Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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624 FXUS63 KIWX 101037 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 637 AM EDT Fri May 10 2024 .KEY MESSAGES... -Dry today and Sunday, with variable cloud cover. Highs in the 60s today, and the 70s on Sunday. -Chances for showers and thunderstorms tonight and Saturday. Severe weather is not expected. Lows tonight will be around 50 degrees, and highs Saturday will be in the 50s and low 60s north of US 24, and the mid to upper 50s south. -Chances for rain for much of the week ahead. Thunderstorms are possible at times, but severe weather is not expected. High temperatures will be in the 60s and 70s. && .DISCUSSION... Issued at 514 AM EDT Fri May 10 2024 At long last, a glorious dry day is upon us! As of this writing, the last of the precipitation just exited the southern CWA. A ridge of high pressure builds in aloft ahead of the next system through the afternoon, drifting slowly eastward with time. Light winds and mostly sunny skies with high pressure centered over the central plains arching up into IN/IL/OH. Highs will be in the low to mid 60s with light north-northwest winds. Chances for showers and thunderstorms return this evening into Saturday as an upper level low settles in over the Great Lakes region. The corresponding surface low will drift into Lake Superior by 6z tonight, then by Saturday evening, drop into southern Lake Huron and Lake Erie. We may see some weak showers with increasing WAA tonight ahead of the warm front (some models suggest as early as 21z but I held pops until after 00z given lower confidence). As the low continues its southeastward progression, it begins to occlude and we see the cold front move through much of the forecast area by 12z Saturday, and east of it by the afternoon. Focused rain chances with the cold front passage tonight, and kept chances into Saturday afternoon as there is a trough that lingers in the far east behind the exiting low/cold front, and I think this could trigger continued chances for showers and storms. Overnight we have decent mid level lapse rates--around 6.5 to 7 C/km with that wave, in addition to strong synoptic forcing with the sharper trough. MUCAPE values grow to around 800 J/kg through 15z Saturday, with surface based values of 100-400 J/kg. Think we have enough with the weak moisture advection at the surface (dewpoints in the low 50s) ahead of the low to warrant likely/cat pops along the front, and to add at least chances for thunder. 0 to 6 km bulk effective shear along/ahead of front looks to be around 35 to 55 knots (with the mid level jet streak in Chicago around 60-75 knots that sinks southwest of our our CWA through the morning), but given limited instability don`t think we`ll see any strong to severe storms. Lows drop to around 50 degrees tonight. Highs on Saturday will be in the 50s and 60s, with blustery NW winds and decreasing cloud cover from west to east. Dry conditions return on Sunday (and possibly into Monday) as another high pressure ridge builds in overhead with a surface high below. Temperatures will warm into the mid 70s west half, and low 70s east as we warm advect ahead of the next system. A cold front stemming from low pressure over James Bay will reach Lake Michigan late Sunday night, then attempt to cross our CWA through the day but washes out or gets hung up. This sets the stage for Tuesday- Thursday`s weather as another system from the central plains lifts in (upper level low included!) and brings intermittent rain and storm chances to our cwa again. Confidence in exact locations for best precipitation chances is low at this far out, so left consensus pops for now and confined thunder to best times of instability. Temperatures Monday into Friday will be in the 60s and 70s. && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 629 AM EDT Fri May 10 2024 Remaining light showers have now moved out of the area and in the wake of the disturbance a more northerly flow will bring in cooler and drier air and allow for light winds and VFR conditions. After about 15z today expect surface warming to allow for some cumulus development around 5000 ft. Another disturbance moves into the region after 00z Sat increasing chances for rain showers. Did leave out mention of thunder at this time but a rumble of thunder late tonight will be possible. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ DISCUSSION...MCD AVIATION...Andersen