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

000
FXUS63 KGRR 262025
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
325 PM EST Sun Feb 26 2017

LATEST UPDATE...
Synopsis/Short Term/Long Term/Hydro/Marine

.SYNOPSIS...
Issued at 325 PM EST Sun Feb 26 2017

Quiet weather will prevail over the next 24 hours. Then by late
Monday night rain showers will move into the Southwest Michigan.
We will continue to see periods of showers and perhaps even a few
rumbles of thunder Tuesday and Tuesday night.

On the back side of this storm temperatures will cool and the
region should see a rain and snow mix Wednesday through Thursday
night. The weekend appears drier.

It will remain warm with daytime temperatures a few degrees
either side of 50 Monday through Wednesday, then we should cool
down to closer to 40 for the latter portion of the week. Another
warm up may begin by Sunday.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 325 PM EST Sun Feb 26 2017

Winds will diminish overnight, signaling a period of quiet
weather that will last until late Monday night. Showers arrive by
then, and they will linger through Tuesday night. Some
thunderstorms are possible Tuesday and Tuesday night for areas
south of I-96.

A short wave was crossing the CWA this afternoon, with partial
clearing behind it. Skies will remain partly to mostly cloudy
overnight. Southwest winds will gradually diminish through the
evening, becoming light late tonight.

Surface ridging develops to our east on Monday. This will give us
a southerly flow which will help temps get into the 40s. Again
expect a mix of clouds and sun through the day, although the south
will cloud up by late afternoon.

A warm front sharpens across the region Monday night as low
pressure tracks from IA into the Great Lakes by Tuesday night. It
appears we will see periods of showers and a few thunderstorms
from this system starting late Monday night. The first wave of
pcpn will be associated with the warm front as it lifts north into
the CWA late Monday night into Tuesday morning. There may be
enough elevated instability for isolated storms south of I-96 in
the morning. The left exit region of the upper jet and a 40 knot
low level jet both come into the region toward 12Z Tue, leading
to confidence to raise POPs to likely.  Then the showers should
become more scattered into the afternoon as we await the surface
low pressure.

The surface low is progged to cross Central Lower Michigan Tuesday
night, keeping most of the CWA in the warm sector. Another low
level jet moves in with the low and since there is liable to be
better instability Tuesday evening, we could see some stronger
storms along I-94 which could produce some hail and marginally
severe wind gusts. Again will add thunder to the forecast, but
keep it along and south of I-96 where the best instability is
expected.

.LONG TERM...(Wednesday through Sunday)
Issued at 325 PM EST Sun Feb 26 2017

There is the suggestion that the rain will change to all snow
Wednesday afternoon and some indications a significant amount of snow
is possible into Wednesday night (northern CWA is the focus of this).
After that the cold air is back into Friday so we get lake effect
snow showers only to have the next Pacific system through tracks in
and pushes the weekend system into Canada well north of Michigan so
we get warm again. However just beyond this is the coldest air since
early January.  That will follow a deeply occluded storm storm, with
a lot of wind early in the following week.

We of course have the building Greenland block, which usually means
cold weather for us.  Also going along with this idea is the MJO is
now in Phase 2 and all of the models forecast to go to Phase 3
within a week. Based on the CPC lagged temperature composites for
the MJO....phase 2 and 3 are cold for the eastern CONUS.  So I am
thinking if anything we will end up colder than we are currently
forecasting.

In event, the system departing the area Wednesday afternoon has a
trailing upper wave.  This should be enough to chance the
precipitation (ECWMF and NAM) and change it to snow (Ecmwf,GFS and
NAM) by 4 pm over most of our Western and Northern CWA.  The ECMWF
is currently forecasting 3 to 4 inches of snow north of I-96 between
1 pm Wed and 1 am Thursday.  The GFS operational run does not amply
the wave as much as the NAM and ECMWF even so there would be lake
enhanced snow by Wed evening. From Thu into Friday we are in the cold
air with NW winds so we should see lake enhanced snow showers.

The Pacific system moves in by Saturday so we could see light snow
with the warm front Saturday morning.  Then is should be dry until
Monday when the next system comes in.

Bottom line more ups and downs (rain to snow to rain to snow...)


&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1229 PM EST Sun Feb 26 2017

Expect solid VFR conditions for all of GRR`s taf sites through 00z
Tuesday. We will have some mid clouds this afternoon due to the
warmer air pushing in but that should be east of the area by this
evening. Winds will be rather gusty today will become light
overnight,

&&

.MARINE...
Issued at 325 PM EST Sun Feb 26 2017

Winds have peaked already this afternoon and we will see a
gradually diminishing trend through the rest of the afternoon, and
then a quick drop off in speeds after nightfall. A small craft
advisory will be continued through 5 AM Monday when waves will
also finally subside.

South to southeast wind will be 10 to 20 knots Monday through
Tuesday. The offshore component will lead ti somewhat safer lake
conditions. These winds become southwest by Tuesday night.

A couple rounds of thunderstorms will be possible Tuesday and
Tuesday night, mainly south of Holland.

&&

.HYDROLOGY...
Issued at 325 PM EST Sun Feb 26 2017

Many rivers have experienced within bank rises after Thursday and
Friday`s rainfall. Some out of bank rises at Croton, Maple Rapids,
and Ionia have occurred. It appears that no further rises will occur
at Croton so the worst may be over. Rain is expected primarily
Tuesday and Wednesday. Some areas may get over a half inch of rain.
While this is not expected to create flooding, there may be
additional within bank rises on rivers or possibly out of bank rises
if more of the rain falls over the Muskegon and Grand River basins.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 5 AM EST Monday for LMZ844>849.

&&

$$

SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...Hoving
MARINE...JK


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