National Weather Service Raw Text Product

Displaying AFOS PIL: AFDGRR Received: 2019-03-14 19:18 UTC


756 
FXUS63 KGRR 141918
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
318 PM EDT Thu Mar 14 2019

LATEST UPDATE...
Synopsis/Discussion

.SYNOPSIS...
Issued at 304 PM EDT Thu Mar 14 2019

-  Next few hours will be the window for severe weather

-  Snow showers arrive Friday 

-  Seasonal temperatures for much of the period


&&

.DISCUSSION...(This evening through next Thursday)
Issued at 304 PM EDT Thu Mar 14 2019

The combination of favorable 0 to 3 km CAPE along 0 to 1 km
helicity and very low lcl's support an increased risk for severe
weather. Water vapor imagery shows a decent vort lobe pivoting
thru IL as well. The storms upstream have not shown stronger
organization yet, but will need to monitor trends very closely. The
storms should be pulling east of Lansing 7 to 8 pm. 

Gusty winds still a risk around any storms and also behind the
passage of the wave. Gusts to 45 mph still possible so no change
to the advisory headline. 

Colder air moves in from the west tonight through Friday. We will
still see considerable snow melt. This combined with storm total
rainfalls of mostly a half inch to an inch could still allow for
flooding across the watch area. We will keep it going for now.

With temperatures going below freezing Friday night some icy 
spots look possible on the roadways. A low risk for impacts at 
this time.

The rest period looks rather quiet as more of a zonal flow
develops. Fairly close to seasonable temperatures are expected.


&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 121 PM EDT Thu Mar 14 2019

Multiple rounds of thunderstorms are expected through about 00z.
Impacts will accompany these storms to aviators will need to
monitor the latest. Without the storms the winds will be gusting
over 25 knots at times with 40 knots possible. The winds will be
shifting as well especially around any storms.

MVFR ceilings look likely tonight with some light rain. There is a
risk for IFR. As the colder air moves in from the west...a
transition to snow is forecasted for Friday morning.


&&

.HYDROLOGY...
Issued at 126 PM EDT Thu Mar 14 2019

A general one third inch of rain fell across West Michigan since 
Wednesday morning.  The heaviest rain fell along and west of Grand 
Rapids with isolated amounts between one half and three quarters of 
an inch.  Lesser amounts...around one tenth of an inch...were 
reported along and east of US Highway 127.  Temperatures remained 
well above freezing overnight across the region...which continued 
the melting of any remaining snow pack. 

Runoff from rainfall and snowmelt will continue to move through the 
river systems into next week. An additional one quarter to one half 
inch of rain is expected through Friday morning.  The 
convective nature of precipitation today will result in more 
localized heavy rainfall.

Significant rises are expected on most of the mainstem rivers across 
West Michigan.  The Chippewa at Mount Pleasant...Maple at Maple 
Rapids...Rogue at Rockford...Muskegon at Newaygo and Bridgeton...and 
the Grand at Comstock Park and Robinson Township may rise above 
flood stage with minor flooding possible.  Other forecast points are 
currently expected to remain below flood stage.

The mild temperatures and rainfall have resulted in significant 
breakup of ice in area rivers.  While the overall threat of ice jam 
development has decreased the threat is greatest for locations 
across Central Michigan in the White and Muskegon Chippewa basins. 
People with interests along rivers in Central Michigan should 
continue to be alert for rapid changes in river levels.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 11 PM EDT this evening for MIZ037-043>046-
050>052-056>059-064>067-071>074.

Flood Watch through Friday evening for MIZ037>040-043>046-
050>052.

&&

$$

SYNOPSIS...MJS
DISCUSSION...MJS
AVIATION...MJS
HYDROLOGY...MWS