Possible Ice Storm (Ryan)

SCENARIO DISCUSSION (DECEMBER 24-26 WINTER STORM)

I am somewhat on board for a disruptive winter storm (in the form of ice) beginning late Christmas Eve and ending very early Friday Afternoon on I-95, with areas west seeing a change to rain in the afternoon. The reason I think that is storm something to watch is the usual model act to underestimate the CAD situation. A prime example is obviously the Dec 9-12 event where the days in which MD was hit the CAD won out and LWX was forced to issue WWA's for the area. Some areas received 4 inches of snow in that case. In this storm, the upper levels will be warm, but the low levels will play an especially large hold on things this time. Another reason besides the usually underestimation of the CAD setup is the High pressure positioning. The High is being modeled as a 1038-1040 per the GFS. On the other hand, the NAM model has a high much further NE than the GFS. I am not liking either model's depiction of this storm. The snowpack that is currently here in the region will also play a large part in the system. Models don't usually factor this into their solutions while in reality, snow pack can mean 1-3 degrees on the temperatures. Snowpack also creates overnight lows that are cooler than expected. This brings me to the next factor, the nowcasting before now actually occurs. Let's be sure to monitor the actual lows tonight and tomorrow night and compare them to the forecast. If the lows are lower than forecast, it could be game on. There are things that do not support this storm though. One of those things is the fact that the warm air plume will be quite strong and it could take the surface temps right up. However, in this storm, it will be more likely for forecasters to bust on predicting less ice and getting more than predicting some and getting none.

In the Midwest, this will be a major blizzard and flooding threat for the Missouri Valley. Many areas in MN, SD, NE, WI, ND, and a few others will get over a foot of snow and high winds. The areas to the southeast of those states such as IA, IL, MI, KS, etc. will see wintry precip then going over to rain, with a large event still in store.

As of now, the intermountain west is getting hit hard by thsi storm system, and Denver, CO could be its next place of impact. All of the western mountains are seeing over a foot of snow and lower snow levels to boot.

The details of the track and definite impact will be posted on my site as soon as things become clearer. Thats all for me as of now, I'll have more soon.

Snow becoming heavier, Forecast (RYAN)

Hello again everyone, its Ryan with a Snowstorm Update. The snowstorm is becoming very paralyzing for the Mid-Atlantic/Northeast. Here in Dundalk, MD, there is heavy snow falling with 11'' on the ground. We are under Blizzard Warnings/Winter Storm Warnings as well.

My expected snowfall totals for the storm(from last night, Dec 17: 9PM)

WASHINGTON D.C.:20-25''
BALTIMORE: 20-25''
Dundalk, MD: 18-24''
Perry Hall, MD: 17-21''
Parkville, MD: 16-20''

There are plenty of things going on here with winds over 30mph and possible thundersnow developing. The snowfall rates will be increasing in the next few hours with 1-3'' through 4PM.

Here is the accumulation timeline for BALTIMORE:

10'' by 11AM
12'' by 12PM
15'' by 3PM
18'' by 5PM
20'' by 8PM
All these totals have a span of 1'' either way, and I will have more updates throughout this Record Breaking Blizzard.

Rain (RYAN)

All today's storm ending up being was a bit of rain with isolated spots of ice to the N and NW of DC/BAL metros. The storm ended up like this instead of a snow event because of the delayed timing until today rather than a more favorable day like yesterday.

I will update tomorrow possibly on this weekend's threat. (Good pattern setting up).

Update on Weekend storm (RYAN)

For this weekends storm, the update for you snow lovers is no good, which shows the much lower possibility of snow affecting the region.

Early Indications for some selected areas:

DUNDALK, MD
The precipitation could start out as a snow/sleet mix but in the matter of a few hours the precip should change to rain or freezing rain. The depiction will have to rest on the surface temperatures in this area along with any potential CAD. ACCUMULATIONS (SNOW C-1'') (Sleet T-0.1'') Ice (0.01-0.05'') (Rain .25-.4)

PERRY HALL, MD
For Perry Hall, the forecast is about the same however with the location being a bit north, there could be another hour or so of wintry precip, with the accumulations being the same as Dundalk. ACCUMULATIONS (SAME AS ABOVE)

JARRETTSVILLE, MD
The forecast has many similarities as well, but in this area, there could be 1-3 extra hours of wintry precip than Dundalk and Perry Hall due to a more north location which results in colder air, along with the possibility of stronger CAD. ACCUMULATIONS (SNOW:1-2'') (SLEET: 0.1-0.2") (ICE: 0.01-0.10'') (RAIN:0.1-0.2")

Coming up later will be updates as the models aren't handling the situation correctly and this forecast could drastically change, stay tuned.

First Call 12/11-13/09 (RYAN)

We have an interesting pattern setting up for the possible snowstorm this weekend. A low pressure entering the US off California has been in the models for several days now. Suppression has been a continuous factor in the implications of the storm, but the models have come around to showing the storm as a threat for 40 S mainly. Some of the models however, including a few residual runs show 40 N getting in on the snow action as well.

Here are some of the basic factors that first need to be examined: The HWO from the National Weather Service in Baltimore, MD/Washington D.C./Sterling, Va.
Disco: A LOW PRESSURE HAS THE POTENTIAL TO PRODUCE ACCUMULATING SNOW ON
SATURDAY INTO SUNDAY.

This is in relation to the NWS HWO which had accumulating snow in it before the 0-6’’ event this past weekend (Dundalk received 2’’.)

The AFD from LWX: LOPRES PASSES S OF AREA LT SAT INTO SUN...BRINGING RISK FOR
ACCUMULATING SNOW TO PORTIONS OF THE CWA. HIGH RMN WELL BELOW
NORMAL THRU MON.

I interpret this by looking at the weather models that DC/BAL are in good shape but Southern MD could face P-type issues.

Now a look at the models (GFS 12z,most reliable run)

850's for layer/temps
102 hours:

108:

114:

120:

126:

After viewing these models: I made a track of the precipitation in relation to the low pressure track:


I also completed a map in which shows the possible QPF areal coverage:

Finally, I made up a map of where I think snow will occur along with the rain and ice threats:

As to the setup, here is a 500mb vort image from 114 when the precip moves in our area of DC/BAL:

Some may some that the pattern at this time is quite zonal, and it is but the Polar Vortex position in Canada and a developing Greenland block will possibly let this storm works it magic and spread the precipitation.

At this point, it is unclear as to whether the storm will move up the eastern seaboard and impact I-95 directly from the storm.

This is only a first call and I will have quite a bit of more developed analysis when some details of this system become a bit clearer.

1st Call (Now a US forecaster) RYAN

Its Ryan again, and I am here to announce I am expanding some of my forecasting to include the US(the big storms) I am even doing some international work :)

With that in mind, my first wide out US map:


I will have an ice and possibly rain map in my final call.

Snowstorm Amounts, Ice Storm Possible (RYAN)

The snowstorm that occurred yesterday had surprises for many in the DC/BAL area. Some amounts to note were:
Perry Hall, MD: 1''
Dundalk, MD: 2''
Woodlawn, MD: 5.5''
Damascus, MD: 6''

This storm was covered on the accuweather.com forums. From now on, they will be discussed there, but this blog is once again active.

There is the potential for an ICE STORM this Tuesday Night into Wednesday Morning.

EARLY HINTS:

The national weather services Hazardous weather outlook for Central MD

A MIX OF WINTRY PRECIPITATION IS LIKELY TUESDAY NIGHT THROUGH
EARLY WEDNESDAY MORNING IN AREAS ALONG AND WEST OF INTERSTATE 95.
WHILE IT IS TOO SOON TO CATEGORICALLY DETERMINE THE EXACT
PRECIPITATION TYPE...THERE IS A GOOD CHANCE FOR IT TO BE FREEZING
RAIN AND SLEET.

Analysis: This shows that the NWS is hinted in on the chance for a Winter Storm, with Ice Storm being the one to focus on.

Our Synopsis from MDWX(How it could play out): The low coming across the Great Plains of the central US will gain strentgh and this could set up a claassic CAD(cold air damming) situation east of the Blue Ridge Mountains to I-95. It is too early to hone in on the exact timing of the precip, or how long it will last, but one thing is for sure; Wednesday afternoon the precip will change to all rain with temps in the 40's.

NWS Forecast for this period(Baltimore MD):
Tuesday Night: Freezing rain and sleet likely. Cloudy, with a low around 30. Chance of precipitation is 70%. New precipitation amounts between a half and three quarters of an inch possible.

Wednesday: Freezing rain and sleet likely before 9am, then rain likely. Cloudy, with a high near 42. Chance of precipitation is 70%.

Analysis: The bolded areas are my focus, and especially how there could be 1/2-3/4'' of precip in the freezing rain/sleet categories. What this means: A large Ice Storm with big effects is definitely a possibiliy and precip chances are already 70%, so this is something that HAS to be watched closely.

Next Update: This evening.