Sunrise 5:20 AM   Sunset 8:08 PM Moonrise 6:33 PM   Moonset 4:02 AM

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LMZ046 Michigan City In To New Buffalo Mi- 424 Am Edt Tue May 21 2024
.small craft advisory in effect from this evening through late tonight - .
Today - East winds 10 knots or less becoming south. A slight chance of showers early. Waves 1 foot or less. Tonight - South winds 10 to 15 knots becoming southwest 15 to 20 knots. Gusts up to 25 knots. A chance of showers and Thunderstorms in the evening, then showers and Thunderstorms likely overnight. Waves 1 to 3 feet. Wednesday - Southwest winds 10 to 15 knots becoming west. Mostly Sunny. Waves 1 to 3 feet. Wednesday night - Southwest winds 5 to 10 knots becoming west. Partly cloudy. Waves 1 to 2 feet.
winds and waves higher in and near Thunderstorms.
the water temperature at st. Joseph is 57 degrees.

LMZ005
No data

FXUS63 KIWX 210810 AFDIWX

Area Forecast Discussion National Weather Service Northern Indiana 410 AM EDT Tue May 21 2024

KEY MESSAGES

- Potential of strong to severe thunderstorms late tonight across most of the forecast area. Greatest risk appears to be west of Interstate 69 where some thunderstorm wind gusts of 70+ mph are possible.

- Warm and muggy conditions to be replaced by somewhat cooler and less humid air later this week into the Memorial Day weekend with some additional chances for showers and storms.

DISCUSSION
Issued at 400 AM EDT Tue May 21 2024

Greatest convective impacts are still expected late tonight with a potential of strong to severe thunderstorms. Damaging wind gusts in excess of 70 mph appear to be the primary threat.

In the near term, convection is ongoing this morning across the Corn Belt with the greatest coverage at the nose of a 40 knot low level jet. Guidance shows some subtle hints of a weak vort max emanating from this convection and progressing across the western Great Lakes this morning. This should allow some enhancement to downstream southerly flow across the Mid Ms Valley and western Great Lakes pushing low level theta-e boundary back northward. Already have seen a few isolated showers develop from northeast Illinois into west central Illinois early this morning along this theta-e gradient. Low level warm front should also sharpen across extreme northern Indiana/southern Lower Michigan later this morning providing some weak low level convergence. Given nebulous large scale forcing, will maintain just some slight chance PoPs across the north for isolated shower/storm later this morning through early to mid afternoon. By later this afternoon, expecting any low end thunder potential to diminish for a time as low level warm front shifts north and some capping likely taking hold into the evening hours. In terms of temperatures today, a very weak cold advection push is noted behind yesterday evening's departing MCV, but aforementioned return advection should push low level thermals back to close to yesterday's level which should support another day of highs in the mid-upper 80s most locations.

Concern for tonight will turn to potential late night severe event.
Confidence remains medium for this event with a couple of competing positive and negative factors to consider for severe weather potential locally. The short wave that will initiate severe weather potential later this afternoon into this evening across Corn Belt will eject northeast out of the northern Rockies this morning. A strong 50+ knot low level jet nosing into eastern IA/northern IL this afternoon will help to initiate convection into early this evening while strong deformation forcing closer to upper low center across central MN creates an expansive precip field. The past 48 hours have exhibited strong diabatic tendencies to modulate strength and track of the mid level forcing across central CONUS and it appears today will be no different with ultimate strength of Upper MS Valley upper level trough largely dictated by these diabatic effects.

Stronger upper level height falls look to just provide a glancing shot to southern Great Lakes region/Ohio Valley with this system as stronger vort max lifts northeast away from the area tonight, so some question still persists as to the longevity of organized convective upstream as it enters the local area. Sharp initial inflection from Upper MS Valley trough and eastern Great Lakes ridge will lead to a sharp gradient in shear with a possibility that outflow dominance could take over across the southern Great Lakes late evening/overnight. Some near sfc CIN may also develop given late evening/overnight timing. One positive factor for maintaining a higher wind threat into local area is presence of elevated mixed layer that appears to enhance downdraft potential (DCAPE's on the order of 1500 J/kg which is a high end value to support strong downdrafts). Updated 06Z SPC Day1 Outlook does indicate a fairly sharp gradient in severe potential from Enhanced Risk far northwest to Marginal Risk across southeast which falls inline with above factors and the gradient in convective environment expected through time. Given strong DCAPEs some concern does exist if integrity of linear convection is maintained to have some 70+ mph wind gusts late evening/early overnight across the west/northwest. Hail looks to be a lower end threat, and focused probably extreme west/northwest. This event looks to have QLCS characteristics upstream with a potential of QLCS tornadoes across WI/IL, but this potential becomes less confident into the southern Great Lakes given expected tendency to some outflow dominance through time, and the fact 0-3km shear will be more marginal with eastward extent compared to upstream across the MS Valley.

On Wednesday, cold front will slow its eastward progress across the area, especially from southern Illinois into central Indiana as another low amplitude upper level short wave shears out. A narrow moderate instability axis is expected to develop from southern Missouri into west central Ohio Wednesday. Still some uncertainty regarding frontal placement, but it does appear secondary wave lags quite a bit with stronger forcing not arriving until Wednesday evening. Guidance trends have favored areas just south/southeast of local area for Slight Risk (wind/hail threat) on Wednesday. A better intrusion of cooler air reaches southern Great Lakes briefly Wednesday night, but low amplitude flow will not allow this baroclinic zone to make much southward progress. Additional stronger eastern Pacific waves will allow for renewed warm/moist advection late Thursday into Friday with periodic chances of showers and thunderstorms Friday into the weekend. Highs may nudge back into low to mid 80s again for Friday-Saturday in advance of expected stronger short wave, but then expected to cool back to near seasonable levels toward the end of the period. In this progressive pattern, have reluctantly kept PoPs in numerous periods from model blend for much of the extended, but several dry periods are expected between systems and should be narrowed down in later forecasts.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
Issued at 108 AM EDT Tue May 21 2024

Showers and storms have weakened, and dry conditions will now prevail through the day Tuesday. VFR ceilings will persist through much of the day Tuesday, and southerly winds will pick up in the afternoon with gusts up to 20-25 kts possible. Showers and storms will be likely Tuesday night (likely arriving in Indiana between 02-06Z), so chances for storms will need to be added in subsequent TAF forecasts as confidence increases.
Storms may be strong to severe overnight Tuesday into early Wednesday, and the primary concern is strong, gusty winds.

IWX WATCHES/WARNINGS/ADVISORIES
IN...None.
OH...None.
MI...None.
MARINE...None.

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