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
333 FXUS63 KDTX 301953 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 353 PM EDT Thu May 30 2024 .KEY MESSAGES... - Another clear and chilly night ahead with lows near 40 outside of metro Detroit, and in the upper 30s in rural or sheltered locations. - Dry weather continues Friday and most of Saturday with a gradual warming trend each day. - The next chance of rain arrives late Saturday through Saturday night. - The weekend finishes dry and warm Sunday with highs near 80. && .DISCUSSION... Rock-solid high pressure is in full control of conditions across the Great Lakes today. Observations throughout the day have shown the surface ridge holding a western position resulting in maintenance of north wind and steady low level cold advection into SE Mi. The inbound colder air faces full sun as the mid level/500 mb ridge is perfectly positioned over the Midwest to force strong subsidence into the area. Despite nearly June 1st surface heating, temperatures have struggled to reach 70 as a testament to the colder air mass in place across the region. This sets the stage for another chilly night as clear sky continues and as high pressure settles overhead for even better prospects of calm wind compared to last night when there were even a few reports of rooftop frost toward interior Thumb locations. HREF mean projections of surface Td hold in the 30s again tonight making another round of upper 30s lows likely by sunrise Friday morning, although warm ground temperature guards against frost threats to vegetation. After the chilly morning start, temperatures rebound sharply in full sun toward mid 70s highs Friday afternoon. These readings are at or a couple degrees above normal for the last day of May and accompanied by dry weather as high pressure maintains control while drifting east of the region. Departure of the surface high and eastward progression of the mid level ridge become more apparent Friday night and Saturday as high clouds thicken and wind returns to light south. The high clouds are the first sign of the next low pressure system on schedule to spread showers into SE Mi late Saturday and Saturday night. There are no big issues with model performance in this medium time range given the involvement of larger scale northern stream mid level systems. The southern stream short wave could be embellished by upscale growth of Plains convection during Friday, however an MCV will likely end up being a component of the wave by Friday night into Saturday. The system otherwise brings a generous Gulf moisture supply in a pattern of deep SW flow theta-e advection that lifts PW toward 1.5 inches in southern Lower Mi. Showers become widespread as a result by late Saturday through Saturday night while the southern stream low tracks through the Ohio valley. A rumble of thunder is also possible in nocturnally enhanced but still weak elevated instability. The weekend wraps up nicely as the Ohio valley system exits to the Atlantic coast leaving weak high pressure to fill in across the Great Lakes. Dry weather with highs near 80 Sunday carry over into Monday while a larger scale zonal flow transition takes place. This typically lowers predictability on short wave features until Pacific jet energy initiates larger scale height falls toward mid week. Extended range model solutions show good agreement on a larger system digging into the Rockies and Plains Tuesday night that could reach the Great Lakes by Wednesday. && .MARINE... High pressure drifts directly overhead tonight maintaining dry conditions and light flow. Winds shift toward southerly Friday as the high center moves over southern Ontario with gusts expected to remain below 20kts. High vacates early Saturday as low pressure lifting into northern Ontario drags a cold front into the Great Lakes. A secondary area of low pressure looks to develop along this boundary over the Ohio Valley before tracking into the central/southern Great Lakes latter part of the day Saturday into early Sunday. System brings mainly showers though a few thunderstorms will be possible over the southern half of the region. Weak high pressure then briefly builds in late Sunday and Monday. && .HYDROLOGY... A pattern of showers moves into SE Michigan late Saturday which continues through Saturday night when a brief period of heavy rain is possible. Low pressure moving into the Ohio valley draws a deep supply of Gulf moisture into the area potentially leading to rainfall approaching totals near 1 inch before ending Sunday morning. The system moves steadily through the area to prevent more excessive totals, however minor flooding of prone areas and ponding of water on roads will be possible. && .PREV DISCUSSION... Issued at 127 PM EDT Thu May 30 2024 AVIATION... High pressure centered over the Door Peninsula of Wisconsin maintains effectively clear skies and weak flow across the terminals for the rest of today and overnight. Meager moisture within the 4.5- 6.0 kft AGL layer that supported areas of FEW cumulus this morning will continue to struggle as active subsidence further dries the column this afternoon. Light northerly winds veer toward the northeast with time as the center of the ridge translates eastward across Lower Michigan. Nocturnal winds then trend toward calm late tonight and early Friday morning before becoming southerly midday Friday. VFR conditions are expected to continue through the end of the TAF period. For DTW/D21 Convection...Thunderstorms are not expected during this forecast period. DTW THRESHOLD PROBABILITIES... * None. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ DISCUSSION...BT MARINE.......KDK HYDROLOGY....BT AVIATION.....KGK You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.