Thursday, March 27, 2014

Rainy Weekend; Warm, Spring Weather Returns Next Week

Sunday (3/30/2014) 10am update
A pretty strong upper level low continues to spin across central Virginia.  Cold air is crashing in behind it causing many areas across western Virginia to change to snow.  There are reports coming in of up to several inches, which I wasn't expecting outside the higher-upslope elevations of West Virginia, SW Virginia, and western NC.  These will continue throughout the day as this upper level low slowly drifts east.

The heaviest band outside of the typical upslope areas appears to have set up across Rockbridge/Augusta county.  Higher elevations of Albemarle and Nelson counties look to be the next areas impacted by this band.


FAIRFIELD 8.0 1011 AM 3/30 PUBLIC 

Spottswood Va, Augusta Co. from Amy Fretwell

Here are the winds at 700 mb (about 10,000 feet up) showing the upper level low quite nicely. If you live east of the Blue Ridge mountains, don't be surprised to see some flakes of snow and sleet mixed in with your rain this afternoon as this moves through.

Once this all clears out, the next big story will be the winds.  The pressure gradient is already really tightening right along the mountains.  The tighter the pressure gradient, the stronger the winds.  There have already been reports of trees down and power outages in western NC and SW VA.  Expect winds to pick up elsewhere this afternoon and evening.  Gusts upwards of 40-50mph will be possible.

End Update

Saturday (3/29/2014) 10am Update
A lot of areas are dry this morning but won't be for long.  Low pressure out across southwestern Kentucky is working east-north-east into the area.  This will enhance widespread showers late this morning through the evening hours.  Still expecting this to be heavy at times.

9:20am Radar/Fronts

This main surface low will move out by late tonight.  The upper level low out to our west will start cranking out the upslope snow.  Once again, the areas highlighted below have the best chance to see anywhere from a coating to 3".  There could even be some locally higher amounts in the highest elevations.
Best Chance for C-3" Snow Sunday

One change to the forecast is that this upper level low is looking a bit more vigorous than it was yesterday.  It will cross the mountains and work through central Virginia before exiting up the coast as well.  I just wanted to add that even areas east of the mountains may see some rain/snow shower activity during the day on Sunday.  Anywhere from the I-81 corridor east to I-95, especially along and north of I-64, will have a shot at seeing some of this.  Also watch out for very high winds with a super tight pressure gradient setting up.  High wind watches have been issued for most of western Virginia where gusts may approach 60 mph at times.
6z nam 700mb via AccuPro
End Update

Friday (3/28/14) 5pm Update

Watching two different areas of precipitation that will work through the area this weekend.

1) A nice slug of precipitation has developed  from the northern Gulf stretching all the way up through the Carolinas into the southern piedmont of Virginia.  This is from moist southerly flow from the combination of clockwise flow around high pressure out in the Atlantic and counterclockwise flow around the developing surface low in Texas. These are bringing in moisture off both the Gulf and Atlantic ocean. This will expand north through this evening producing light to moderate showers mainly east of the mountains.

2) A low is beginning to develop across Texas producing some severe weather across parts of the Ark-La-Tex.  This low will head right for our area, producing heavy rain during the afternoon and evening hours on Saturday.  Widespread 1-2" amounts look likely.

We will also have to watch for some upslope snow as this low passes and winds crank up out of the northwest and some colder air works in.

The best chance at this will once again be along the western facing slopes of the Allegheny Mountains late Saturday night into Sunday.  A coating to as much as 3" will be possible in the areas highlighted below.  Fortunately, this cold air looks short lived as much warmer air is still on tap to work in next week with most areas back into the 60s/70s.

End Update

Thursday (3/27/14) 10am Update
Our next storm system is currently out across the central plains bringing with it late season snow to much of the upper midwest and northern Great Lakes.  The trailing cold front from this system will approach the area on Friday with a line of showers out ahead of it.
6z nam for Friday afternoon (AccuPro)

There will be a lull in precipitation during the evening hours Friday.  This front will then stall out across the area leading to a pretty damp weekend.  An area of low pressure will develop across the Tennessee Valley and ride along the stalled front bringing another round of rain late Friday into the day on Saturday.  This batch will bring a steadier, heavier rain.  Looks like most of Saturday will be a washout.
6z nam for Saturday afternoon (AccuPro)

There may be enough instability for some thunderstorms with chances increasing the further south and east you go.  I think areas west of the Blue Ridge Mountains will be too stable, but can't rule out some isolated thunder.  Things will clear out west to east Saturday night into Sunday.  Total rainfall will be pretty impressive with amounts generally ranging from 0.75-1.50" with some areas of eastern Virginia that see thunderstorms up to 2".  
00z euro total precipitation through Sunday afternoon (AccuPro)

High pressure will work in behind this front clearing everything out for the first half of next week.  We will finally have a decent stretch of warm, spring weather Monday through at least Wednesday with temperatures climbing back well into the 60s (even 70s for central/southeast Virginia).

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