Sunrise 6:05 AM   Sunset 8:52 PM Moonrise 4:10 PM   Moonset 3:08 AM

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LCZ423 320 Am Edt Fri Apr 19 2024
.strong Thunderstorms approaching the waters - .
the areas affected include - . Detroit river - . Michigan waters of lake erie from detroit river to north cape mi - .
at 320 am edt, doppler radar indicated strong Thunderstorms, capable of producing winds up to 30 knots. These Thunderstorms were located along a line extending from 6 nm northwest of bolles harbor of refuge to 9 nm south of north cape, moving northeast at 40 knots.
strong Thunderstorms will be near - . Monroe harbor, bolles harbor of refuge, north cape, luna pier, and detroit beach around 325 am edt. Stony point and woodland beach around 330 am edt. Estral beach and gibraltar around 340 am edt. Lake erie metropark harbor and detroit river light around 345 am edt. Elizabeth park marina around 350 am edt.
other locations impacted by strong Thunderstorms include woodland beach, stony point, gibraltar, estral beach, and detroit beach.
precautionary/preparedness actions - .
mariners can expect gusty winds up to 30 knots, locally higher waves, and lightning strikes. Boaters should seek safe harbor immediately until these storms pass.
&&
lat - .lon 4173 8345 4173 8350 4180 8350 4195 8337 4197 8328 4217 8321 4219 8319 4218 8313 4212 8312 4203 8315 4196 8311 4180 8333 4172 8341 4172 8347

LCZ400
No data

FXUS63 KDTX 191623 AFDDTX

Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1223 PM EDT Sun May 19 2024

KEY MESSAGES

- Warm and muggy conditions are expected today and during the early part of the week with daytime highs in the 80s.

- Showers and thunderstorms are likely this afternoon from Port Huron southwestward to Adrian including Metro Detroit. Brief heavy downpours and gusty winds are the main concerns this afternoon.

- Chances exist for thunderstorms Monday afternoon mainly north of I 69. There will be a potential for strong to severe thunderstorms, but low confidence exists with exactly the strong to severe threat will occur.

- A much less humid airmass is expected for the end of the week.

AVIATION

Higher based (6-10 kft) cloud bases this afternoon with light southwest flow giving way to weak and variable winds/lake breezes/outflow boundaries. Thunderstorm coverage remains challenging, as surface based capes reach and exceed 2500 J/kg.
However, mid levels remain very dry with an upper level ridge axis in place also attempting to hinder activity/coverage. Will be counting on some low level convergence from the cold front and marine influence to get additional activity going, and still have plenty of mixed signals in hires solutions, as subtle upper level wave currently tracks northeast through southern Lake Huron. Will continue to monitor real time trends and continue to fine tune/adjust inherited TAFS, which is advertising thunderstorms for the southern taf sites late in the day. Confidence remains shaky, as muted response with just isolated-scattered disorganized showers/thunderstorms is in play as well, which could lingering into early evening hours. Once diurnal activity dissipates, anticipating mostly clear skies tonight, as the low levels attempt to dry out with light easterly winds. Still could be some residual higher surface dew pts over the southern tafs to support light fog/MVFR visibility reduction late tonight.

For DTW/D21 Convection...Confidence is high clouds bases outside of any thunderstorms/showers will be above 5000 feet this afternoon/evening, but still seems like there is a reasonable chance for a slow moving thunderstorm/shower to impact the terminal late today, with potential for a strong wet micro-burst wind gust and heavy downpours leading to IFR visibility restriction. Timing is still uncertain, and could occur anytime between 19-01z, if at all.

DTW THRESHOLD PROBABILITIES...

* Low-moderate for scattered thunderstorms in the airspace between 19Z-01Z. Low for thunderstorms on Monday.

PREV DISCUSSION
Issued at 1144 AM EDT Sun May 19 2024

UPDATE...

Brief update to the PoP forecast prior for the isolated shower and thunderstorms activity developing within the narrow thetae plume ahead of the frontal boundary. Increased PoPs to 20-25% from roughly the I-94 corridor up through the Thumb through 2 pm. Greater shower and thunderstorm coverage still anticipated towards the St Clair County to Monroe corridor during the afternoon.

PREV DISCUSSION...
Issued at 357 AM EDT Sun May 19 2024

DISCUSSION...

A dynamic upper level jet streak is forecasted to broaden today while lifting to Hudson Bay. The broadening will force geopotential heights to flatten across Lower Michigan which will not only allow a surface cold front to settle southward through northern Lower Michigan but also result in increasing boundary layer warming immediately ahead of the approaching cold front. A notable but narrowing thetae plume is expected to be in place during peak heating this afternoon with forecast soundings supporting a well mixed boundary layer of upwards to 4.0 to 6.0 kft agl. An interesting scenario for this afternoon as a strong consensus of hiresolution models support convection over the southeastern 2/3rds of the cwa. This is despite fairly convincing background anticyclonic vorticity advection over all of the forecast area and a resolved weak 700mb anticyclonic circulation pushing overhead. At first glance of the environmental wind profile, cell movement would appear to be light west to east. However, the strong consensus in convection this afternoon is unanimous in a slow northeast to southwest track that is in agreement with the backward propagating Corfidi vectors.

Based on the model support, increased PoPs into the likely-numerous category for the afternoon in southeast sections of the forecast area. Trigger/lifting mechanisms are expected to be near the shorelines where increased convergence is located due to differential heating. Do not really see a true lake breeze signal per se, but convection will likely behave similarly with the backbuilding and convective reinforced outflow. Very little to no shear suggest no strong or severe thunderstorm risk. The main threat with the convection will be heavy rainfall due to slow storm movement. Precipitable water of 1.3 inches and flow aligned along the axes of lift increases the concern. Will forgo any thoughts of a Flood Watch due to an extremely small footprint to any modeled convective cells and a favorable setup for anticyclonic vorticity advection. Gusty winds due to pulse type-water loading and small hail (Surface based CAPE in excess of 1000 J/kg) will be possible.

An upper level trough pushing into the Pacific Northwest will cause downstream amplification to a ridge over the central United States Monday and Tuesday. The cold front that approaches the area today will quickly lift northeastward on Monday. Some uncertainty exists with the Monday afternoon forecast as trends suggest upstream convective activity from the Plains will approach northern Lower Michigan Monday afternoon. Convective parameters are in the ballpark to support a threat of severe weather. Mixed Layer CAPE is forecasted to reach and exceed 1750 J/kg and 0-6km bulk shear will possibly reach/exceed 35 knots. While the magnitude of the bulk shear suggests some potential for mesocyclones, the morphology of the cam output suggests convective line with possible forward propagating characteristics. The severe threat will likely hinge on the track of convective vorticity which points to northern Lower Michigan. Will need to monitor trends in future model data as SPC has included Southeast Michigan in a Marginal risk for severe weather. The majority of the models are dry here for Metro Detroit but many including the latest ECMWF are bullish on late afternoon convective activity near Saginaw Bay and Lake Huron. Expect revisions to the convective Outlooks. Southeast Michigan will be well within the warm sector with an unstable air mass and highs on Monday expected to again reach the middle 80s. The inherited forecast included a range of slight chance to chance for the northern forecast area.

Uncertainty continues into Tuesday as convectively augmented vorticity maxima will have the potential to stream out of the trough toward Southeast Michigan. A dynamic low pressure system is progged to wrap up over the northern Mississippi River Valley Tuesday with background forcing downstream again supporting large scale subsidence over Lower Michigan. Confidence is not particularly high given the favorable conditions for convection across the Plains, but there is a signal for Tuesday morning activity then pushing out and drying for the afternoon. Confidence is then reasonably high for a cold front pushing through the area early Wednesday. Drying with dewpoints falling into the 40s is expected to carry out the remainder of the week.

MARINE...

Humid conditions persist with pockets of fog across the region this morning. Fog should largely dissipate from Lake Huron early this morning as southerly flow increases ahead of a cold front.
Meanwhile, fog expands across western Lake Erie and possibly into Lake St. Clair as light southeast wind persists there. This should mix out by midday. Today's cold front will be weak but may produce isolated showers or thunderstorms this afternoon and evening, especially along the nearshore waters. An area of low pressure then tracks in from the Midwest late Monday into Tuesday, bringing the next chance for showers and storms with the highest likelihood across northern Lake Huron. Winds and waves are expected to remain below Small Craft Advisory criteria outside of any localized higher winds within any thunderstorms. A period of stronger south wind is increasingly likely late Tuesday night into Wednesday as a stronger low and associated cold front lift into the region.

DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.

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