GFS EXPERIMENTAL Froude Number for the Green Mountains

Dangerous Cold Expected This Weekend

An Extreme Cold Watch has been issued for all of northern New York and Vermont for Saturday into Sunday afternoon. Wind chills of 20 to 35 below zero are possible, especially Saturday afternoon through Sunday morning. The risk of frostbite and hypothermia will be elevated, especially for vulnerable populations. Prepare now for the extreme cold, especially if you plan to be outdoors. Read More >

Subject: GFS EXPERIMENTAL Froude Number for the greens Model run: BTV_GRID_D2D_GFS_20260205_0000 Using the MB925 to MB850 layer. Assumes greens are orthogonal to 270 degree winds. 925-850 mb Layer Average Wind/RH. Avg QPF over the greens. Date Time Wind RH% 700 850T QPF Day mm/dd hhZ Frd# DDFF (%) RH% (C) (in) === ===== === ==== ==== === === === ==== Thu 02/05 00Z 0.33 3115 90 40 -12 0.00 Thu 02/05 03Z 0.34 3013 92 43 -13 0.00 Thu 02/05 06Z 0.36 2812 93 47 -13 0.00 Thu 02/05 09Z 0.42 2815 92 69 -14 0.01 Thu 02/05 12Z 0.38 3015 94 7 -15 0.01 Thu 02/05 15Z 0.28 3113 93 6 -16 0.01 Thu 02/05 18Z 0.27 3111 83 5 -15 0.00 Thu 02/05 21Z 0.17 3110 68 5 -13 0.00 Fri 02/06 00Z 0.09 3208 54 6 -12 0.00 Fri 02/06 03Z 0.03 3404 46 13 -11 0.00 Fri 02/06 06Z 0.02 1300 34 21 -10 0.00 Fri 02/06 09Z 0.01 1806 33 16 -10 0.00 Fri 02/06 12Z 0.05 2006 38 16 -10 0.00 Fri 02/06 15Z 0.06 2007 49 54 -11 0.00 Fri 02/06 18Z 0.06 1908 64 97 -11 0.00 Fri 02/06 21Z 0.12 2008 80 98 -11 0.00 Sat 02/07 00Z 0.12 2009 78 98 -11 0.00 Sat 02/07 03Z 0.12 1911 94 98 -12 0.00 Sat 02/07 06Z 0.13 2011 95 98 -12 0.02 Sat 02/07 09Z 0.10 2009 95 99 -11 0.02 Sat 02/07 12Z 0.06 2004 96 100 -12 0.03 Sat 02/07 15Z 0.14 3310 97 99 -14 0.06 Sat 02/07 18Z 0.22 3317 97 99 -18 0.04 Sat 02/07 21Z 0.29 3321 99 100 -21 0.02 Run total areal avg QPF for the greens is: 0.22 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