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332
FXUS63 KDTX 281922
AFDDTX

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
322 PM EDT Sun Apr 28 2024

.KEY MESSAGES...

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- Another round of showers and scattered thunderstorms tomorrow,
some of which could be strong.

- Well above normal temperatures expected continue through the week.
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&&

.DISCUSSION...

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Moist airmass in place over southeast Michigan, as the 12z DTX raob
came in with a near record high PW value of 1.35 inches or 221
percent of normal. Short lived, modest mid level dry slot, is moving
in for the rest of the afternoon over the Central Great Lakes, which
has allowed the widespread showers this morning to taper off. Still
have warm frontal boundary hanging around, with enough instability
(MLcapes 400-800 J/kg) to potentially trigger convection through the
evening hours, mainly north of the boundary (north of M-59). 0-1 KM
bulk shear values 30+ knots along/near the front draws concern for
cells to rotate, but limited cape and modest mid level lapse rates
expected to keep storms non-severe, with 700-500 MB upper level
ridging also tending to suppress activity.

Large, well developed, mid-upper level low/circulation over the
Plains will be slowly lifting northeast into Ontario Tuesday
morning. Better large scale support arrives Monday with height falls
and surface cold front tracking through during the day. Favorable
timing of the front during/near peak heating draws concerns for
severe storms, but once again, instability is expected to be limited
with MLcapes mainly under 1000 j/kg. Wind fields are elevated, with
850 MB winds (30-40 knots) and favorable 0-6 KM bulk shear around 40
knots. Would not rule out storms approaching severe limits with more
substantial cloud breaks developing during the day than currently
anticipated.

Muddled forecast for next week as strong upper level low and energy
comes out of the Gulf of Alaska moves through the northern Rockies
early next week and mostly loses it`s eastern push/momentum.
Southeast Michigan loses to be caught in between the building upper
level trough over the southeastern U.S. and the series of height
falls tracking through the Midwest and upper Mississippi River
Valley. Higher confidence in temperatures ending up solidly above
normal. Low confidence in rain and thunderstorm chances.
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&&

.MARINE...

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A low pressure system will travel north across the western Midwest
today, settling over western Lake Superior by tomorrow night. This
will push a stalled frontal boundary, which is currently draped over
central Michigan, north into the northern Great Lakes. Rain and some
rumbles of thunder remain likely along this frontal boundary through
early tomorrow morning. The position of the low will also reinforce
northeast flow across the Great Lakes through tomorrow morning,
bringing elevated wave heights across the Saginaw Bay to Harbor
Beach, where Small Craft Advisories are in effect.

A very shallow mixing layer is expected to develop tomorrow morning
across north to north-central Lake Huron which will allow for some
localized higher wind gust potential with flow coming from the
northeast. Gusts around 30 to 35 knots will be likely, centered
between 10Z to 20Z. Was on the fence with the issuance of a Gale
Warning, but confidence remains low whether gale potential will
persist in any given three hour window, especially if the marine
layer is more stable relative to modeled sounding projections. A
short fused Gale Warning will still be considered for future updates
if model trends suggest higher probabilities for gale potential.

Otherwise, shower and storm potential will increase for all
locations tomorrow afternoon and evening, ahead of a cold front.
Thunderstorms will have the potential to produce isolated gusts to
or above 30 knots.
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&&

.HYDROLOGY...

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Scattered-numerous showers and thunderstorms will remain
mainly north of M-59 through tonight as a frontal boundary
holds steady through this evening before lifting north by Monday
morning. Another round of numerous showers and scattered
thunderstorms are expected across all of southeast Michigan Monday
afternoon as cold front tracks through. Additional rainfall
this evening through tomorrow evening looks to average around
half an inch across most locations, but any stronger thunderstorms
will push totals to at or above 1 inch. While significant flooding
is not expected at this time, minor flooding in prone urban and poor
drainage areas is possible, with notable rises in area rivers.
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&&

.PREV DISCUSSION...
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Issued at 123 PM EDT Sun Apr 28 2024

AVIATION...

A frontal boundary currently positioned between MBS and FNT will
ease southward through the afternoon and evening period, nearing the
PTK area toward 00z. Pockets of showers will continue to percolate
along and north of a frontal boundary through the late day period,
with the greatest coverage likely at MBS with lesser potential at
FNT. This will occur within an expanding region of lower stratus,
highlighted by IFR at MBS and eventual MVFR to IFR at FNT. This
corridor remains susceptible to isolated thunderstorm development
given proximity to the front, but with confidence in occurrence
quite low as instability wanes rapidly with northward extent. VFR
with dry conditions favored across the Detroit airspace through the
evening, with a gusty southwest wind. Pockets of light rain will
remain possible overnight as higher moisture works across the
boundary. Low stratus likely entrenched throughout the night at MBS
in northeast flow, with potential for a period of LIFR during the
early morning hours. Northward progress of the front supports a
decreasing coverage of stratus with time at FNT overnight.

For DTW/D21 Convection...Focus for thunderstorm development expected
to remain west and north of the airspace through this evening. Next
chance of thunderstorms arrives Monday afternoon ahead of a cold
front.

DTW THRESHOLD PROBABILITIES...

* Low in thunderstorms Monday afternoon.

* Low in ceilings at or below 5000 feet this afternoon
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&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory from 11 PM this evening to 4 PM EDT Monday for
     LHZ421-441.

     Small Craft Advisory until 10 AM EDT Monday for LHZ422.

Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

$$

DISCUSSION...SF
MARINE.......SF
HYDROLOGY....SF
AVIATION.....MR


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