
Snow accumulations between 3 and 6 inches are expected across much of the area from 10 AM today to 7 AM Wednesday. Some locally higher amounts are expected in the northern Adirondacks. The heaviest snowfall rates are anticipated during this evening's commute. Plan on slippery road conditions. Roads, especially bridges and overpasses, will become slick. Read More >
Subject: NAM3 EXPERIMENTAL Froude Number for the Central_Greens
Model run: BTV_GRID_D2D_NAM3_20260210_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 02/10 00Z 0.19 3221 53 69 -9 0.00
Tue 02/10 01Z 0.18 3222 56 68 -9 0.00
Tue 02/10 02Z 0.14 3222 55 70 -8 0.00
Tue 02/10 03Z 0.11 3321 54 73 -8 0.00
Tue 02/10 04Z 0.09 3319 54 79 -7 0.00
Tue 02/10 05Z 0.09 3318 57 83 -7 0.00
Tue 02/10 08Z 0.13 3215 84 89 -7 0.00
Tue 02/10 09Z 0.13 3113 87 88 -7 0.00
Tue 02/10 10Z 0.13 3112 85 87 -7 0.00
Tue 02/10 11Z 0.13 3111 80 85 -7 0.00
Tue 02/10 12Z 0.15 3010 72 82 -6 0.00
Tue 02/10 13Z 0.13 2907 58 72 -6 0.00
Tue 02/10 14Z 0.12 2706 43 58 -6 0.00
Tue 02/10 15Z 0.14 2507 36 54 -6 0.00
Tue 02/10 16Z 0.14 2307 33 47 -6 0.00
Tue 02/10 17Z 0.14 2207 33 49 -5 0.00
Tue 02/10 18Z 0.17 2109 31 69 -5 0.00
Tue 02/10 19Z 0.19 2111 36 91 -6 0.00
Tue 02/10 20Z 0.22 2013 63 94 -6 0.00
Tue 02/10 21Z 0.12 1815 81 94 -5 0.00
Tue 02/10 22Z 0.09 1818 94 94 -3 0.00
Tue 02/10 23Z 0.15 1922 95 94 -4 0.00
Wed 02/11 00Z 0.19 1923 95 96 -3 0.01
Wed 02/11 01Z 0.33 2025 96 98 -5 0.07
Wed 02/11 02Z 0.41 2124 97 97 -5 0.10
Wed 02/11 03Z 0.42 2222 97 98 -4 0.09
Wed 02/11 04Z 0.41 2320 97 95 -4 0.06
Wed 02/11 05Z 0.39 2418 98 85 -4 0.06
Wed 02/11 06Z 0.37 2416 98 37 -5 0.05
Wed 02/11 07Z 0.40 2516 98 18 -5 0.03
Wed 02/11 08Z 0.47 2617 97 9 -5 0.02
Wed 02/11 09Z 0.50 2718 97 19 -6 0.02
Wed 02/11 10Z 0.54 2819 98 29 -7 0.02
Wed 02/11 11Z 0.55 2920 97 45 -8 0.02
Wed 02/11 12Z 0.51 3021 96 65 -8 0.02
Wed 02/11 13Z 0.54 3021 96 74 -9 0.02
Wed 02/11 14Z 0.58 3021 95 80 -10 0.01
Wed 02/11 15Z 0.62 3021 94 82 -10 0.01
Wed 02/11 16Z 0.74 3020 93 81 -10 0.01
Wed 02/11 17Z 1.48 3019 94 82 -11 0.01
Wed 02/11 18Z 2.73 3018 94 84 -11 0.01
Wed 02/11 19Z 2.61 3018 94 86 -11 0.01
Wed 02/11 20Z 1.75 3019 95 88 -11 0.01
Wed 02/11 21Z 0.92 3120 95 86 -11 0.01
Wed 02/11 22Z 0.69 3223 96 85 -12 0.01
Wed 02/11 23Z 0.57 3225 96 83 -13 0.01
Thu 02/12 00Z 0.42 3325 96 82 -13 0.01
Thu 02/12 01Z 0.34 3326 95 81 -12 0.01
Thu 02/12 02Z 0.34 3326 96 81 -12 0.00
Thu 02/12 03Z 0.26 3324 96 81 -12 0.01
Thu 02/12 04Z 0.19 3324 95 80 -12 0.01
Thu 02/12 05Z 0.17 3324 95 79 -12 0.01
Thu 02/12 06Z 0.14 3325 93 76 -12 0.01
Thu 02/12 07Z 0.12 3426 92 75 -11 0.00
Thu 02/12 08Z 0.12 3326 92 75 -12 0.00
Thu 02/12 09Z 0.14 3326 93 73 -12 0.00
Thu 02/12 10Z 0.15 3327 94 73 -13 0.00
Thu 02/12 11Z 0.18 3327 94 74 -13 0.00
Run total areal avg QPF for the Central_Greens is: 0.75 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