Friday, March 18, 2016

Spring Begins With A Winter Finale


  • LIGHT-TO-MODERATE SNOW EVENT SATURDAY NIGHT INTO SUNDAY.
  • COMPUTER MODELS BACKED OFF EARLIER IDEAS OF A HEAVY SNOWFALL. PERHAPS 1-2" WILL ACTUALLY SHOW UP ON THE GROUND, AND PRIMARILY ON GRASSY & UNPAVED SURFACES.
  • PAVED SURFACES SHOULD REMAIN MOSTLY WET WITH SOME SNOWCOVER ON SUNDAY MORNING. 
  • REFREEZING OF RESIDUAL MOISTURE POSSIBLE SUNDAY NIGHT.
BELOW: 
Updated current snowfall projection of what may fall (but not actually be on the ground) by 8 AM Sunday from the U.S. GFS model. Snow will exit the region Sunday night.



10:00 AM EDT 3/19 -  The map above depicted a recent computer model surface projection for 8 PM Saturday 3/19. The expected arrangement which has been shown for several days now is a moderate High pressure system in southeast Canada favorably positioned offset a coastal Low. This would lead to an overnight timing of precipitation that may produce accumulation on grassy, unpaved surfaces and some untreated surfaces. Key considerations:
  • Temperatures: Recent warm conditions will permitted residual heat to be retained in paved surfaces. Even though air temperatures are projected to go below freezing at times Sunday night, some ground areas should stay above freezing. Areas that are shaded, at elevations above 500 feet, or less traveled cannot be ruled out for accumulation on paved surfaces.
  • Precip Amounts: The European model backed off earlier ideas of a 10-14" snowfall along the I-95 corridor, and is now in line with the NOAA GFS model showing 3-5".
  • Sun Angle: This time of year, any model projection for high accumulation has to be taken as suspect. Angle of the sun by midday is the equivalent to mid-October. Although snow is likely to be "falling" quite heavily on Sunday, you may actually see the sun shining through the clouds -- and not much beyond an inch at any one time laying on the ground. 
PRECIP AT 2 AM SUNDAY 



 TEMPERATURES AT 2 AM SUNDAY

THE MONDAY AM COMMUTE? 



Some refreezing is possible due to temperatures dropping into the mid 20s early Monday AM as snow exits the region. However, it is probable that many roads may be just wet and any pre-treatment by salting crews should negate accumulation problems on roadways.
TEMPERATURES AT 8 AM MONDAY


1 comment:

Edwin Guevara said...

I'll take Monday off if possible.