1 / 77

Week in Review 8/28/13 to 9/4/13

Week in Review 8/28/13 to 9/4/13. John Cassano. Weather Situation. Strong upper level ridge over central US Jet stream well north of US Weak frontal boundary from mid-Atlantic to northern Plains Southwest monsoon activity over Rocky Mtns. Denver Key Weather Elements.

zeheb
Download Presentation

Week in Review 8/28/13 to 9/4/13

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Week in Review8/28/13 to 9/4/13 John Cassano

  2. Weather Situation • Strong upper level ridge over central US • Jet stream well north of US • Weak frontal boundary from mid-Atlantic to northern Plains • Southwest monsoon activity over Rocky Mtns

  3. Denver Key Weather Elements • Strong upper level ridge over central US persists through period (500 mb) • Ridge builds westward over CO during forecast period • No jet dynamics (300 mb – not shown) • Surface high over mtns with low over plains (SLP) • Airmass warms slightly through period (700 mb T) • Increasing monsoon moisture to west (500 mb RH)

  4. Impact of Key Weather Elements • Expect slight warming of airmass in response to: • Building upper level ridge • Generally clear skies and strong daytime heating • Large diurnal range in T with clear skies and dry airmass • Winds will be mainly diurnal – downslope at night, weak, upslope during the day with no significant impact on T or precip • Generally clear skies, although increasing monsoon moisture may lead to high clouds late in the day • No precipitation expected

  5. 2013082812

  6. 2013082900

  7. 2013082912

  8. 2013083000

  9. 2013083012

  10. 2013083100

  11. 2013083112

  12. 2013082812

  13. 2013082900

  14. 2013082912

  15. 2013083000

  16. 2013083012

  17. 2013083100

  18. 2013083112

  19. Boston: Key Weather Elements • 500 mb trough east of Boston Wednesday through Friday AM, then flow becomes zonal • Weak 500 mb shortwave passes north of Boston on Thursday • No jet dynamics • H in eastern Canada early in period forces NE flow and CAA • Sfc ridge over Boston on Thursday – light winds • Ridge shifts east of Boston on Friday with return flow and WAA • Lots of low level (850 mb) moisture – clouds and fog

  20. Impact of Key Weather Elements • Cooling trend through Thursday in response to CAA from Canadian H • Warming on Friday as surface ridge shifts east of Boston • Fog and clouds will reduce diurnal temperature range • Winds will be NE’ly on Thursday, become light Thursday night / Friday morning with ridge axis over Boston, and then switch to SW’ly as ridge shifts east • These changes in wind direction will drive change of CAA to WAA • Ample low level moisture will result in mostly cloudy skies with fog likely overnight • Little dynamic forcing for precipitation despite moisture availability – expect no measurable precipitation

  21. 2013082812

  22. 2013082900

  23. 2013082912

  24. 2013083000

  25. 2013083012

  26. 2013083100

  27. 2013083112

  28. 2013082812

  29. 2013082900

  30. 2013082912

  31. 2013083000

  32. 2013083012

  33. 2013083100

  34. 2013083112

  35. Model Verification • 500 mb • DEN: 500 mb ridge slightly stronger in obs than forecast • SLP / 1000-500 mb thickness • BOS: Slightly smaller 1000-500 mb thickness over Boston on Thursday, otherwise good agreement • 700 mb T • DEN: Obsslightly warmer than forecast on Wednesday and Thursday and cooler on Friday • 500 mb RH • DEN: Higher RH in obs Thursday afternoon and Friday

  36. GFS 24 h forecast Thursday AM

More Related