Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, 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
674 FXUS63 KDTX 160353 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1153 PM EDT Sat Jun 15 2024 .KEY MESSAGES... - Dry with seasonable temperatures through tonight before abnormally warm conditions commence late Sunday and continue through next week. - Temperatures likely peak in the mid 90s early next week with heat indices topping out near 100F at times. - Low confidence in periodic widely scattered thunderstorms that could offset some of the warming, depending on coverage and timing. && .AVIATION... Thicker high clouds overhead at forecast issuance shift northward late tonight leaving mostly clear sky in the morning. At the same time, surface high pressure positioned over southern Ontario begins an exit toward the New England coast while still supplying dry easterly boundary layer wind that gradually veers toward the south by afternoon. The still dry low level air mass inhibits any cumulus development while another round of mid and high clouds arrives ahead of a warm front strengthening along the MS valley region. These clouds are associated with showers and thunderstorms ongoing across the Midwest which are projected on a track into the northern Great Lakes through the afternoon into Sunday evening. For DTW/D21 Convection...No thunderstorms are expected late tonight through Sunday evening. DTW THRESHOLD PROBABILITIES... * None. && .PREV DISCUSSION... Issued at 305 PM EDT Sat Jun 15 2024 DISCUSSION... The area will remain under the influence of surface high pressure as it shifts off to the east tonight. Light easterly flow will maintain pleasant conditions with lows dropping into the 50s area-wide (which is average for this time of year). Southeasterly flow will increase on Sunday as this high continues to the east coast. As upper level high pressure centered over North Carolina begins to intensify, this flow will draw warmer air north into the region with highs reaching the mid/upper 80s by afternoon. A shortwave trough is still progged to race east along the northern periphery of this expanding upper level ridge late Sunday and a few showers may brush the northern edge of the forecast area from Sunday into Sunday night. Once this shortwave passes east through Ontario into Quebec (and beyond), the upper ridge will build north and northwest into the region and bring a rapid expansion of hot and modestly humid air into the area on Monday as H5 heights build to near 590 dam as the upper high over North Carolina expands to 595 dam. This air mass change will bring high temperatures into the mid (to locally upper) 90s with heat indices topping out in the upper 90s to around 100 degrees. With the influx of more humidity, isolated showers and thunderstorms will also be possible late in the day, especially along lake breeze boundaries. The hot weather will then continue on through much/all of the week as the upper high re-orients such that the western lobe pivots into the Tennessee and Ohio Valley regions and upper heights remain quite high over the area. Overall, it appears lower 90s will be common with occasional temperatures into the mid 90s. As such, messaging remains the same as impacts from the heat compound which each successive day. Some combination of a Heat Advisory and/or Excessive Heat Warning will be likely with the eventual configuration likely determined by the degree to which the upper ridge builds north into the area by midweek. Medium range models vary in the degree of shortwave energy traversing the northern edge of the ridge. This will impact the eventual northward expanse and also the coverage and frequency of isolated to scattered mainly late day showers and thunderstorms which will be possible at times throughout the week. MARINE... A warm and humid airmass will set up over the Great Lakes late tomorrow through early Monday and will last through the end of the week. This will produce relatively stable over-lake conditions. Prior to the arrival of this airmass, the leading warm front will provide the chance for showers and thunderstorms over portions of Lake Huron tomorrow. Additional isolated to scattered shower and storm chances will exist Monday and Tuesday over the Great Lakes as an upper-level disturbance moves over the region. Otherwise, south to southwest flow will become established through early next week after the passage of the warm front. Some breezy conditions with gusts to 20-25 knots will be likely Sunday as flow transitions from southeast to south-southwest, but otherwise gusts stay aob 20 knots through the early week with the stable conditions in place. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....BT DISCUSSION...DG MARINE.......AM You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.