Expires:No;;269607 FXUS63 KIND 240228 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 1028 PM EDT Tue Apr 23 2024 .KEY MESSAGES... - Afternoon/evening rain expected. Total QPF under a half inch; Cooler - Becoming Partly Cloudy on Wednesday. - Cooler mid-week, with some frost possible Wednesday night for northern portions of Central Indiana - Active pattern returns Friday into next week with above normal temperatures and frequent rain chances && .FORECAST UPDATE... Issued at 1028 PM EDT Tue Apr 23 2024 Made minor adjustments to account for the location of rain and current surface observations. Radar shows that the rain has almost completely moved out of the forecast area. The front itself still hasn't made it's way through central Indiana but it sits just off to the NW and will move through overnight. Until then, the majority of clouds have also exited with the rain but while we still sit in a humid and relatively warm sector, a patchy stratus deck is forming over the area. Satellite shows that much of the stratus is currently over the NE counties, but there are some spots of stratus forming over the Indy metro and areas both north and NE. Can't rule out shallow patchy fog in low lying areas as well. && .SHORT TERM (This evening through Wednesday)... Issued at 235 PM EDT Tue Apr 23 2024 Synopsis: Surface analysis early this afternoon shows low pressure over the Central Great Lakes and a second area of low pressure was in place over OK and the TX panhandle. A cold front across WI, SE IA and eastern KS connected these two lows. Broad and elongated high pressure was found across the east coast and stretching west across the gulf coast. This was resulting in southerly flow across Central Indiana, however the high pressure system was effectively blocking moist gulf flow from reaching the Ohio Valley. Aloft, a moderate short wave was found over WI and MN, with a trough axis extending SW across IA. This was resulting in moderate westerly flow aloft across Indiana. This short wave was being influenced by the broader cyclonic flow across northeast North America as a deep upper low was anchored near Hudson Bay. Water Vapor showed moisture ahead of the trough over IL and Indiana and MI. GOES16 shows abundant cloud cover ahead of the frontal boundary, pushing toward Central Indiana. An area of rain was found over North Central Indiana, sagging southward. Dew points ahead of the line have reached the 40s, but current dew point depressions of 15-20F still exist. Tonight... Models suggest the forcing with the approaching short wave will pass across Indiana this evening as the trough axis and the associated surface cold front lag behind, passing overnight. Given the recent radar trends showers over the northern parts of the forecast area and the expected southern progression of the upper trough, the band of showers will sag southward to nearly the I-70 corridor by 4-5pm and farther south by 8p-9p. Forecast soundings through this time period continue to a saturated column through the late afternoon and early evening hours. Thus will continue with the ongoing near 100 pops with this band as it sags southward late this afternoon and evening. After the forcing clears, residual lingering clouds will be left in the wake of the rain, as clearing skies will hold off until the wake of the front overnight. HRRR Suggests lower level saturation toward 12Z hence some lingering lower clouds may still remain during the late overnight and early morning hours. Cold air advection will be in place overnight as winds become northerly. Ongoing lows in the lower to middle 40 appear on the mark. Wednesday... Models on Wednesday show the upper trough departing. Strong ridging is shown to build across the Rockies, leading to NW flow aloft and lee side subsidence over the upper midwest, Great Lakes and Ohio Valley. A strong area of surface high pressure is shown to build behind the front, reaching the Great Lakes by Wednesday afternoon. This appears to be a large area of high pressure, extending its influence from Ontario across the Ohio Valley to the Gulf of Mexico. Models show relatively high RH within the column in the area as the day begins, but as heating and mixing resumes, a dry column is realized. Hence we will look for skies to become partly cloudy as the day progresses and the surface high builds across the area. Given the ongoing cold air advection highs will only reach the lower to middle 50s. && .LONG TERM (Wednesday night through Tuesday)... Issued at 235 PM EDT Tue Apr 23 2024 Wednesday night and Thursday... Quiet weather can be expected during this period with high pressure in control at the surface and rising upper heights. The main question is frost potential Wednesday night. Winds will be light, and the cooler airmass will remain in place. However, uncertainty remains in how much cloud cover there will be. There will be likely some high clouds moving in over the ridge, but they may be initially thin. Will go with lows in the mid 30s north and continue to mention some frost. Lows will be in the upper 30s elsewhere. On Thursday, filtered sunshine will boost temperatures into the upper 50s to mid 60s. Friday and beyond... A couple of upper systems will eject out of the southwestern USA during this period. The first on Friday will bring a warm front northeast through the area. Good southwest flow aloft will bring in moisture for the front to work with. Will go with likely PoPs most areas on Friday and Friday night. Forcing weakens on Saturday but there will still be some around, so will keep chance PoPs then. The next upper system will begin influencing the area on Sunday, with better forcing arriving with a front on Sunday night into Monday. Continued southwest flow will keep moisture available, so will go with likely PoPs again. Of course, some uncertainty in timing of the best forcing remains this far out, so details could change. CSU Machine Learning is hinting at some potential for strong to severe storms at times, but feel that the better threat will remain west of central Indiana (closer to stronger forcing and better instability) at least through the first half of the weekend. Will have to watch the Sunday/Monday system to see if things align better. Temperatures will be above normal through much of the period. With the stronger southwest flow aloft, mixing will allow some breezy conditions through much of the long term period. && .AVIATION (00Z TAF Issuance)... Issued at 845 PM EDT Tue Apr 23 2024 Impacts: - Rain is exiting the area - Winds shifting from SW to out of the north, sustained at 7 to 10 kts - MVFR ceilings possible at a few sites tomorrow morning under a low stratus deck Discussion: The rain is moving out of the area at the top of the forecast period leaving behind VFR conditions for much of the night. Then expecting a low stratus deck to move in from the NE bringing MVFR ceilings early in the morning and lasting into midday. These clouds will likely reach LAF and IND but could also get to BMG and HUF briefly. Winds will shift from SW to NW to N behind the front which will pass through the region near to after midnight. Expect sustained winds of 7 to 10 kts through the period. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...KF SHORT TERM...Puma LONG TERM...50 AVIATION...KF