Monday, August 31, 2015

Monday Morning Note

Good morning everyone. It is going to be a quiet but hotter week with temperatures in the upper 80's in most spots. Not seeing much of a threat of any rain at this time. I will have more details along with some other weather related tidbits tomorrow morning. 

Enjoy your day!

Friday, August 28, 2015

Friday Morning Tropical Update: Erika Loosing Steam

Good morning again everyone. Wanted to give you all an update on tropical storm Erika based on latest model guidance. The good news is model trends overnight have shifted the track of Erika more westward. This is key as the storm now runs into a very hostile environment in terms of gaining any strength. There are two reasons why this westward track does this. For one, it now is going to travel directly over terrain of the Caribbean which will cut off a lot of its development the warm ocean is providing. Secondly, it is going to run into a lot of upper level wind shear. Just think of this as fast winds that cut off rising air from developing into strong thunderstorms- a key ingredient for any tropical system. 

So lets take a look at the updated NHC track..



You can see a clear shift west from yesterday. Notice the land it is traveling over now. This relates to the latest model spread which is also further west..


Based on the projected paths of those models above, most of them would be taking this directly into upper level wind sheer as seen below by the orange colors to the west of the low center..


The key yesterday was that models were projecting this storm would turn more north and avoid most of this shear. Now it looks to be running literally into a brick wall.

IF this guidance holds, the end result might be nothing more than this..



Nothing to impressive there. Yes it would bring rain early next week to Fl, but not anything to write home about. 

To summarize, this situation still needs to be monitored. You guys can now see the difference one day can make on the evolution of this. I think we will have a better handle on this by tomorrow. IF last nights trends continue then we can close the book on Erika. I am not ready to make that call yet however. 

Stay tuned!

Thursday, August 27, 2015

Thursday Morning Special Update on Tropical Storm Erika

Good morning everyone. I wanted to give a special update on projections for a tropical storm/hurricane that could impact the SE United States next week. This is only a preliminary update and as the days go I will go into more detail, but I want to give everyone an idea of what is currently going on.  The potential impact timing is early to mid next week. 

Lets start off with the current situation...



Looking above you can see we have a tropical system just to the north of S. America. This is tropical storm Erika and it has been developing over the last 24 hours. The National Hurricane Center has issued this outlook..



You can see the cone which represents its possible tracks and the timing they are expecting for this system. The H in the black circles represent that they are expecting this to develop into a hurricane. It is not a surprise that if you compare the current model spread to the NHC's track it looks similar below..


You can see that at this point many models are pointing to a storm that either hits southeastern FL and then curves northward or in some cases drifts into the Gulf. In order to determine which solution will be likely we have to monitor the upper level pattern which steers hurricanes. 



Looking above at the GFS Ensemble you can see a big ridge over SE Canada, and a circle off of GA which represents the storm. The placement of this upper level ridge (red colors) is key. If you get that ridge slightly more east or west it will have a drastic impact on the trak of this storm. That is what will determine if it skirts FL and goes out to sea or its more of a direct land hit. I am not ready to jump on any solution yet. I just want you guys to know this track can change over next few days even tho the model spread says one thing. 

Looking at an actual projection of the HWRF model (special hurricane model) of where it expect this to make landfall. Below is the simulated radar..


Just one model projection, but it is a model that will be come more relevant as we get closer to the event. 

Stay tuned I will be updating daily as this situation evolves!

Monday, August 24, 2015

Monday Weekly Weather Summary: Quiet Week Ahead, Eyeing Tropical Systems

Good morning everyone. Going to be very brief today as it will be a very busy day at work (market). An upper level ridge of high pressure is just offshore today which will keep things more on the humid side with temps in the mid to upper 80's. As we head into tonight/tomorrow morning a weak cold front will approach from the west..


Expect a few showers but nothing to really write home about. In the wake of the front things cool down again in the low to mid 80's with very low humidity for the rest of the week. You can see below the overall jet stream pattern for this week..

Anytime the jet stream dips over us we get cooler and at times unsettled weather. In this case I am not expecting much unsettled weather outside of tonight and tomorrow morning. 

Moving on briefly we actually do have a tropical storm in the Caribbean. Its name is Danny and has been the talk of the weather community over the past few days..


Here is the satellite image..


There has been a lot of debate on where this goes  and if it strengthens, but here are current model projections..



I will keep you guys updated if this situation gets more interesting. Also, there will be another tropical system developing in the longer range that we will need to track. You can see the storm on the euro out in the Atlantic about a week from today..


Stay tuned!



Thursday, August 20, 2015

Thursday Night Update: Taking a Look at the Front

Good evening everyone. Well i'm sure by now most of you have heard about rain for Friday but I am here to tell you Friday will not be a washout. The main rain event is tonight into tomorrow and in fact, we will see clearing by the afternoon. It appears many of the weather outlets are now showing this. Lets dive in...

We currently have a cold front just to our west and approaching..


Rain is breaking out to our west as the result of "forcing" from this front..


This rain will last into the morning then taper off. Models are now showing this. Take a look at nam model for 11am tomorrow below. You can see most of the rain is clearing out.

Yesterdays run at this time showed this..

You can see the front is projected to come in faster than originally modeled. I see this a lot with these frontal system which is why my first hunch was Friday would be sparred when did the Tuesday weekly summary. 

As the front finally clears we will have absolutely phenomenal weather conditions with low humidity and temps in the low to mid 80's!

Thats all for now. 

Tuesday, August 18, 2015

Tuesday Weekly Weather Summary

Good Tuesday morning everyone! We are currently undergoing a hot and humid weather regime. There will be relief to this late in the week but for now you can see the ridge of high pressure off the Atlantic coast that is responsible for the heat..



Temperatures will remain hot today and go into the 90's. As this ridge starts to retreat tomorrow we get some relief with temperatures back in the 80's but the humidity values will still not make it feel so nice. There will remain the slight chance of a pop up shower or two today and tomorrow. 

The arrival of a cold front Thursday night will be the game changer...


Showers and T-storms will start to develop on Thursday afternoon and last into early Friday. Behind this front temperatures will fall into the low 80's with low humidity. This should make for an excellent summer weekend. 

I will have more on this as we approach the weekend. I also might share a few more long term (fall/winter) thoughts.

Thursday, August 13, 2015

Ocean Temperatures are Big Factor in Winter Outcomes

Good morning everyone. Since we are currently experiencing excellent weather that will continue into the weekend I thought I would share a factor that goes into my winter forecasts, the ocean.

In order to make a contrast between the ocean temperatures in cold/stormy winters vs warm/non eventful winters I ran an analysis that subtracted the 10 most snowless winters from the 10 snowiest winters over the last 60 years. Here is the result..
What is most glaring in the image above is that in the winters that produced the most snowfall, you can see a distinct area of warmer than normal sea surface temperatures off the coast of California into gulf of Alaska. There is a reason for this as warmer water off the west coast tends to support a high pressure ridge that extends up into western Canada. The result is a downstream trough over the east coast. The image below shows this using the same difference in top 10 vs bottom 10 winters.



Notice the large dark blue area south of the Aleutian Islands and the orange area extending into Alaska and western Canada. This represents a tough and a ridge in the jet stream. The downstream effects of this are a deep trough over the eastern 1/3 of the country. As a reminder troughs cause colder and stormier conditions as they represent low pressure. 

Although this is not the only factor when it comes to predicting a winter, you can see it is something that we need to keep a close eye on. Right now, here is what models are predicting for ocean temps for the winter of 2016..



For snow lovers out there you can see AT THIS TIME models are hinting that the warm water stays off the west coast. However, also notice the very warm water off the coast of South America in the tropical pacific. As I have discussed, this is EL Nino (click tab at top of page for more info) and that will also be a MAJOR factor when trying to put together a forecast. We simply do not know how all these variables will change over next 4-5 months so that is why its premature to try to make a forecast at this time. All we can do is study trends and identify the major drivers behind cold/warm winter weather. I am a firm believer ocean temps are one of them.

Stay tuned for more sneak peaks at other relevant factors. The actual Winter Forecast 2016 comes out in October. 

Monday, August 10, 2015

Monday Weekly Weather Outlook: A Beautiful Week Ahead

Good morning everyone, hopefully everyone enjoyed the excellent weather this weekend. Its amazing how comfortable it can really feel when you take the humidity out of the air.  As we look forward to this week this trend if going to continue. That is except for one speed bump in the road on Tuesday. 

As is very common in the summer, most of our unsettled weather comes from the passage of fronts and here is a projection for tomorrow morning..

Expect rounds of heavy showers and some thunderstorms as we move though the morning. I expect the chance for a few storms as well as we get into the afternoon hours.

Once this front clears the humidity drops again and temps stay in the low to mid 80's all week with mostly sunny skies! You can see the upper level pattern below which is characterized by a trough over the east (dip in jet stream, blue areas) which helps usher in this nice feeling air mass..


Taking a first look at the weekend, it looks to stay dry overall with temps rising into the high 80's.  That's all for now, noting really too exciting to talk about. Then again when the weather is nice out it often times does not bring much excitement. 

We will save the excitement for the fall and winter seasons as things start to get more dynamic. As I have mentioned on twitter, I am starting to follow trends in climate signals for the fall and winter. I will not have a grasp on things until Oct but I will share a tidbit here and there on where I see things going.

Thanks for checking in. 

Thursday, August 6, 2015

Thursday Weekend Weather Update: Weekend Will be Spared!

Kudos to the GFS weather model! It had it right from the start this week regarding tomorrows storm system by keeping it south out of the area. Up until last night, other models kept hinting at the idea that a low pressure center would track more north and effect most of our area with rain on Friday. I tended to agree with some of those models based on anticipating the GFS would correct north and west. That did not occur and the other models gave in. This is an interesting case study for winter as I begin to evaluate model performance.

Anyhow, lets take a look at tomorrow heading into the weekend.  We currently have a stalled frontal boundary to our south..


Notice also the low pressure center over  Illinois. That low pressure center will track eastward along that stalled frontal boundary you see to the south of Delmarva. Originally I thought that front would drift more back north than it will.

Here is the result for tomorrows weather as that low approaches..

Notice tomorrow morning most of the rain stays to the south and only will effect parts of south NJ etc. By the time we get to the afternoon I think the sun will be out. The simulated satellite agrees..


That will then set us up for an excellent weekend with mostly sunny skies, low humidity and highs in the low to mid 80's!

Thanks for checking in. 

Tuesday, August 4, 2015

Tuesday Weekly Weather Update: Eyeing Wet Weather for Friday

Good morning everyone. Been pretty busy lately so lets get right to the point. A cold front will cross into the area this afternoon leaving the slight chance of a few thunderstorms..



The good news is in the wake of this front expect a break in the heat we are currently witnessing. Temps will hover in the low 80's through most of the week. This same front that will usher in cooler temps however will also cause an issue when it comes to the weekend weather.

The frontal boundary is going to stall to our south. This is never a good scenario because it means there is an increased chance for waves of low pressure to develop along that frontal boundary and cause rounds of rain as we get later into the week. How and where these waves of low pressure occur depends on the upper level pattern.

So lets jump into late week and take a look..



The image above is one models projection of a wave of low pressure developing along the stalled front on Friday. You can see the widespread area of rain which would cause the whole day to be a washout.

If I go to another model (GFS) however you will notice it keeps this rain to our south..



This all has to do with how amplified the upper level pattern is. The first image I showed was the NAM model and it has a sharper eastern trough due to a stronger western ridge. The gfs has a much weaker trough due to a weaker ridge. 

I do not have the images for the European model but they are closer to the NAM with the wetter scenario. You can see the position of the low below on the euro, I just do not have the printout of precip..



So what is the bottom line? At this time I am expecting a wet day for Friday. This could possibly bleed into to Saturday, but based on the data I am looking at I think we can salvage most of the weekend. The GFS model is likely in its error mode and too far south and east with the frontal boundary. This means the NAM and European most likely have the right idea with this system. 

Since this is a complicated situation I will definitely have an update tomorrow or Thursday.

Thanks for checking in.