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Winter Storm Threat: January 25-27 (Only/Final Call)

Not going to go into details because I have spent way too much time looking at this storm between work and home. Also, I’m prepping for a snow chase in New Jersey, so that has taken up much of my afternoon.

20150125-27_MAsnow_final

A bit more conservative than the Euro and NWS overall. The lack of support of big totals from some of the other models in the Mid-Atlantic gave me pause. There’s a lot of moving parts to this system, so it’s really anyone’s game still. I just hope I’m not terribly wrong.

Winter Storm Threat: Mar 24-25 (Final Call)

Same general theme, with a slight shift south along the southern edges and a more pronounced southern shift towards the upper part of the map. Risks are generally to the higher side on the southern fringe areas if the models are to be believed (especially if the overnight front-end thump is fairly wet).

Winter Storm Threat: Mar 24-25 (Initial Call)

The DC-Baltimore-Philly areas are expected to miss out on the more significant accumulations yet again as bothersome low-level temperatures above freezing and March climo. rear their ugly heads.

One of the saving graces with this event is the onset of snow will be overnight, though this did not really help the I-95 corridor and points east during the last event back in the first week of March. Surface temperatures will generally be above freezing in the lower elevations, so these areas will need good rates to make up for it. A large chunk of the precipitation is expected during the daytime hours, where we will have the March Sun to contend with in addition to the temperatures. Higher elevations that stay at or below freezing will fare much better with accumulation.

Forecast confidence is normal to slightly below normal.

Winter Storm Threat: Jan 25 (Final Call)

Somewhat higher confidence in the QPF totals brought about an expansion of the 2-4″ area. The GFS/NAM continue to suggest a snow hole in the northern VA and DC region, which remains a slight risk to the low side. Overall, I think risks are more to the high side, with localized 2-4″ totals possible within the 1-2″ contour. Likewise, the 2-4″ contour could see localized totals of 4-8″ (which is more so for the Appalachians than anywhere else).

Winter Storm Threat: Jan 25 (Initial Call)

Certainly a new breed of winter storm for this winter as we now have plenty of cold air in place, but moisture will be lacking in most areas. The good news is most of the Mid-Atlantic will see high snow ratios around 15-20:1, giving the event more bang for the buck.

Risks are more to the low side at the moment, with the current forecast leaning more towards the wetter European solutions. The NAM and GFS have been fairly insistent on a DC snow hole where accumulations are less than an inch. While entirely possible, I still think there’s enough QPF for most to get around an inch. Some of those east of the mountains in PA and NJ have a shot at 2-3″ if the higher-end QPF verifies.

Confidence is lower than normal with this storm due to the QPF issues and because the energy that will create this system is still somewhat offshore in the Pacific Northwest, so it is not getting sampled as well as it would if it was onshore.

Widespread rain event over the next 5-7 days… some severe

An upper-level low is forecast to move into the Midwest tomorrow before cutting off from the main flow, which will allow it to linger over the Midwest and Tennessee Valley regions through around Monday or Tuesday before it lifts out of the eastern U.S. This has a couple of different implications for the region…

The most pronounced threat with the cut-off low is the potential rainfall, with widespread totals of 1-3 inches or more in the Mid-Atlantic and Northeast. Normally 1-3 inches isn’t that critical, but when you add it to the recent record-breaking rainfall in these regions any larger rainfall potential becomes a significant event.

Here’s a look at the total rainfall and the percent of normal rainfall for the period starting August 1st and ending yesterday, September 19th:

With some areas with over 20 inches of rain in the last 45-50 days, anything over a couple of inches will cause some of the rain-soaked areas to flood once again. Right now it looks like the coastal areas are more at risk for heavy rain compared to the inland/mountain areas in the Mid-Atlantic.

In terms of severe weather, strong to severe storms will be possible Thursday through next Monday or Tuesday, depending on the position of the cut-off low. This complex cut-off will have a few pieces of energy floating around it (at least initially… some guidance suggests one of the pieces breaks away before it completely stalls):

Having 2-3 pieces of energy in this cut-off low will make the forecast very difficult as models struggle to resolve the complex mesoscale interactions between the different pieces of energy and what they’ll do in turn at the surface.

Also associated with this energy will be an upper-level jet streak out ahead of the trough, which will help enhance lift. The problems, at least initially, will be the fact that the energy is just a bit too far to the west to have that great of an impact on the Mid-Atlantic, and clouds and rain could inhibit heating and worsen the lapse rates. My main focus for severe is when the trough does finally push eastward over the region… hopefully the timing will be good and it could trigger some afternoon/evening storms over the Mid-Atlantic. Once it progresses into the region, the energy involved with it will cause greater lift and the lapse rates should improve.

Not getting my hopes up on severe yet, but at least it’s something to watch over the next several days.