883
FXUS63 KGRR 141155
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
655 AM EST Thu Nov 14 2024
.KEY MESSAGES...
- Showers Today into Tonight
- Very light rain chances Saturday night into Sunday
- Pattern evolution disparity within the models Monday - Wednesday
&&
.DISCUSSION...
Issued at 330 AM EST Thu Nov 14 2024
- Showers Today into Tonight
A cloudy rainy day is ahead as showers emanating from a passing
low pressure system continue to move over Lower Michigan today.
A half an inch to an inch of QPF is expected overall.
The upper level low will continue its eastward trek as it moves
into the Mid Atlantic region with a positively tilted ridge
building into the region tonight into Friday. Clouds will linger
keeping lows tonight into Friday morning in the 40s. Clouds will
linger into Friday with dry air eroding cloud cover through
daytime Friday. Fair weather will continue Friday through
Saturday. Near normal temperatures today will bounce back into
the 50s for Friday and Saturday which is around 5 to 10 degrees
above normal.
- Very light rain chances Saturday night into Sunday
A weak cold front associated with a shortwave passing through the
northern Great Lakes will bring chances for light rain Saturday
night into Sunday. Model precipitation is paltry on the order of
trace amounts to a few hundredths of an inch. The low QPF is
associated with the fact the main shortwave passes off to our north
and limited moisture depth.
- Pattern evolution disparity within the models Monday - Wednesday
The main focus of the longer term is really on how the upper pattern
evolves during this time frame and how that affects precipitation
amount and type. Bottom line is at this point there is quite a bit
of model disparity between the ECMWF and the GFS. One trend that is
seen tonight is the backing off in a blast of cold air mid next week
and along with it the chances for snow. Our forecast goes through
next Wednesday and we just do not see a significant cold air
intrusion that would bring snow.
Beginning on Tuesday the operational GFS and ECWMF begin to diverge
where the GFS phases a shortwave lifting out of the southern plains
states with an upper trough moving in from the western U.S. The GFS
therefore closes off a deeper low. Conversely, the ECWMF does not
phase the waves appreciably and results in a weak low that trends
into ridging. We keep 850mb temperatures in the +5 to +10 C range
from Friday night all the way into next Wednesday. Even in the more
developed GFS the low stays well to our west which is why we stay in
the "warmer" air. So, we have light rain chances in the forecast
from Monday night through Wednesday. Precipitation does not look
heavy as the low will be occluding and filling with time.
Highs are generally forecast to be in the 50s through the forecast
period.
&&
.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 656 AM EST Thu Nov 14 2024
IFR cigs continue to overspread the region and along with the
rainshowers will be the dominate concern through the TAF period.
Expect these conditions to continue through the day. Passing
rainshowers could be heavy at times which could reduce vsbys to
IFR. Rain will taper off as the day continues which will allow for
vsbys to improve, mainly after 00Z. However the IFR cigs will
linger through most of the TAf period, improving to MVFR around
06Z.
&&
.MARINE...
Issued at 330 AM EST Thu Nov 14 2024
Southeasterly, offshore flow will continue through today with
winds shifting to the northwest with the passage of the low. Winds
will be out of the northwest tonight into Friday. Both winds and
waves will be slightly higher tonight into tomorrow however waves
will remain below 2 feet and winds will below 20 knots.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Duke/Ceru
AVIATION...Ceru
MARINE...Ceru
NWS GRR Office Area Forecast Discussion
