National Weather Service Raw Text Product

Displaying AFOS PIL: AFDGRR Received: 2018-05-16 05:56 UTC


546 
FXUS63 KGRR 160556
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
156 AM EDT Wed May 16 2018

LATEST UPDATE...
Aviation

.SYNOPSIS...
Issued at 330 PM EDT Tue May 15 2018

Fair weather will return tonight through mid to late week as a
high pressure ridge takes hold of the weather pattern. Seasonably
mild temperatures are forecast for the rest of the week with high
temperatures in the 70s daily. The next chance for rain and 
thunderstorms will come Saturday night through Sunday. 

&&

.UPDATE...
Issued at 625 PM EDT Tue May 15 2018

A few isolated showers, on with a top near 20,000 ft near Rockford
have developed on the lake breeze convergence boundary. There is
just enough instability to get cumulus clouds tall enough for
showers near the lake breeze convergence boundary and this is 
shown nicely on the latest Hrrrx (last few actually). These 
shower will be gone by sunset. Since one of them actually has 
moderate to heavy shower under it I updated the grids to show the 
most likely area for them over the next hour or two. 

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 330 PM EDT Tue May 15 2018

Short term fcst concerns are minimal. An isolated light rain shower 
or sprinkle may still develop late this afternoon into early evening 
with very weak instability in place (latest mesoanalysis shows 
around 250 j/kg or less of sb/mu cape over our fcst area). This 
notion is supported by the latest HRRR. Otherwise skies will be 
partly cloudy overnight and northeast to east winds will advect a 
drier airmass in. 

A high pressure ridge will bring fair wx with seasonably mild temps 
Wednesday through Thursday. High temps both days will reach the 
middle 70's to near 80 degrees. The nam cu scheme shows potential 
for some sct fair wx cumulus tomorrow and Thursday afternoon. 

With a weak gradient in place tomorrow under the ridge we expect a 
lake breeze to develop early in the afternoon and push inland which 
will result in a wind shift to the west and allow skies to become 
mostly clear.  

.LONG TERM...(Friday through Tuesday)
Issued at 330 PM EDT Tue May 15 2018

The pattern is looking rather quiet for the long term.  Models are 
showing on relatively weak wave of low pressure to track through the 
region later Saturday night through Sunday.  The mid level pattern 
features a positively tilted trough tracking through.  850 mb moist 
advection will feed this system somewhat...supporting at least some 
showers.  Overall the risk for thunder is relatively low.  

A surface ridge of high pressure will be in place for Friday into 
Saturday of this week.  Subsidence associated with this feature 
should support dry conditions.  High pressure is forecasted to move 
in for Monday behind the departing wave of low pressure and will 
likely persist into the middle part of the week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 156 AM EDT Wed May 16 2018

We are looking at a forecast period with little to impacts to
aviation operations. Clouds around 3-5k ft from earlier have just
about totally dissipated as of 0530z, with only high clouds
remaining. Other than patchy fog near standing water, we expect
that conditions will remain VFR through the morning. A cumulus
field will likely form this afternoon based around 4k ft at inland
locations. KMKG will likely remain mostly clear with a lake breeze
kicking in and bringing more stable air inland. Cumulus will
dissipate around sunset, and winds will go light and variable.

&&

.MARINE...
Issued at 330 PM EDT Tue May 15 2018

Northerly winds will produce wave heights in the 2 to 4 foot range
late this afternoon into this evening. Wind speeds and wave
heights will subside tonight as high pressure builds in. Minimal
winds and wave heights are forecast through midweek with high
pressure in place.


&&

.HYDROLOGY...
Issued at 146 PM EDT Tue May 15 2018

One to two inches of rain fell across the Kalamazoo River basin in 
the last 24 hours...with lesser amounts in the Grand and Muskegon 
basins.  This has increased the forecast crest for rivers in that 
system and/or pushed the time of crest out further in time.  

River flood warnings continue for the Sycamore at Holt, Grand at 
Jackson, and Portage at Vicksburg.  Some of the other sites that are 
seeing strong rises could flirt with flood stage...but forecast 
trend is for them to crest lower with each issuance so will not 
issue any other warnings at this point.

Scattered showers and thunderstorms this afternoon should not have 
the areal coverage or intensity to produce rainfall/runoff that will 
impact area rivers.  Dry weather for the rest of the work week will 
allow runoff to complete and the flood crests to move downstream 
without further enhancement.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&

$$

UPDATE...WDM
SYNOPSIS...Laurens
SHORT TERM...Laurens
LONG TERM...MJS
AVIATION...NJJ
HYDROLOGY...MWS
MARINE...Laurens