I provide a weather email service for people in MD. I am a storm chaser & Skywarn spotter. For daily weather tidbits follow me on Twitter: @wxmanMD.
By: cws6196, 3:08 AM GMT on March 25, 2013
The NWS has extended the Winter Weather Advisory, but not yet into central nor S MD. The areas around Baltimore and into DC are the sweet spots for snow accumulation (as I mentioned yesterday). In my earlier post today I said I was not going to look at the models, rather I would study the storm itself. This I am doing.
Thus far there has been some decent snow falling in S MD with a dusting accumulating on the ground. This is more snow and earlier than thought. There are also indications of thunderstorms in WV meaning the upper level energy of the storm is strong. But will this translate to a sizable amount of snow...... A couple of posts ago I detailed my pro's and con's so will not again bore you with them. But, one thing going for us this time is that the bulk of the moisture will be at night, so the angle of the sun and the surface temp will not be an issue as it was March 6. Although, as long as the winds continue from the E it will be hard to get the temps just right.
Currently the Low's are phasing, therefore the lull in the precip. Once the coastal Low gets moving I will have a better idea of what will happen, but indications are that that Low will be stronger than March 6's Low. If this is the case we could see a bit more snow than predicted.
I am basically sticking with my accumulations I stated in a couple posts ago, although I will leave open the possibility that those N of Baltimore could see a bit more, and central MD may get surprised with a couple inches. All depends on the outcome of the phasing of the Low. Here's how I see it:
TIMING: Once the phase ends the precip will resume. I see the heaviest snowfall around 4:00am until 10:00am or so. Rain/snow the rest of the day, depending on the strength of the coastal Low. Precip to end late Monday, possibly as light snow.
ACCUMULATION: Those N and W of Baltimore could see 2+" with those closer to DC and W 4 or so inches. Baltimore could be surprised with an inch or so, and S MD, although should only have a dusting, could be surprised with a couple inches if the snow is heavy enough over night.
I would not be surprised to see the Winter Weather Advisory extended S into Baltimore toward Annapolis by morning. Follow me on Twitter (@wxmanmd) for weather updates and tidbits.
By: cws6196, 5:46 PM GMT on March 24, 2013
There is currently rain in VA heading toward S MD. For most of us, this storm will start as rain, later changing to snow. I am sticking with my previous forecast, waiting to see what the storm does. The models have not done us justice this winter, so I am not trusting them now. Rather, I want to see how the rain tracks, the direction of the wind, and how soon snow accumulates. The ground temp is warm, so we need heavy precip to begin accumulating snow. Light snow will not stick. The wind direction is important. Winds from the E, SSE or NNE will keep the surface temps warm, just like March 6. So I want to see what is happening tonight, taking that trend into account to determine if I will or will not modify my forecast.
Follow me daily on Twitter (@wxmanmd) for weather updates and tidbits.
By: cws6196, 5:16 PM GMT on March 23, 2013
Ok, y'all remember the March 6 fiasco of a weather forecast? Here we go again! This current potential system is very similar to that other system, and if we didn't get snow earlier in March, why would we get it now? That is the cynical part of me, because historically Maryland has received snow into late March. Many weather persons are now comparing this past winter with our winter in 1942. Both winter snow falls were almost exact (just over 4" total) and in 1942 there was a Palm Sunday historic snowfall dump of over 2 feet. Hmmmm......and tomorrow is Palm Sunday.... Will it happen again? Nope. Here are my pros and cons for our snow chance:
1. In comparison to March 6, much of the precip will be during the night so the March sun angle is not a factor.
2. The days preceding March 6 were quite warm, but lately we have had below normal and sub-freezing temps at night.
3. It happened in 1942.
1. It's late March and the ground is warm.
2. We have another situation where there will be a phasing (joining) of two Low pressure systems. During the phase the precip drops off. For snow to stick in March we need a consistent heavy snowfall. We won't have this during the phase period.
3. The Bay water temp is quite warm, so any winds coming over the Bay will warm the atmosphere (as we saw March 6. The precip was right; the temps never cooled).
So, here is how I see it:
TIMING: For most the precip will start late afternoon on Sunday lasting through the morning of Monday.
ACCUMULATION: This depends on your location, and the exact location of the Low. For those around DC and SSW of Baltimore (west of I-95) you could see a few inches of accumulation overnight. As snow accumulates it will allow more to accumulate as the snow will lower the surface temps. Those due N and S of Baltimore most likely will see a mixed precip with "possibly" a dusting to an inch. Those to the E, enjoy the rain.
I will have another update later Sunday, but for the moment I feel confident in this forecast. Follow me on Twitter (@wxmanmd) for weather updates and weather tidbits.
By: cws6196, 1:48 AM GMT on March 20, 2013
Yes, Spring is officially coming (Wed morning), but no one told the weather. Due to a Canadian High pressure system, we will remain cold with below normal temps. And, yes, snow. Nothing major though.
Wednesday evening into Thursday morning we should see a repeat of the other day with light snow and little to no accumulation. A dusting at most for central and S MD. But snow nonetheless.
Then, Sunday into Monday I am watching a potentially strong storm system clip us. The trend of the Low's path appears to be such that we will see a good amount of rain. But, a slight change in that path and we could be hit with a good amount of snow. Am I saying we will see snow? Most likely no; but this is definitely worth watching.
Follow me daily on Twitter (@wxmanmd) for weather updates and tidbits.
By: cws6196, 12:03 AM GMT on March 18, 2013
As I mentioned in my last post, this snow event is not something to concern ourselves with, unless you are travelling into VA or western MD. Overnight into the morning there will be mixed precip but little to no accumulation. What is happening is the upper atmosphere is cold enough for snow, but as the snow falls to the surface, where it is warmer, it turns to rain or sleet. Those N and W of Baltimore could see an inch or so of accumulation, everyone else should be fine.
Follow me daily on Twitter (@wxmanmd) for weather updates and tidbits of weather info.
By: cws6196, 9:48 PM GMT on March 16, 2013
I really am hesitant to write this, but since it is on the official forecasts from many outlets I figured I have to say something. Yes, snow is in the forecast for Sunday evening into Monday morning. What are the odds? I have no doubt there will be flakes falling. The odds of accumulation in central and S MD is low. It is possible for a dusting, but that should be all.
I will have another update later Sunday. Follow me daily on Twitter (@wxmanmd) for weather updates.
By: cws6196, 10:00 PM GMT on March 06, 2013
It's over.... This has been a frustrating day. I am not so much upset that I blew the forecast, but more so because I love snow and am disappointed not to get any. Sorry to say this, but for us, winter is now over.
What happened? Good question. All the components were in place and the model data was consistent for days. Late last night the short term models upped the snow amount, and as a result so did the NWS (mine were always up so I didn't adjust). I will not blame the models (although, after this winter I do question the calibration since they were wrong more than they were right), I blame me. I am the forecaster, not the models. I pride myself on being cutting edge, not simply going with the flow. And I wasn't; I stuck with this storm longer than most did.
WHAT WAS CORRECT: The formation of the Low and it's path. The amount of precip was on target. Converting the rain I measured it would have equaled about 7-8 inches of snow. Many areas in MD and S PA had accumulating snows; lots!
WHAT WAS WRONG:
1. The temps! I warned about the temps, yet given the projected intensity of the Low and the amount of moisture, all indications were that the precip would overcome the temp issue. Wrong!
2. The Low! It is still just off the VA/MD coast! It was supposed to move!! ...sorry... The Low stalled most of the day which allowed for an easterly wind flow bringing us warmer temps most of the day. Once the Low started to move it moved too slowly for any significant cold air influence.
1. The temps overnight will drop below freezing, so moisture on the roads will freeze.
2. The wind gusts will remain strong as the Low slowly moves up the coast. Power outages and damage are still possible.
I appreciate all of your support and sticking with me through this forecast. In all my years I have never seen a forecast bust as big as this one. Even to the end all the factors were in place for this to be big. But, onward to Spring thunderstorms and tornadoes.
Continue to follow me daily on Twitter (@wxmanmd) for weather updates and tidbits.
By: cws6196, 7:30 PM GMT on March 06, 2013
Where is it?! I still have faith, and here's why:
1. The coastal Low has stalled in VA. The counterclockwise motion is bringing in warm ocean air, hence the rain.
2. The March sun angle has eroded some of the cold air and some of the snow as it fell.
3. This time of day the sun is beginning to set, so the radiational heat will now turn to cooling.
4. As the Low in VA moves ENE it will wrap around cold air and all the moisture on the eastern shore should become snow for central and maybe S MD.
In many ways my forecast is on track, but the timing is off since the Low stalled. I still have faith in multiple inches of snowfall by tomorrow morning. Some of the concerns I wrote about in previous posts are coming true, but I think we can overcome them. Could this bust and be all rain for central and S MD? It could, but I'm not yet ready to pull the plug for the reasons listed above.
Follow me on Twitter (@wxmanmd) for updates on the storm. Running out of patience? Read my reflection on patience here: http://tinyurl.com/cm3a2vp
By: cws6196, 5:26 PM GMT on March 06, 2013
The NWS is continuing the Winter Storm Warning for all areas except St. Mary's and Calvert Co where they now are under an advisory (see text below).
If you want snow don't stress. Since Sunday I have been posting that rain will happen Wednesday morning, changing to all snow in the afternoon. The Low is now strengthening and moving off the VA coast. As it does the counterclockwise flow of the Low will draw in cold air. Already we are witnessing a wind shift to the north.
As the afternoon progresses into the evening we will see snow intensify and accumulate. I will say, though, that in my previous posts I did talk about the possibility of a longer rain duration lowering snow accumulation. This may be the case, but I won't yet say that until we see when the complete change over happens.
Follow me on Twitter (@wxmanmd) for storm updates and weather tidbits.
INCLUDING THE CITY OF.ST MARYS CITY
1207 PM EST WED MAR 6 2013
.WINTER WEATHER ADVISORY IN EFFECT UNTIL 3 AM EST THURSDAY.
.WINTER STORM WARNING IS CANCELLED.
THE NATL WEATHER SVC IN BALTIMORE MD/WA HAS
ISSUED A WINTER WEATHER ADVISORY FOR PORTIONS OF S. MD.
WHICH IS IN EFFECT UNTIL 3 AM EST THURSDAY. THE WINTER STORM
WARNING HAS BEEN CANCELLED.
* PRECIPITATION TYPE.SNOW.MIXING WITH RAIN AT TIMES NEAR THE
* ACCUMULATIONS.2 TO 4 INCHES.
* TIMING.SNOW WILL RESUME THIS AFTERNOON.OCCASIONALLY MIXING
WITH RAIN NEAR THE CHESAPEAKE BAY. SNOW MAY BE MODERATE TO HEAVY
AT TIMES THIS AFTERNOON & EVENING. THEN TAPER OFF AFTER
* TEMPS.IN THE MID 30S.
* WINDS.NORTH 20 TO 30 MPH WITH GUSTS UP TO 40 MPH.
* IMPACTS.HEAVY WET SNOW & GUSTY WINDS COULD LEAD TO
SCATTERED POWER OUTAGES. SNOW COVERED ROADS & POOR
VISIBILITIES IN HEAVY SNOW WILL MAKE DRIVING DIFFICULT.
A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW WILL CAUSE
TRAVEL DIFFICULTIES. BE PREPARED FOR SLIPPERY ROADS & LIMITED
VISIBILITIES.& USE CAUTION WHILE DRIVING.
DISTRICT OF COLUMBIA-CARROLL-NORTHERN BALTIMORE-HARFORD-
PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX-
INCLUDING THE CITIES OF.WA.WESTMINSTER.
1207 PM EST WED MAR 6 2013
.WINTER STORM WARNING REMAINS IN EFFECT UNTIL 3 AM EST
* PRECIPITATION TYPE.SNOW.
* ACCUMULATIONS.4 TO 8 INCHES.
* TIMING.SNOW WILL CONTINUE THROUGHOUT THE DAY & EVENING.
THEN TAPER OFF AFTER MIDNIGHT. SNOW WILL BE HEAVY AT TIMES
DURING THE LATE MORNING & AFTERNOON.
* TEMPS.IN THE LWR 30S.
* WINDS.NORTH 15 TO 25 MPH WITH GUSTS UP TO 40 MPH.
* IMPACTS.HEAVY WET SNOW & GUSTY WINDS WILL LEAD TO POWER
OUTAGES. SNOW COVERED ROADS & POOR VISIBILITIES IN HEAVY
SNOW WILL MAKE DRIVING DIFFICULT.
A WINTER STORM WARNING FOR HEAVY SNOW MEANS SEVERE WINTER WEATHER
CONDITIONS ARE EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF
SNOW ARE FORECAST THAT WILL MAKE TRAVEL DANGEROUS. ONLY TRAVEL IN
AN EMERGENCY. IF YOU MUST TRAVEL.KEEP AN EXTRA FLASHLIGHT.
FOOD.& WATER IN YOUR VEHICLE IN CASE OF AN EMERGENCY.
By: cws6196, 5:48 AM GMT on March 06, 2013
Wed morning quick update
Just a quick note of patience. Many are asking where the snow is. As I have been posting, the bulk of the snow will be in the afternoon through the evening. Right now the east wind is bringing in warmer temps, but as the Low in VA intensifies and moves off the coast the winds will shift to come from the north. When that happens not only will we have Atlantic moisture, but colder air. Not the arctic air we would like for a full out blizzard, but cold northern air nonetheless.
Timing is hard to determine, but it should be happening in a few hours.
Since my last post, watching and bemoaning the fact that the NWS took away watches and advisories as they lowered snow totals in S MD and elsewhere, it appears the NWS found my weather blog and read it. Not long ago they upgraded all of S MD and central & N MD to a Winter Storm WARNING and increased the accumulation totals for all locales in the warning area. So, since they did that I deleted much of the draft I was going to post wherein I explained my disagreement of their forecasting, etc etc etc.
Ok, onward.... Not much has changed from my forecast with the exception of the possible need to up some of my totals. The latest data shows the storm on track, yet stronger than predicted. Also, as I write this, many areas in MD are already seeing steady snowfall, something which was not supposed to happen until well after midnight into Wednesday morning. Many areas in S MD up toward DC did not have much rain prior to the change over to snow. If that trend continues in MD we could be looking at higher totals (A possibility I mentioned in a previous post).
TIMING: Now through Thursday morning coming from the SW.
PRECIP TYPE: Start as rain later turning to snow. As I mentioned above, this change is occurring quicker, so it is possible your rain period may be short.
ACCUMULATIONS: Those W of I-95 will receive more snow than those closer to the Bay. Central & N MD could see 8+" with more further W while S MD could see 6+" with more further W and N.
THREATS: The snow will be wet and heavy, the weight of which could bring down tree limbs, power lines and roofs. Also, we will be contending with strong wind gusts around 30mph. Minor damage and power outages are to be expected.
I will have another update sometime Wednesday depending on the conditions and situation. For more detailed and up to the moment storm updates follow me on Twitter (@wxmanmd). If you don't have a Twitter account that is not a problem. Simply go to this link and you will see all my tweets: www.twitter.com/wxmanmd). My Weather Phone is updated, 443-470-9804, feel free to leave VM with questions or comments.
By: cws6196, 7:14 PM GMT on March 05, 2013
So far all is still on track according to my previous posts. Do not let this warm weather discourage you, we knew it would be warm. The real issue are the dewpoints, and they are currently where we want them. The cloud cover is moving in, just as we need. So, no worries if you want snow. There are concerns though: how much rain before the turnover and how much of an impact the warm Bay water temps will have on the area. Overall though I am confident in my forecast.
Keep in mind that the storm will start as rain, so don't despair when the rain begins. Once the sun goes down the air will cool, and the rain falling will aid in the cooling of the air.
I would not be surprised to see some of the Watches turn to Warnings later today.
I will have a complete update later this evening. Follow me daily on Twitter (@wxmanmd) for weather and storm updates.
By: cws6196, 4:35 AM GMT on March 05, 2013
I think my last couple posts have elaborated in detail on the dynamics of this system including my concerns about accumulations, so I will not rehash all that here. We are currently under a Winter Storm Watch, but don't be surprised to see the watch in central MD turn to a warning. So, let's get to the good stuff...
TIMING: Late Tuesday into late Wednesday, although if the storm stalls it could last through Thursday morning.
PRECIP TYPE: Rain to start than changing over to snow. Those in S MD will see a longer period of rain, but it will change to snow. For S MD the change may not happen until later Wednesday afternoon, while those in central MD could see the change earlier Wednesday.
ACCUMULATIONS: There will be a fine line between those who get a lot of snow and those who don't. Generally speaking, those around DC into Baltimore then N and W should see more while those in S MD and along the Bay should see a bit less. Generally, central MD toward the PA border should see around 6-10" while those in S MD around 4-8".
THREATS: The snow will be wet and heavy, therefore there is the potential for power outages and tree damage.
CONCERNS: The accumulations will drastically change up or down depending on the exact path of the Low; the timing between the rain / snow change over; the surface temperatures. My forecast is taking these conditions into account, but until we know how quickly this changes to all snow will I know better if my amounts are too high or low.
I will have another update on Tuesday as needed. Follow me daily on Twitter (@wxmanmd) for weather/storm updates and tidbits.
By: cws6196, 5:29 AM GMT on March 04, 2013
LOTS OF INFO; PLEASE READ ALL THE WAY THROUGH This has not been a typical winter: we had snow on Christmas Eve, the first time in a decade; model data has not been good; we have been dry slotted; had storms simply die out over us; very little snow accumulation (in most, not all, areas); and now a March storm that if it happens would be the first in the past 14 years! Here is what the local NWS wrote to the area forecasters this evening: A STRONG LATE-SEASON WINTER STORM IS EXPECTED TO IMPACT THE MID-ATLANTIC REGION LATE TUE THROUGH WED. AFTER LOOKING OVER 12Z MODEL GUIDANCE...WHICH HAVE COME INTO BETTER AGREEMENT...THERE IS INCREASING CONFIDENCE OF A SIGNIFICANT SNOWFALL FOR AT LEAST PORTIONS OF THE AREA.
Much of the model data is coming in and although there are some consistencies in the output I still can't say for sure how much we will get. In previous posts I have explained my concerns about snow accumulating in March; now add to the list the chance that we may have rain before it turns to snow. Rain will melt the first layer of snow, and it also skews forecast amounts since it is impossible to figure out how many inches are lost due to rain melt and how long it will rain before turning over to snow. One other caution, one which I do not believe will happen this time, but one I do need to mention: part of the dynamics of this storm is for the main Low to phase (join) with a weaker Low. As we have seen this winter, as two Low systems phase there is a dry slot created as the energy transfers from one Low to another. We already had one storm go bust because of the dry slot. I don't really think it will happen this time, but we do need to be aware of it.
But, with that said, I can make some educated guesses as to what is possible (although many people would say that is all forecaster do anyways).
TIMING: Looks to be late Tuesday evening (near midnight) into late Wednesday.
PRECIP TYPE: Those in W MD and N of DC should see all snow while the rest of us should see rain at the start turning to snow as Wednesday progresses. Those in S MD and along the Bay may turn over to snow a bit later Wednesday. Late Wednesday afternoon into the evening everyone should be all snow.
SNOW TYPE: This should be a wet and heavy snow. This means shoveling and plowing will be very difficult. We could see power outages as tree limbs come down and power lines snap under the weight of the snow. Since this will start as rain the roads can't be pre-treated and will have to wait for the snow to begin to salt, therefore many roads may be slippery.
ACCUMULATIONS: This may change, but right now most of MD should see more than 6 inches with those around DC, N and W could see 18+". S MD is a bit trickier but I still see 4-6+". This all depends on how long the rain lasts and the exact position of the Low off the coast.
FORECAST CONCERNS: Right now I think my forecast is on track, but as I have been mentioning there is the potential for either a complete bust or only a couple inches of snow. There are some data hints that this could actually be stronger than forecast, and if so we all could be looking at over a foot of heavy snow.
UPDATE: I will have another update later Monday when I see the morning data. I am also watching the Low currently in the W to see if it is moving and positioning as the models said it would. What the Low is doing in reference to what the models said helps me to see not only what the Low's position may ultimately be, but also which models to watch and which aren't producing well.
Follow me daily on Twitter (@wxmanmd) for weather updates and tidbits.
By: cws6196, 4:20 PM GMT on March 03, 2013
Yes, Maryland, there is snow coming .... I will have a more complete and detailed report late tonight, but for now, here is how things are shaping up.
The future storm is now on land in the west, so we will now be able to collect more and accurate data to feed into the computers. Throughout today we should see the computer models begin to synthesize the outputs more consistently. But, thus far there is consensus in the models that we will have snow this week. The question mark which remains is the accumulation.
Why is accumulation a question mark? This time of the year (as I detailed in my previous post) it is more difficult to have snow stick. Snow will only accumulate this week IF it falls at a very heavy rate. If that happens, the moisture will cool the atmosphere near the surface, and the snow will build upon itself on the ground faster than the ground can melt it. When that happens, the top snow layer stays cold since the surface atmosphere has now cooled, and the lower layers of snow stay frozen because the top layer is insulating the bottom. But this can only happen if the snow falls at a heavy pace.
Another question mark is if there will be any mixing of rain. If rain mixes in that will reduce accumulation. Given the projected temps, we are most likely looking at wet and heavy snow. Not only is that snow dangerous to power lines, it is more difficult to estimate how much will accumulate. Wet heavy snow compacts when it hits the ground, with the weight of the top layer forcing itself closer to the ground.
Snow accumulation is calculated from the surface temp computed with the amount of precip. The models predict the amount of precip but not how much snow. Given all that I said above, we can't just use the mathematical model. For instance, generally 0.1" of precip equals 10" of snow. But given what I said above, that same 0.1" might only accumulate to 4-5". The conditions make it difficult to forecast amounts.
TIMING: It appears the timing is now late Tuesday into early Thursday.
ACCUMULATION: Didn't I say enough on this above? hehe ... This is NOT my forecast, but data is showing central MD could see 4-6+ with S MD maybe a bit more. But again, this is based on pure data, NOT yet my forecast.
I will have a detailed update late today. Follow me daily on Twitter (@wxmanmd) for weather updates and tidbits.
By: cws6196, 5:52 AM GMT on March 02, 2013
I'm sure many of you have already heard from the media that there is a chance for a snow storm next week. Yet, I have been silent on this. Don't you usually hear about these events from me before you hear it from the media, like everyone else!? Well, I have been silent for a couple reasons. One, I'm trying to work some reverse-psychology on Mother Nature. You know, if I don't say anything maybe it will happen. Secondly, I have been quiet because the potential storm is almost a week away! I actually have been tracking this possibility since a few days ago.
The deal is, some of the model data is indicating a potential coastal storm to hit next week. I will grant that many dynamics needed for us to have a strong coastal storm are in place, and have not been in place earlier this winter. On that point I can see why some forecasters are getting excited. But, I have many concerns, which I will mention below. I am not yet going to say if this storm will or will not happen. It is too soon. But yes, the potential exists, and yes, I have been watching it.
TIMING: At this moment it appears it would start late Tuesday and last into mid-Thursday of this coming week.
ACCUMULATIONS: Don't even ask..... But if you must know, anywhere from 0 inches of snow to over a foot of snow, if it doesn't rain.
PROBLEMS: I am not jumping on the hype bandwagon for a number of reasons, but my top reasons are the following: 1. The models this winter, in the long range, have not performed well; 2. The angle of the earth to the sun is such that not only are the days longer, the sun is able to melt more of the snow; 3. The ground is warm; 4. We need the Low to phase at just the right time to subsequently place it in just the right position for us to get snow. If any of the timing or strength of the Low changes, that potential storm system goes out to sea and all we get is rain. 5. The potential system is still in the Pacific just south of Alaska - quite a distance from here. Much can happen.
So, it is worth watching, but don't get into the hype, and don't yet start believing forecasters who say they know what will happen or who start to give accumulation rates over the weekend. They are just guessing. Late Sunday into Monday we all will know more and can then rightly talk about accumulation rates.
Follow me daily on Twitter (@wxmanmd) and I will keep you posted later in the weekend.
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.