Heat index values near 95 are expected for the central and southern Champlain Valley and portions of the Connecticut River Valley today. Heat Advisories have been issued for these locations, valid from noon to 8 PM today. The highest heat index values will occur between 1 PM and 5 PM. Read More >
Subject: BTV4 EXPERIMENTAL Froude Number for the greens Model run: BTV_GRID_D2D_BTV4_20220521_1200 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) === ===== === ==== ==== === === === ==== Sat 05/21 12Z 0.48 2519 91 68 15 0.00 Sat 05/21 13Z 0.49 2518 90 66 16 0.00 Sat 05/21 14Z 0.50 2616 88 63 16 0.00 Sat 05/21 15Z 0.47 2514 85 53 17 0.00 Sat 05/21 16Z 0.50 2413 82 47 17 0.00 Sat 05/21 17Z 0.60 2313 80 44 17 0.00 Sat 05/21 18Z 0.72 2315 80 42 17 0.00 Sat 05/21 19Z 0.98 2317 81 42 17 0.00 Sat 05/21 20Z 1.12 2318 83 48 17 0.00 Sat 05/21 21Z 1.07 2320 85 50 17 0.01 Sat 05/21 22Z 1.14 2423 82 61 17 0.01 Sat 05/21 23Z 0.62 2318 77 59 18 0.05 Sun 05/22 00Z 0.60 2321 79 79 17 0.03 Sun 05/22 01Z 0.59 2419 88 78 17 0.26 Sun 05/22 02Z 0.81 2622 90 72 16 0.15 Sun 05/22 03Z 0.58 2516 88 79 16 0.08 Sun 05/22 04Z 0.78 2418 91 76 16 0.09 Sun 05/22 05Z 0.86 2821 92 82 14 0.43 Sun 05/22 06Z 0.35 2612 75 80 16 0.10 Sun 05/22 07Z 0.39 2513 73 75 15 0.00 Sun 05/22 08Z 0.35 2412 76 72 15 0.00 Sun 05/22 09Z 0.36 2413 77 65 15 0.00 Sun 05/22 10Z 0.38 2415 74 60 16 0.00 Sun 05/22 11Z 0.41 2416 71 61 16 0.00 Sun 05/22 12Z 0.43 2316 69 63 15 0.00 Sun 05/22 13Z 0.48 2318 72 69 15 0.00 Sun 05/22 14Z 0.56 2320 74 67 15 0.00 Sun 05/22 15Z 0.66 2222 73 63 16 0.00 Sun 05/22 16Z 1.05 2222 71 60 16 0.00 Sun 05/22 17Z 2.10 2222 73 56 16 0.00 Sun 05/22 18Z 2.70 2223 76 58 16 0.00 Sun 05/22 19Z 4.19 2223 78 62 16 0.00 Sun 05/22 20Z 5.86 2321 80 78 16 0.03 Sun 05/22 21Z 3.68 2321 74 73 16 0.04 Sun 05/22 22Z 2.31 2619 81 79 16 0.04 Sun 05/22 23Z 3.15 2835 94 90 12 0.36 Mon 05/23 00Z 0.63 2928 92 87 12 0.25 Mon 05/23 01Z 0.55 3026 92 85 10 0.04 Mon 05/23 02Z 0.47 3124 92 62 8 0.03 Mon 05/23 03Z 0.45 3123 94 42 7 0.02 Mon 05/23 04Z 0.41 3223 93 28 5 0.01 Mon 05/23 05Z 0.38 3223 92 20 5 0.01 Mon 05/23 06Z 0.34 3223 89 16 4 0.01 Mon 05/23 07Z 0.30 3223 85 13 4 0.01 Mon 05/23 08Z 0.26 3322 79 12 4 0.00 Mon 05/23 09Z 0.23 3322 74 12 3 0.00 Mon 05/23 10Z 0.19 3322 69 12 3 0.00 Mon 05/23 11Z 0.15 3421 64 11 3 0.00 Mon 05/23 12Z 0.11 3421 61 11 3 0.00 Mon 05/23 13Z 0.08 3520 60 12 3 0.00 Mon 05/23 14Z 0.06 3520 58 13 2 0.00 Mon 05/23 15Z 0.05 3518 60 14 2 0.00 Mon 05/23 16Z 0.11 3517 63 15 1 0.00 Mon 05/23 17Z 0.40 3516 65 16 1 0.00 Mon 05/23 18Z 0.64 3515 65 16 1 0.00 Mon 05/23 19Z 0.74 3515 65 16 2 0.00 Mon 05/23 20Z 0.92 3515 65 15 2 0.00 Mon 05/23 21Z 0.81 3514 66 15 2 0.00 Mon 05/23 22Z 0.61 3514 68 15 2 0.00 Mon 05/23 23Z 0.24 3514 68 16 1 0.00 Tue 05/24 00Z 0.15 3515 67 16 1 0.00 Tue 05/24 01Z 0.12 0016 65 16 1 0.00 Tue 05/24 02Z 0.09 0015 64 16 1 0.00 Tue 05/24 03Z 0.10 0014 64 15 1 0.00 Tue 05/24 04Z 0.14 0112 64 15 1 0.00 Tue 05/24 05Z 0.19 0111 63 14 1 0.00 Tue 05/24 06Z 0.24 0211 61 15 1 0.00 Tue 05/24 07Z 0.31 0310 60 15 1 0.00 Tue 05/24 08Z 0.37 0410 61 15 1 0.00 Tue 05/24 09Z 0.38 0410 59 15 1 0.00 Tue 05/24 10Z 0.37 0510 55 15 1 0.00 Tue 05/24 11Z 0.35 0609 52 16 1 0.00 Tue 05/24 12Z 0.32 0708 51 16 1 0.00 Tue 05/24 13Z 0.35 0807 53 16 1 0.00 Tue 05/24 14Z 0.65 1006 57 16 1 0.00 Tue 05/24 15Z 1.92 1105 59 17 1 0.00 Tue 05/24 16Z 2.69 1306 60 17 2 0.00 Tue 05/24 17Z 2.22 1506 60 19 2 0.00 Tue 05/24 18Z 2.10 1508 60 20 3 0.00 Tue 05/24 19Z 1.69 1609 60 22 4 0.00 Tue 05/24 20Z 0.89 1710 61 24 4 0.00 Tue 05/24 21Z 0.70 1711 62 26 4 0.00 Tue 05/24 22Z 0.67 1712 64 29 4 0.00 Tue 05/24 23Z 0.39 1715 66 32 4 0.00 Run total areal avg QPF for the greens is: 2.06 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