Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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403 FXUS63 KMPX 181200 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 700 AM CDT Tue Jun 18 2024 .KEY MESSAGES... - Additional thunderstorms likely this afternoon and evening, some of which could be strong to severe with additional heavy rainfall. - Locally heavy rain is still possible later today into tonight, however flash flooding is no longer expected to pose a widespread threat, prompting a cancellation of the Flood Watch. - A brief break in the rain tomorrow should make for a nice day, before additional precip chances return Thursday through Saturday. && .DISCUSSION... Issued at 343 AM CDT Tue Jun 18 2024 Yesterday evening/night`s storms have progressed north of our area this morning, allowing skies to begin clearing out. Increasing S/SE low-level flow behind the northward advancing frontal boundary will allow temperatures to rise into the low-mid 80s across much of the area. Dewpoint temperatures in the low 70s will certainly make things fell muggy again today, with heat indices potentially creeping above the 90 mark. This will also depend on our cloud cover, which the latest hi-res models suggest will fill back in shortly after sunrise. Airmass destabilization will be the big thing to watch today as we prep for another round of storms along a passing cold front from the west. A moderate to strongly unstable airmass with SBCAPE values of 2500+ J/kg would provide enough buoyancy for some robust updrafts to form within an area of adequate deep-layer shear. The primary threats will be damaging wind gusts and isolated large hail along and ahead of the leading edge of the front during the afternoon/evening when instability is maximized. As previously noted, the relatively high low-level wind shear warrants the need to watch for potential bowing structures as the line comes together. Given its progressive nature, QPF totals associated with the system look to most likely range from 0.5-1" with more localized amounts up to 2" possible. While locally heavy rain is still possible through tonight, there is a decreasing risk for widespread flash flooding potential, prompting the cancellation of the Flood Watch for our central Minnesota and western Wisconsin counties. Temperatures / dew points will drop off pretty quickly behind the front, which should feel nice after a muggy day! Tomorrow should be nice day with highs generally in the mid-70s, partly sunny skies, and relatively weak winds. Any precipitation should stay southeast of our area as well, which will allow for a nice break before rain chances return again on Thursday. Southwest flow aloft will aid several more chances for precip from Thursday through Saturday, with an additional 1-2" of rain likely for most locations, and 4"+ still possible where the strongest storms move through. Thus, continued surveillance of rivers and streams for potential flooding concerns will be needed through the end of the week. A final kick from a h500 shortwave on Saturday should give way to a more settled pattern at the start of next week, providing, at the very least, a brief break in the active weather. && .AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 638 AM CDT Tue Jun 18 2024 A line of weakening showers/storms is slowing tracking ENE across portions of northwestern MN, which could impact AXN within the next hour or so. The main story this morning will be increasing southerly winds, generally persisting at 10-20kts and gusting up to 30-35kts at times. They will gradually turn more SW this afternoon ahead of an approaching cold front, which will bring another round of showers/storms and a wind shift out of the west. Some of these storms could produce severe wind gusts and reduced visibility with heavy rainfall rates. Cigs will generally be MVFR/VFR, with some periods of IFR possible as storms move through the region. KMSP...Expecting a gusty day, with strong winds around 45-50kts just above the surface that could mix down during the afternoon. Collaboration with ZMP led to increased confidence of this potential, and have illustrated this in the latest TAF. Later issuances may warrant a need for further increases in wind speed/gust potential depending on how this morning plays out. Confidence in TS development this afternoon has increased, with the most likely onset around 22/23z. After the initial push of heavy rain and strong gusts, lighter showers could persist into the evening. Winds will quickly shift out of the west as the front moves through, and then gradually turn more NW into the night. /OUTLOOK FOR KMSP/ WED PM...VFR/MVFR, chc -TSRA/-SHRA. Wind N 5-10kts. THU...VFR/MVFR, chc -TSRA/-SHRA. Wind E 5-10kts. FRI...VFR/MVFR, chc -TSRA/-SHRA. Wind S 10-15kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...BED AVIATION...BED