A frontal boundary extending from the western High Plains to the Southeast will focus additional showers and thunderstorms this weekend. Some of these storms may become severe, alongside frequent lightning, and isolated instances of flash flooding. Meanwhile dry conditions will continue for the Great Basin where fire weather concerns linger. For the mid-Atlantic and Northeast, seasonable weather. Read More >
Subject: NAM3 EXPERIMENTAL Froude Number for the greens Model run: BTV_GRID_D2D_NAM3_20250602_0600 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) === ===== === ==== ==== === === === ==== Mon 06/02 06Z 0.72 2717 96 61 0 0.00 Mon 06/02 07Z 0.71 2718 95 72 0 0.01 Mon 06/02 08Z 0.71 2720 96 80 0 0.02 Mon 06/02 09Z 0.72 2820 96 91 0 0.02 Mon 06/02 10Z 0.67 2919 93 93 0 0.01 Mon 06/02 11Z 0.66 2919 92 82 1 0.00 Mon 06/02 12Z 0.68 2819 92 61 1 0.00 Mon 06/02 13Z 0.69 2819 90 38 2 0.00 Mon 06/02 14Z 0.73 2818 84 16 2 0.00 Mon 06/02 15Z 1.23 2717 85 5 2 0.00 Mon 06/02 16Z 7.61 2716 85 2 2 0.00 Mon 06/02 17Z 9.90 2716 76 6 3 0.00 Mon 06/02 18Z 9.20 2715 71 10 3 0.00 Mon 06/02 19Z 9.30 2714 66 11 4 0.00 Mon 06/02 20Z 7.97 2713 65 11 4 0.00 Mon 06/02 21Z 5.60 2712 66 12 4 0.00 Mon 06/02 22Z 2.22 2712 66 16 5 0.00 Mon 06/02 23Z 1.06 2712 65 23 5 0.00 Tue 06/03 00Z 1.02 2814 64 19 5 0.00 Tue 06/03 01Z 1.50 2915 60 22 5 0.00 Tue 06/03 02Z 1.03 3015 60 20 5 0.00 Tue 06/03 03Z 0.94 3014 60 18 5 0.00 Tue 06/03 04Z 0.97 2913 62 15 5 0.00 Tue 06/03 05Z 0.70 2910 58 14 5 0.00 Tue 06/03 06Z 0.69 2910 55 12 5 0.00 Tue 06/03 07Z 0.65 2909 54 11 5 0.00 Tue 06/03 08Z 0.52 2908 53 9 5 0.00 Tue 06/03 09Z 0.38 3007 50 9 6 0.00 Tue 06/03 10Z 0.32 3007 48 9 6 0.00 Tue 06/03 11Z 0.23 3005 45 9 6 0.00 Tue 06/03 12Z 0.21 3004 45 8 6 0.00 Tue 06/03 13Z 0.33 2604 47 6 6 0.00 Tue 06/03 14Z 0.61 2505 49 4 7 0.00 Tue 06/03 15Z 1.18 2405 49 4 7 0.00 Tue 06/03 16Z 2.34 2506 48 7 7 0.00 Tue 06/03 17Z 2.46 2506 46 27 8 0.00 Tue 06/03 18Z 2.16 2506 43 63 9 0.00 Tue 06/03 19Z 1.51 2507 45 80 9 0.00 Tue 06/03 20Z 0.93 2507 51 91 9 0.00 Tue 06/03 21Z 0.44 2507 53 84 10 0.00 Tue 06/03 22Z 0.33 2407 56 70 11 0.00 Tue 06/03 23Z 0.28 2307 61 54 11 0.00 Wed 06/04 00Z 0.24 2307 63 42 12 0.00 Wed 06/04 01Z 0.26 2309 60 35 12 0.00 Wed 06/04 02Z 0.29 2310 57 35 13 0.00 Wed 06/04 03Z 0.30 2311 57 31 13 0.00 Wed 06/04 04Z 0.27 2311 56 29 13 0.00 Wed 06/04 05Z 0.24 2310 55 25 14 0.00 Wed 06/04 06Z 0.25 2211 54 22 14 0.00 Wed 06/04 07Z 0.29 2312 53 16 14 0.00 Wed 06/04 08Z 0.32 2313 54 16 14 0.00 Wed 06/04 09Z 0.41 2315 56 16 14 0.00 Wed 06/04 10Z 0.46 2416 56 18 14 0.00 Wed 06/04 11Z 0.53 2417 56 18 13 0.00 Wed 06/04 12Z 0.55 2416 57 18 13 0.00 Wed 06/04 13Z 0.49 2315 56 15 13 0.00 Wed 06/04 14Z 0.41 2213 55 14 14 0.00 Wed 06/04 15Z 0.34 2112 55 12 14 0.00 Wed 06/04 16Z 0.34 2011 57 14 14 0.00 Wed 06/04 17Z 0.37 1911 59 14 14 0.00 Run total areal avg QPF for the greens is: 0.06 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