Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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233 FXUS63 KMPX 061729 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 1229 PM CDT Sat Jul 6 2024 .KEY MESSAGES... - Scattered showers and storms this afternoon and evening, diminishing after sunset. Locally heavy rain could result in up to a half inch of accumulation, most of the area within a quarter inch. - Further chances for daytime heating driven showers and storms for the next few days. Temperatures gradually warm throughout the week. && .DISCUSSION... Issued at 309 AM CDT Sat Jul 6 2024 Compared to yesterday morning at this time, we are dealing with a lower both spread and depth of fog with the main tricky spots still persisting over western Wisconsin, which makes sense given the longer residence time of showers over that area today. Visibility has dropped below 3 miles in spots but should improve quickly after sunrise with free mixing expected today. Satellite imagery shows some deeper clouds with weak convection in central South Dakota, however the states of Minnesota and Wisconsin are generally clear with only a few smaller banks of stratus aside from the fog. An extremely broad trough is currently stretching over the CONUS with the only forcing to speak of being an upper level jet in eastern Canada with weak high pressure holding over the center of the country. This makes for a perfect setup for mostly clear skies and sunshine to begin the day, which will allow for efficient mixing and eventually the potential for showers and thunderstorms by the afternoon through the evening. Deterministic CAMs and also HREF output show a broad area of showers and storms favoring western Minnesota this afternoon with instability building to upwards of 1000 J/KG SBCAPE. There is a lack of deep layer shear and much of the activity will end up being pulse-like or multicellular such that the potential for severe storms is low but non-zero. We`ve slightly bumped up both PoP and QPF for the afternoon as guidance is consistent in producing showers and storms, with activity quickly cutting off after sunset with the mixing resulting in a loss of forcing as it diminishes. This setup is more or less what we have to work with over the next few days, with chances for mainly afternoon to early evening showers and storms through at least Tuesday afternoon. Compared to today, the chances seem marginally weaker as we head into early next week with an upper level trough taking on a positive tilt and further solidifying a lack of synoptic scale reinforcement of what looks to be diurnally driven activity. Temperatures will likewise reflect our sunshine and lack of movement, with highs in the upper 70s to low 80s across the area through the majority of the forecast period, creeping up towards the mid 80s by the end of the week. The primary thing to watch out for will be the atmospheric response to Beryl as it makes landfall and begins to modify the surrounding environment, as at least for now the track does not bring it far enough north to affect us aside from keeping weak high pressure locked in place. Overall, a fairly quiet period with some typically summertime activity, a far cry from the setup which gave us the persistent rainfall over the last few weeks. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1211 PM CDT Sat Jul 6 2024 Pop-up thunderstorms have begun to develop across western to central MN early this afternoon. This activity should be short- lived but could pass by RWF, AXN, and STC. The more likely timing for more widespread thunderstorms will be late this afternoon in western MN as a mid-level disturbance arrives from the west. These scattered storms will travel west to east across MN this evening, likely weakening to just rain around 06Z, and reaching WI early Sunday morning. Have included TEMPOs at MN terminals for possibility of MVFR during thunderstorms. Outside of the storms, VFR is likely with cigs dropping to low end VFR at RNH and EAU towards the end of the period. However, patchy fog does look possible at AXN near sunrise Sunday. South- southwesterly winds will slow overnight (with a more southerly component) before returning again Sunday morning. KMSP...Kept PROB30 for isolated -TSRA from 22-02Z today. Rain showers look possible from midnight to sunrise as a disturbance passes through but conditions should remain VFR. Chance of afternoon -TSRA again Sunday. /OUTLOOK FOR KMSP/ MON...VFR. Chc aftn SHRA/TSRA. Wind W 5-10 kts. TUE...VFR. Chc aftn SHRA/TSRA. Wind NW 5-10 kts. WED...VFR. Chc aftn SHRA/TSRA. Wind NE 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...TDH AVIATION...CTG