Tuesday, January 22, 2019

No comments:
When is the next one?
  • An "intermission" of southern jet stream-enhanced mild air will overtake eastern third of the U.S. from midweek into Friday, with temperatures trending into the 40s. After this raucous cold, we're not sure if our hearts want to "come back from Havana" anyway until the thermometer at least crosses 32.
  • Brief periods of snow possible Thursday afternoon in the Mid-Atlantic at back edge of departing cold front. Little or no impact expected due to warm air & rainfall prior. Refreezing unlikely as snow should be light, intermittent and roadways mild.
  • By Friday afternoon, a new Arctic High pressure system will be reintroducing a fresh supply of much colder air into eastern U.S. This is a strong indicator for the next storm: Accumulating snow has a better chance when cold air is in place before a system develops. 
ABOVE: Probability that your area exceeds the liquid equivalent of 0.25" in snow or sleet, projected for the Sunday 1/27 into Monday 1/28 time period. A similar map is shown for Day 7, Monday into Tuesday.

BELOW:  Long range projection of general surface low position by early Monday morning 1/28 indicates the potential for a favorable setup of a classic "Nor'easter" type system. 


When you see the whiplash weather coming for February, you may look back on January with fondness for the days when temperatures would go above 32 F for more than one day. 

And, if you're a Powderhound, there is so much fun lurking in the long range, we are sure it will be a delight to behold once we can map out all the possibilities coming up. 

- Forecasters Foot and Wise

Saturday, January 19, 2019

4 comments:
IF ARCTIC AIR IS NOT YOUR THING, 
we recommend one of these, today.


8:00 AM SAT 1/19  With current temperatures in many areas east of the Blue Ridge mountains a few degrees above forecasted levels -- it would seem wise to take full advantage of today and GET STUFF DONE that you prefer not to do when temperatures are 10-15 F. 

For most of Maryland east of I-81 to the 95 corridor and Eastern shore -- as well the DC metro area -- precipitation onset may not occur until at least Noon. This should permit road temperatures to improve into upper 30s, and would reduce potential for ice to develop this afternoon in areas where roads are well above 32 F. 

HOWEVER, THE SUNDAY ICE AGE IS STILL COMING. 

  • The Arctic front is still going to barrel through Sunday morning, dropping temps 30+ degrees in 12 hours or less and dropping below 32 F in most areas by mid morning. Below is an hourly projection for Ellicott City in Howard County MD as a sample location for timing and precipitation types.
  • Untreated roads, which will be many, are going to see standing water quickly refreezing by Noon, despite windy conditions. Doc Brown from Back to the Future would be vindicated,because after the ice develops, some of us won't need any roads on Monday -- or even Tuesday.
  • Winds will rise to 15-25 mph with higher gusts, producing sub zero wind chills for 24+ hours from Sunday afternoon through Monday. It will be the coldest air you've felt beating again your house or apartment in a long time. So consider today as one good chance to get ahead of the cold and wind while you can.
  • Additional details on the 4-day weekend potential in the previous post.
NWS HOURLY FORECAST for Ellicott City in Howard County, MD as the example location for precip timing and temperatures in the region.

FOUR DAY WEEKEND ?
How ice on Sunday could threaten Tuesday
Projected mid-day highs for Martin Luther King, Jr. Day, 2019

  • For the upcoming "Big Wet Kahuna" weekend storm, regardless of if your area receives all snow, snow to rain or a wintry mix -- temperatures region wide will crash 30-40 degrees on Sunday from the 40s to the 10s or lower. 
  • THE SALT PROBLEM: Road crews are not likely to apply salt treatment to many surfaces prior to or during 12+ hours of rain Saturday into Sunday would wash all that chemical and effort away. For areas south of I-70 in Maryland, along the I-95 corridor from Phila to Baltimore & DC - rain changes to snow by Noon on Sunday, as temperatures crash. By nightfall, all the rainfall and snow is flash freezing on parking lots, overpasses, off ramps, secondaries, driveways and everywhere else left untreated.
  • THE COLD PROBLEM: In wake of the storm Sunday night into Monday, temperatures continue dropping to single digits for most locations north of Washington DC. All that standing water freezes solid, and the saturated, slushy ground along with it. Then what happens to temperatures Monday and Tuesday? Almost nothing! Highs Monday for most areas north of DC are 15-20 F. In Pennsylvania, highs may not break 10 F. Monday night, lows dip to single digits again. 
  • THE ICE PROBLEM: Neither Sun, nor Salt nor Shovels nor Spears will be able to dislodge and de-ice what could become a region-wide paralyzing, widespread ice event that will severely impact travel Monday and Tuesday. The good news is, this *probably* won't be the start of the next Ice Age. But for a time, it sure will feel like it...


Thursday, January 17, 2019

3 comments:
I N F I N I T Y  W I N T E R ?
Three weather words for the weekend: 
Monsoon, Whiteout, Glacier. See below for updates.

FOR MARVEL FANS, EVEN THAT VIBRANIUM-INFUSED SHIELD MAY NOT BE ENOUGH PROTECTION FROM THE WICKED RAIN, SNOW & COLD THAT'S COMING.


Update as of 5:30 AM ET Thu 1/17

  • THU PM - FRI AM: For most areas from the DC metro to Baltimore metro & the PA line- Light accumulating snow is expected late this afternoon into the PM commute. Snow may fall at a moderate pace for several hours, continue overnight and being tapering toward daybreak. At least 1.0" of snow is likely, and with recent snowpack in place, a chilled surface may reduce loss of the first 1/2", providing for many areas to reach 2" or slightly more.  Below is Mount. Airy, MD in Carroll County as representative location for the region, to indicate timing and general amounts.


  • SATURDAY ( THE MONSOON) For most of the region, precip begins as rain and snow mixed or a period of snow, then turns to mostly rain as temperatures rise well above 32 F ahead of an Arctic front. Late Saturday into Sunday, potentially torrential rain is possible during embedded cells. Up to 1.5 inches of liquid is possible in this period.
  • SUNDAY (THE WHITEOUT?) As the Arctic front crosses the area, temperatures near 40 F around Noon will rapidly drop to the low teens before midnight. Rain in the morning will switch back to snow by 2 PM and could become heavy at times, producing even whiteout or blizzard-like conditions. Have your umbrella, popcorn and water proof phone ready for the weathertainment to come. THEN, all that leftover water seeping everywhere across roads, parking lots, sidewalks and your front step? It will FLASH FREEZE and be a solid block of ice before daybreak. This sets the stage for...
  • MONDAY (THE GLACIER!) With temps between 5-10 F, and no pre-treatment on roads, and all that water having frozen, it's a good thing Monday is a holiday. We think most area roads will be a complete sheet of ice. The safest thing to do is stay home if you don't have to work. With temperatures holding below 20 F until late Tuesday, we wonder how road & grounds crews will prepare buses, lots and sidewalks given that salt treatment generally is much less effective at very low temperatures.
  • BY THEN, YOU'LL HAVE a Captain America or Wonder Woman-level of fortitude to conquer the Infinity Winter that is coming next... (Click image for a larger version)




And if you're a snow plow operator, you'll be saying this a lot the next 2 weeks.