Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 261922

Area Forecast Discussion
National Weather Service Grand Rapids MI
322 PM EDT Sat May 26 2018

Synopsis/Short Term/Long Term/Marine/Hydro

Issued at 319 PM EDT Sat May 26 2018

Temperatures will warm to near record readings for the
remainder of the Holiday weekend, with highs across the area
reaching mostly into the low 90s. It will be noticeably cooler
immediately near Lake Michigan, however, where some morning and
early afternoon fog will be possible. Chances for showers and
thunderstorms Sunday will remain east of a line from Big Rapids to
Battle Creek, keeping the Grand Rapids area and the lakeshore dry.
Dry weather is expected for Memorial Day.


.SHORT TERM...(This evening through Monday night)
Issued at 319 PM EDT Sat May 26 2018

Warm and unstable airmass will continue to favor showers and
thunderstorms this afternoon and evening where a trigger exists for
upward forcing. Best chance will be over the far southeast portion
of the forecast area (Jackson/Ingham counties), closer to upper
energy tracking through the Ohio Valley. Another area where we will
have better potential for development will be along/north of M-10 as
a weak surface trough tracks through Northern Michigan. Very slow
storm motion and high PW values (1.1 to 1.4 inches per AM Raobs and
model estimates) will bring potential for heavy downpours with
storms that develop. Modest ML CAPE (1000-1500 J/kg) but low shear
may allow strong but brief updrafts to develop. Biggest threat from
storms will be gusty winds, and of course lightning.

Showers and thunderstorm potential will decrease through the evening
as shortwave trough passes through and drier air at the mid-levels
works in. Another warm and muggy night is in store for the area as
dewpoints remain in the 60s. Min temps tonight should also reach
low/mid 60s. Warm, high dewpoint airmass, flowing over Lake Michigan
will again create potential for fog (some dense) to develop along
the lakeshore tonight into Sunday afternoon, similar to today.

We will slowly transition to surface high pressure and ridging aloft
Sunday and Monday. Stability provided by warming mid-levels should
keep the far western portion of the state dry tomorrow. Showers and
thunderstorms will remain possible roughly east of a line from Big
Rapids to Battle Creek during the afternoon and evening. Dry weather
is then expected Sunday night through Monday night as ridging at the
surface and aloft settles in overhead. Potential for fog over and
near Lake Michigan will continue each night through early afternoon.

Continuation of seasonably hot conditions will likely be the most
noticeable weather trend of the Holiday weekend as temperatures the
next few days soar to near records (see below). Warming trend can be
expected the next few days as H850 temps rise to near 18C and 588dm
ridge builds at H500 near Chicago.

Grand Rapids
May 26...90 (2010)
May 27...93 (1911)
May 28...92 (1978)
May 29...92 (1962)

May 26...90 (1911)
May 27...93 (1911)
May 28...96 (1874)
May 29...94 (1895)

May 26...87 (2010)
May 27...86 (2012)
May 28...89 (2012)
May 29...93 (1962)

.LONG TERM...(Tuesday through Saturday)
Issued at 319 PM EDT Sat May 26 2018

Looks like we`ll have a few opportunities for rain during the long
term. The first will come Tuesday afternoon. As the upper ridge over
the eastern Great Lakes moves east, the gfs shows a weak short wave
moving north toward Lower Michigan. The ecmwf doesn`t show this so
confidence is still fairly low that we`ll see rain.

A higher chance of rain will come Wednesday and Thursday. Both the
gfs and ecmwf show the remnants of Alberto moving north from the
Gulf and rain reaching Lower Michigan perhaps as early as Wednesday
(gfs/Canadian) or Thursday (ecmwf). Either way, all of the models
show a pretty good signal for rain.

There`s also a chance of rain Friday as a cold front move south
across the state.

Tuesday will be the warmest day with highs in the mid 80s and then
highs falling back into the 70s for the rest of the period.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 149 PM EDT Sat May 26 2018

Mainly VFR weather is expected the next 24 hours. A couple of
items to watch are the potential for showers and thunderstorms
this afternoon and evening inland and fog potential overnight.

Showers and storms should continue to develop east of KGRR and
KBTL this afternoon, mainly affecting the KLAN and KJXN TAF sites.
The showers/storms will fade after sunset with dry weather
expected overnight. Areas of fog will likely develop tonight given
some rain last night and high dew points in place. Any fog will
burn off fairly quick Sunday morning, with VFR weather through 18z
on Sunday.

Winds will be under 10 knots through 18z Sunday.


Issued at 319 PM EDT Sat May 26 2018

Main concern for marine interests will continue to be
potential for dense fog to form as a warm and moist airmass remains
in place through Tuesday. The highest potential will be from late
each night through early afternoon. Otherwise, the weather is
expected to remain quiet as thunderstorm potential remains mainly
east of the lake and winds stay fairly light.


Issued at 319 PM EDT Sat May 26 2018

River stages continue falling. This trend will continue through the
holiday weekend. The next risk for basin wide, measurable rainfall
will hold off until the middle of next week when the remnants of
Alberto will likely move into the Great Lakes region. Projected
rainfall amounts may boost a few river sites out of their banks, but
flooding appears unlikely at this time given the progressive nature
of the system across the area. Trends will continue to be




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