A winter weather and wind advisory is in effect for portions of the North Country from late this afternoon into Thursday evening. A wintry mix of precipitation will quickly overspread the area late this afternoon into tonight, but change to rain by Thursday morning. Gusty winds develop late tonight and continue at times on Thursday. Isolated power outages and locally slick travel expected. Read More >
Subject: NAM3 EXPERIMENTAL Froude Number for the Northern_Greens Model run: BTV_GRID_D2D_NAM3_20250402_1800 Using the MB925 to MB850 layer. Assumes Northern_Greens are orthogonal to 290 degree winds. 925-850 mb Layer Average Wind/RH. Avg QPF over the Northern_Greens. Date Time Wind RH% 700 850T QPF Day mm/dd hhZ Frd# DDFF (%) RH% (C) (in) === ===== === ==== ==== === === === ==== Wed 04/02 18Z 0.05 1502 37 23 -7 0.00 Wed 04/02 19Z 0.11 1504 34 29 -6 0.00 Wed 04/02 20Z 0.14 1608 34 49 -5 0.00 Wed 04/02 21Z 0.17 1612 34 73 -4 0.00 Wed 04/02 22Z 0.24 1617 32 90 -3 0.00 Wed 04/02 23Z 0.18 1820 43 95 -4 0.00 Thu 04/03 00Z 0.18 1820 76 94 -5 0.00 Thu 04/03 01Z 0.22 1722 93 96 -3 0.04 Thu 04/03 02Z 0.24 1727 94 99 -3 0.04 Thu 04/03 03Z 0.28 1732 93 99 -2 0.03 Thu 04/03 04Z 0.29 1735 94 99 -3 0.03 Thu 04/03 05Z 0.28 1838 94 99 -2 0.06 Thu 04/03 06Z 0.24 1841 95 98 -1 0.07 Thu 04/03 07Z 0.16 1843 95 98 0 0.12 Thu 04/03 08Z 0.11 1946 95 97 2 0.18 Thu 04/03 09Z 0.14 1947 94 96 3 0.34 Thu 04/03 10Z 0.14 1950 95 95 3 0.30 Thu 04/03 11Z 0.05 1950 96 93 6 0.21 Thu 04/03 12Z 0.04 1950 97 97 8 0.14 Thu 04/03 13Z 0.06 2050 97 98 7 0.20 Thu 04/03 14Z 0.17 2148 97 90 9 0.11 Thu 04/03 15Z 0.29 2245 97 84 9 0.03 Thu 04/03 16Z 0.45 2344 97 89 8 0.03 Thu 04/03 17Z 0.59 2439 97 72 8 0.02 Thu 04/03 18Z 0.66 2434 96 58 7 0.02 Thu 04/03 19Z 0.64 2433 97 42 8 0.04 Thu 04/03 20Z 0.85 2534 98 27 7 0.05 Thu 04/03 21Z 0.91 2537 92 3 7 0.02 Thu 04/03 22Z 1.03 2536 79 5 7 0.00 Thu 04/03 23Z 1.60 2538 75 3 6 0.00 Fri 04/04 00Z 2.38 2541 78 2 5 0.00 Fri 04/04 01Z 1.90 2644 86 2 4 0.00 Fri 04/04 02Z 1.60 2641 91 3 3 0.00 Fri 04/04 03Z 1.56 2737 94 14 2 0.01 Fri 04/04 04Z 1.50 2838 93 7 1 0.03 Fri 04/04 05Z 1.68 2837 87 5 0 0.01 Fri 04/04 06Z 1.66 2835 83 7 -1 0.01 Fri 04/04 07Z 1.89 2834 79 11 -2 0.00 Fri 04/04 08Z 1.73 2832 82 13 -3 0.00 Fri 04/04 09Z 1.05 2830 83 13 -3 0.00 Fri 04/04 10Z 0.94 2831 86 14 -3 0.00 Fri 04/04 11Z 0.80 2832 88 17 -3 0.00 Fri 04/04 12Z 0.71 2931 88 17 -2 0.01 Fri 04/04 13Z 0.65 2930 87 6 -2 0.01 Fri 04/04 14Z 0.63 2930 83 3 -2 0.01 Fri 04/04 15Z 0.62 2931 79 1 -1 0.01 Fri 04/04 16Z 0.60 3031 74 1 -1 0.01 Fri 04/04 17Z 0.58 3031 73 1 0 0.00 Fri 04/04 18Z 0.56 3130 72 0 0 0.01 Fri 04/04 19Z 0.53 3130 71 0 0 0.00 Fri 04/04 20Z 0.50 3230 68 1 0 0.00 Fri 04/04 21Z 0.44 3230 65 1 0 0.00 Fri 04/04 22Z 0.40 3328 66 1 0 0.00 Fri 04/04 23Z 0.35 3328 61 1 1 0.00 Sat 04/05 00Z 0.28 3426 58 1 2 0.00 Sat 04/05 01Z 0.24 3425 57 2 2 0.01 Sat 04/05 02Z 0.17 3522 54 6 3 0.01 Sat 04/05 03Z 0.11 3520 49 7 3 0.01 Sat 04/05 04Z 0.06 0017 40 7 4 0.00 Sat 04/05 05Z 0.02 0213 37 8 4 0.00 Run total areal avg QPF for the Northern_Greens is: 2.23 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