245
FNUS72 KMLB 100926
FWSMLB
SPOT FORECAST FOR GRASSY ISLAND...SOUTH FLORIDA WATER MANAGEMENT DISTRICT
NATIONAL WEATHER SERVICE MELBOURNE FL
526 AM EDT THU JUL 10 2025
FORECAST IS BASED ON IGNITION TIME OF 0900 EDT ON JULY 10.
IF CONDITIONS BECOME UNREPRESENTATIVE, CONTACT THE NATIONAL WEATHER
SERVICE.
DISCUSSION
A LIGHT AND VARIABLE WIND THIS MORNING GRADUALLY BACKS TO THE
SOUTH-SOUTHEAST THIS AFTERNOON, AROUND 5 MPH. SHOWERS AND
LIGHTNING STORMS ARE FORECAST TO DEVELOP ALONG THE WESTWARD-MOVING
SEA BREEZE IN THE AFTERNOON, ESPECIALLY AFTER 4 PM. GUSTY, ERRATIC
WINDS MAY ACCOMPANY THE STRONGEST OF STORMS, ALONG WITH FREQUENT
LIGHTNING STRIKES. OTHERWISE, EXPECT HIGH TEMPERATURES TO REACH
THE LOW 90S WITH HEAT INDEX VALUES PEAKING AROUND 103-107 DEGREES.
TODAY
SKY/WEATHER.........MOSTLY SUNNY (35-45 PERCENT). SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS EARLY IN THE
AFTERNOON. CHANCE OF SHOWERS AND THUNDERSTORMS
LATE IN THE AFTERNOON, THEN SHOWERS AND
THUNDERSTORMS LIKELY LATE IN THE AFTERNOON.
CHANCE OF PCPN......60 PERCENT.
MAX TEMPERATURE.....AROUND 92.
MIN HUMIDITY........60 PERCENT.
WIND (20 FT)........LIGHT WINDS BECOMING SOUTH 5 TO 6 MPH LATE IN
THE MORNING. GUSTY AND ERRATIC WINDS EXPECTED
NEAR THUNDERSTORMS IN THE AFTERNOON.
MIXING HEIGHT.......2000 FT AGL INCREASING TO 4400 FT AGL LATE IN
THE MORNING.
TRANSPORT WINDS.....SOUTH 5 TO 7 MPH.
DISPERSION INDEX....6 INCREASING TO 28.
LVORI...............8 INCREASING TO 10 EARLY IN THE MORNING, THEN
DECREASING TO 6 EARLY IN THE MORNING DECREASING
TO 4 LATE IN THE MORNING DECREASING TO 2.
TIME (EDT) 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
SKY (%).........23 22 21 30 34 41 45 49 54
WEATHER COV..... SCH CHC CHC CHC CHC LKY
WEATHER TYPE.... RW RW RW RW RW RW
TSTM COV........ SCH CHC CHC CHC CHC LKY
CHC OF PCPN (%).10 10 10 20 30 40 50 50 60
TEMP............81 85 88 89 90 91 91 90 88
RH..............85 75 68 66 62 60 60 60 63
20 FT WIND DIR..S S S S S S S SE SE
20 FT WIND SPD..3 3 5 5 5 6 6 6 6
20 FT WIND GUST.7 8 8 8 9 9 10 12 12
MIX HGT (KFT)...1.5 2.0 2.7 3.5 4.0 4.4 4.1 3.5 2.9
TRANSP WIND DIR.S S S S S S S SE SE
TRANSP WIND SPD.6 6 6 7 6 6 6 7 7
DISPERSION IDX..10 15 19 27 28 32 29 29 24
LVORI...........4 4 3 3 2 1 2 2 2
TONIGHT
SKY/WEATHER.........MOSTLY CLOUDY (50-60 PERCENT) THEN BECOMING
PARTLY CLOUDY (40-50 PERCENT). SHOWERS AND
THUNDERSTORMS LIKELY EARLY IN THE EVENING, THEN
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
EARLY IN THE EVENING.
CHANCE OF PCPN......60 PERCENT.
MIN TEMPERATURE.....AROUND 75.
MAX HUMIDITY........100 PERCENT.
WIND (20 FT)........SOUTH WINDS 5 TO 6 MPH IN THE EVENING BECOMING
LIGHT. GUSTY AND ERRATIC WINDS EXPECTED NEAR
THUNDERSTORMS EARLY IN THE EVENING.
MIXING HEIGHT.......400 FT AGL.
TRANSPORT WINDS.....SOUTH 6 TO 12 MPH.
DISPERSION INDEX....29 DECREASING TO 5.
LVORI...............4 INCREASING TO 7 IN THE LATE EVENING AND
OVERNIGHT.
TIME (EDT) 6 PM 8 PM 10 PM MIDNGT 2 AM 4 AM
SKY (%).........54 55 55 50 40 36
WEATHER COV.....LIKELY S CHC
WEATHER TYPE....RNSHWR RNSHWR NONE NONE NONE NONE
TSTM COV........LIKELY S CHC
CHC OF PCPN (%).60 20 10 10 0 0
TEMP............86 81 78 77 76 76
RH..............68 82 91 90 94 94
20 FT WIND......SE 6 S 6 S 5 S 3 S 2 S 2
20 FT WIND GUST.12 13 12 10 9 8
MIX HGT (FT)....2200 1000 600 400 400 400
TRANSPORT WIND..SE 12 S 8 S 8 S 6 S 6 S 6
DISPERSION IDX..29 6 5 3 3 3
LVORI...........3 4 6 6 6 6
FRIDAY
SKY/WEATHER.........MOSTLY SUNNY (35-45 PERCENT) THEN BECOMING
MOSTLY CLOUDY (65-75 PERCENT). CHANCE OF
SHOWERS EARLY IN THE MORNING. CHANCE OF
THUNDERSTORMS LATE IN THE MORNING, THEN SHOWERS
AND THUNDERSTORMS LIKELY LATE IN THE AFTERNOON.
CHANCE OF PCPN......60 PERCENT.
MAX TEMPERATURE.....AROUND 91.
MIN HUMIDITY........64 PERCENT.
WIND (20 FT)........LIGHT WINDS BECOMING SOUTHEAST 5 TO 6 MPH IN
THE LATE MORNING AND AFTERNOON. GUSTY AND
ERRATIC WINDS EXPECTED NEAR THUNDERSTORMS LATE
IN THE MORNING.
MIXING HEIGHT.......2300 FT AGL INCREASING TO 4500 FT AGL LATE IN
THE MORNING, THEN DECREASING TO 2300 FT AGL
LATE IN THE AFTERNOON.
TRANSPORT WINDS.....SOUTH 6 TO 7 MPH.
DISPERSION INDEX....4 INCREASING TO 25.
LVORI...............9 DECREASING TO 3.
TIME (EDT) 6 AM 10 AM 2 PM
SKY (%).........33 35 70
WEATHER COV..... CHANCE LIKELY
WEATHER TYPE....NONE RNSHWR RNSHWR
TSTM COV........ LIKELY
CHC OF PCPN (%).0 40 60
TEMP............75 86 90
RH..............100 75 64
20 FT WIND......S 2G7 S 5G9 SE 6G10
MIX HGT (FT)....400 2300 4500
TRANSPORT WIND..S 6 S 7 S 6
DISPERSION IDX..2 21 29
LVORI...........9 3 3
FORECASTER...SCHAPER
REQUESTED BY...ANDREW WEST
TYPE OF REQUEST...PRESCRIBED
.TAG 2517668.0/MLB
.DELDT 07/10/25
.FORMATTERVERSION 2.0.0
.EMAIL ANWEST@SFWMD.GOV
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