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FXUS63 KDTX 170753
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
353 AM EDT Tue Sep 17 2024

.KEY MESSAGES...

- The lengthy stretch of warm and dry weather is projected to hold
today through Friday.

- The Mid Atlantic tropical system is only able bring a modest
increase in cloud cover tonight and Wednesday.

- A weak cold front from the Plains states has a low chance of
reaching Lower Mi with spotty light rain later Friday into Saturday.

&&

.DISCUSSION...

Today marks day 11 in the string of consecutive dry weather days for
the bulk of SE Mi to go along with 16 out of 17 for September. Today
is also day 8 in a string of above normal temperatures after a
cooler start during the first week of the month. This remarkable
stretch of warm and dry conditions is driven once again today by a
larger scale blocked 500 mb ridge and associated surface high
pressure locked in from the Great Lakes eastward across the NE
States. To the south is the Mid Atlantic tropical system drifting
inland far enough to graze SE Mi with high clouds during the day
which might be just enough to hold temperatures down slightly
compared to recent days when combined with persistent easterly flow
off Huron and Erie. Temperature guidance offering highs around 80
looks good while readings warm more firmly in the lower to mid 80s
toward the Tri Cities and interior Lower Mi.

High clouds are about the only concern associated with the Mid
Atlantic system as it drifts to the SC/TN border and stalls during
mid week. The last few model runs have converged on a 500 mb low
position that is nearly stationary through 12Z Wednesday. This
occurs partially due to reinforcement of the rex ridge over Ontario
and the Great Lakes downstream of the strong central Rockies low as
it lifts into the northern Plains. The system then spends the late
week period filling and opening up toward the Atlantic coast while
high pressure is reestablished in the Great Lakes to ensure dry
weather through Friday.

Extended range/global models show the powerful Pacific jet finally
bringing a larger scale pattern change during the weekend, or
perhaps better described as a northward reorientation of high
amplitude mid level flow that still exhibits blocking tendencies.
The Pacific cold front associated with the late week northern Plains
system has a chance to reach Lower Mi Friday into Saturday. It has a
weak and moisture-starved character but represents our next chance
to see a few raindrops heading into next weekend.

&&

.MARINE...

Sprawling high pressure continues to govern conditions for the
central Great Lakes through the forecast period offering mainly dry
weather and light southeast winds (AOB 15 knots). A subtropical
cyclone tracking west across The Carolinas remains positioned
downstream of more meaningful steering dynamics over western CONUS.
Latest guidance shows the system turning toward the southwest by
late morning which precedes a rather rapid collapse over SC/GA. This
effectively keeps the resident ridge of high pressure in control of
the waterways featuring persistent light easterly composed flow
which yields favorable marine conditions into the weekend.

&&

.PREV DISCUSSION...
Issued at 1147 PM EDT Mon Sep 16 2024

AVIATION...

Expansive area of high pressure maintains influence this period.
This ensures dry and stable conditions, precluding lower cloud
development. Shallow ground fog will again be possible at daybreak
Tuesday due to favorable radiative cooling conditions. Light winds
generally from the southeast persist.

For DTW/D21 Convection... Thunderstorms are not in the forecast for
the foreseeable future.

 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.......KGK
AVIATION.....MR


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