
Severe thunderstorms will remain possible in the Mid-Atlantic through Tuesday. Severe thunderstorms and heavy rain will also be possible in the central/southern Plains on Tuesday and Wednesday. Hazardous heat will linger across the southern U.S. and build across the West through mid-week. Hot and dry weather will create Elevated to Critical fire weather conditions in the Four Corners Region. Read More >
Subject: NAM3 EXPERIMENTAL Froude Number for the Central_Greens
Model run: BTV_GRID_D2D_NAM3_20260623_0000
Using the MB925 to MB850 layer.
Assumes Central_Greens are orthogonal to 260 degree winds.
925-850 mb Layer Average Wind/RH. Avg QPF over the Central_Greens.
Date Time Wind RH% 700 850T QPF
Day mm/dd hhZ Frd# DDFF (%) RH% (C) (in)
=== ===== === ==== ==== === === === ====
Tue 06/23 00Z 0.28 1416 93 99 8 0.00
Tue 06/23 01Z 0.29 1421 94 99 9 0.03
Tue 06/23 02Z 0.15 1520 96 93 10 0.03
Tue 06/23 03Z 0.05 1620 97 95 10 0.02
Tue 06/23 04Z 0.07 1719 98 98 11 0.03
Tue 06/23 05Z 0.11 1815 99 99 11 0.03
Tue 06/23 06Z 0.10 1910 99 98 11 0.03
Tue 06/23 07Z 0.07 1907 99 96 11 0.03
Tue 06/23 08Z 0.05 1804 99 95 11 0.03
Tue 06/23 09Z 0.05 1902 99 92 10 0.03
Tue 06/23 10Z 0.04 2801 99 86 10 0.01
Tue 06/23 11Z 0.05 3204 99 79 10 0.01
Tue 06/23 12Z 0.04 3407 99 70 10 0.00
Tue 06/23 13Z 0.04 3409 97 60 10 0.00
Tue 06/23 14Z 0.03 3409 95 40 10 0.00
Tue 06/23 15Z 0.03 3410 93 24 10 0.00
Tue 06/23 16Z 0.04 3411 90 15 10 0.00
Tue 06/23 17Z 0.04 3412 88 12 10 0.00
Tue 06/23 18Z 0.08 3412 86 8 10 0.00
Tue 06/23 19Z 0.11 3412 86 6 10 0.00
Tue 06/23 20Z 0.17 3312 86 6 10 0.00
Tue 06/23 21Z 0.15 3313 85 5 10 0.00
Tue 06/23 22Z 0.20 3314 86 6 10 0.00
Tue 06/23 23Z 0.18 3315 89 5 10 0.00
Wed 06/24 00Z 0.21 3318 93 7 10 0.00
Wed 06/24 01Z 0.24 3319 91 11 10 0.01
Wed 06/24 02Z 0.21 3318 88 10 10 0.01
Wed 06/24 03Z 0.15 3319 85 12 10 0.01
Wed 06/24 04Z 0.14 3321 90 15 10 0.01
Wed 06/24 05Z 0.10 3421 94 20 9 0.00
Wed 06/24 06Z 0.07 3420 94 22 9 0.00
Wed 06/24 07Z 0.06 3418 93 21 9 0.00
Wed 06/24 08Z 0.07 3417 91 21 9 0.00
Wed 06/24 09Z 0.14 3317 89 24 9 0.00
Wed 06/24 10Z 0.21 3217 87 27 9 0.00
Wed 06/24 11Z 0.29 3118 85 28 8 0.00
Wed 06/24 12Z 0.34 3118 87 30 8 0.00
Wed 06/24 13Z 0.38 3118 87 30 8 0.00
Wed 06/24 14Z 0.55 3118 86 34 7 0.00
Wed 06/24 15Z 1.06 3017 86 34 7 0.00
Wed 06/24 16Z 3.32 2915 86 37 8 0.00
Wed 06/24 17Z 5.10 2815 88 48 8 0.00
Wed 06/24 18Z 5.34 2815 86 44 8 0.00
Wed 06/24 19Z 5.87 2815 85 43 9 0.00
Wed 06/24 20Z 4.00 2816 85 40 9 0.00
Wed 06/24 21Z 3.35 2917 85 40 9 0.00
Wed 06/24 22Z 2.62 3018 83 41 9 0.00
Wed 06/24 23Z 1.31 3018 83 38 9 0.00
Thu 06/25 00Z 0.95 3019 83 39 9 0.00
Thu 06/25 01Z 1.12 3018 84 36 9 0.00
Thu 06/25 02Z 0.97 3018 88 36 9 0.00
Thu 06/25 03Z 0.84 3019 87 35 9 0.00
Thu 06/25 04Z 0.67 3019 84 38 9 0.00
Thu 06/25 05Z 0.49 3118 82 38 9 0.00
Thu 06/25 06Z 0.36 3217 79 38 10 0.00
Thu 06/25 07Z 0.31 3215 78 40 10 0.00
Thu 06/25 08Z 0.21 3313 77 39 10 0.00
Thu 06/25 09Z 0.17 3311 77 40 10 0.00
Thu 06/25 10Z 0.12 3307 76 39 10 0.00
Thu 06/25 11Z 0.10 3305 76 39 10 0.00
Run total areal avg QPF for the Central_Greens is: 0.32 inches.
Froude Number (Frd#):
Frd# < 0.5 Flow is subcritical and blocked.
Upslope clouds/precip backed farther upwind of and up to mtn crest.
W Upslope snow favors eastern Champlain Valley, BTV, and Western slopes.
Gap winds possible.
Frd# 0.5-1 Flow is subcritical/slow moving/blocked.
Upslope clouds/precip falls immediately upwind of mtn crest.
W Upslope snow favors western slopes to the Green Mt. spine including:
Montgomery,Underhill,Jericho,Bolton,Richmond,Huntington,Lincoln.
Gap winds possible.
Frd# 1-2 Flow is critical.
With strong winds, Mountain waves/downslope winds possible.
Precip falls close to mountain ridge crests and on lee side.
W Upslope snow favors Green Mt Spine,Jay,Stowe,Waterbury,NE Kingdom.
Froude > 2 Flow is supercritical/unblocked(rapid flow).
Air flows freely over terrain.
Persistent upslope snow not favored. Scattered snow showers and flurries.
Relative Humidity (RH):
925-850 mb RH > 90% needed for upslope precipitation.
with 700mb RH > 70% favors upslope snow.
with 700mb RH > 90% greater amounts of W upslope snow possible.
850mb Temperature (T degC) Westerly Upslope Snow Ratios: (Avg=28:1)
T > -11 10-15:1
T -11 to -15 25-35:1
T < -15 15-20:1