Area Forecast Discussion
Issued by NWS Twin Cities, MN

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314 FXUS63 KMPX 171749 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 1249 PM CDT Fri May 17 2024 .KEY MESSAGES... - Low RH values Saturday afternoon could result in areas of elevated fire weather conditions. - Increasing confidence for showers and thunderstorms Sunday night into Monday morning. The risk for severe weather is low. - An active pattern set to begin Sunday night. Multiple chances for rain, possibly heavy, and thunderstorms over the next seven days. && .DISCUSSION... Issued at 322 AM CDT Fri May 17 2024 TODAY THROUGH SUNDAY... Scattered thunderstorms across west & central Minnesota north of I-94 this morning that`ll taper off as the storms move further east into a more stable and drier environment. Warm air advection will kick in today as an impressive low level jet roaring aloft. Temperatures climb into the low to mid 80s across MN & WI, with a solid shot at 90 across western Minnesota. There is a non-zero chance for isolated thunderstorms this afternoon, but there is a lot working against it. Forecast soundings highlight an impressive inverted V featuring very dry low levels that`ll limit any chance for precip to make it to the surface (virga). Saturday will feature another pleasantly warm day, but we`ll have to keep an eye on elevated fire weather potential Saturday afternoon post-fropa as RH values could drop into the 20-25 percent range. A sfc cold front will pass through the Upper Midwest. This will present western Wisconsin with a slight chance for thunderstorms to develop along it Saturday afternoon. Rusk Co is included in SPC`s day 2 outlook, but most CAMs don`t initiate until past the MPX WI CWA. Sunday will see an uptick in PoPs throughout the day as southeast flow will ramp up moisture advection into the region. The quasi-stationary front across Iowa will become a focal point for a rather active pattern setting up over the next week or so. SUNDAY NIGHT THROUGH THURSDAY NIGHT... A mid-level trough amplifying over the western CONUS will drive southwest flow aloft over the region throughout the week. WPC has highlighted days 3-5 with marginal chances for excessive rainfall. The first shortwave moves through Sunday night and will bring widespread rain and thunderstorms across Minnesota and western Wisconsin. It looks like the best chance for widespread and heavy rain will be across S MN and into W WI. Monday will dry out, but by Monday night another round of storms and showers will ride along the stationary boundary set up across the Upper Mississippi Valley. This batch of possible heavy rainfall will be in the late Monday into Tuesday time frame when guidance indicates a more potent shortwave energy lifting across the stationary frontal boundary draped across the region. Model uncertainty spikes later into the week but it certainly looks possible that additional round of showers Wednesday evening into Thursday morning. Showers could linger into Thursday before drying out on Friday. Temperatures start off in the extended with highs in the upper 70s Sunday and Monday. However, temperatures will trend cooler in the wake of the Tuesday low pressure system/frontal boundary pushing off to our south and east. This pattern also would suggest a cloudier forecast that would support cooler temperatures. This active pattern looks to continue into Memorial Day weekend before things "dry out" toward the end of May. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
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Issued at 1226 PM CDT Fri May 17 2024 Morning line of showers has all but dissipated in western Wisconsin, with satellite revealing mostly clear skies over the Minnesota terminals. Southerly winds will increase this afternoon as a warm front lifts through the state. Have added/continued the potential for LLWS this evening given the expected strengthening LLJ across the Upper Midwest. EAU is the only site to not feature wind shear concerns at this time, given the the expected weakening of the LLJ with eastern extent tomorrow morning. Also of note, latest CAM guidance has trended upward with the potential for isolated convection on the nose of the LLJ this afternoon and evening. AXN, STC, MSP, and RNH would be the primary terminals to watch for this activity, however the chances appear too low/isolated to include in the 18z TAF set. KMSP...Eastward approach of the strengthening LLJ has prompted the threat for LLWS overnight, so have opted to include mention in the 18z TAF. Threat for LLWS will decrease by daybreak Saturday, followed by a shift in the winds from southerly to westerly by midday. /OUTLOOK FOR KMSP/ SUN...VFR. MVFR/SHRA likely late. Wind SE 10-15kts. MON...MVFR/-TSRA thru mrng. VFR chc SHRA aftn. Wind SE 5-10kts. TUE..MVFR/-TSRA likely. Wind NE 10-15 kts.
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&& .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...BPH AVIATION...Strus