Feb 2-4th Here We Go Again…

Just as soon as one storm ends the tracking of another begins. Yes it is true that before this time frame comes we will have two clipper systems that will pass thru the region. However, for the most part these clipper systems will struggle to make it over the Mountains and any accumulations would be light ..on the order of a T to an inch or two. So with those not amounting to much our attention turns to Feb 2-4th.

The talk of the internet. Earlier yesterday afternoon there was talk of this being similar to 1996. This completely is not true and is a total fabrication. Set up is not the same and neither is the 500 mb pattern being modeled. This system on the models has gone from a Great Lakes Cutter to a South and east solution and now as of 00z this system has gone to basically a low pressure area in the SW that travels on a ENE track across the country. Of course there are timing /phasing issues ..however this is to be expected.

Now what I want to do is I want to show you the 00z guidance and some of the ensemble means as well but on each of the models at 120 hours you are going to notice that something is circled on these maps. Pay close attention cause this is an ALL important detail to trying to figure this out.

So lets look at the model guidance tonight…First up is the GFS..

Ok here is 120 hrs and we can see an area of low pressure getting organized over the southwest around Tx. We also see off to the North/Northwest of this area of low pressure two strong areas of high pressure of which behind these highs are arctic air. Arctic Air is cold deep dense air that likes to press south and southeast. This is because cold air is sinking air. Keep this thought in mind as you view the rest of the images and the rest of the guidance.

 

As you can see the system rides from the Southwest East North East and goes off around the SNJ coastline. While 850s rise across the southern side the surface remains below freezing. Does the GFS OP have support from its means? Completely!

As you can see it is very similar in track just slightly colder then the OP at the 850 level. All in all this would be conducive of another Significant snowstorm across the east.

GGEM is next..

At 120 hours we see that circled in the upper right hand panel is also an area of high pressure around 1050 or so MBS. You can see a moisture loaded system as well..

Here to we see the SW to ENE movement ..

Now here, we see a system that is much further to the North then for example the GFS. However, one should also understand that this has also come south and east from its 12 Z run and is actually trending towards its means from 12 Z..

Matter of fact an argument could be made that the 00z op of the GGEM looks exactly like 12 Z GGEM means but the means are colder then the op. 00z means have not come out yet..but chances are that they too probably are going to be further to the south and to the east. This would then put it more in line with the GFS..

Next up is the UKMET @ 120 hrs

Here as well we also see a strong area of high pressure..

At 132 hrs it is over E TN …and at 144 hrs we find it to the east of Maine..

Next model up is 120 hr ECM and for this we turn to ewall for the image because the normal sites image that i use, was messed up with the graphics.

Here to we see the same area of high pressure similar in strength…and we are missing the in between hours and tonight my source has not yet updated that would show them but at 144 hrs it has the primary low close to W PA ..

However you can also see some indication of another area of low pressure off the jersey coast. Now when you look at all the guidance you see a very strong area of high pressure to the NW of the low pressure area at 120 hrs. This high pressure which is pushing south and east with its confluence would essentially force this system to move off towards the ENE as majority of the guidance shows it. It can not cut up into the lakes because of that force of air coming down on the backside against the system.

Now one must understand that none of the models show a lakes cutter and there is no low pressure going into SE canada on the ECM here. Instead the model is simply showing a further N solution before it would have to redevelop off the Jersey coast line. On the ECM it ends up off of Cape Cod by 150 hrs.

You also notice that the area of high pressure over the NE on the UK and the ECM is already well off the coast. This is what allows the low pressure to take that more northern track..but notice how the UK while agreeing with the ECM in that high pressure area takes the primary into E TN and then starts to redevelop it off the coast at 132 hrs. It does not get as far North as the ECM. Also at 120 hrs the ECM is alot slower then what the UK is.

One more model to take a look at ..

00z NOGAPS. Notice this too has an area of high pressure to the NW and also notice the location of the high pressure to the NE of the low.

You can see this too goes on the ENE track and ends up basically  over C NJ. From there it ends up around the CAPE COD region.

Perhaps the most important question is what does the pattern support? Currently the MJO is in phase 8 heading towards phase 1. Phase 1 would be supportive of normal temperatures across the east/NE with below normal in the west and a SE ridge in place. This means we would not have a storm sliding off the southeast coast and is why models moved away from that scenario.

We still have a positive PNA however which would be supportive of a trough along the east coast.  NAO + AO however..are both neutral essentially during this period. So all the teleconnections point to something that would be more like a bowling ball system that would go from the SW to the ENE and be relatively inland and then either hugging the coast or inland as it makes the turn.

We think essentially right now that we would be taking a track from the SW towards the ENE into E KY across N central VA and then across Southern NJ and then along the coast perhaps crossing very near or just inland of Cape Cod.

We also feel initially that the area of high pressure will be stronger over the NE at 120 hrs and then this will begin to slide eastward but will leave colder air trapped at the surface so that it will turn the cities over from snow to ice and southern NJ will go from wintery mix to a rain and further inland it will be cold enough to support all snow.

This will have a lot of moisture to work with so if the above very early preliminary scenario does play out then we could be looking at a Significant East Coast storm once again. We do not think with that strong area of high pressure coming down on the backside and pressing south and east that this would be able to cut into the lakes…So we feel , right now, that a GLC is not on the table.  Stay tuned for more information on this developing system!

Level 3 Alert Continues For Majority of the Region

Low pressure developing over the GOM will continue to move towards the east before beginning to move NNE till a position over DE or just east of DE by 00z thursday! This area of low pressure will then proceed to move NNE hugging the eastern seaboard and deliver a variety of weather across the area. With the passage of the low being so far west..mixing issues will become a concern..especially for I-95 SE…North of this area should be cold enough for a primarily snow & sleet event!

The snowfall that falls will be of the heavy variety meaning a wet snowfall. This could present a problem on trees and wires! Stay tuned for further updates and or information!

Level 3 Alert Continues Across The Interior Regions!

We are briefly going to take a look at the guidance from 12 Z to 18 Z and then we are going to issue along with this guidance a special weather statement.

First model we are going to take a look at has been the model that we have been using as a guide. Keep in mind that this model is a progressive model with a southeast bias. So if any of the other guidance is taking a similar track you can pretty much figure that at 24 hrs out the models will trend more to the west Northwest.

Once, again if any guidance is further to the east then this model then we know that it will be coming back west more. So lets look at the rest of the guidance from 12 Z.

Basically you see that the 12 Z UKMET would actually be west of the 12 Z Nogaps so at this point and time this model is probably fairly close to accurate with its track depiction.

With the 12 Z GGEM we feel that pretty much at 48 hrs it is correct with the track of the low (although it will not be that depiction per say) at 60 hrs the GGEM however is too far to the east..this is probably occurring because prior runs were to far west ..so the model over compensated with its adjustment. At 72 hours, however..it makes up for this over adjustment and gets back within track range.

GFS has actually finally come on board with this system as well and has joined the rest of the camps with a very similar solution.

European Computer Model while we feel has probably the most accurate depiction of the track ..we feel that at 48 hrs it simply is not amped and organized enough. When you see the ECM means more amped and organized you know this will become stronger on future runs.

As is evident by the ensemble means above being alot more amped up then the operational run.

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As you can see by the above image the ECM has a very sharp cut off to its QPF shield. At this point and time we do not feel the cut off is going to be that sharp.

A brief look at 18 Z ..we are excluding the NAM because at 12 Z it was a slow outlier and it is no different with 18 Z run. The NAM will not become useful with this until about 24 hrs out. Again we are going to set the standard with this system by looking at the NOGAPS. When we say standard we are talking track wise.

As you can see this progressive se biased model has actually come in further to the N & west then its previous run and this is actually in line with our thinking.

Current thinking is that the models are not quite far enough west with this system & that in the last 24 hrs this will probably trend more to the N & W. So the track we are currently thinking would take it from the GOM along the coast and then rounding the corner inland and then be west of Hatteras inland. From there it will move on a NNE basis and track across DE. From that location it will move NNE and then track across Cape May NJ…and then NNE from there and track across Eastern LI and keep moving NNE and track across Cape Cod.

If this track is realized then..another map will be needed as this would end up sending more QPF to the N & the W. As it stands right now…we are expecting inland regions to receive a heavy wet snowfall. Travel will become impacted & roads will become snow covered & slippery. This is a snowfall that could potentially bring power lines down due to its wetness!

Current thinking..however this is subject to change with final issuance ! Stay tuned for more info on this latest winter storm!

Level 3 Alert Continues For Interior Regions for the 26-27th .

Models are beginning to come into agreement on this system. As of 00z yesterday the only model that remained to be south and east and OTS was the 00z NAM.

It should be noted however that as of the 6 Z NAM run ..it to has decided to come around to the party of the rest of guidance but pretty much like the GFS is still playing catch up.

People continue to not understand how the NOGAPS is actually used as a forecasting tool. They continue to say its a horrible model etc ..but this boils down to ignorance on their part.

A pro met went so far to say that HPC never references the NOGAPS and yet yesterdays morning HPC said the following:

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
140 PM EST SUN JAN 23 2011
VALID 12Z WED JAN 26 2011 - 12Z SUN JAN 30 2011
GUIDANCE OFFERS A COMPLICATED SHORT RANGE MESS INTO MIDWEEK WITH
MUCH ABOVE NORMAL FORECAST SPREAD WITH POTENTIAL SRN STREAM STORM
DEVELOPMENT AND ASSOCIATED HEAVY PCPN POTENTIAL OUT FROM THE SERN
US AND UP/OFF THE EAST COAST INTO THU. UNCERTAINTY WITH UPSTREAM
KICKER ENERGY...CONVECTIVE FOCUS...AND NRN STREAM INTERACTION HAS
LEAD TO SIGNIFICANT TIMING AND SUPPRESSION ISSUES WITH THE STORM.
THE OO UTC ECMWF/UKMET/CANADIAN AND TO A LESSER EXTENT THE 00 UTC
GFS CONTINUE TO FAVOR A DEEPENING LOW TRACK MORE ON THE WESTWARD
PORTION OF THE ENTIRE SOLUTION ENVELOPE IN STARK CONTRAST TO THE
MORE SUPPRESSED 00 UTC NOGAPS AND 06 UTC GUIDANCE INCLUDING THE
NAM/DGEX AND ESPECIALLY 06 UTC GFS THAT WAS LESS PROGRESSIVE WITH
BOTH SRN STREAM KICKER ENERGY AND LEAD LOW DEVELOPMENT.

Now, as you can see by that..the NOGAPS was indeed mentioned and the NOGAPS was referenced to which means that HPC considers it part of the guidance that they use and view. Essentially like i said..some people including Pro Mets are ignorant of reality and we here at R.W.S like to keep things real!

So, lets look at the NOGAPS once again and see where it is and see if indeed the models have trended west of it.

Now lets look at the rest of the guidance. We are going to start with the GFS.

As you can see the GFS is in about the same location that the NOGAPS is in. This is a flag to the GFS..even though it has trended west and amplified more..this model continues to play catch up to the rest of the guidance.

Next up is the GGEM..

At 72 hours you can see that the GGEM is over approximately DE. Many think that this is east of its run at this point but the reality of it is that it is actually south at this time because it is slower.

At 78 hrs is where it actually came east…

However, it is still inland and basically going over the top of NYC. Almost looks to travel over Cape May and move NNE from there.

So you can see that the GGEM is west of the NOGAPS but this should not be surprising because this model has been consistently west at one point showing the extreme western track of the NOGAPS that i actually noted in earlier discussions was too far west…

UKMET at 72 hours is tucked in well to the coast and is also west of the NOGAPS. I do not have the in between image for 78 hours but at 84 hours it is also relatively in the same place as the Nogaps which means it will be trending further to the west in future runs. Remember UKMET also has a suppressive bias beyond 72 hours.

Next model up is the ECM..

You can see that the ECM is also tucked into the coast at 72 hours. At 78 hrs the 850 low is literally hugging the coast of NJ..By 84 hrs its literally about 50 miles from Cape Cod. ECM means are slightly inside the BM..

Here is the total QPF image

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The above image is thru 96 hrs. Now for the breakdown of the 850s and the surface temps.

1.@ 60 hrs the 850s are below freezing from the N half of MD east into NJ ..the only part of NJ above freezing at 850 is SNJ…the lower portion.

@ 60 surface all areas are below freezing with the exception of SNJ ..lower portion again which is 35-40

2.@66 hrs 850s are below freezing from about western central MD and west.. to the east in MD 0 to +5 and that goes NE and divides NJ in half..southern is above and northern is below with NYC straddling the middle. SE pa also above ..but only 20 miles N & W of cities it is below freezing.

@66 surface..se PA all of NJ but extreme NW NJ and along the coast of SNE temps are 35-40. Extreme SC & SE NJ along the coast is 40-45 . 20-30 miles N & west of the big cities temps are at 30-35.

3. @ 72 hrs..850s are at about the ABE area as the dividing line between below freezing and above freezing. Essentially use I-78. All of MD with the exception of W Central Md is above freezing at 850..All of NJ as well with the exception of extrem NNJ and NW NJ..going along the coast of SNE the region remains below freezing.

@ 72 surface..surface crashes back so that south of KPHL NE into NJ drawing a line dividing the state in half on a SW to NE basis from the PA/NJ border (south of KPHL) ..is 35 to 40. KPHL and areas N & W are 30-35 and 20s further North into NY state area.

4. @ 78 All areas are below freezing with the 850s with the exception of extreme southern NJ and into East DE.

@ 78 surface virtually all areas at 30-35 or lower other then the areas above mentioned at 72 hrs.

5. @ 84 hrs.. all areas below freezing at 850 level but cape cod…

@ 84 surface all areas are at 30-35 or lower depending on location (basically same as 78 hrs) with the exception of extreme SNJ & Cape Cod.

6. 90 hrs 850s all areas are now below freezing and surface temps are 35-40 from SE PA into all of NJ but NW NJ..North and W of those locations are 30-35 or lower.

There you have the break down with the latest QPF above from the European Computer Model. Verbatim basically it looks like the Major Cities would go from a rain over to a heavy wet snow ..the exception to this would probably be South Central NJ along the coast into NJ and Delaware. This area at this present time looks to be mainly rain perhaps starting off as a wintery mix.

It must be noted that every track that you see tonight on guidance has already been shown on the NOGAPS long before any of the other guidance picked up on it. So for those that say the NOGAPS is not a good model..when it is more NW then the rest of the guidance..there is a reason that the rest of the guidance moves more NW with time. That reason is the NOGAPS is a progressive model with a SE bias and should not be that far NW to begin with so it points the errors out to the rest of the guidance.

So to sum things up..R.W.S is keeping the Level 3 alert for interior regions for the potential of a heavy wet snowfall.

If the QPF is anywhere near what the GGEM/ECM is suggesting these interior regions more east to less west would see anywhere from 15-17 inches in the east to 6-12 inches more to the west. These type of accumulations of heavy wet snow would be the type that would lay heavy on the trees and wires and could also cause power outages.

This storm has the potential to be a dangerous storm. The above is not a forecast but just laying down what the ECM is actually showing and suggesting.

Stay tuned for more information on this developing winter storm & look for future special weather statements as the specifics become more clear!