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So weather folks aren’t always right

UPDATE 5:40 pm:  I give up on this wedge moving out.  Here’s what the folks at the National Weather Service Sterling office said in this afternoon’s forecast discussion:

“THE WEDGE OF MOIST MARINE AIR HAS AGAIN THWARTED AN ABNORMALLY WARM DAY FOR AREAS E OF THE BLUE RIDGE. HIGH TEMPS WILL STILL LIKELY REACH 10 DEGREES ABOVE AVERAGE FOR THIS TIME OF YEAR…BUT CERTAINLY MUCH COOLER THAN WHAT THE 850MB TEMPS WOULD HAVE PRODUCED GIVEN NO CLOUD COVER. A MUCH DIFFERENT STORY W OF THE BLUE RIDGE…W/ SHENANDOAH VLY READINGS NOW WELL INTO THE 60S AND WILL LIKELY HIT THE M70S BEFORE THE EVE DECLINE.”

So the answer to getting out from under this wedge is to move west of the Blue Ridge?  Hmmmm….don’t think that will fly with most folks in the ‘Burg.  Sorry for the clouds and cool temperatures today, even if it was warmer than normal for January.

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Okay, I admit it…to date the weather folks – including me! – have blown this weekend’s nice warm forecast for the ‘Burg.  I should have known better than to expect this #$@#$%$%^ cold air damming wedge to clear out of the area by yesterday morning but I (and a lot of professional forecasters) were suckered by the models.  The current models usually have a difficult time handling these wedges since this shallow cold air mass (typically <2000 feet thick) is very dense and heavy, which makes it hard for warmer lighter air to push it out of the way.   Given the limited amount of upper air data provided to the models the math says the wedge should have been outttahere 24 hours ago…but it isn’t, thus the low ceilings and the cool temperatures.  I will cautiously go out on a limb and say that the wedge will be gone by mid-afternoon today (Sunday).  A check of both the NWS Sterling forecast graphics and a higher resolution short range model (the RAP) indicates that things will improve sometime between 1 and 2 p.m. with temperatures rising into the mid- to upper 60′s (F).

The warmup will last about 18 hours ahead of a cold front that will crawl through the area Monday morning and stall out not far to our south.  Thus Monday will start out with temperatures in the upper 50′s and then temperatures will cool down behind the front under rainy skies.  This rain will hang around thru midweek as a couple of surface low pressure systems develop and move northeastward along the buckling stalled front.  As shown in this graphic the ‘Burg could see about an inch of rain between Monday and Wednesday mornings, which will be good news for our dry region.

So how about the promised cold air invasion?  It IS coming but it will occur in stages, the first of which is another cold front that will push through here late Wednesday.  This air mass, which has produced a lot of very cold temperatures out west where it first hit, will have warmed up quite a bit by the time it gets here and thus will only cool us down to near normal temperatures for late this week and into next weekend.  The next stage will involve a stronger cold front coming through early next week which will open the door to much colder air.  Exactly how cold yet remains to be seen, as does any potential frozen moisture.  This winter is not over with by any stretch of the imagination.

Permalink: http://news.fredericksburg.com/weather/2013/01/13/so-weather-folks-arent-always-right/

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