Now, after just about exactly 3 years at the helm of this blog it is time for me to sign off.  The first post was April 30 2009 on a Blogger website in an initial attempt at drawing attention to the specific weather conditions here in the Fredericksburg vicinity.  I felt then – and still feel the same way – that our area and its rapidly growing population receives very little weather coverage by the high profile DC and Richmond media markets.  Thus I embarked on a quest to fill some of the resulting information gap.

Along the way the good folks at fredericksburg.com took notice of my efforts and offered to host the blog (past and present) on their website.  That transition occurred on September 1 2010, and since that day I tried even harder to provide readers with weather-based commentary that included a mixture of (amateur) forecasting, some weather education, and some entertainment.  I freely admit to continually falling into the trap of focusing on forecasting when there are some very capable professional forecasters out there who do a much better job, but I still feel that the unique geography of the Fredericksburg region creates weather nuances that a news media forecaster located many miles away may not pay attention to.  I do feel that the National Weather Service forecasters do a good job of providing accurate local forecasts, but they have time and staffing constraints that limit their ability to quickly update us on weather events in and around the ‘Burg.

I am not giving up the role as weather blogger lightly as I have thoroughly enjoyed it…but I am moving out of the area and thus don’t feel that I can provide the level of commentary that Fredericksburg deserves. I’m certain a replacement blogger will step up and continue to fill the weather coverage gap that this blog is aimed at.  I will continue to post storm chasing experiences on my other blog .  Also, starting on or about May 13th you can also follow along with the Hokie Stormchasers on the Virginia Tech stormchase blog and Facebook pages as I will be driving one of the vehicles for the ten day May chase event.  Keep an eye to the sky and pay attention to the weather!  It affects all of us!

Meanwhile the upcoming weekend weather system has taken an abrupt turn toward less rain per last night’s model solutions.  In fact this morning’s NWS Sterling forecast discussion states that the “model trend for the weekend has become more progressive.” Translated this means the approaching cold front is going to push through here earlier and faster on Saturday and then continue well off the East Coast before slowing down.  Hence the surface low pressure that is forecast to form along the front will also be further offshore than previously thought as shown in this GFS model forecast graphic for Sunday evening:

Note the position of the surface low and the associated heavy rainfall indicated by the red and pink shading; it’s now well offshore Cape Hatteras instead of being in the Nags Head vicinity as during earlier runs.  This jog to the east looks like it will carry most of the previously promised rainfall out to sea with it.

We could still see some strong thunderstorms mid-afternoon Saturday if the sun peeks through the forecast cloud cover long enough to warm things up and destabilize the atmosphere.   Then high temperatures will fall from the mid-70′s on Saturday to the mid-60′s on Sunday and Monday under cloudy and somewhat rainy skies.  How much wetness we will actually get from this system is now in question, but we should receive more than the paltry amount we saw yesterday.

Forecast rainfall for Saturday through Monday mornings

The darkest purple shading represents 2 inches of rain while the darker red shading is the 2.5 inch range.  Spread over several days that will provide very welcome moisture to counter the extreme dryness and Red Flag warnings that we’ve experienced over the past several weeks.

Ahead of the low we will likely see thunderstorms Saturday afternoon with temperatures in the mid-70′s.  Then, as the low approaches on Sunday the rain really shows up.  If this were January or February and a source of cold air was available I’d be finding my snow shovel and boots, but since it’s April it will all fall as rain.  It means a wet weekend for the ‘Burg but we can use the moisture!

That same front will stall south of here over the Carolinas before pushing back into southern Virginia Tuesday night thanks to a weak upper level system. The result will be sunshine Tuesday and a few scattered showers Wednesday…but it won’t provide much moisture as shown in this HPC forecast graphic that summarizes the five day total expected precipitation through Friday night:

Notice the very light amounts shown for our part of Virginia.  We are officially classified as “abnormally dry” by the Climate Prediction Center.

When will we see some more substantial precipitation?  There are some forecast model hints that a juicy surface low pressure system will form and track across the Old Dominion over this next weekend.  We’ll have to watch that one carefully.

850 mb temperatures at 8:00 p.m. Thursday 12 April

Now check out the same temperature map for this coming Sunday evening:

850 mb temperatures Sunday 8:00 p.m. 15 April

Note the colder air associated with the persistent East Coast trough has finally moved away in the second graphic, opening the door for warmer and moister air to enter our area over the weekend.  In fact, although the high temperature forecast for the ‘Burg today (Friday) is only in the mid-60′s (F) it will climb 8-10 degrees daily both Saturday and Sunday.  That results in 80+ degree temperatures by Sunday!

The 80+ degree warmth will continue early next week ahead of a cold frontal passage on Tuesday, which will hopefully bring some rainfall with it to alleviate our dryness and wash some of the pollen out of the air.  But even after the frontal passage our high temperatures will still remain in the 70′s rather than diving back down into the 50′s like the past couple of days.  This pattern change comes with a downside, however, as the folks living in Tornado Alley out west are facing a very dangerous setup tomorrow.  The Storm Prediction Center has issued a rare high risk for severe weather out that way.  We here in the ‘Burg won’t see this dangerous situation but we should keep the folks living under the gun in our thoughts and prayers.

Jet stream winds as of 8 pm Wednesday night

By late Friday the trough will have exited off the East Coast and an approaching ridge will replace it,  ushering in warmer temperatures and moister air on the wings of southerly breezes.  This will result in significantly warmer days over the weekend into early next week.  Will we see any substantial rain soon?  Not likely.

These warnings are issued when the humidities are very low, the fuel moisture is low, and the winds are gusty, all of which will be in place today.

Moreover, this graphic from the Climate Prediction Center indicates that northern Virginia is beginning to experience abnormally dry conditions (the yellow shading):

So will we see any substantial rain this week?  Apart from some light showers this afternoon and evening (<0.1 inches expected) the answer is “nope”.  After today the models show dry conditions until the early part of next week.  We’ll have nice weather, but we may be wishing for some decent rainfall soon.

The Climate Prediction Center temperature forecast graphics provide both 6-10 day and an 8-14 day outlooks.  The ones currently on their website show some interesting differences for the middle of April.  First, here’s their 6-10 day temperature forecast:

Note the cooler than average (blue shades) chances for the East Coast for April 12-16.   Now, here’s the 8-14 day outlook:

Note the warmer than average temperatures (brown shades) forecast for April 14-20.  So it would seem that our current cooler weather will transmute into warmer than average weather fairly soon, starting next weekend.  And, in fact, a quick look at the GFS forecast model shows a pattern change by that time.  See, if you don’t like the weather in April just wait a few days!!

A large scale upper air trough – a southern dip in the jet stream – will then form over the East Coast early next week, keeping the ‘Burg under the influence of more cool Canadian air and providing some clouds and showers on Monday and Tuesday.

Upper level "trough" over the East Coast; this is the forecast position for Wednesday morning.

This feature looks like it will move off the East Coast beginning Thursday of next week, paving the way for warmer and moister air to once again invade the ‘Burg for next weekend.   Springtime in Virginia…a season of changes!

Note that Texas literally gets ten times the number of yearly tornadoes that Virginia sees.  And these numbers don’t include the incredible 2011 tornado season, which is illustrated here:

So, what does that have to do with our current weather?  Not much, seeing as how blue skies and high temperatures in the 60′s and low 70′s (F) will reign supreme for the next week or so (with a small chance of rain next Monday and Tuesday).  This “Chamber of Commerce” weather is wonderful, but let’s make sure we heed any upcoming watches and warnings of severe weather as the spring progresses.