Area Forecast Discussion
Issued by NWS St. Louis, MO
Issued by NWS St. Louis, MO
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322 FXUS63 KLSX 060720 AFDLSX Area Forecast Discussion National Weather Service Saint Louis MO 220 AM CDT Thu Jun 6 2024 .KEY MESSAGES... - Today and tomorrow will be dry before the chance of showers and thunderstorms arrives Friday night through Sunday. The greatest potential for widespread precipitation will be Saturday (40 to 70% maximized in southeast Missouri). Dry conditions are expected after rain exits Sunday night. - Temperatures will remain near to below average through early next week. The coolest days of the period will be Sunday and Monday with highs in the mid to upper 70s. && .SHORT TERM... (Through Late Friday Afternoon) Issued at 219 AM CDT Thu Jun 6 2024 A weak, dry cold front is pushing through the forecast area this morning. The front is expected to exit the area by mid-day, but temperatures won`t take much of a hit. Highs in the upper 70s to mid- 80s are forecast today, with areas in southeast Missouri forecast to be warmer than they were yesterday. Lows tonight, however, will be slightly cooler than what we`ve seen lately due to surface high pressure promoting radiational cooling conditions. Widespread mid to upper 50s are forecast for tonight as a result with cooler temperatures likely in sheltered areas. Friday will be very similar to today with highs in the 80s and mostly clear skies. High clouds will begin to move in from the west in the afternoon ahead of our next rain-making system. The arrival of high and eventually mid and low-level clouds will work in tandem with low-level warm air advection to boost low temperatures back to average Friday night. Low 60s are forecast areawide. Jaja && .LONG TERM... (Friday Night through Wednesday) Issued at 219 AM CDT Thu Jun 6 2024 Deterministic guidance is converging on an MCS moving through the region Saturday morning. There are still discrepancies concerning the exact timing and track of this feature, but trends are consistent in having the majority of the showers and thunderstorms passing through between the pre-dawn hours and midday. Latest guidance is pulling the system further north as well, increasing the chance of precipitation areawide. Of course, the track of the system may still wobble north or south before Saturday, but as of now most deterministic guidance pulls precipitation chances as far north as KUIN, a notable change from this time yesterday. Ensemble members at this time yesterday (12z June 4 run) had a 20 to 30% probability of precipitation at KUIN, whereas today (12z June 5 run) that probability has increased to 40 to 50%. For this reason, I think the NBM`s increase in PoPs in this area from 15 to 35% is justified. A cold front will follow the MCS Saturday afternoon through Saturday night. Most global models show convection developing along the front as it moves through the forecast area. How much of the area that sees convection depends on the speed and timing of the cold front, which varies among guidance. Right now, confidence is highest in southeast Missouri seeing additional showers and thunderstorms Saturday afternoon and again overnight Saturday as convective activity increases along the exiting cold front. After the cold front exits completely, largely dry conditions will persist through at least early next week. Temperatures from Saturday through Wednesday will remain near average with Sunday and Monday forecast to be the coolest days of the period. These days are forecast to feature widespread 70s despite partly cloudy to mostly clear June skies. Monday will be the cooler of the two as a weak backdoor cold front reinforces ongoing cold air advection. Temperatures will begin to rebound thereafter, bouncing back to above average by late next week under the influence of upper level ridging. It`s difficult to say how long the ridging will last, but the latest CPC 8 to 14 outlook favors above average temperatures and below average precipitation for the middle of this month, so this pattern change may stick around. Jaja && .AVIATION... (For the 06z TAFs through 06z Thursday Night) Issued at 1049 PM CDT Wed Jun 5 2024 Dry weather and VFR flight conditions will continue through the entire TAF period. A dry cold front will traverse across the area overnight into early Thursday morning. Winds behind the front will increase and become gusty between 15-18 UTC on Thursday. Expect scattered mid-level clouds to accompany the cold front. MMG/Glass && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX