Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
196 FXUS63 KMQT 171901 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 301 PM EDT Wed Jul 17 2024 .KEY MESSAGES... - Light scattered lake-effect rain showers end from west to east this afternoon. -Dry weather Thursday and Friday. -Best chances for rain (up to 40%) in the interior west on Saturday. Impacts should be minimal. && .SHORT TERM /THROUGH TONIGHT/... Issued at 244 PM EDT Wed Jul 17 2024 Scattered light lake-effect rain showers continue across Upper Michigan this afternoon as cold air advection has brought 850mb temps as low as 5C over Lake Superior, where water temperatures of 20+C are currently being seen. As high pressure continues to build in from the west the rest of today through tonight, expect the lake- effect cloud cover and rain showers to dissipate from west to east this afternoon, eventually ending late this afternoon over the east. Due to the lake-effect cloud cover across the area today and the cold air that`s dropped down from Canada, temperatures have struggled to get into the 60s across the north central and west, making the area feel like it`s more of a September day today. Meanwhile, the south central and east have comfortably reached the 60s, with the Menominee airport having just reached 70 recently. Moving into the overnight period, expect clear skies. Given the antecedent cooler air over us tonight and the clear skies, we could see temperatures plummet into the low 40s over the interior west late. In addition, we could see some patchy fog develop late tonight too, but confidence is fairly low (20-30%) given that dry air is moving into the area and CAM soundings don`t show temperatures reaching the dewpoints during the overnight period. Nevertheless, given the lake-effect rainfall today, some patches of fog could develop. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 259 PM EDT Wed Jul 17 2024 The pattern aloft is fairly stagnant over much of the CONUS as a large ridge over the Four Corners region will not progress much through the forecast period, paired with broad troughing over the US Southeast. To the north in Canada, anomalous 500mb ridging extending north from the Four Corners right will cause height anomalies to 20+ dam by Sunday. Despite the ridge causing prevailing northwesterly flow aloft which typically brings cooler air to the UP, the upstream anomalous heat associated with that ridge will counter the usually cooler pattern, resulting in mainly seasonal temperatures over the UP through this forecast period. A deep trough passing through the eastern Hudson Bay and Quebec will perturb the flow pattern enough to cause some weak shortwaves that in junction with diurnal heating, will cause some periodic low (15-35%) chances of showers and isolated thunder in the interior west particularly later in the forecast period. Thursday and Friday will be dry as a 1022 mb high pressure slides south of the region. Highs will continue a warming trend, with highs in the 70s Thursday and low 80s Friday. The next credible chances of precipitation reenter the forecast Saturday as a weakening surface trough passes through the area in response to a trough aloft passing through Quebec and the eastern Hudson Bay area. Given how weak the synoptic forcing is, the showers that do form will need a boost from diurnal heating, thus the highest PoPs are in the interior west. With 00Z LREF mean SBCAPE values around 400 J/kg, some thunder is possible especially along the MI/WI state line but nothing severe is expected. Ensemble solutions that keep the track of the surface trough a bit slower are present enough to keep some slight (15-20%) diurnal PoPs right along the state line for Sunday afternoon, but otherwise it should be a pleasant Sunday with highs around 80. Ensembles diverge into next week, but ensemble mean 500mb plots do show the ridge over the Canadian Plains retreating somewhat and northwesterly flow dominating over the UP, which should support weak clipper shortwaves bringing periodic, low-impact rain chances for next week. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 253 PM EDT Wed Jul 17 2024 TAFs look to improve to VFR over the next few hours as the lake- effect cloud deck gives way to high pressure ridging to our west. The northwest to northerly gusty winds this afternoon will slowly die down as the high pressure builds in. Expect fairly light winds and calm/SKC conditions across the TAF sites tonight through Thursday morning. That being said, there is a small (20% or less) chance of some patchy fog moving over the TAF sites tonight due to the temperatures plummeting to the dewpoint. && .MARINE... Issued at 259 PM EDT Wed Jul 17 2024 Northwest winds of 20-25 knots will diminish tonight across eastern Lake Superior as a trough axis departs from the lake. After that, the remainder of the forecast will have sub-20 kt wind gusts with the exception of Friday afternoon, where the region of Lake Superior between the Keweenaw Peninsula and Isle Royale will see southwesterly wind gusts of 20-25 knots due to a disturbance in Canada tightening the pressure gradient. Once wave heights fall below 4 feet tonight, expect waves to remain below 4 feet through the forecast period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Beach Hazards Statement until 11 PM EDT this evening for MIZ005-006. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...TAP LONG TERM...GS AVIATION...TAP MARINE...GS