Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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758 FXUS63 KDLH 081130 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 630 AM CDT Wed May 8 2024 .KEY MESSAGES... - Areas of dense fog clear by 8-9 AM this morning. - Showers and drizzle this morning and afternoon, with isolated thunderstorm potential (20%) later this afternoon and evening in inland northwest Wisconsin. - Frost is expected tonight in the interior parts of the Arrowhead. Freezing temperatures are expected in northwest Wisconsin Thursday night, with additional frost in northeast Minnesota. - The next round of light rain begins Friday morning in north- central Minnesota and builds southeastward Friday daytime. && .DISCUSSION... Issued at 340 AM CDT Wed May 8 2024 Areas of fog, locally dense, are being observed on satellite imagery early this morning. The most widespread coverage is in the east-central MN to Iron Range region, and more isolated over northwest Wisconsin. Surface observations have shown intermittent dense fog create visibility less than 1/4 mile, but more widespread reduced visibilities range from 1/2 to 2 miles so far this morning. Fog will clear from 8-9 AM this morning. Drizzle very early this morning becomes more showery in nature as slightly better forcing drops southward along a mid-level backdoor front extending from a shortwave centered in northwest Quebec from 6 AM to Noon today. In the meantime, a weak surge of mid-level south-southwesterly flow sets up in inland northwest Wisconsin late this morning into this evening. Model forecast soundings show a fairly dry 700-500mb profile, but a few hundred J/kg of elevated CAPE may allow for a couple hour period of an isolated thunderstorm to develop. These chances last into the evening hours for mainly Washburn through Price Counties today. Severe weather is not expected if any thunderstorm does form. Drier north to northeasterly flow moves southward through tonight to scour out skies overnight tonight to partly to mostly clear. A cold-enough air mass, progged at 850 mb temperatures around -1 C, will help to create frost formation chances (around 80%) for east-central and northeast St Louis County and all of the interior parts of the Arrowhead after Midnight tonight and lasting into early Thursday morning. A Frost Advisory was issued for these expected conditions. Any limiting factor is most likely to be surface wind speeds (forecast 4-8 mph) in this time period so low-lying basins in the interior Arrowhead have the best chances of any for that frost. Another round of frost formation is expected in northeast Minnesota again Thursday night into Friday morning, but widerspread coverage even down into the I-35 corridor of Pine County and Aitkin County. Calm winds, dewpoints into the upper-20s F and 850 mb temps around 0 C support the potential of freezing or a few degrees below freezing for inland Bayfield/Ashland/Iron Counties and across Sawyer and Price Counties from late Thursday evening through Friday mid-morning. A Freeze Watch may be necessary over coming forecasts for this potential. The shortwave trough that moves southeastward from the Canadian Plains Friday morning is progged to have a bit better frontal forcing with the 08/00Z guidance. The result is increased confidence on most locations seeing at least some very light rainfall beginning Friday mid-morning first in far north- central Minnesota and ending last in the Arrowhead and northwest Wisconsin Friday evening. The one region which has the best possibility of missing out on more than a trace would be Cass and Crow Wing Counties in the Brainerd Lakes region. Another shortwave trough is progged to move through the region Sunday to keep chances of rain in the forecast, with temperatures warming into the low to mid-70s for early next week as zonal flow to a low-amplitude mid-level ridge sets up. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 624 AM CDT Wed May 8 2024 Dense fog creating a swath of LIFR and IFR conditions will lift 13-14Z today across the Northland. An area of MVFR ceilings may linger last not north-central Minnesota towards 18Z though before VFR conditions setup across the region. Otherwise, drizzle and isolated rain showers are expected along a backdoor front dropping southward today. Easterly winds increase after 15Z near Lake Superior shorelines and remain locally breezy this evening and tonight. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 624 AM CDT Wed May 8 2024 Another round of gusty northeast winds is expected first along the far northern parts of the North Shore early to late this morning before winds increase in the southwest arm and along the South Shore towards mid-day today. Small Craft Advisories have been issued for these increased northeast winds. Wave heights will again build as well along the South Shore and at the Head of the Lake by this afternoon and linger into the evening. As winds decrease from north to south this afternoon and evening, future changes to the ending time of the headlines may be necessary. A similar setup to today is expected Thursday where lighter winds overnight quickly give way to increasing northeast winds and building wave heights. Another round Advisories may also be needed Thursday daytime. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...Frost Advisory from 1 AM to 9 AM CDT Thursday for MNZ011-012- 019. Dense Fog Advisory until 9 AM CDT this morning for MNZ025-026- 034>036-038. WI...Dense Fog Advisory until 9 AM CDT this morning for WIZ006>008. MARINE...Small Craft Advisory until 4 PM CDT this afternoon for LSZ140- 141. Small Craft Advisory from 10 AM this morning to 10 PM CDT this evening for LSZ142>148-150. && $$ DISCUSSION...NLy AVIATION...NLy MARINE...NLy