Foggy start to Severe Weather Awareness Week

Thick fog covers much of the area east of U.S. Route 29 this Monday morning, with a Dense Fog Advisory in place until 10:00 a.m. The cold front which slowly crossed the Appalachians yesterday has settled nearby as it dissipates, leaving enough moisture in place to condense into fog as temperatures neared the air's dew point overnight. Visibility will improve as the sun does its warming thing, "mixing out" - not "burning off" - the fog.

Local thermometers will climb from this morning's mid-50s into the mid-70s this afternoon under sunny skies. Meanwhile, today's emphasis during this Severe Weather Awareness Week centers on the difference between Watches and Warnings. This video explains:

Tonight, temperatures will drop into the low 50s under clear skies and with light winds. More fog could be on the weather menu early Tuesday morning as thermometer readings again approach the dew point. Tomorrow afternoon's highs will boost into the low 80s under continued clear skies, providing another preliminary taste of spring.

Also occurring on Tuesday morning, there will be a statewide Tornado Drill conducted at 9:45 a.m. Organizations and individuals are encouraged to register for and participate in this event as part of their severe weather plans. It's important to know where safe places are and when to head there if severe weather is imminent.

The warmth continues this week

The jet stream remains well north of Mecklenburg County this week, keeping the cold air at bay for at least another week. Today - Sunday - will be mostly cloudy while still being much warmer than average for early March. After morning lows in the mid- and upper 60s(!) afternoon temperatures will top out in the mid-70s. 

A few showers will dot the landscape today ahead of a cold front which is still west of the Appalachians as this is written. That boundary will slowly make its way eastward, finally easing through the area near midnight. The Storm Prediction Center has southeastern Virginia under a Marginal Risk - level 1 of 5 - for severe weather today, but any stronger storms look to occur south and east of Mecklenburg County.

However, this nearby potential for severe weather sets the stage for the upcoming work week, which is Virginia's Severe Weather Awareness Week.

Each day information will be available on different severe weather threats, including the annual Tornado Drill Tuesday at 9:45 a.m. Schools, businesses, and households can sign up for this drill and participate. The emphasis for understanding severe weather and having a safety plan in place ahead of time is important. As the saying goes, "Hope is not a plan".

Temperatures will remain well above average the first part of the week, dropping back a bit by Friday. A return to more typical March weather will hold off until St. Patrick's Day.

The warmth continues as Daylight Saving Time arrives

This Friday morning's low temperatures only dropped into the mid- and upper 50s around Mecklenburg County. That's the average high for this date, so it's definitely warmer than is typical during the first week of March. Today's high will top out in the low 80s under sunny skies, with a touch of humidity as moisture moves into the region.

Saturday morning will again bring warm temperatures ahead of the potential for afternoon showers and even a thunderstorm. A cold front pressing across the Appalachians will provide the impetus for that precipitation, which is much-needed given the continued drought situation locally. Indeed, the first severe weather outlook of the year for Virginia has been issued for tomorrow, but Mecklenburg County isn't in the area of concern:

And then comes the switch back to Daylight Saving (no "s") Time Saturday night. The change officially occurs at 2:00 a.m. Sunday morning, when clocks which automatically change will push ahead to 3:00 a.m. and we all lose an hour of sleep. For those timepieces which don't change themselves it's a good idea to set them an hour ahead before going to bed.

Sunday then looks to be cloudy with showers and perhaps a couple of storms - nothing severe - as that cold front takes it sweet time pushing through the area. Temperatures will still top out in the mid- and upper 70s Sunday, so the spring-like conditions will stick around even behind this boundary.

NOTE: Next week is Virginia's Severe Weather Awareness Week. A lot of very useful information will be coming out via social media and other news sources. 

The "Wedge's" retreat = immediate spring-like conditions

Tuesday's failure to meet forecast high temperatures was a direct result of a stubborn cold air damming wedge. Once established across the Piedmont east of the Appalachians, that thin but dense layer of chilly moist surface air is difficult to dislodge. Last night, however, "Da Wedge" finally broke and local thermometers began to rise during the wee hours. Thus this - Wednesday - morning began with sunshine and temperatures which already exceed yesterday's maxima as of the time of this writing.

As today progresses the increasingly strong March sunshine coupled with southwesterly breezes will boost afternoon highs into the low 70s. Meanwhile, a cold front is perched across far northern Virginia:

That boundary looks to stall up that way, wobbling north and south a bit until the weekend. The upper level winds are in "zonal flow", blowing basically west to east and not providing a push to move that front. The cooler air will thus remain locked up well north of Mecklenburg County, which will bask in the warm air to the south.

Thursday and Friday will then feature repeats of today's conditions, but with steadily warming temperatures. Highs tomorrow afternoon will approach 80º, while Friday looks to reach into the low 80s. Welcome to that spring feeling!

Raw, wet, and chilly to begin the work week

Welcome to March, a transitional weather period. Average daily high temperatures begin the month in the mid-50s, climbing to the mid- and upper 60s by the end of the month. That change isn't a smooth one, with ups and downs in temperatures pretty much the norm. A perfect example is the plunge from Sunday's highs in the low 70s to today's (Monday's) forecast high near the 40º mark.

Another cold air damming (CAD) wedge is responsible for this particular rollercoaster. This graphic from the National Weather Service office in Sterling Virginia illustrates:

A thin layer of dense cold air at the surface is "wedged" across the Piedmont east of the mountains, forced southward by high pressure currently centered across New England. Warm moist air - being lighter and less dense -  is being pushed up and over the CAD wedge, creating clouds and precipitation. 

As of the most recent forecast model runs the precipitation from this setup will begin across Mecklenburg county as rain just after the lunch hour today. Although there could be a few cases of "fuzzy rain" with snowflakes mixing in, today's precipitation will be liquid instead of frozen. Rain will continue through the overnight hours, gradually tapering off Tuesday morning.

The wedge will slowly dissipate tomorrow. The official NWS forecast is for a mid-50s high temperature Tuesday afternoon. However, one forecast model which is particularly good at sniffing out CAD behavior indicates that the upper 40s may be all that can be expected tomorrow. Regardless, expect mostly cloudy skies until late tomorrow afternoon.

By Wednesday the temperature rollercoaster will be on the upswing. The latter part of the work week will see the 70s and perhaps the 80s(!) as warmer air reasserts itself across the region. 

Spring-like Sunday conditions, then wintry stuff(?) Monday

Welcome to meteorological spring! For weather and temperature accounting data that season runs from March 1st through May 31st, a bit different than the astronomical season that begins March 20th with the spring equinox, Regardless, today - Sunday - will feature a taste of spring under mostly sunny skies and with temperatures topping out in the upper 60s this afternoon.

A backdoor cold front will slide through Mecklenburg County before the dinner hour, pushed along by a strong high pressure center crossing the Great Lakes region. That will swap surface winds around out of the northeast, bringing a slight chance of a late day sprinkle. Behind this boundary a cold air damming scenario will set up. Here's one model's look at the dense cold air at the surface pushing down the Piedmont east of the Appalachians Monday evening:

A couple of weak upper air disturbances will then lift warm moist air up and over this thin surface layer, creating precipitation Monday that may well be in the form of "fuzzy rain", i.e. mixed rain and snow. Tomorrow will thus be gloomy and raw, with local thermometers struggling to make it up to the 40º mark. 

Tuesday then looks to begin wet and cloudy, but skies will begin clearing during the afternoon. Temperatures will begin the second day of the work week in the mid-30s before rising to near or just above 50º. The rest of the week? Plan on spring-like 70s for daily highs!

Finally, a spring-like weekend!

Lately, weekends have been punctuated by less-than-desirable weather. Last weekend was a perfect example, with the snowstorm turned nor'easter that dropped wintry precipitation across the area as shown on this summary graphic from NWS Wakefield:

This weekend, however, will bring much nicer conditions. Today - Friday - will bring afternoon highs in the low 50s under mostly cloudy skies and with lighter winds. The weekend days will then feature bonus weather to end February (Saturday) and begin March (Sunday). Both days will see sunny skies with temperatures bumping up into the mid-60s to the low 70s, ten to fifteen degrees above the average.

Enjoy the warmth! By Monday another cold air damming wedge will take charge, possibly resulting in another bout with wintry weather. More on that potential will come in Sunday's blogpost.