066
FNUS71 KBOX 181518
FWSBOX
SPOT FORECAST FOR LEYDEN PRESCRIBED FIRE...MASSWILDLIFE
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
1118 AM EDT FRI APR 18 2025
FORECAST IS BASED ON IGNITION TIME OF 1200 EDT ON APRIL 18.
IF CONDITIONS BECOME UNREPRESENTATIVE, CONTACT THE NATIONAL
WEATHER SERVICE.
DISCUSSION
DRY CONDITIONS TODAY WITH SOUTH WINDS BETWEEN 10 AND 15 MPH WITH
GUSTS UP TO 30 MPH. RELATIVE HUMIDITY VALUES FALL TO BETWEEN 20
AND 30 PERCENT. SKIES WILL BE MOSTLY CLEAR FOR THE MAJORITY OF THE
DAY.
SATURDAY FEATURES INCREASING SOUTHWEST WINDS THAT WILL START
BETWEEN AND 5 AND 10 MPH, THEN QUICKLY INCREASING TO 10 TO 15 MPH
WITH GUSTS UP TO 30 MPH. MINIMUM RH VALUES FALL TO 45 TO 50
PERCENT. SKIES WILL BE MOSTLY CLOUDY THROUGHOUT THE DAY. THERE
WILL BE A CHANCE FOR A SPOTTY SHOWER LATER IN THE AFTERNOON BUT
CHANCES WILL BE LIMITED AND ANY RAIN THAT DOES FALL WILL NOT BE A
SOAKING RAIN.
REST OF TODAY
SKY/WEATHER.........MOSTLY SUNNY THEN BECOMING MOSTLY CLOUDY.
CWR.................0 PERCENT.
MAX TEMPERATURE.....AROUND 63.
MIN HUMIDITY........29 PERCENT.
DEWPOINT............29 INCREASING TO 33 LATE IN THE AFTERNOON.
MAX APPARENT TEMP...62.
SURFACE WINDS (MPH).SOUTH WINDS 6 TO 10 MPH. GUSTS UP TO 24 MPH IN
THE AFTERNOON.
WIND (20 FT)........SOUTH WINDS 6 TO 10 MPH. GUSTS UP TO 24 MPH IN
THE AFTERNOON.
MIXING HEIGHT.......4500 FT AGL.
TRANSPORT WINDS.....SOUTHWEST 18 TO 25 MPH.
SMOKE DISPERSAL.....GOOD (55600 KNOT-FT) EARLY IN THE MORNING
INCREASING TO EXCELLENT (93400 KNOT-FT) IN THE
AFTERNOON.
LVORI...............1.
ADI.................78 INCREASING TO 101 EARLY IN THE AFTERNOON,
THEN DECREASING TO 87 TO 94 EARLY IN THE
AFTERNOON INCREASING TO 97 LATE IN THE
AFTERNOON DECREASING TO 82.
CEILING (KFT).......25 DECREASING TO 11.
TIME (EDT) 12P 1PM 2PM 3PM 4PM 5PM
SKY (%).........27 23 31 55 72 84
WEATHER COV.....
WEATHER TYPE....
TSTM COV........
CWR.............0 0 0 0 0 0
TEMP............55 58 60 61 62 61
DEWPOINT........27 28 28 30 31 33
RH..............34 32 29 31 31 35
HEAT INDEX (F)..55 58 60 61 62 61
20 FT WIND DIR..S S S S S S
20 FT WIND SPD..6 8 9 9 10 10
20 FT WIND GUST.17 20 22 22 23 24
SURFACE WND DIR.S S S S S S
SURFACE WND SPD.6 8 9 9 10 10
SURFACE WND GST.17 20 22 22 23 24
MIX HGT (KFT)...3.5 4.1 4.5 4.4 4.2 3.3
TRANSP WIND DIR.SW SW SW SW SW S
TRANSP WIND SPD.18 21 22 24 25 24
LVORI...........1 1 1 1 1 1
ADI.............78 101 87 94 97 82
VRATE KT-FT/1K..56 74 86 92 93 70
VENTRATE CAT....FR GD GD GD GD GD
CEILING (KFT)...25 25 25 20 14 11
TONIGHT
SKY/WEATHER.........MOSTLY CLOUDY.
CWR.................0 PERCENT.
MIN TEMPERATURE.....AROUND 49.
MAX HUMIDITY........86 PERCENT.
DEWPOINT............35 INCREASING TO 45.
MAX APPARENT TEMP...59.
SURFACE WINDS (MPH).SOUTH WINDS 8 TO 10 MPH. GUSTS UP TO 24 MPH IN
THE EVENING.
WIND (20 FT)........SOUTH WINDS 8 TO 10 MPH. GUSTS UP TO 24 MPH IN
THE EVENING.
MIXING HEIGHT.......400 FT AGL.
TRANSPORT WINDS.....SOUTH 12 TO 21 MPH.
SMOKE DISPERSAL.....GOOD (42400 KNOT-FT) EARLY IN THE EVENING
DECREASING TO POOR (3800 KNOT-FT) LATE IN THE
NIGHT.
LVORI...............3.
ADI.................57 DECREASING TO 10 TO 19.
CEILING (KFT).......13 DECREASING TO 10 LATE IN THE EVENING, THEN
DECREASING TO 9.0 INCREASING TO 10 AFTER
MIDNIGHT INCREASING TO 15.
TIME (EDT) 6PM 7PM 8PM 9PM 10P 11P MID 1AM 2AM 3AM 4AM 5AM
SKY (%).........84 81 73 71 72 75 79 83 87 84 82 80
WEATHER COV.....
WEATHER TYPE....
TSTM COV........
CWR.............0 0 0 0 0 0 0 0 0 0 0 0
TEMP............59 57 54 52 51 50 51 50 50 51 51 50
DEWPOINT........34 35 36 37 37 39 40 41 42 44 45 46
RH..............39 43 50 56 59 66 66 71 74 77 80 86
HEAT INDEX (F)..59 57 54 52 51 46 51 46 46 51 51 47
20 FT WIND DIR..S S S S S S S S S S S S
20 FT WIND SPD..9 10 10 10 10 10 9 9 9 9 9 8
20 FT WIND GUST.24 24 21 20 20 20 18 18 17 17 17 17
SURFACE WND DIR.S S S S S S S S S S S S
SURFACE WND SPD.9 10 10 10 10 10 9 9 9 9 9 8
SURFACE WND GST.24 24 21 20 20 20 18 18 17 17 17 17
MIX HGT (KFT)...2.4 1.4 0.5 0.5 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4
TRANSP WIND DIR.S S S S S S S S S S S S
TRANSP WIND SPD.21 17 17 15 14 14 13 13 13 13 12 13
LVORI...........1 2 2 2 2 3 3 3 3 4 4 5
ADI.............57 19 15 13 12 12 11 11 11 11 10 11
VRATE KT-FT/1K..42 21 8 6 5 5 5 5 4 4 4 4
VENTRATE CAT....FR PR PR PR PR PR PR PR PR PR PR PR
CEILING (KFT)...13 14 13 10 9.0 9.0 10 10 11 11 15 15
SATURDAY
SKY/WEATHER.........MOSTLY CLOUDY. SLIGHT CHANCE OF RAIN SHOWERS
EARLY IN THE AFTERNOON. CHANCE OF RAIN SHOWERS
LATE IN THE AFTERNOON.
CWR.................0 PERCENT.
MAX TEMPERATURE.....AROUND 76.
MIN HUMIDITY........51 PERCENT.
DEWPOINT............49 INCREASING TO 53 EARLY.
MAX APPARENT TEMP...74.
SURFACE WINDS (MPH).SOUTHWEST WINDS 8 TO 9 MPH WITH GUSTS TO AROUND
22 MPH INCREASING TO 9 TO 10 MPH WITH GUSTS TO
AROUND 26 MPH IN THE AFTERNOON.
WIND (20 FT)........SOUTH WINDS AROUND 8 MPH SHIFTING TO THE
SOUTHWEST 9 TO 10 MPH WITH GUSTS TO AROUND 26
MPH IN THE AFTERNOON.
MIXING HEIGHT.......5400 FT AGL.
TRANSPORT WINDS.....SOUTHWEST 12 TO 20 MPH INCREASING TO WEST 22 TO
31 MPH EARLY.
SMOKE DISPERSAL.....POOR (4000 KNOT-FT) EARLY IN THE MORNING
INCREASING TO EXCELLENT (100200 KNOT-FT) IN THE
AFTERNOON INCREASING TO EXCELLENT (113100
KNOT-FT) LATE IN THE AFTERNOON.
LVORI...............3.
ADI.................9 TO 11 INCREASING TO 103 TO 105.
CEILING (KFT).......15 DECREASING TO 10 EARLY IN THE MORNING, THEN
DECREASING TO 8.0 LATE IN THE MORNING
DECREASING TO 7.0 DECREASING TO 5.0 INCREASING
TO 8.0 EARLY IN THE AFTERNOON INCREASING TO 9.0
DECREASING TO 7.0 LATE IN THE AFTERNOON
INCREASING TO 8.0.
TIME (EDT) 6AM 7AM 8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
SKY (%).........78 75 73 73 73 73 70 66 62 63 64 64
WEATHER COV..... SCH SCH SCH CHC CHC
WEATHER TYPE.... RW RW RW RW RW
TSTM COV........
CWR.............0 0 0 0 0 0 0 0 0 0 0 0
TEMP............51 52 54 57 60 64 67 69 72 74 74 74
DEWPOINT........47 48 49 50 51 52 53 54 55 55 55 55
RH..............86 86 83 77 72 65 61 59 55 51 51 51
HEAT INDEX (F)..51 52 54 57 60 64 67 69 72 74 74 74
20 FT WIND DIR..S S S S SW SW SW SW SW SW W W
20 FT WIND SPD..8 8 8 8 8 8 9 9 9 9 9 10
20 FT WIND GUST.16 16 16 17 20 21 22 22 23 24 25 26
SURFACE WND DIR.S S S S SW SW SW SW SW SW W W
SURFACE WND SPD.8 8 8 8 8 8 9 9 9 9 9 10
SURFACE WND GST.16 16 16 17 20 21 22 22 23 24 25 26
MIX HGT (KFT)...0.4 0.5 0.5 1.4 1.7 1.9 2.7 3.5 4.4 4.7 5.1 5.4
TRANSP WIND DIR.S S S SW SW SW W W W W W W
TRANSP WIND SPD.12 12 14 17 20 22 23 25 26 28 30 31
LVORI...........5 5 4 3 3 1 1 1 1 1 1 1
ADI.............9 9 11 32 42 41 70 89 103 105 105 105
VRATE KT-FT/1K..4 5 7 22 29 36 55 78 100 113 132 147
VENTRATE CAT....PR PR PR PR PR PR FR GD VGD VGD VGD VGD
CEILING (KFT)...15 12 10 8.0 7.0 5.0 8.0 8.0 8.0 9.0 7.0 8.0
FORECASTER...FT
REQUESTED BY...BEN MAZZEI
TYPE OF REQUEST...PRESCRIBED
.TAG 2510975.1/BOX
.DELDT 04/18/25
.FORMATTERVERSION 2.0.0
.EMAIL BEN.MAZZEI@MASS.GOV
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