
Extremely critical fire weather conditions are expected to develop across the Great Basin and Southwest today, and exceptionally dry and windy conditions will promote rapid wildfire spread through the weekend. Scattered severe thunderstorms and heavy rain are possible across parts of the Ozark Plateau into lower Ohio Valley and parts of the northern Rockies into adjacent Great Plains. Read More >
Subject: NAM3 EXPERIMENTAL Froude Number for the Central_Greens
Model run: BTV_GRID_D2D_NAM3_20260627_0600
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)
=== ===== === ==== ==== === === === ====
Sat 06/27 06Z 0.15 3108 81 63 11 0.00
Sat 06/27 07Z 0.14 3208 81 63 11 0.00
Sat 06/27 08Z 0.12 3208 82 66 11 0.00
Sat 06/27 09Z 0.09 3207 81 69 11 0.00
Sat 06/27 10Z 0.08 3105 80 72 11 0.00
Sat 06/27 11Z 0.08 3105 80 76 11 0.00
Sat 06/27 12Z 0.08 3104 81 77 11 0.00
Sat 06/27 13Z 0.07 3104 82 73 11 0.00
Sat 06/27 14Z 0.05 3203 82 67 11 0.00
Sat 06/27 15Z 0.05 3002 85 64 11 0.00
Sat 06/27 16Z 0.05 3001 87 62 11 0.00
Sat 06/27 17Z 0.05 3101 88 58 11 0.02
Sat 06/27 18Z 0.05 3201 87 55 11 0.03
Sat 06/27 19Z 0.06 3201 87 50 12 0.02
Sat 06/27 20Z 0.10 3202 86 50 12 0.03
Sat 06/27 21Z 0.07 3302 86 46 12 0.04
Sat 06/27 22Z 0.04 3502 86 44 12 0.01
Sat 06/27 23Z 0.07 0103 86 50 12 0.01
Sun 06/28 00Z 0.08 0202 86 47 12 0.01
Sun 06/28 01Z 0.09 0402 85 47 12 0.01
Sun 06/28 02Z 0.11 0502 85 48 12 0.00
Sun 06/28 03Z 0.08 0402 85 49 12 0.00
Sun 06/28 04Z 0.07 0302 86 51 12 0.00
Sun 06/28 05Z 0.08 0203 87 53 11 0.00
Sun 06/28 06Z 0.05 0103 86 55 11 0.00
Sun 06/28 07Z 0.03 0003 84 55 11 0.00
Sun 06/28 08Z 0.03 3505 79 45 11 0.00
Sun 06/28 09Z 0.03 3505 76 35 11 0.00
Sun 06/28 10Z 0.02 3506 73 26 11 0.00
Sun 06/28 11Z 0.04 3507 71 25 11 0.00
Sun 06/28 12Z 0.07 0007 70 27 11 0.00
Sun 06/28 13Z 0.07 0106 70 26 11 0.00
Sun 06/28 14Z 0.10 0105 71 25 11 0.00
Sun 06/28 15Z 0.12 0204 73 21 11 0.00
Sun 06/28 16Z 0.14 0103 76 19 11 0.00
Sun 06/28 17Z 0.13 0003 78 15 11 0.00
Sun 06/28 18Z 0.08 3503 79 12 12 0.00
Sun 06/28 19Z 0.09 3504 79 13 12 0.01
Sun 06/28 20Z 0.08 3404 79 12 12 0.00
Sun 06/28 21Z 0.07 3404 80 8 12 0.00
Sun 06/28 22Z 0.05 3404 79 6 12 0.00
Sun 06/28 23Z 0.04 3405 78 8 12 0.00
Mon 06/29 00Z 0.11 0007 78 8 12 0.00
Mon 06/29 01Z 0.16 0009 79 12 12 0.01
Mon 06/29 02Z 0.23 0209 78 9 12 0.01
Mon 06/29 03Z 0.23 0209 76 7 12 0.00
Mon 06/29 04Z 0.25 0309 74 7 12 0.00
Mon 06/29 05Z 0.21 0407 75 8 12 0.00
Mon 06/29 06Z 0.11 0304 72 10 12 0.00
Mon 06/29 07Z 0.03 0004 70 12 12 0.00
Mon 06/29 08Z 0.03 3405 69 14 12 0.00
Mon 06/29 09Z 0.03 3406 67 16 12 0.00
Mon 06/29 10Z 0.03 3507 63 16 12 0.00
Mon 06/29 11Z 0.04 3508 61 15 12 0.00
Mon 06/29 12Z 0.08 0008 60 15 12 0.00
Mon 06/29 13Z 0.12 0107 60 14 12 0.00
Mon 06/29 14Z 0.12 0106 63 15 12 0.00
Mon 06/29 15Z 0.16 0105 68 16 12 0.00
Mon 06/29 16Z 0.13 0002 71 16 12 0.00
Mon 06/29 17Z 0.20 0301 70 14 12 0.00
Run total areal avg QPF for the Central_Greens is: 0.21 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