Figure 14: Low-Level Significant Weather (SIGWX) Prognostic Charts

120W 90W 80W 100W 70W 40N VT 18Z Sat Apr 14 2012 12 HR SIG WX PROG LOW LVL SFC-400MB 120 120 040 040 080 080 120 / 120 / 240 / 180 / 240 / 120W 90W 80W 40N VT 06Z Sun Apr 15 2012 24 HR SIG WX PROG LOW LVL SFC-400MB 120 040 040 040 040 080 120 / 120 / 240 / 180 / 080 / 240 / 070 / 120W 90W 80W 100W 70W 40N VT 18Z Sat Apr 14 2012 12 HR SIG WX PROG R R R TROF TROF TROF TROF 1015 0271 2251 1018 0571 1450 0571 1002 4501 999 TROF L L H L L R 120W 90W 80W 100W 40N VT 06Z Sun Apr 15 2012 24 HR SIG WX PROG L L L L L H TROF TROF TROF TROF 1027 1027 997 4501 4201 1021 2281 0281 1013 0471 1000 R R R FSTHS INPLY POSSIBLE SVR OR GARATER TURBC SVR ICING AND LLNS Flight planning only see TAF & for specific terminal forecast Ceiling less than 1,000 feet and/or visibility less than 3 miles Ceiling 1,000-3,000 feet inclusive and/or visibility 3-5 miles incl. Moderate or greater turbulence Freezing level at surface Freezing level above mean sea level Moderate turbulence Severe turbulence Extreme turbulence Top (hundreds of feet MSL) Base (hundreds of feet MSL) 100 / 070