Recent Weather Discussion

1. Review of recent weather:
   • a. Primary charts:
     hemispheric 500 mb Z
     • i. to get overview of major troughs, ridges, short-waves, etc. present & their motion
     • ii. (geostrophic) wind pattern (jet axis, direction of flow, etc.)
     • iii. possible PVA, NVA locations
     • PSU -- 500&SLP loops - - NOAA-CDC 250mb Z-WSpd loop - -
     500 mb Z and vorticity (N. America)
     • i. possible PVA, NVA locations
     • UM -- Z+vort - - NAM initial (12Z) - - NAM initial (18Z)
     1000/500 mb thickness (hemispheric or N. America)
     • i. for assessing warm & cold airmasses,
     • ii. finding occluded fronts
     • iii. possible locations of WAA, CAA
     • UM -- SLP+thickness - - NAM initial (12Z) - - NAM initial (18Z) - - PSU (upper right plot)
     500mb Z overlay on IR satellite -- see links between Z pattern & satellite imagery
     • SFSU - - PSU - ConUS, anim
     satellite imagery (N. Pacific, N. America) latest image AND loops
     • i. to see motion of main systems
     • ii. usually use IR, especially for loops.
     • iii. visible imagery can be useful for finding fog and other special events
     • SFSU (various choices; e.g. 12hr IR animation) Also overlays like 500/IR animations (Pacific) and 500/IR animations (CONUS) - - PSU -- IR - - CSU-CIRA-RAMSDIS -- various - - Univ. Illinois -- GoesE IR with SLP & wind overlay
     • iv. total PW (or integrated PW) useful to find atmospheric rivers
     • U Wisc -- CIMSS 'MIMIC-TPW2' integrated microwave imagery: total precipitable water - - NOAA-SIS -- SSM/I WV (oceans only)
     current radar imagery
     • i. to see which clouds are precipitating and what type of precip
     • ii. if radar not available: use significant weather chart.
     • NOAA-NWS national map - - NOAA-NWS national loop NOAA national maps archived for 24 hrs at PSU
       - - Intellicast - - SFSU - - PSU - - OSU - - NCAR-RAP site with other links
       Plymouth State 'make your own' radar site
       Canada Radars map
     current surface chart -- try to explain:
     • i. all areas of precip,
     • ii. identify locations of major fronts & trofs and their properties (e.g. type, intensity, change, direction of motion).
     • iii. other unusual weather like severe winds, severe convection, fog, hard freezes, etc.
     • NOAA-WPC (CONUS) - - NOAA-WPC (NAmer) - - PSU - - OSU - - NOAA sfc analysis/radar - - NOAA sfc analyses, interactive map/archive -- - U Illinois sfc products .
   • b. Supplementary charts (as needed to justify explanations & information presented above)
     • 200/300 mb level Z and isotachs -- jet stream, especially jet streaks location(s)
       • UM-COLA - - - NAM 12Z - - - NAM 18Z
     • Convective-related products
       • GEFS initial - CAPE - - - GEFS initial - LI - - - NAM initial - CAPE/CIN
       • UM-COLA - CAPE
     • skew-T ln-P charts -- useful for discussion of:
       • i. convection,
       • ii. freezing rain,
       • iii. cloud depths, etc.

       • NOAA SPC soundings, including archived soundings
       • NCAR-RAP - - Univ. Wyoming skew-T charts - -
       • iv. alternatives include LI/RH and 4-panel moisture charts. CAPE plots (above)
       • blank
     • meteograms -- useful for noting a time sequence at a station:
       • i. frontal passage
       • ii. time of occurrence of max T or min T, or precip.
       • meteograms map at George Mason - COLA, can choose location, model. Custom location

     • potential temperature charts -- assesing potential vorticity (PV) movement
       • LINK to GOES x-section page by NOAA (NESDIS)
       • various GOES horizontal convection-related sounding field maps from NOAA
       • various GOES soundings from NOAA
       • various GOES products from NOAA
       • various GOES products from SSD
       • generic GOES info -- links to different variables
       • CSU RAMSDIS entry point
       • NOAA ARL archives - storm, satellite, climate

     
     link to contiguous US streamlines map.

2. Forecast evaluation
   a. Review of recent forecast performance (typically, one compares models. 12 or 24 hr fcsts with most recent observations). Can also include human forecasters and statistical techniques like MOS.
   • Compare 500mb and Sfc recent fcsts over CONUS (and AK) for NAM, ECMWF, GFS, UKMO
     NOAA Website
   500 mb Z
   • i. compare troughs (locations, strengths, orientation & shape)
   • ii. location of strongest gradient (e.g. geostrophic wind jet)
     PSU
     NOGAPS (may need to confirm a security connection)
   surface chart
   • i. compare SLP (locations, strengths, and shapes of highs and lows)
   • ii. areas of precipitation
   24 hour precip chart C how does distribution & amount of precip compare to fcst in past 24 hrs?
   PSU
   • b. Specific forecasts: 24 hour max T & min T C how did guidance and forecasters do?
     PSU
   • c. List of subjective model performance characteristics at WPC (Weather Prediction Center)

Forecast Discussion

1. Primary charts:
   • a. text discussions (e.g. 'prog' discussions., 'QPF', 'DIFAX prog. chart').
     General entry point for WPC at NCEP
     Text discussion at NCEP-WPC, short term public version
     NOAA Schematic WPC National Forecast Charts -- surface maps
     NOAA-SPC: maps of watches, warnings & advisories
   • b. begin with current surface map -- indicate features to be tracked
   • NOAA-WPC (CONUS) - - NOAA-WPC (NAmer) - - PSU - - OSU
   • c. time sequences of:
     • 500 mb Z with vorticity -- motion, intensity, PVA/NVA
       NAM (NAmer; pick combo, 500 vort ht, then loop)) - - GFS (NAmer; pick 500 vort ht, ploop) - -
       U_Md - - PSU
     • surface pressure -- (frontal movements, low centers, highs, special wx conds.)
       NAM (NAmer; pick combo, 1000 500 thick, then loop)) - - GFS (NAmer; pick 1000 500 thick, loop) - -
       U_Md
     • precip -- types & amounts
       NAM (NAmer; pick combo, precip p03 or precip ptot, then loop)) - - GFS (NAmer; pick precip p03 or precip ptot, loop) - -
       U_Md

     • NOAA - NCEP maps
       GFS & NAM products -- 1-4 panels still-animation
       Tables Pick region, then model, then field, then time (e.g. 4-panel animation)

     • Dr. Grotjahn's Model Comparison Page Experimental

     • Misc Model Products
       U_Md eta matrix - - U_Md GFS-Short range matrix - - U_Md GFS-medium range matrix
       NCEP Model Guidance Page - -NCEP NAM NAmer page - -
     • NOGAPS model matrix
     • Univ. Wyoming NAM-Short range forecasts create your own overlays
     • NOAA-ARL Eta anims
       NOAA-Sac Models Page
       GFS data extracted for -KSAC
       twisterdata.com: general entry - - NAM data - - GFS data
   • d1. NAM field comparisions (under construction)
     • LINK to RG's NAM fields comparison page based on NCEP maps Links on that page no longer working
   • d2. model comparisions (including ensembles)
     • LINK to RG's model comparison page based on OSU and UNISYS maps
       PSU Models Page
       NCAR's WRF model links page
   • e. MOS (difax) -- max/min, PoP for selected cities
   • NOAA Eta MOS - - PSU -- MOS comps
2. Secondary charts (as needed to justify explanations & information presented above)
   • a. Other gridded forecasts:
     1. Unisys LI & RH broken link
     2. Unisys 300mb Z & Spd broken link
   • b. forecast 'meteograms' for selected cities
     NCEP-EMC
   • c. hemispheric maps (including N. Pac.) for longer range discussion

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