
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_0600
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 06Z 0.06 3314 55 78 -7 0.00
Tue 02/10 07Z 0.07 3314 58 78 -7 0.00
Tue 02/10 08Z 0.10 3213 61 90 -7 0.00
Tue 02/10 09Z 0.13 3112 75 89 -7 0.00
Tue 02/10 10Z 0.13 3110 84 90 -7 0.00
Tue 02/10 11Z 0.12 3008 83 91 -6 0.00
Tue 02/10 12Z 0.15 2808 77 89 -6 0.00
Tue 02/10 13Z 0.17 2708 71 83 -6 0.00
Tue 02/10 14Z 0.18 2608 63 73 -6 0.00
Tue 02/10 15Z 0.22 2510 51 68 -6 0.00
Tue 02/10 16Z 0.24 2410 41 63 -6 0.00
Tue 02/10 17Z 0.20 2309 39 48 -6 0.00
Tue 02/10 18Z 0.20 2209 40 53 -5 0.00
Tue 02/10 19Z 0.16 2011 43 85 -4 0.00
Tue 02/10 20Z 0.22 2014 49 94 -6 0.00
Tue 02/10 21Z 0.10 1815 91 94 -4 0.00
Tue 02/10 22Z 0.08 1818 95 95 -3 0.05
Tue 02/10 23Z 0.13 1822 96 98 -3 0.06
Wed 02/11 00Z 0.22 1924 96 97 -3 0.07
Wed 02/11 01Z 0.33 2025 96 95 -4 0.06
Wed 02/11 02Z 0.41 2125 98 89 -4 0.05
Wed 02/11 03Z 0.42 2223 98 96 -4 0.04
Wed 02/11 04Z 0.48 2323 97 76 -4 0.05
Wed 02/11 05Z 0.54 2423 97 46 -5 0.03
Wed 02/11 06Z 0.58 2522 97 27 -6 0.02
Wed 02/11 07Z 0.59 2620 97 17 -6 0.02
Wed 02/11 08Z 0.58 2720 97 22 -7 0.01
Wed 02/11 09Z 0.60 2720 97 26 -7 0.01
Wed 02/11 10Z 0.58 2820 97 34 -8 0.01
Wed 02/11 11Z 0.57 2821 96 50 -8 0.01
Wed 02/11 12Z 0.54 2921 95 52 -9 0.01
Wed 02/11 13Z 0.58 2921 96 54 -9 0.00
Wed 02/11 14Z 0.63 2819 96 66 -10 0.01
Wed 02/11 15Z 0.81 2819 96 76 -10 0.01
Wed 02/11 16Z 1.08 2919 95 81 -10 0.01
Wed 02/11 17Z 2.17 2918 95 82 -10 0.01
Wed 02/11 18Z 2.08 2817 96 83 -10 0.01
Wed 02/11 19Z 1.79 2919 96 85 -10 0.02
Wed 02/11 20Z 1.66 2920 95 86 -10 0.02
Wed 02/11 21Z 1.16 3020 95 86 -11 0.02
Wed 02/11 22Z 0.81 3122 96 85 -11 0.02
Wed 02/11 23Z 0.70 3223 95 82 -12 0.01
Thu 02/12 00Z 0.53 3224 95 82 -12 0.01
Thu 02/12 01Z 0.45 3225 95 83 -12 0.01
Thu 02/12 02Z 0.40 3226 96 83 -12 0.01
Thu 02/12 03Z 0.35 3225 96 83 -12 0.01
Thu 02/12 04Z 0.26 3324 96 83 -12 0.01
Thu 02/12 05Z 0.20 3324 95 81 -12 0.01
Thu 02/12 06Z 0.16 3324 94 79 -12 0.00
Thu 02/12 07Z 0.14 3325 93 78 -12 0.00
Thu 02/12 08Z 0.14 3325 93 79 -12 0.00
Thu 02/12 09Z 0.12 3326 93 78 -12 0.00
Thu 02/12 10Z 0.13 3326 93 76 -12 0.00
Thu 02/12 11Z 0.14 3327 93 74 -13 0.00
Thu 02/12 12Z 0.17 3328 93 72 -13 0.00
Thu 02/12 13Z 0.15 3329 93 64 -13 0.00
Thu 02/12 14Z 0.14 3327 92 50 -13 0.00
Thu 02/12 15Z 0.12 3326 92 28 -13 0.00
Thu 02/12 16Z 0.13 3326 90 12 -13 0.00
Thu 02/12 17Z 0.15 3326 86 7 -12 0.00
Run total areal avg QPF for the Central_Greens is: 0.70 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