444
FNUS71 KPHI 200900
FWSPHI

Spot Forecast for Bethlehem and Hypsie Gap...The Nature Conservancy
National Weather Service Mount Holly NJ
500 AM EDT Tue May 20 2025

Forecast is based on ignition time of 0800 EDT on May 20.
If conditions become unrepresentative, contact the National Weather
Service.

Please contact our office if you have questions
or concerns with this forecast.

.DISCUSSION...
High pressure centered to our north today will extend into our area.
Low pressure then moves into the upper Ohio Valley tonight into
Wednesday, with a new low pressure system developing off the Mid-
Atlantic coast into Thursday. The low pressure system gradually
moves away Thursday night and Friday, however the upper level energy
lingers nearby through most of the holiday weekend.

.REST OF TODAY...

Sky/weather.........Mostly sunny.
CWR.................0 percent.
Chance of pcpn......0 percent.
Max temperature.....Around 62.
Min humidity........46 percent.
Wind shift..........None.
Wind (20 ft)........North winds 8 to 15 mph. Gusts up to 30 mph
                    early in the morning.
Mixing height.......4100 ft AGL.
Transport winds.....North 13 to 23 mph decreasing to around 10 mph
                    late in the afternoon.
Smoke dispersal.....Fair (17500 knot-ft) early in the morning
                    increasing to good (47400 knot-ft) in the
                    afternoon.
ADI.................27 to 66.

TIME (EDT)      8AM 9AM 10A 11A 12P 1PM 2PM 3PM 4PM 5PM
Sky (%).........8   12  13  17  21  16  30  49  54  58
Weather cov.....
Weather type....
Tstm cov........
CWR.............0   0   0   0   0   0   0   0   0   0
Chc of pcpn (%).0   0   0   0   0   0   0   0   0   0
Temp............43  47  50  54  56  58  60  61  61  60
RH..............66  58  54  50  49  48  47  46  47  49
20 FT wind dir..N   N   N   N   N   N   N   N   N   N
20 FT wind spd..14  15  14  13  12  10  9   9   8   8
20 FT wind gust.28  25  25  23  21  20  17  16  15  14
Mix hgt (kft)...1.0 1.4 1.8 2.6 3.1 3.6 4.0 4.1 4.0 4.0
Transp wind dir.N   N   N   N   N   N   N   N   N   N
Transp wind spd.22  22  20  18  16  15  13  13  13  12
ADI.............27  41  45  54  54  66  61  62  47  43
Vrate kt-ft/1K..20  28  31  42  45  47  45  45  45  41
Ventrate Cat....PR  PR  PR  FR  FR  FR  FR  FR  FR  FR

.TONIGHT...

Sky/weather.........Mostly cloudy. Chance of rain after midnight.
CWR.................10 percent increasing to 30 percent early in
                    the morning.
Chance of pcpn......30 percent.
Min temperature.....Around 45.
Max humidity........89 percent.
Wind shift..........None.
Wind (20 ft)........Northeast winds 5 to 7 mph shifting to the east
                    late in the evening.
Mixing height.......300 ft AGL.
Transport winds.....Northeast 9 to 12 mph shifting to the east 10
                    to 13 mph in the late evening and overnight.
Smoke dispersal.....Good (37000 knot-ft) early in the evening
                    decreasing to poor (3300 knot-ft) late in the
                    night.
ADI.................51 early in the evening decreasing to 6 late in
                    the night.

TIME (EDT)      6 PM   8 PM   10 PM  MIDNGT 2 AM   4 AM
Sky (%).........64     73     75     74     78     85
Weather cov.....
Weather type....NONE   NONE   NONE   NONE   NONE   NONE
Tstm cov........
CWR.............0      0      0      10     10     10
Chc of pcpn (%).0      0      0      10     10     10
Temp............59     55     51     49     47     46
RH..............51     61     68     74     76     83
20 ft wind......N 7    NE 5   E 5    E 6    E 6    E 7
20 ft wind gust.13     8      9      10     12     15
Mix hgt (ft)....3700   700    800    600    500    300
Transport wind..N 12   NE 9   E 10   E 13   E 10   E 13
ADI.............51     6      7      8      7      8
Vrate kt-ft/1K..37     6      9      7      5      7
Ventrate Cat....POOR   POOR   POOR   POOR   POOR   POOR

.WEDNESDAY...

Sky/weather.........Cloudy. Chance of rain early in the morning,
then periods of rain in the afternoon.
CWR.................40 percent increasing to 100 percent.
Chance of pcpn......100 percent.
Max temperature.....Around 50.
Min humidity........83 percent.
Wind shift..........None.
Wind (20 ft)........East winds 7 to 10 mph.
Mixing height.......1400 ft AGL.
Transport winds.....East 13 to 21 mph.
Smoke dispersal.....Poor (5800 knot-ft) early in the morning
                    increasing to fair (26000 knot-ft) in the
                    afternoon.
ADI.................11 to 33.

TIME (EDT)      6 AM      9 AM      NOON      3 PM
Sky (%).........91        96        98        98
Weather cov.....CHANCE    PERIOD    PERIOD    PERIOD
Weather type....RAIN      RAIN      RAIN      RAIN
Tstm cov........
CWR.............40        90        100       100
Chc of pcpn (%).40        90        100       100
Temp............46        49        49        48
RH..............86        86        89        89
20 FT wind......E 9G17    E 9G15    E 10G17   E 12G20
Mix hgt (ft)....600       900       1200      1300
Transport wind..E 13      SE 18     E 20      SE 20
ADI.............11        20        31        30
Vrate kt-ft/1K..6         15        21        23
Ventrate Cat....POOR      POOR      POOR      POOR

$$
Forecaster...DeSilva
Requested by...Patrick McElhenny
Type of request...PRESCRIBED
.TAG 2514233.1/PHI
.DELDT 05/20/25
.FormatterVersion 2.0.0
.EMAIL pmcelhenny@tnc.org,brianwilli@pa.gov