Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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467 FXUS63 KMPX 101815 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 115 PM CDT Fri May 10 2024 .KEY MESSAGES... - Chance for frost/freeze in western WI this morning. - Scattered showers and thunderstorms Friday afternoon, best chance eastern MN to western WI. - Chance to see the northern lights tonight, mostly clear skies expected. - Temperatures in the 70s through the period with a chance at 80 on Sunday. && .DISCUSSION... Issued at 300 AM CDT Fri May 10 2024 Mostly clear skies are evident on Nighttime Microphysics satellite imagery this morning with a few areas of fog developing over south- central Minnesota. Fog is not expected to be a widespread issue and is mainly a symptom of week winds coupled with temperatures falling to dew points in the mid 40s where the fog is developing, with dew point depressions in the 5-10 degree range elsewhere. Another classic late Spring day is in store for us today with temperatures in the 70s under mostly sunny skies until a chance for a few showers and thunderstorms arrive by the afternoon from a weakening upper level trough centered over Ontario. Northwesterly flow aloft will allow for a transient shortwave to push across north-central Minnesota to western WI, with the best chance for seeing showers and a few thunderstorms in far eastern MN and western WI from roughly 1pm to 5pm this afternoon. A few severe storms are possible mainly for wind gusts spurred by a stronger shower or two with fairly weak instability in the 250-500 J/KG range per RAP forecast soundings over New Richmond WI with lower amounts west. The sounding profile is dry adiabatic at ground level with dew points being the primary limiting factor in regards to surface based convection with LCL heights above 3000ft as a result making for lower end strong thunderstorm potential. AVA on the western side of the trough will clear skies out by the evening with clear skies continuing through Saturday and for most of Sunday before our next chance for showers and storms arrives. The clear skies will also allow a chance to see the northern lights due to a geomagnetic storm caused by a series of CMEs. See the Space Weather Center`s webpage for more specific details, the bottom line for us is a chance to see the northern lights much later in the season than is typical and right now skies look mostly clear at its peak tonight. Saturday appears to be a perfect day to open the windows and enjoy sunshine, low 70 high temperatures, and light winds at 5-10mph. Northwesterly flow aloft continues with troughing to the east and ridging to the west, with surface flow weak due to a lack of a dominant synoptic scale surface based system. Flow aloft turns more westerly by Sunday morning and a weak upper level trough occluding over the plains should allow for southerly flow to increase at ground level, with WAA coupled with sunny skies resulting in temperatures approaching 80 for a high on Sunday in the Twin Cities and upper 70s elsewhere. Sunday afternoon will also begin what looks to be a trend for much of next week, that being zonal flow aloft with embedded shortwave impulses allowing for sporadic shower and storm chances but nothing that looks strong or significant. Deterministic guidance is fairly consistent in showing a series of shortwaves moving through the upper midwest, however without greater instability or synoptic scale lift we are looking at isolated chances for stronger storms. It is not until later in the week towards next weekend where a stronger system begins to poke its head, arriving late Wednesday to early Thursday with a negatively tilting trough sweeping across the northern CONUS resulting in more widespread showers and chances for storms due to stronger forcing. The main question in regards to storm chances will be access to moisture which right now looks decent with PWAT values from 1-1.25 on Thursday, however the greater access to Gulf moisture looks to cutoff to the south likely resulting in stronger storms in the central plains. For now, expect a `normal` late Spring to early Summer weather pattern with isolated to scattered weak storms for most of next week with a chance for more widespread rain on Thursday. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1258 PM CDT Fri May 10 2024 VFR conditions throughout. Main concern is the wind shift and gusty winds as a cold front moves through the region today. A few showers and possibly a thunderstorm is possible at KMSP, KRNH, and KEAU, but overall the threat for thunder has decreased. Wind gusts will taper off around sunset, with light westerly winds expected on Saturday. KMSP...The chance for thunder has decreased at KMSP, so only have VCSH in the TAF. Any rain showers will be scattered, so unlikely to affect KMSP. Winds will transition to the northwest this afternoon, with gusts near 30 kts possible. The winds will decrease toward evening and become more westerly for Saturday. /OUTLOOK FOR KMSP/ SUN...VFR. Wind SW 10-15G25kts BCMG N 10-15kts. MON...VFR. Wind NNE 10-15kts. TUE...VFR. Wind E at 5-10kts && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...TDH AVIATION...JRB