Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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060 FXUS63 KMPX 231147 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 647 AM CDT Thu May 23 2024 .KEY MESSAGES... - Warmer temperatures return today with thunderstorms and showers developing ahead of a cold front this evening. A few storms could be strong to severe tonight. - Seasonable temperatures through the Memorial Day weekend with a few chances of showers through early next week. && .DISCUSSION... Issued at 357 AM CDT Thu May 23 2024 TODAY... The pattern remains active for the near term with a shortwave trough ejecting out of the northern Rockies. This leads to a sub 1000mb sfc low pressure approaching Minnesota from the Dakotas tonight. This will set the table for another round of showers and thunderstorms across western and central Minnesota. At the surface, warm front will move north through the region today allowing temperatures to rebound into the upper 70s and lower 80s. One thing to keep an eye out for this afternoon is the potential for a few isolated showers/storms popping up in the diurnal cumulus field across central Minnesota. These storms will likely stay sub-severe, but gusty winds and small hail. Most should stay dry throughout today. Additional development is expected along and ahead of the approaching cold front over the Dakotas this evening. The main concern with how intense these storms will be as they approach W MN given the limited instability in place ahead of the line. Timing is also working against it as these storms are forecast to move through late evening through Friday morning. There will be a LLJ that will aide in moisture and elevated instability advection. Storms may take a more linear appearance allowing them to maintain some organization into Friday morning. If we look at the hires guidance, forecast soundings aren`t exactly screaming severe potential. Instability will be modest at best, but the one positive will be the shear profile. Forecast hodographs show a sickle shape with increasing speeds with height across W MN after sunset. If storms organize into a more linear complex, damaging wind potential will be higher vs cluster convective mode. SPC`s day 1 SWO Marginal (1/5) is reasonable considering the favorable shear environment limited by modest instability during the diurnal minimum. QPF amounts of 0.25 to 0.50" are likely with locally higher amounts by Friday AM. FRIDAY THROUGH WEDNESDAY NIGHT... Guidance signals that the pattern should remain somewhat active into the middle of next week. On Friday, the focus shifts to the next shortwave emerging from the mid- level troughing across the western CONUS. The first shortwave lifts NE through the central Plains into the northern Great Lakes, eventually swinging into Manitoba and Ontario. Saturday for the most part should be dry with ridging/subsidence behind the exiting shortwave. Broad isentropic ascent spawn showers that`ll move across southern Minnesota. Forecast soundings show very limited instability so only isolated t-storm coverage at best. Temperatures will remain seasonable, in the 60s and 70s, but temps begin to warm by the end of the long term forecast period (next thursday). QPF amounts should remain on the lighter side, generally 0.25" or less, through Sunday night. Model spread and uncertainty ramps up for Memorial day onward regarding the next shortwave to eject from the western US. Have continued to lean on the NBM rain chances, given the degree of spread present with generally 30 to 60% rain chances Sunday/Memorial Day. This uncertainty means those of us with holiday weekend plans will have to pay attention Sunday night into Monday for possible impacts. Looking ahead towards the middle of next week most guidance seems to be in general agreement showing a trend toward ridging building in and drier conditions for Tuesday and Wednesday next week. We will have to monitor the latter half of the forecast due to the increased uncertainty in placement of any shortwaves moving through the mid- level trough over the western CONUS. As a result, low end rain chances exist into Wednesday night into Thursday. Temps should be fairly seasonable for late May/early June. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 605 AM CDT Thu May 23 2024 VFR conditions expected through this evening, with mainly SCT coverage but a few periods of BKN mid-level decks cannot be ruled out. Chances for precipitation ramp up tonight through Friday morning as a well-organized system approaches from the southwest. MVFR conditions may well accompany the -RA close to daybreak. CB/TS cannot be ruled out but chances are too low at this time to pinpoint timing/location, so will hold off such mention for later TAF issuances as CAMs come into good agreement, potentially with radar trends, and confidence increases. Winds will be generally from the SE, with speeds increasing to 10-15kt with gusts 15-20kts this afternoon through tonight. KMSP...Benign conditions through tonight with mid-level decks, occasionally developing as BKN coverage. Lower clouds approaching close to daybreak Friday morning with precipitation moving in around the start of the morning push. Steadier rainfall is likely from sunrise onward, with ceilings dropping to MVFR range. CB/TS possible but chances too low to include at this time. /OUTLOOK FOR KMSP/ FRI...VFR/MVFR with -SHRA/TSRA likely. Wind S 10-20 kts, becoming W 15-25 kts during the afternoon. SAT...VFR. Wind SW 10 kts. SUN...VFR. Wind E 10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...BPH AVIATION...JPC