Fri May 10 2024 The Ohio Valley and Great Lakes will remain under the influence of the upper trough to begin the weekend with cool northwest flow. A quasi-zonal pattern will develop by early next week with a slow moving cutoff upper level low set to bring another round of wet and unsettled weather for the first half of next week. After a brief respite...another system will approach towards the end of the 7 day with another chance for rain. While there will be threats of rain throughout the extended...it will be especially quieter than the active and stormy regime experienced over much of the central U S east into the Ohio and Tennessee Valleys over the last few days. With the subtropical jet displaced well to our south throughout the extended...severe weather is not expected and the lack of appreciable instability will keep even the threat for thunderstorms limited through much of next week. Saturday through Sunday Night In the wake of the frontal passage early Saturday...strong cold advection within the cyclonic flow aloft will make for a windy Saturday aided by a tight pressure gradient between the departing front and an approaching high pressure. Peak gusts Saturday afternoon could be near if not in excess of 30mph at times. Model soundings again show a well mixed boundary layer developing through the course of the day with steep lapse rates present up to near 700mb. This will aid in cu development within the cold advection regime again during the afternoon but the lack of any substantial moisture should mitigate most concerns for isolated showers to mainly eastern counties into the early afternoon. High pressure will then build in late Saturday and hold serve for the rest of the weekend as the upper trough finally pulls away to the east and is replaced by ridging aloft. Skies will clear for Saturday night with chilly temps falling into the mid and upper 40s over much of the area. With the high overhead...a fantastic Sunday is on the docket with abundant sunshine and temperatures recovering into the 70s across the forecast area. Mid and high clouds will begin to increase Sunday night as the aforementioned cutoff upper low and associated surface wave approach from the west. May begin to see a few showers slip into the lower Wabash Valley prior to 12Z Monday but generally expect dry conditions to persist all night. Monday through Tuesday Night The upper low and associated surface wave will be over eastern Kansas Monday morning...and will track slowly east on a wobbly track through the Missouri...mid Mississippi and Ohio Valleys through early Wednesday. Showers will gradually increase in coverage throughout the day Monday with the best chances for rain to come Monday night into Tuesday with the surface low over the region. Instability will remain weak throughout much of the period with abundant cloud cover limiting heating. CAPE values are a bit better on Tuesday in the immediate vicinity of the surface low but expect thunderstorms to be scattered at best. Model soundings show precip water values rising to between 1.25 and 1.50 inches late Monday night into Tuesday with deep moisture present throughout the depth of the column. The setup supports the potential for pockets of heavy rainfall...particularly on Tuesday with any slow moving convection. Expect up to an inch for much of the forecast area by Tuesday night with locally higher amounts possible. After mid and upper 70s for highs Monday...temperatures will be held down slightly by rain and clouds on Tuesday with most areas remaining between 70 and 75. Wednesday through Thursday The upper low will weaken and eventually become absorbed by the mean flow aloft as it moves away from the region on Wednesday. Ridging aloft will build in and should enable a quiet midweek with temperatures warming back up into the mid and upper 70s under dry conditions and sunshine returning. A surface low with an associated frontal boundary will approach the Ohio Valley for late week but rain and storms should hold off across central Indiana until Thursday night continuing into Friday. && .AVIATION (18Z TAF Issuance)... Issued at 1253 PM EDT Fri May 10 2024 Impacts: - Northwesterly wind gusts to around 25kt Saturday Discussion: A broken VFR cumulus field will persist this afternoon then scatter out as heating is lost. Mid and high clouds will increase this evening, then as a front moves through overnight an area of rain with lower VFR ceilings will move through. Brief MVFR in rain cannot be ruled out, but odds are too low to include. Clouds will scatter out on Saturday, and winds will become gusty. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...50 SHORT TERM...Ryan LONG TERM...Ryan AVIATION...50