National Weather Service Raw Text Product
Displaying AFOS PIL: AFDIND Product Timestamp: 2025-02-11 10:36 UTC
Previous in Time Latest Product Next in Time
View All KIND Products for 11 Feb 2025 View All AFD Products for 11 Feb 2025 View As Image Download As Text
733 FXUS63 KIND 111036 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 536 AM EST Tue Feb 11 2025 .KEY MESSAGES... - An inch or less snowfall over areas mainly south of Bloomington and Rushville Today - Another wintry system Wednesday and Wednesday night with potential for greater impacts due to a combination of freezing rain and snow && .SHORT TERM (Today and tonight)... Issued at 233 AM EST Tue Feb 11 2025 Rest of the Overnight and Today... GOES-16 RGB Nighttime Microphysics loop and obs were indicating a thick cloud deck with ceilings above 6K feet and mostly near 10K feet streaming northeast across central Indiana in the fast southwest flow aloft. Meanwhile, the MRMS reflectivity loop and obs were showing an area of rain from eastern Oklahoma into the Missouri Bootheel and into eastern Kentucky and northeastern Tennessee. This area was make little northeasterly progress. Meanwhile, temperatures across central Indiana were stationary or only slowly falling due to the cloud cover with upper 20s to around 30 degrees over northern sections to the middle 30s over south central sections. Dew points were only in the teens to lower 20s in the very dry deep boundary layer. 295K isentropic analysis was showing upglide that will continue through today. However, Hi-Res soundings are indicating very dry low levels that will be reinforced by the northeasterly boundary layer winds and should make it difficult for any snow accumulation from making it as far north as the I-70 corridor. The bulk of the precip should stay south of central Indiana but wouldn't rule out areas south of Bloomington and Rushville getting possibly a half an inch to an inch from near daybreak through the early evening. Areas further north could see a few flurries but no impacts. The thick cloud cover and northeasterly winds will keep temperatures from rising much with highs mostly in the middle and upper 30s. Tonight... More mid and high clouds will be rolling in tonight in the continued fast southwest flow aloft, ahead of the next system. This will keep temperatures from falling below the middle 20s north to lower 30s south despite the northeast winds increasing to around 10 knots. && .LONG TERM (Wednesday through Monday)... Issued at 233 AM EST Tue Feb 11 2025 Wednesday and Wednesday Night: System #2 still looks on track to pass through the Ohio Valley Wednesday through Wednesday night providing a mix of different precipitation types for central Indiana. Lets take a closer look. This system is being set up by shrinking the available baroclinic zone and creating tight pressure gradients over the CONUS. In return the subtropical and polar jets will merge creating inhabitable zones for pressure depletion, especially within the mid-Mississippi Valley. The alignment of the jet streaks isn't quite ideal for deep , but as the subtropical jet streak becomes prominent late Tuesday, a corridor of negative height tendency develops leading to a gradual deepening of the upper level trough. What will fuel this winter storm is actually more focused further down in the troposphere, in the 700-850mb layers. Once again, high pressure over the SE coast will act as a blocking mechanism, tightening the pressure gradient as the upper level trough deepens. By Wednesday, this LLJ becomes strong and orients towards the SW, pushing very moist air northward into the Great Lakes and Ohio Valley. These diabatic effects along with supper of upper level diffluence will likely lead to a low level low deepening with a surface low developing over the mid Ohio Valley late Wednesday through Wednesday night. As typical with winter storms the 850mb low will be a marker for where greatest snowfall rates are expected with this system. Currently this generally progged to pass through central IL, northwest IN and southern MI. The next corridor of interest will be where the surface low will track and the subsequent warm nose attached with the LLJ. Just N/NE of the surface-to-925mb low will be a corridor of freezing rain, where the warm nose is warm enough to melt any falling snowfall before reaching the surface, but the surface remains below freezing allowing for rain to freeze upon contact. This corridor is currently progged to pass through southern IL, and central IN. The greatest ice accumulation rates are likely to occur Wednesday evening as both diurnal cooling near the surface, and nocturnal LLJ increases lead to greater QPF rates and a wider zone of potential FRAM. Even with all of these known commodities, there are still many uncertainties that are present within this forecast. Ensemble members as of the 00Z runs still have a 50-75 mile spread in system track, of which could shift the greatest snowfall and ice amounts by a similar magnitude. With that said, there is a cluster of solutions, leading to a greater probability that the surface low passes near/along the Ohio River, with subsequent lows aloft passing generally NW of this. The amounts within the summary below are generally represented by expectations if this cluster of solutions is correct Even though location of greatest accumulation has some remaining uncertainty, magnitude/amounts have begun a decline in variance, with a general agreement that the greatest FZRA axis will have have greater than 0.15" of FRAM. The current uncertainty is if the high end will get to 0.25" or higher, of which could lead to greater impacts. Snowfall amounts very a bit more, as this will have a high dependence on SLRs and the width of the transition zone between rain and snow. There is high confidence in far NW central Indiana receiving the most snow within central Indiana, but these high end amounts could be anywhere from 1-4" as of this issuance. Generally, any snow accumulations above an inch should remain N/W of a Rockville to Lebanon to Tipton line, leaving Indianapolis and the surrounding suburbs primarily in the threat for either ice or rain. Sleet looks to be less of a factor for this storm, as the near surface airmass is likely not cold or deep enough to refreeze any melted snow; that said, there could be brief period of sleet mixing into snowfall on the northern edge of the transition line. Timing also has had a greater consensus as of the 00z runs, with most ensemble members placing greatest precipitation rates Wednesday evening, and most areas out of the precipitation shield sometime shortly after midnight. That said, there could be some lingering snow showers on the backside due to wraparound moisture along with building high pressure. ********************************************************************* Storm Summary: This summary correlates with the current expectated low track. As stated above, there is still some variance in ensemble track, and specific location's amounts could shift. Current expectation is for generally 1-4" of snowfall over NW portions of central Indiana, with lesser amounts the closer you get towards a Rockville, to Lebanon to Tipton line. Greatest ice accumulations are expected to be generally just north of I-70 (west of Indy) west/north of I-69 (east of Indy). Total ice accumulations could be 0.2" or greater in some areas. Further south/east all rain is currently expected with total rain amounts around 0.25 to 0.5 inches ********************************************************************* Thursday Through Monday. High pressure will quickly move in during the daytime hours Thursday with single digit temperatures are likely for at least portions of central Indiana Thursday night into early Friday as cold air rapidly moves in as the aforementioned low pressure exits. The pattern will remain active into the weekend with yet another two part low pressure system expected Friday night through Sunday. Ensemble spread is even higher for this system, but the general consensus is that rain is the most likely precipitation type for the first portion of the low passage, and then increasingly drier as the primary low passes to the south. Another surge of anomalously cold air will move into central Indiana Monday into Tuesday with the potential for temperatures 15-25 degrees below normal. && .AVIATION (12Z TAF Issuance)... Issued at 535 AM EST Tue Feb 11 2025 Impacts: - MVFR ceilings and visibilities in light snow possible at KBMG through 24z - MVFR ceilings possible at all but KLAF after 02z-08z Wednesday Discussion: MVFR ceilings and visibilities in light snow are expected at KBMG today. Further north, there will be a big cutoff in the snow with with a few flurries possible at KIND and KHUF and perhaps a brief period of MVFR at KHUF. MVFR ceilings will then roll in tonight ahead of the next wintry system. Winds will be northeast near and less than 10 knots. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...MK LONG TERM...Updike AVIATION...MK