Marine Weather and Tide Forecast for West Peoria, IL

DISCUSSION
Issued at 136 AM CDT Sun Oct 13 2024

At 130am, a regional radar mosaic shows a pair of boundaries - one, an outflow from storms to the northeast across northern IN and OH, and the second a cold front sharpening as a surface low near Lincoln strengthens. The outflow boundary is primarily distinguishable (apart from the light reflectivity returns) by a wind shift, while the true cold front will separate airmasses of very different density, particularly as cool and dry advection strengthens behind it this afternoon with a tightening surface pressure gradient. While HRRR guidance suggests the probability for meeting Red Flag conditions is low (generally less than 30%), fire danger will be elevated this afternoon given gusty northwest winds and RH values falling to less than 35%. Last Sunday, the region experienced similar elevated fire conditions (but, like today, fell short of reaching RFW criteria)...and during the afternoon there were quite a few small field fire starts. Today, minimum afternoon RH values should be higher compared to last Sunday (25-35% vs 18-25%), but winds will be slightly higher (peak gusts 30-35mph, vs 20-30mph) as well. The 00z HRRR and ARW came in a little higher with gusts compared to previous iterations, and as a result there is even a small (20%) chance that along and north of I-74 winds could gust as high as 40 mph. Taking the BUFKIT mixing technique of multiple CAMs together with HRRR mean and NBM deterministic, I'm thinking most locations will top out at 30-35 mph, which is what's in the deterministic forecast at this time; even so, we want to encourage folks to avoid burning and exercise caution today with harvest efforts.

The upper trough diving into the region from the north tonight into Tuesday will be quite strong, bringing 850mb temps down from 17 degC on the 00z Sunday (i.e., last evening) ILX raob to between -2 and -4 degC (75% of LREF membership) by Tuesday morning. This translates to high temperatures in the upper 50s to low 60s tomorrow, mid to upper 50s Tuesday, and low 60s Wednesday. Morning lows will be a function of cloud cover and winds, which should stay up enough tonight to prevent frost in most places but Monday, Tuesday, Wednesday, and possibly even Thursday nights will be low enough for frost. NBM continues to advertise even a 40-60%+ chance for a freeze across rural locations Tuesday and Wednesday nights, while the raw ensemble (LREF) probabilities are generally less than 20%. Based on recent observed low temperatures on nights when similar conditions to what we're forecasting (i.e., calm winds, few to no clouds) occurred, my gut tells me NBM's probabilities are better, but time will tell; in either case, those with tender vegetation they wish to keep alive and healthy should take precautions to protect them.

Temperatures for late week have trended a little less warm as the upper level trough is slow to pull away to the east, but there's still a bit of spread with NBM's 10th to 90th percentile range extending from 62 to 76 degF for high temps by Saturday in Lincoln; this means there is a 90% (10%) chance high temps will be warmer (cooler) than 62, and 10% (90%) chance high temps will (not) be warmer than 76. While ensemble guidance is noisy this upcoming weekend, around 40% of LREF membership brings measurable precip to the region at some point Saturday-Sunday.

Bumgardner

AVIATION
(For the 12z TAFs through 12z Monday Morning)
Issued at 554 AM CDT Sun Oct 13 2024

Nighttime microphysics reveals patchy low stratus which surface obs indicate is around 700 to 1000 ft along portions of the I-74 corridor this morning. That should last only a couple more hours, burning off shortly after sunrise. Northwest winds will increase this afternoon, gusting over 25 kt at times until after sunset when they'll gradually ease.

Bumgardner

ILX WATCHES/WARNINGS/ADVISORIES
None.