Spot Forecast
Issued by NWS Melbourne, FL
Issued by NWS Melbourne, FL
620
FNUS72 KMLB 191440
FWSMLB
Spot Forecast for Emeralda Marsh Area 4 Cattail Rx...SJRWMD
National Weather Service Melbourne FL
1040 AM EDT Tue Aug 19 2025
Forecast is based on ignition time of 0800 EDT on August 20.
If conditions become unrepresentative, contact the National Weather
Service.
.DISCUSSION...
Good morning. The NHC forecast keeps Hurricane Erin well east of
the Florida peninsula as it continues to move northward over the
next few days. High pressure and some drier air around the
periphery of Hurricane Erin will keep rain chances lower than
normal through Wednesday, with a low (30 percent) chance of rain
and lightning storms on Wednesday. Rain chances increase on
Thursday as Erin continues to move away from the Florida
peninsula, with a medium (60 percent) chance of rain and storms in
the afternoon. The pressure gradient will tighten ever so
slightly over the burn site through Wednesday, producing north to
northwest winds around 10 mph with gusts to around 15 mph. Winds
turn westerly on Thursday and become light, with speeds around 5
mph. No min RH concerns over the next several days. Seasonably
warm through Thursday, with afternoon highs in the low to mid 90s,
with peak heat indices of 100-105 degrees. Smoke dispersion
values will be very good through Thursday.
.WEDNESDAY...
Sky/weather.........Sunny (15-25 percent). Slight chance of showers
early in the morning. Slight chance of
thunderstorms late in the morning, then chance
of showers and thunderstorms late in the
afternoon.
Chance of pcpn......30 percent.
Max temperature.....Around 93.
Min humidity........58 percent.
Wind (20 ft)........North winds 6 to 7 mph. Gusty and erratic winds
expected near thunderstorms late in the
morning.
Mixing height.......2600 ft AGL increasing to 5200 ft AGL late in
the morning.
Transport winds.....North 8 to 14 mph.
Dispersion index....13 increasing to 30 late in the morning, then
increasing to 46 late in the morning increasing
to 63 late in the morning decreasing to 53
decreasing to 43 late in the afternoon.
LVORI...............5 decreasing to 1.
TIME (EDT) 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........5 4 9 14 20 25 31 30 28 27
Weather cov.....SCH SCH SCH SCH SCH SCH CHC CHC CHC CHC
Weather type....RW RW RW RW RW RW RW RW RW RW
Tstm cov........ SCH SCH SCH CHC CHC CHC CHC
Chc of pcpn (%).20 20 20 20 20 20 30 30 30 30
Temp............78 81 84 86 88 89 90 90 90 89
RH..............91 85 77 72 66 64 60 60 58 61
20 FT wind dir..N N N N N N N N N N
20 FT wind spd..6 7 7 7 7 6 6 6 6 6
20 FT wind gust.13 14 15 15 15 16 16 16 16 15
Mix hgt (kft)...0.8 1.7 2.6 3.5 4.1 4.6 5.2 4.7 4.2 3.7
Transp wind dir.N N N N N N N N N N
Transp wind spd.13 14 14 14 13 12 10 9 9 8
Dispersion idx..13 30 46 60 64 65 65 55 50 43
LVORI...........5 3 3 2 1 1 1 1 1 1
.WEDNESDAY NIGHT...
Sky/weather.........Mostly clear (15-25 percent). Chance of showers
and thunderstorms early in the evening.
Chance of pcpn......30 percent.
Min temperature.....Around 78.
Max humidity........91 percent.
Wind (20 ft)........Northwest winds around 5 mph early in the
evening becoming light. Gusty and erratic winds
expected near thunderstorms early in the
evening.
Mixing height.......1800 ft AGL decreasing to 500 ft AGL early in
the evening.
Transport winds.....Northwest 5 to 7 mph shifting to the west 7 to
8 mph in the late evening and overnight.
Dispersion index....27 decreasing to 3.
LVORI...............3 increasing to 6.
TIME (EDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
Sky (%).........28 28 29 28 27 26 21 17 12 11 9 8
Weather cov.....CHC CHC
Weather type....RW RW
Tstm cov........CHC CHC
Chc of pcpn (%).30 30 10 10 10 10 10 10 0 0 0 0
Temp............88 87 86 84 83 81 80 79 79 79 79 79
RH..............63 65 68 72 77 82 85 88 88 88 88 88
20 FT wind dir..NW NW NW NW W W W W W W W W
20 FT wind spd..5 5 3 3 2 2 2 2 2 2 3 3
20 FT wind gust.13 10 8 7 6 6 6 6 6 6 7 7
Mix hgt (kft)...2.8 1.8 0.8 0.8 0.7 0.6 0.6 0.5 0.5 0.5 0.5 0.5
Transp wind dir.NW NW W W W W W W W W W W
Transp wind spd.7 6 5 6 7 8 8 8 8 8 8 8
Dispersion idx..27 14 2 3 3 3 3 4 4 4 4 4
LVORI...........2 2 3 3 4 5 5 6 6 6 6 6
.THURSDAY...
Sky/weather.........Mostly sunny (25-35 percent). Chance of showers
early in the morning. Slight chance of
thunderstorms late in the morning, then showers
and thunderstorms likely late in the afternoon.
Chance of pcpn......60 percent.
Max temperature.....Around 92.
Min humidity........61 percent.
Wind (20 ft)........Light winds becoming west 5 to 6 mph in the
late morning and afternoon. Gusty and erratic
winds expected near thunderstorms late in the
morning.
Mixing height.......1600 ft AGL increasing to 4000 ft AGL late in
the morning, then increasing to 5100 ft AGL
late in the afternoon decreasing to 2200 ft AGL
late in the afternoon.
Transport winds.....West 7 to 12 mph.
Dispersion index....5 increasing to 17 late in the morning, then
increasing to 32 late in the morning increasing
to 53 late in the morning increasing to 56
decreasing to 42 late in the afternoon
decreasing to 30.
LVORI...............6 decreasing to 2.
TIME (EDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........8 8 8 12 17 21 30 40 49 48 47 46
Weather cov..... CHC CHC CHC CHC CHC CHC LKY LKY LKY LKY
Weather type.... RW RW RW RW RW RW RW RW RW RW
Tstm cov........ SCH SCH SCH LKY LKY LKY LKY
Chc of pcpn (%).0 0 30 30 30 30 30 30 60 60 60 60
Temp............79 78 79 81 84 87 88 89 89 89 88 87
RH..............88 91 91 85 77 70 66 61 61 61 66 70
20 FT wind dir..W W W W W W W W W W W W
20 FT wind spd..3 3 3 5 5 6 6 6 6 6 6 6
20 FT wind gust.7 7 7 8 10 12 13 14 14 14 14 14
Mix hgt (kft)...0.5 0.6 0.7 1.6 2.5 3.4 4.0 4.6 5.1 4.2 3.2 2.2
Transp wind dir.W W W W W W W W W W W W
Transp wind spd.7 7 7 8 10 12 12 10 9 10 10 12
Dispersion idx..4 3 6 17 32 48 55 57 59 52 42 30
LVORI...........6 6 6 4 3 1 1 1 1 1 1 2
$$
Forecaster...Watson
Requested by...Brent Keith
Type of request...PRESCRIBED
.TAG 2520210.0/MLB
.DELDT 08/19/25
.FormatterVersion 2.0.0
.EMAIL bkeith@sjrwmd.com