Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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976 FXUS63 KDLH 180833 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 333 AM CDT Wed Sep 18 2024 .KEY MESSAGES... - A couple more days of warm and muggy conditions - Chance (30%) of storms some strong to severe entering from the west late this afternoon. - Better chances for showers and storms (60%) Thursday. Slight risk (2 out of 5) of severe for the region with all hazards (large hail, damaging winds, tornadoes) possible in the afternoon and evening. - More seasonable temperatures return Sunday and linger into next week && .DISCUSSION... Issued at 326 AM CDT Wed Sep 18 2024 Current Conditions/Today: A deepening upper level low over the Northern Rockies with a weakening Rex Block across the Appalachians has spurned another robust LLJ across the Midwest. Activity isn`t quite as high as the previous night due to lack of forcing. However, there is still enough to give a few echoes extending from the Twin Cities and up into Aitkin. The better dynamics still look to be over the Dakotas. But these storms wil likely not be able to sustain themselves into our area as the LLJ weakens. The rest of the morning and early afternoon will be similar to what we`ve seen the past couple days. Winds out of the south with temperatures and dewpoints a bit higher than what we normally see for this time of year. Afternoon/Overnight Storms: This afternoon and overnight could see some more active weather with storms developing across our west. While the main frontal boundary remains off to the west, strong warm air advection out ahead combines with an upper level shortwave and divergent jet to promote storm growth. The strongest storms are expected to be during the late afternoon and early evening hours with the primary hazards being damaging winds and hail 1 inch in diameter. A strengthening LLJ could help to maintain storm chances through the night and carry them over into Thursday morning, however severe chances quickly drop off after 10 PM amongst most of the high res guidance. The NAMNEST is a bit of an outlier right now keeping stronger storms past midnight. Thursday Severe Storms: Thursday has potential to be quite an active weather day. We will see lingering showers and convection in the morning hours but is largely expected to dissipate by late morning. There is fairly high agreement in having the environment recover in the afternoon building dewpoints into the mid and upper 60s. This sets us up for some fairly high instability (MLCAPES > 2000 J/kg). We will also have bulk shear values of over 40 kts helping to provide the much needed tilt for storm longevity. The focal point for convection will be the cold front moving west to east in the afternoon and evening hours. CAMs are in good agreement with the development of a line of storms, however placement of the line varies from our western counties to our central ones. The initial threat will be large hail. Steep mid level lapse rates greater than 7.5C/km will increase updraft strength producing quarter to ping pong sized hail. Hodographs also show some low level veering in the winds leading to some tornado potential. As the event continues storms may cluster into more of a linear complex shifting the threat to more damaging winds. The current outlook from SPC has the area in a slight risk for severe (2 out of 5). Friday into next week/Cool Down: Storms will have vacated the region for Friday with highs dropping into the mid 70s. The temperature drop isn`t done quite yet though. Another cold front is poised to move through Saturday bringing some showers and storms (currently non severe). By Sunday highs drop into the 60s and low 70s. Beyond Sunday models are diverging on the handling of the next upper level low out of the southwest. For now, we are carrying some 20-40% PoPs and maintaining the more seasonable temperatures. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1231 AM CDT Wed Sep 18 2024 Strong low level jet out of the south across the region this morning causing some low level shear across the MN terminals. Radar is largely quite so far but can`t fully rule out some activity forming on the nose of the low level jet later this morning. For now, the activity has been north of the International Border with a few weak echoes spotted near BRD. Ceilings will continue to be VFR through the period with some showers and storms possible in the afternoon and evening hours. The low level jet will once again ramp up overnight leading to more shear problems. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 326 AM CDT Wed Sep 18 2024 Southeast winds today with speeds up to 10 kts. Thunderstorm chances return after midnight. The best chance for storms will be tomorrow afternoon and evening, some of which will be strong to severe. Winds will also increase a bit out of the southeast with some gusts up to 20 kts at times. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. MARINE...None. && $$ DISCUSSION...Britt AVIATION...Britt MARINE...Britt