IWX issues Area Forecast Discussion (AFD) at Aug 18, 4:45 AM EDT304
FXUS63 KIWX 180845
AFDIWX
Area Forecast Discussion
National Weather Service Northern Indiana
445 AM EDT Sun Aug 18 2024
.KEY MESSAGES...
- There is a high swim risk for Lake Michigan beaches in Berrien
County, Michigan and La Porte County, Indiana through late
Monday night. A beach hazards statement is in effect. Life
threatening currents and waves are expected. Those visiting
the beaches should plan to stay out of the water.
- There are chances for showers and thunderstorms through this
evening. Severe weather is not expected. Dry conditions to
follow for the work week. Otherwise, expect partly to mostly
cloudy skies today, with patchy fog possible until just after
sunrise this morning.
- High temperatures will be in the 70s and low 80s through much
of the week, then climb into the mid to upper 80s this
weekend. Lows will be predominantly in the 50s and 60s.
&&
.DISCUSSION...
Issued at 441 AM EDT Sun Aug 18 2024
Patchy fog is possible this morning before rain showers move in and
winds pick up and shift from west to northwest, gusting to around 25-
30 mph further west (especially near Lake MI). As of right now, most
sites with reduced visibility are between 2-5SM, but there are a few
that have dropped to 1 mile or less (KGGP is 1/4SM, 1/2SM at KOKK,
KMZZ is 1SM). Expect we'll see a few more sites drop closer to 1SM
towards sunrise before dissipating. Added patchy fog to the forecast
through 13z, but held off on any SPS as I don't think the dense fog
will become more widespread. It seems fairly isolated and is likely
shallow given winds aren't completely calm (most around 3-5 knots).
Blustery northwest winds that develop today will persist but
gradually veer more north-northeast through Monday evening. With a
stronger wind and more favorable fetch (versus present light
westerly winds), waves on Lake Michigan will build to 4 to 8 feet by
mid afternoon. Waves approaching at a 60-90 degree angle (relative
to shore), and wave periods of 6 to 8 seconds will be extremely
favorable for strong rip and structural currents. Conditions will be
life-threatening for swimmers. Those visiting the beaches today
should plan to stay out of the water. Do not venture out on
piers, as waves are likely to be washing over them. Winds die
down overnight Monday into Tuesday, with waves diminishing to 2
to 3 feet. There is a moderate swim risk for Tuesday.
Otherwise, the surface/upper level low overhead will linger through
the evening hours before shifting eastward overnight, with the upper
level ridge and associated surface high pressure in it's wake. Until
then, expect variable cloud cover as we see another shortwave
pinwheel around the low, kicking off additional showers and a few
thunderstorms. Chances for showers and even a few thunderstorms
increase into the afternoon, with most models hinting at around 300-
1200 J/kg of surface CAPE building in the 18-00z time frame. Right
now, isolated showers are confined to near Lake Michigan, though as
the trough (currently over central Lake MI) swings southeastward
through the morning expect coverage to increase. Mid level lapse
rates aren't all that impressive, and we have little to no shear so
don't expect anything in the way of severe weather. Similarly as we
lose our daytime heating and the trough exits our forecast area this
evening, we'll see dry conditions and decreasing clouds. Highs today
will be in the mid to upper 70s. Lows tonight will be in the upper
50s and low 60s.
Monday into next Sunday will be dry as an upper level ridge builds
in overhead. By Monday afternoon the expansive ridge will extend
from the desert southwest/Southern plains all the way up into the
Canadian Prairies, with surface high pressure encompassing the Upper
Great Lakes. This will slowly meander eastward and flatten through
next weekend as several shortwaves attempt to break it down on the
northeastern periphery. Temperatures will remain on the cooler side
through Thursday, mainly in the 70s (low-mid 70s Mon-Wed behind the
system) and lows in the upper 40s and low to mid 50s. Temperatures
will then heat up into the mid to upper 80s for the weekend, with
some locations possibly reaching 90 degrees. Lows will be in the
60s and low 70s.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 139 AM EDT Sun Aug 18 2024
Spokes of energy will continue to wrap around the upper low
situated over northern Lake Huron. Widely scattered showers may
impact KSBN over the next couple of hours, but somewhat greater
potential exists once again during peak heating as the final
disturbance passes through bringing at least isolated to maybe
sct showers (isol storm) to both sites. MVFR cigs will advect in
from the north overnight into early Sunday before mixing out
once again (only to be replaced by an expanding CU field.
Removed any mention of IFR cigs for the time being as confidence
not high enough at this point.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Beach Hazards Statement from 10 AM CDT this morning through
late Monday night for INZ103.
OH...None.
MI...Beach Hazards Statement from 11 AM EDT this morning through
late Monday night for MIZ177-277.
MARINE...Small Craft Advisory from 11 AM this morning to 5 AM EDT
Tuesday for LMZ043-046.
&&
$$
DISCUSSION...MCD
AVIATION...Fisher
Source:
IWX issues Area Forecast Discussion (AFD) at Aug 18, 4:45 AM EDT---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!
