
A Cold Weather Advisory is in effect from 1 AM to 8 AM Monday for portions of northern New York. Very cold temperatures temperatures and/or wind chills as low as 15 to 25 below zero are expected. The dangerously cold wind chills as low as 15 to 25 below zero could cause frostbite on exposed skin in as little as 30 minutes. Wear appropriate clothing, a hat, and gloves. Read More >
Subject: NAM3 EXPERIMENTAL Froude Number for the Central_Greens
Model run: BTV_GRID_D2D_NAM3_20260301_1200
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)
=== ===== === ==== ==== === === === ====
Sun 03/01 12Z 0.19 3213 87 88 -12 0.00
Sun 03/01 13Z 0.17 3217 85 72 -13 0.00
Sun 03/01 14Z 0.20 3217 77 53 -13 0.00
Sun 03/01 15Z 0.29 3118 73 43 -13 0.00
Sun 03/01 16Z 0.32 3120 72 42 -14 0.00
Sun 03/01 17Z 0.34 3120 70 30 -15 0.00
Sun 03/01 19Z 0.50 3119 70 30 -16 0.00
Sun 03/01 20Z 0.51 3119 74 38 -17 0.00
Sun 03/01 21Z 0.53 3119 77 47 -17 0.00
Sun 03/01 22Z 0.54 3119 80 53 -17 0.00
Sun 03/01 23Z 0.53 3020 78 59 -18 0.00
Mon 03/02 00Z 0.54 3021 74 53 -19 0.00
Mon 03/02 01Z 0.47 3122 65 41 -19 0.00
Mon 03/02 02Z 0.37 3122 55 29 -19 0.00
Mon 03/02 03Z 0.31 3121 49 21 -19 0.00
Mon 03/02 04Z 0.28 3121 47 16 -19 0.00
Mon 03/02 05Z 0.27 3120 46 12 -19 0.00
Mon 03/02 06Z 0.26 3119 44 9 -19 0.00
Mon 03/02 07Z 0.26 3119 42 7 -19 0.00
Mon 03/02 08Z 0.27 3119 40 6 -19 0.00
Mon 03/02 09Z 0.28 3119 41 7 -19 0.00
Mon 03/02 10Z 0.28 3018 42 8 -19 0.00
Mon 03/02 11Z 0.31 3019 47 9 -19 0.00
Mon 03/02 13Z 0.36 2920 55 18 -19 0.00
Mon 03/02 14Z 0.36 2919 55 18 -19 0.00
Mon 03/02 15Z 0.37 2918 52 19 -19 0.00
Mon 03/02 16Z 0.40 2917 46 19 -18 0.00
Mon 03/02 17Z 0.41 2917 40 17 -18 0.00
Mon 03/02 18Z 0.38 2916 39 14 -17 0.00
Mon 03/02 19Z 0.36 2914 41 14 -16 0.00
Mon 03/02 20Z 0.32 2912 41 12 -15 0.00
Mon 03/02 21Z 0.32 2812 41 9 -14 0.00
Mon 03/02 22Z 0.32 2712 42 15 -13 0.00
Mon 03/02 23Z 0.33 2613 42 33 -13 0.00
Tue 03/03 00Z 0.35 2515 43 50 -12 0.00
Tue 03/03 01Z 0.40 2418 39 50 -11 0.00
Tue 03/03 02Z 0.45 2422 33 62 -10 0.00
Tue 03/03 03Z 0.51 2425 26 58 -9 0.00
Tue 03/03 04Z 0.56 2528 29 57 -8 0.00
Tue 03/03 05Z 0.57 2529 29 55 -7 0.00
Tue 03/03 06Z 0.57 2530 27 55 -6 0.00
Tue 03/03 07Z 0.55 2529 29 55 -5 0.00
Tue 03/03 08Z 0.53 2527 29 53 -4 0.00
Tue 03/03 09Z 0.50 2526 30 50 -4 0.00
Tue 03/03 10Z 0.50 2526 30 46 -4 0.00
Tue 03/03 11Z 0.50 2426 30 42 -3 0.00
Tue 03/03 12Z 0.48 2425 29 37 -3 0.00
Tue 03/03 13Z 0.45 2424 34 29 -3 0.00
Tue 03/03 14Z 0.43 2424 40 23 -2 0.00
Tue 03/03 15Z 0.44 2325 49 16 -2 0.00
Tue 03/03 16Z 0.46 2326 61 14 -2 0.00
Tue 03/03 17Z 0.48 2326 77 12 -2 0.00
Tue 03/03 18Z 0.51 2327 88 13 -3 0.00
Tue 03/03 19Z 0.52 2326 93 17 -3 0.00
Tue 03/03 20Z 0.51 2326 95 34 -3 0.01
Tue 03/03 21Z 0.46 2324 96 38 -2 0.01
Tue 03/03 22Z 0.40 2321 96 61 -1 0.01
Tue 03/03 23Z 0.36 2320 96 91 0 0.01
Run total areal avg QPF for the Central_Greens is: 0.04 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