Practical Exercise et simulated assessment:Thunderstorm, icing, turbulence
- Your team need to produce a TS SIGMET, a ICING SIGMET and a TURBULENCE SIGMET.
Info needed:
TS SIGMET
-CB max top
-CB qualifiers : FRQ TS (TSGR or TSGR PSLB +FC) SQLN TS (TSGR or TSGR PSLB +FC)
-Direction and speed
-Trend :Intensifying/weakening/no change
ICING SIGMET
-Base FL, Top FL
-Direction and speed
-Trend :Intensifying/weakening/no change
TURBULENCE SIGMET
-Base FL, Top FL
-Direction and speed
-Trend :Intensifying/weakening/no change
- Would you need to include these infos (severe TS, ICING or TURB) into another forecast product?
- AMF assessment :Appropriate techniques
3.1a Forecasting severe thunderstorms
- Demonstrates ability to forecast the intensity, extent, movement and tops:
- Verifies upstream data for intensity and visibilities in thunderstorms;
- Uses satellite imagery to determine extent, evolution and movement;
- Compares IR cloud-top temperature to soundings to determine tops;
- Determines thunderstorm tops using radar;
- Uses different NWP models and compares to reality;
- Considers synoptic patterns (warm front vs. cold front thunderstorms);
- Verifies different convective indices (K, LI, SWEAT, etc.);
- Coordinates with other weather offices;
- Determines the 0-6km mean wind for thunderstorm movement.
- Demonstrates ability to forecast wind gust strength and wind shear:
- Verifies upstream data;
- Verifies upper-level winds using soundings (model and actual);
- Uses the Doppler radar to locate possible mesocyclones and potential gusts;
- Uses satellite imagery to determine whether gust fronts are present;
- Coordinates with other weather offices for wind warnings.
- Demonstrates ability to forecast thunderstorms:
- Knows the necessary ingredients for thunderstorm formation (moisture, instability and trigger);
- Uses water vapour imagery to locate jet streams (right-entrance and left-exit regions) and shortwaves;
- Uses radar extrapolation tool to determine arrival time and duration;
- Enumerates different indices/clues that indicate a thunderstorm might be severe (overshooting tops, hail, meso, strong winds, etc.).
3.1b Forecasting turbulence
- Demonstrates ability to forecast type: MECH, CAT, LEE WV
- Knows the formation criteria for different types of turbulence;
- Considers local effects;
- Uses different types of satellite imagery for clues of turbulence (transverse bands, mountain waves, etc.);
- Uses NWP models to determine levels and hence the type;
- Determines surface stability (MECH vs. LLWS);
- Verifies the Outgoing Flux field to locate lee waves (vertically-propagating);
- Compares NWP model soundings to actual soundings;
- Knows the moderate and severe MECH wind criteria;
- Verifies soundings to determine moderate-to-severe wind shear levels.
- Demonstrates ability to forecast severity:
- Uses different tools;
- Knows the difference between moderate and severe mechanical turbulence (wind force);
- Uses water vapour imagery (strong moisture contrasts, well-defined transverse bands, etc.);
- Considerssynoptic patterns (deformation zones, etc.);
- Monitors PIREPs.
- Demonstrates ability to forecast base, top, onset, duration and dissipation time for the phenomenon:
- Uses different tools;
- Verifies IR cloud-top temperature and compares to soundings to determine level of tropopause and tops of lee wave turbulence;
- Verifies soundings to determine levels of moderate-to-severe wind shear.
3.1d Forecasting icing
- Demonstrate ability to forecast type: CLR, MXD, RIME
- Considers synoptic patterns;
- Knows which type of icing is most dangerous and why;
- Accurately explains what each type of icing is associated to;
- Uses NWP soundings for profiles (warm nose) and cloud type and compares to actual soundings;
- Uses satellite imagery to determine cloud type and therefore icing type;
- Monitors PIREPs.
- Demonstrates ability to forecast severity: LGT, MDT, SEV
- Considers synoptic patterns;
- Uses NWP soundings for profiles and cloud type and compares to actual soundings;
- Uses satellite imagery to determine cloud type;
- Monitors PIREPs;
- Demonstrates ability to forecast base/top, onset, duration and dissipation time:
- Uses NWP models and compares to reality;
- Uses satellite imagery and extrapolates clouds;
- Uses model soundings to forecast base and top;
- Monitors PIREPs.
- Decode a TS, ICING and TURBULENCE SIGMET
SIGA0E
KZNY SIGMET ECHO 2 VALID 201330/201730 KKCI-
NEW YORK OCEANIC FIR FRQ TS OBS AT 1330Z WI N3200 W05645 - N2645
W05700 - N2645 W06845 - N3045 W06915 - N3200 W05645. TOP FL450.
MOV ESE 15KT. NC.
ENOB SIGMET E02 VALID 201401/201801 ENVN-
ENOB BODO OCEANIC FIR OCNL SEV TURB FCST WI 30 NM FM LINE N7620 -
E01000 AND N7720 - E03000 FL200/290 MOV SE NC=
NZZO SIGMET 27 VALID 201424/201824 NZKL-
NZZO AUCKLAND OCEANIC FIR SEV ICE FCST WI S3820 W14030 - S3800
W13700 - S4110 W13830 - S4750 W13450 - S4620 W14000 - S4120 W14300 -
S3820 W14030 3000FT/FL160 STNR NC=
Find the following info for TS :
-CB max tops
-CB qualifier
-Direction and speed
-Intensifying/weakening/no change
Find the following info for ICING :
-FL base and top
-Direction and speed
-Intensifying/weakening/no change
Find the following info for TURBULENCE :
-FL base and top
-Direction and speed
-Intensifying/weakening/no change