Area Forecast Discussion
Issued by NWS Grand Rapids, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

507
FXUS63 KGRR 250358
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
1158 PM EDT SUN JUL 24 2016

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 330 PM EDT Sun Jul 24 2016

A cold front will bring scattered showers and thunderstorms
this evening. High pressure will build in and produce fair and
continued very warm weather Monday through Tuesday. Temperatures
should cool slightly to near normal late in the week into next
weekend.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 330 PM EDT Sun Jul 24 2016

Primary short term fcst concerns involve assessment of convective
potential late this afternoon and evening.

Scattered showers will linger mid to late this afternoon and a few
thunderstorms should redevelop late this afternoon and evening
along and out ahead of the approaching cold front. Convective
potential is mitigated by several factors including weak lift from
the front. Upper level dynamics/pva favorable for convective
development will stay well north of our area.

Nevertheless we do expect scattered thunderstorms to redevelop
late this afternoon and evening in the axis of weak sfc convergence
near the approaching front. Vis sat trends show a cu field developing
near MKE ssw to near Rockford with a developing line of showers and
thunderstorms.

We cannot rule out potential for strong to marginally severe storms
late this afternoon and evening with hail and gusty winds. This is
largely contingent on extent of mid to late afternoon
diurnal heating. 19Z mesoscale analysis does show moderate
instability building into our far sw fcst area south of KGRR out
ahead of the developing line of convection over extreme SE
WI/northern IL.

The relatively best chance for organized convection and severe
weather will stay a little further south of our area across portions
of IL/IN late this afternoon and evening where 19Z mesoscale analysis
indicates much stronger instability. Convection will develop
there on outflow boundaries from the MCS earlier today and also along
and just ahead of the cold front.

Fair weather will return Monday through Tuesday as high pressure
builds in behind the departing system. It will remain very warm
with high temps in the mid to upper 80s both days but there will
be somewhat less humidity.

.LONG TERM...(Wednesday through Sunday)
Issued at 330 PM EDT Sun Jul 24 2016

Surface high pressure that is in place at the beginning of the
period will begin to break down and move eastward by Wednesday
afternoon. Medium range models continue to point to more of a zonal
flow pattern during the midweek period with increasing chances for
showers and thunderstorms during the later half of the work week.

Upper level ridging that was responsible for bringing low to mid-90s
to the area will continue to weaken, eventually being outdone by
a building high over the Southwestern U.S. by Thursday. This results
is somewhat of northwest tilt to the 500mb heights over the Upper
Midwest, which coincides with a broad trough. A weak surface low
takes shape over Southeastern Iowa, slowly tracking into the Southern
Great Lakes through the end of the week.

It does not look like a wash out by any means, but each day could
feature at least the chance for a few showers and thunderstorms. The
likelihood is that the best rain probabilities hold off until late
Thursday into Friday as the main area of lift pushes northeast
through Lower Michigan. Temperatures look much more comfortable with
highs hovering closer to average, even slightly below normal by
Friday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1158 PM EDT Sun Jul 24 2016

VFR conditions overnight except for a few areas of haze or fog
obscuring vsbys to about 4 to 6 miles. This is most likely at JXN
where dew points will be higher through the night. VFR expected
for Monday.

&&

.MARINE...
Issued at 330 PM EDT Sun Jul 24 2016

A small craft advisory and beach hazards statement remains in
effect through late this afternoon from Grand Haven north to
Manistee due to brisk south southwest winds up to 20 to 25 kts
resulting in waves up to 4 to 5 feet. Scattered thunderstorms
could also pose a hazard to mariners through mid evening. Fair
weather with fairly minimal winds and waves returns Monday through
Tuesday.


&&

.HYDROLOGY...
Issued at 1250 PM EDT Sun Jul 24 2016

No river flooding is expected through next week. Area wide rain of
around an inch with locally up to 3 inches (mainly near Lake
Michigan) has fallen since Saturday evening. Another wave of showers
and storms are possible tonight. A small chance of rain is also in
the forecast Wednesday through Friday. River levels are at or below
normal for this time of year, so this rain should not bring any
rivers to flood.

Strong thunderstorms could produce localized rainfall totals over an
inch and lead to localized ponding of water. Rainfall totals will
probably vary substantially over short distances.

&&

.GRR Watches/Warnings/Advisories...
MI...Beach Hazards Statement until midnight EDT tonight for MIZ037-
     043-050.

LM...Small Craft Advisory until midnight EDT tonight for LMZ847>849.

&&

$$

SYNOPSIS...Laurens
SHORT TERM...Laurens
LONG TERM...JAM
AVIATION...Ostuno
HYDROLOGY...63
MARINE...Laurens



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.