Scientific Forecaster Discussion
fxus63 kdtx 141858
Area forecast discussion
National Weather Service Detroit/Pontiac Michigan
258 PM EDT Mon Oct 14 2019
Expect a bit of a roller coaster the next few days in terms of
temperatures as a strong shortwave disturbance tracks into the
central Great Lakes by midweek.
While warm air advection in advance of this system will already be
underway tonight, at least above the boundary layer, it still
appears to be a decent setup for frost as ridging at the surface
should provide a period of generally clear skies and light winds
through about 09z Tuesday morning. Cloud cover this afternoon has
become more and more diurnal in nature and should dissipate fairly
steadily from the early to mid evening hours. With temperatures
starting in the 40s to around 50 late today, this will allow for
widespread low temperatures in the middle 30s with the trend to
clearing and lighter winds promoting widespread frost.
Warm air advection within increased southerly flow will lead to a
rather mild day on Tuesday as skies start out mostly sunny. Highs
should reach the 60s in many locations (and at least mid/upper 50s
over northern portions of the forecast area).
Dynamically, the aforementioned shortwave is organizing quickly as it
progresses into the area with the strong forcing developing over the
region and then quickly surging east of the area overnight Tuesday
night. Rain showers will become likely as the cold front associated
with the system tracks into the area by late evening/early Tuesday
morning. However, rainfall totals look to remain on the light side
as notably better coverage/intensity look to be forestalled until
late Tuesday night/early Wednesday morning to the east of the area.
Conditions on Wednesday will be much cooler as cold air advection
ensues as the developing upper low pivots east of the area. Expect
highs to only reach the lower 50s in most locations with gusty
northwest winds develop. Showers on the backside of this system will
not be especially heavy either, but will definitely be widespread
enough (aided to some degree by lake effect processes) to further
emphasize what will already be cool and blustery day. No frost is
anticipated into Wednesday night as skies only gradually become
partly cloudy and the boundary layer remains mixed with wind gusts
still reaching 20 mph throughout the overnight hours. Lows in this
weather regime will settle into the upper 30s to lower 40s.
Mature/strong low pressure system along the New England coast on
Thursday will be slow to pull off to the northeast. With the
amplified East Coast trough, a longer period of upper level
northwest confluent flow over Southeast Michigan will exist, which
allows surface high/ridge to persist right into Friday before warm
advection pattern spreads in Friday night into Saturday, with 850 mb
temps making a run aoa 10 c. Weakening cold front tracking through
on Saturday perhaps touching off a few showers, but 12 Euro
continues to suggest the frontal precipitation drying up. Ridging
returns for the second half of the weekend, before next surge of
moisture/warm front arrives Sunday night into Monday, leading to
what looks to be widespread showers developing.
As low pressure pulls off to the northeast tonight, high pressure
slides across the Ohio Valley bringing light winds across the
region. Winds then back to the southeast and restrengthen Tuesday in
advance of a developing low pressure system that will track through
the northern Great Lakes Tuesday night. Winds may briefly approach
25 knots Tuesday night but the center of the low tracking across
Lake Huron will limit duration and gust potential. Fresh cold
advection and strong northwest flow in the wake of the system will
then have potential to produce gales late Wednesday through Thursday
morning. A gale watch has been issued for Lake Huron and Saginaw Bay
for this potential.
issued at 147 PM EDT Mon Oct 14 2019
Low pressure continues to pull away from the area while northern
extent of a region of high pressure builds northward into the area
through the overnight. Currently, cold westerly flow is advecting a
fair amount of moisture under a sharpening inversion exciting an
extensive cu field. Ceilings are VFR mainly around 4kt but vary between
3-5kft. Dry air will work into the area as low level moisture mixes
out which will all lead to clear skies out this evening. Westerly
winds gusting into the upper teens will relax overnight with the
ridge overhead. Winds will then then southerly on Tuesday as the
ridge slide off to our southeast.
For dtw...confidence in shower chances/timing/coverage remain too
low at the moment to include a mention in the taf for late Tuesday.
Dtw threshold probabilities...
* high for ceilings aob 5 kft this afternoon. Low this evening
through the overnight.
Michigan...frost advisory from 2 am to 8 am EDT Tuesday for miz047>049-053>055-
Lake Huron...gale watch from Wednesday afternoon through Thursday morning for
Lake St Clair...none.
Michigan waters of Lake Erie...none.