790
FNUS73 KGRR 301345
FWSGRR

Spot Forecast for Gourdneck Prairie...MIDNR
National Weather Service Grand Rapids MI
945 AM EDT Tue Apr 30 2024

Forecast is based on ignition time of 1400 EDT on April 30.
If conditions become unrepresentative, contact the National Weather
Service.

Please contact our office at (616) 949-5150, if you have questions
or concerns with this forecast.

.DISCUSSION...A dry westerly flow will prevail today leading to
sunny skies.  The wind will be on the increase as the mixing
height deepens, peaking out during the burn.  Humidity levels
will drop steadily into the afternoon, bottoming out
in the 40 to 45 percent range in the middle part of the
afternoon.

.REST OF TODAY...

Sky/weather.........Sunny (0-10 percent).
Temperature.........64 at ignition...Max 69.
RH..................47 percent at ignition...Min 42 percent.
Wind (20 ft)........Winds west at 15 mph at ignition...otherwise
                    West winds 10 to 16 mph.
Mixing height.......3800 ft AGL at ignition...otherwise 3900 ft
                    AGL.
Mixing winds........West 17 to 24 mph decreasing to around 14 mph
                    in the evening.
Smoke dispersal.....880 /excellent/ at ignition. Max...940
                    /excellent/.
Haines Index........5 or moderate potential for large plume
                    dominated fire growth at ignition...max 5.

TIME (EDT)      2 PM   4 PM   6 PM   8 PM   10 PM  MIDNGT
Sky (%).........3      3      3      2      0      8
Weather cov.....
Weather type....NONE   NONE   NONE   NONE   NONE   NONE
Tstm cov........
Temp............64     66     67     64     58     54
RH..............47     42     44     54     62     74
20 ft wind......W 15   W 16   W 13   W 7    E 3    SE 5
20 ft wind gust.23     24     20     10     6      7
Mix hgt (ft)....3800   3500   2900   500    400    400
Mixing wind.....W 23   W 22   W 17   W 7    SE 6   SE 9
Haines index....5      5      5      5      5      5
Smoke disprsl...880    760    510    30     20     30

.TONIGHT...

Sky/weather.........Mostly clear (20-30 percent) then becoming
                    mostly cloudy (55-65 percent).
Temperature.........Min 53.
RH..................Max 80 percent.
Wind (20 ft)........West winds around 7 mph in the evening becoming
                    light, then becoming southeast 5 to 6 mph late
                    at night shifting to the south 8 to 13 mph.
Mixing height.......400 ft AGL.
Mixing winds........West around 7 mph shifting to the north around
                    3 mph in the evening, then shifting to the
                    south 6 to 14 mph shifting to the southwest 15
                    to 17 mph toward daybreak.
Smoke dispersal.....10 (poor).
Haines Index........4 to 5 or low to moderate potential for large
                    plume dominated fire growth.

.WEDNESDAY...

Sky/weather.........Mostly sunny (30-40 percent).
Temperature.........Max 71.
RH..................Min 33 percent.
Wind (20 ft)........Southwest winds 15 to 16 mph shifting to the
                    west 12 to 16 mph.
Mixing height.......4100 ft AGL.
Mixing winds........Southwest 20 to 25 mph shifting to the
                    northwest around 13 mph.
Smoke dispersal.....180 (fair) early in the morning increasing to
                    960 (excellent) in the afternoon.
Haines Index........5 or moderate potential for large plume
                    dominated fire growth.

$$
Forecaster...Sekelsky
Requested by...Jeff Vasher
Type of request...PRESCRIBED
.TAG 2412776.0/GRR
.DELDT 04/30/24
.FormatterVersion 2.0.0
.EMAIL vasherj@michigan.gov