August 1st Severe Weather Potential

Low pressure is located over the SE coast with a stationary front attached to it. This front is expected to stay across the SE area and this front should serve as a mechanism for showers and garden variety type storms with isolated severe possible.

Elsewheres: A cold front will be dropping across the Great Lakes region tomorrow and should be crossing into and towards the coast by evening time. This front will serve as the mechanism for severe potential in the form of damaging winds and large hail across the mid atlantic/Northeast and the midwest and plains states where the cold front turns into a warm front and will be lifting across that region.

In the midwest & plains a tornado or two could be possible ..however the main threat there will be winds.

Invest 91 L Now @ 80% But Have Things Changed Any?

The title reflects the discussion. National hurricane center has this now at a 80% chance of developing within the next 48 hrs.  So have conditions actually improved with this system?

AS of last update..shear was not an issue and shear continues to be not an issue with this particular system trying to develop.

If you remember last night the greatest area of convergence was off to the NW of the system and that continues to be the case at this point and time. The system is in decent divergence which was also the case when we updated last about this system.

Latest vorticity shows it continues to have the same problem as it did at last update which was a very elongated or broad system. Now last night the center of circulation was closer to the best area of vorticity but as you can see that area is now further to the west of the COC.

Perhaps the greatest problem that has to be overcome by this system is the dry air which you can see is encroaching on all sides of this system. A tropical wave trying to develop does not want to ingest dry air into it because it simply will not develop.

So as you can see ..nothing has really changed with this system. We still do not have a vertically stacked low pressure area, we still have low shear, outside the best area of convergence, decent divergence and still an astronomical amount of dry air in place.

Steering also shows the ridge in place that is still guiding this system and it should continue to mainly head off to the west north west towards the islands.

Guidance is still split as well with the 12 Z GFS showing a recurve and the ECM showing a weaker system.

We will continue to keep the chances for development at 50% for this system . If 91 L is able to overcome the obstacles in its path we still do think it can obtain Tropical Depression status. However..beyond that with the guidance split we will continue to monitor the system for any further development!

Invest 91 L ..70 % development chances..some things to overcome!

This is the latest look at Invest 91 L . The next tropical system that we have to keep a watch on.

91 L definitely has some “spunk” to it but as you know we like to look at the environment that surrounds the system that we are watching..

First problem that lies ahead is the dry air that is to the north and to the south and to the east and to the west of this system.

Second problem which is only a temporary problem we believe is that the best convergence lies to the NW of the system. Divergence is good ..

Another problem is that right now the vorticity is very broad in nature or elongated. Whenever you have something that is this broad in nature it always takes more time for it to tighten up and this is the case as this system is not vertically stacked..

Shear is not an issue what so ever with this system at the current time..

So as you can see there is some issues that have to be overcome before this can develop. If it can overcome these issues mentioned above then it should be able to develop but once it develops the next question is where does it go?

Well guidance has been pretty much split. There really is no sense in looking at the hurricane models because until there is a center of circulation for them to pinpoint and feed off its going to go back and forth between no development/development.

So we look to the GFS and at 12 Z it shows a strong system that recurves and so does the 00z ..Here it is below:

So if the GFS is correct we have a hurricane on our hands that will do nothing more to the USA then rough surf possible along the coast.

However..the ECM says not so quick. At 12 Z it was not impressed at all with the system…and 00z we see this:

And 144 it looks like this:

Still continues to be unimpressed with the system over all. The problems already start at 120 hrs out in the guidance…here is the GFS at 120

So you can see the difference…right from 120 hours out! ECM is generally the better performing model in the 3-5 day range..

One thing for certain is that because of the high pressure in the Atlantic this invest should continue to head off on a west track and the antille islands would be the first that will have to deal with whatever becomes of Invest 91 L.

National hurricane center has this developing in the next 48 hrs to a tropical depression at 70%. We feel that 50% would be more accurate at this point and time.

If this keeps heading on a westerly track it will take it across the islands and this would more or less favor a weaker system AKA ECM..this is what we are going with right now as our thinking.. Depression status will probably occur within the next 36-60 hrs …

Stay tuned for more information over the coming days!

July 28th Severe Weather Outlook

Currently a warm front is pushing thru the western half of PA with a low pressure area back over eastern Iowa. This warm front is attached to a low pressure moving across southern Canada and is part of a complex frontal situation. A cold front also extends from the low pressure in Canada and this cold front trails back to another area of low pressure over Wyoming!

As the warm front lifts to the North the cold front will begin to drop southward and should be approaching western PA by about 2 PM in the afternoon. A couple different waves or impulses of low pressure will develop along this front .

By 8 PM this front will have cleared western PA and western NY.

This front will be the focus of severe weather potential. Across portions of SE NY and into portions of eastern PA and NE PA it could be possible that in addition to the winds and hail potential that even an isolated tornado could occur. This will be possible because of the low level shear that will be in place in that region and the timing of the low pressure area. So that is something to keep in the back of your mind as we go thru the day tomorrow!

Stay tuned for more information should it become needed!

Tropical Storm Don Thoughts

As the above satellite image shows DON we can see that DON had gone thru some issues as of late yesterday afternoon. We think this was contributed to being so close to land. In other words interaction with land contributed to what we seen yesterday afternoon and evening. Overnight DON started to take on a slightly better appearance. However, as you can see he is very small in size..Tropical cyclones this size usually do one of two things:

1. They can ramp up very quickly and become microcanes

2. They can just go poof.

Original thinking was that this had potential to become the first hurricane of the Atlantic Season. We think that this potential is still possible but expectations for this occurring have become lower then what they originally were.

If you go back to the first discussion we mentioned about the TCHP and how you generally want the TCHP to be at 80 or above. While there is no denying the warm water temperatures of the GOM..the TCHP is a different case..

If you can compare the TCHP image to the above satellite image you can see that DON for the moment is travelling to the south of the greatest TCHP. However, off to his NW is warmer TCHP. If DON can continue on a NW movement he would be travelling over the greater area of TCHP and this could allow DON to restrengthen.

Lets look at the rest of the surroundings to see if there is anything that could hinder further strengthening from occurring.

Shear is not an issue at this present time because it is only in 5-10 knots of shear. This is certainly not detrimental to development.

You can see some dry air off the Tx coast and the Mx coast and it is possible that DON could be ingesting some of this dry air which is holding back intensification..however..we have seen systems develop with more dry air then what is shown above.

Convergence and divergence is good across the COC of DON.

Here is another possible problem as you can see that the greatest area of vorticity is south of where the center is. There is no doubt that some weakening has occurred since the inception as the pressure went from 1001 MBS to 1005 mbs as of current update.

So as you can see there are some issues that potentially could be holding DON back from intensifying.

Movement should continue to maintain a NW or WNW track and this is due to the ridge that is in place and will persist at least for the next 48 hrs.

Anyone from the Southern TX coast to the TX/MX border needs to keep an eye on this system. Tropical cyclones are entities that seem to have a mind of their own and small compact ones are capable of rapidly intensifying or going “poof”..

Next update will be issued this evening on Tropical Storm Don!

Tropical Storm Don is Born on the 27th & Severe Potential the 28th

To start with we have tropical storm Don being born today! We had actually talked about this yesterday becoming the first hurricane of the Atlantic Season and you can not get there without going thru a Tropical Storm first! Proud to say we called this before the National Hurricane Center!

With that mentioned the above is based on the latest GFS/NAM/SREF blend!

Low pressure will be moving across southern Canada and attached to this is a complex frontal system. As this low moves to the east the warm front will lift up towards the North..

This frontal system will be the trigger for severe weather tomorrow across the outlook area.

The main threats across the zone area will be severe winds and hail.. As is the rule an isolated tornado can never be ruled out but that should be confined to the midwest/plains region!

Brief Update on 90 L

Two negatives this evening. First the dry air to the west has increased slightly. Second the shear has also increased slightly as of 21 Z update..

However, the system is now in the best area of convergence, divergence and vorticity!

We still feel that this system has a good chance at becoming the first hurricane of the season . We will continue to monitor this system thru the evening and daytime tomorrow!We are keeping the chances of this developing into a tropical cyclone at 60% .

July 27th Severe Weather Potential

The following is based off the latest SREF/NAM/GFS. A blend of the three models.

CAPE generally 500-5000

Lift Index is 0 to – 8 depending where you are

Lapse rates 6.5-8.0

Shear is more then ample with 40 + knots

Low pressure north of NY state with a cold front off the coast by this evening trailing to the south and then to the west and then north to another area of low pressure over  the Dakotas.

The low pressure over the Dakotas will lift NNE and this will push a warm front to the north/northeast as well. By about 2 AM this low pressure will be located over Minnesota with a cold front trailing to the south and another low pressure should develop over Kansas.

That secondary low pressure will move NE and should be located over IOWA by tomorrow evening. This low pressure will also be associated with a complex frontal set up.

It will be these low pressure areas and their associated fronts that will be the trigger for showers and thunderstorms of which some will be severe. The main threats will be winds over 60 MPH along with large hail but with the wind shear present we can not rule out tornado’s in the severe weather zone!

Current Thoughts On Invest 90 L

This is the latest in the tropical wave department and it is 90 L. 90 L was an invest that was deactivated and is getting its act together and doing so quite nicely.

We here at Real Wx Services feel that 90 L has the potential to become the first hurricane of the season and this potential hurricane could very well take a track towards southern Tx. We put the chances of 90 L developing into a tropical system at 60 % with in the next 48 hours!

Lets look at the surroundings:

As you can see via above shear is not an issue as it is splitting the shear with the highest north and south with only 5-10 knots of shear and this is not in any way detrimental to the development of the system.

Dry air is also not going to be a hindrance to the development of 90 L. So the two things that are normally setbacks for developing tropical waves , are actually preventing a favorable setting for development!

AS of 15 Z the best area of convergence was off to the NW of the system but the divergence over the system is very favorable for development!

The only other negative that we can see is the best area of vorticity was off to the NW as well..

Now lets take a look at some other things such as direction and also water temps and tropical cyclone heat potential ..

The steering flow suggests that we should continue to move off to the west northwest over the time being which would take it thru some warm waters..

Now the last image is the TCHP image and you can see that where the invest is currently the heat potential for development is very favorable for development but as we get further into the GOM things become slightly less favorable with cooler heat potential. Generally when you look at the scale you want to see the area in 80 or above and that is why where it is now located is a very favorable setting.

As you can see this is what the GFS means are thinking trackwise for this system. The ECM however has a bit more south tracking around the Tx/Mexico border.

AS the most recent image above shows the convection is really starting to blossom around the center and this is no surprise given what we said above!

Residents in southern TX to Mexico need to pay attention to this system because ATM there is nothing holding this system back from developing into the first hurricane of the season on the atlantic side!

Stay tuned for more information and further updates!

July 25th Severe Weather Outlook

Low pressure off the delmarva with a stationary front dividing western PA from eastern PA. This stationary front is attached to a low pressure which is North of ohio over the Great Lakes. From this low is a cold front that stretches south and then west and then towards the NW to a low pressure over Montana (western) .

Stationary front should lift NE as a warm front as the low pressure off the delmarva lifts NE. The low north of ohio will also lift NE and cut thru NY state. This will drag a cold front across the area tomorrow evening and into the overnight hours. Garden variety and severe storms will be possible along with heavy rain in association with this front. Main threats will be winds and hail and heavy rains!

July 24th Severe Weather Discussion

Low pressure is over lake Ontario. From this low extends a cold front to the NE which is moving thru Maine. Extending southwest from this low is a cold front to another area of low pressure over Western Minnesota.Another low pressure should form over SE PA.

The low pressure over SE PA should move Northeast ..While the low pressure over Western Minnesota moves off towards the east. This will cause the cold front to start to sag and drop towards the south and should be dissecting PA in half by about 00z. However..it looks to stall in that location.

This front will be the focus for the potential of showers and thunderstorms during the day tomorrow of which some could become severe. Winds and hail being the primary threats across the zone above.

Monday a more potent cold front will come thru and should be the better potential for severe storms across the region as before that point and time we are depending more on weak impulses to break down the strong heat ridge.

Monday another cold front will come thru and will give us a very brief break from the heat but then that cold front will also stall to the south and after tuesday will begin to lift back towards the north as a warm front and temperatures will once again be back into the 90s.

At this point and time it does not look like we will be dealing with temperatures like the past few days where they were at 100 or greater. Never the less it is going to be hot after a brief cool down!

Stay tuned for more information!

July 22nd Severe Weather Outlook

Hot weather continues across majority of the USA with a cold front currently across Northern Ohio into the NE with a low pressure north of NY state in Canada..cold front then stretches from that low to the ENE to another low over SE Canada. This cold front stretches back west to a low pressure area over E Kansas.

This cold front over the next 24 hrs is going to be dropping Southeast and should be by 00z sliding southwards across the central PA area.

This cold front coupled with strong day time heating…CAPE of 500-5000, Lift index as low as –10 , lapse rates 6.0-7.0, high dewpoints could create the potential for thunderstorms and severe thunderstorms with the main threats being large hail and damaging winds.

Stay tuned for more information should it become needed

July 18th Severe Weather Potential

The above map is based off the latest GFS/NAM/SREF. The area in red lines is the area that we think has the potential for a moderate risk for straight line winds and large hail. This does not necessarily mean that SPC will issue one but we feel the potential does exist.

Warm southerly or southwesterly flow will be moving into the region. The weather is going to take a turn for being hot and sticky across the region.

With this heat ..we also have the potential for garden variety thunderstorms as well as severe thunderstorms almost on a daily basis starting with tomorrow.

Low pressure will be in southern Canada above Lake superior by 00z this evening. From this low pressure is a cold front that is stretching south and west to another low pressure over the western part of the Dakotas.

By 00z tomorrow evening low pressure should be over Northern Michigan and the cold front is going to start pushing towards the south and be across Northern NY at that time. A lee trough should also develop.

CAPE will be 500-5000 depending on where you live

Lift index will generally be in the –4 to –8 range.

Mid level lapse rates will be decent at 6.0-6.5

The main threats from these storms will be straight line winds over 60 MPH and large hail. The showers and thunderstorms will break out in advance and ahead of the cold front.

Stay tuned for further information should it become necessary

July 17th Severe Weather Outlook

Stationary front continues to reside across the south with a low pressure area off the southeast coast. This front will continue to keep showers and thunderstorms across the southeast with the possibility of some of them in the Louisiana becoming severe.

Meanwhile across the northern areas there are multiple pieces of energy over the montana region with a cold front extending into canada with a low pressure area moving across Canada. It will be this front and these pieces of energy moving across the Northern Periphery of the heat ridge that is across the central part of the country that will be responsible for severe weather across the northern plain states.

A lee trough should start to develop on Monday then and the cold front to the north will start to drop towards the south and this cold front could be responsible for some severe weather potential on monday across the Northeast region but it could start to bring showers and thunderstorms into ohio and west PA already after 8 PM tomorrow evening…

Once again the main threat with any storms will be winds and hail but in the evening time the lower level jet is predicted to strengthen and this could bring the chance of some tornados into the northern plains region and Great lakes region.

July 16th Severe Weather Outlook

Stationary front continues to be draped across the southeast with a low pressure over the florida panhandle. Low pressure over SE Colorado connected to a warm front which is associated or connected to the stationary front.

Multiple pieces of energy over the Dakotas & Montana with a cold front.

It will be these features that will continue to bring the chance of severe weather to the regions highlighted above with a very warm humid air mass in place thanks to an upper level ridge across the region.

CAPE values will be as high as 4000

Shear between 40-50 knots which is more then ample for severe thunderstorms.

Lift index will be 0 to –10 across the area..

Mid level lapse rates go from 5.5 to 8 depending where you are in the zone above.

All and all we think that the storms should begin to develop towards evening and this would be more of an evening threat for the potential of large hail and strong damaging winds.

July 15th Severe Weather Outlook

Stationary front has moved further south across the deep south. Low pressure is off the coast of the carolinas attached to this stationary front.

This is the low pressure that some weather outlets were talking about tropical development but as long as it would be associated and attached to a frontal system it can not be considered tropical.

Anyways that stationary front goes back west to another area of low pressure over Mississippi/Alabama border…to a low pressure over SE Colorado.

Another frontal system with an area of low pressure over SE Montana.

The low over Montana is going to slowly move east pushing a warm front to the north and east.

A cold front from a low pressure system over Canada will catch up with this area of low pressure and warm front.

So by 00z we have a warm front with a area of low pressure over the Dakotas with the warm front stretching towards upper Michigan. The cold front on top of this area of low pressure and then stretching back west to the PNW with multiple pieces of energy.

This will be the focal point for storms in that region.

And it will be the stationary front across the south that continues to provide showers and thunderstorms with the potential for some to be severe.

The main threats of severe will once again be large hail and winds though isolated tornado’s can not be ruled out across parts of the region. Mainly the NE side of the low pressure system .

July 14th Severe Weather Outlook

Currently there is a low pressure system along the carolina coast line and a stationary front draped west to east to a low pressure system over Northern Alabama and then that stationary front runs NW into a low pressure over Montana and another one over Canada.

Multiple pieces of energy are also over the rockies and these impulses will start lifting NE and the stationary front out west will start to move North as a warm front while over the southeast it remains stationary.

This front in the southeast will be responsible for the potential for severe weather and heavy rains .

A very moist southwest flow is in place thanks to a upper level ridge across the central united states.

Severe Parameters :

Shear of 35-50 knots across the region

CAPE from 500-5000 depending on where you live

Lift index is 0 to –8 depending on where you live

Hail and damaging winds appear to be the primary threats for tomorrow however a tornado can not be ruled out!

July 12th Severe Weather Outlook

Weather Synopsis

Low pressure in SE Canada with a cold front trailing south and west approaching NE Ohio and trailing back west cutting indiana and illinois in half to a low pressure over the Kansas /Nebraska borderline.

This front will continue to move off to the south and the east and should be crossing the Eastern Pa region between 2 PM and 8 PM. However, with a CAP in place PA and most of the NE is not expecting to see anything in the way of severe weather. In Maine ..close proximity to the low pressure in Southeastern Canada as it moves to the east should bring showers and thunderstorms with some of them being severe.

There will be multiple pieces of energy moving along this front and one piece of energy which we talk about above over the KS/Nebraska border will move east to a position near Eastern Missouri by evening time.

It will be this front and multiple shortwave energies and associated troughs that will trigger the severe weather potential today!

As was the case with yesterday it looks like hail and winds in excess of 60 MPH will be the main weather threats.

As a side note it is very hot across majority of the region so please make sure you intake plenty of fluids!

July 11th Severe Weather Potential

The above image is based off the latest SREF /GFS combination. We have included portions of the Northeast in this outlook due to a Upper level trough should be moving across the lakes into the Northeast.

Essentially most of the conus from the central part of the US into the east is under the influence of ridging. This is providing a very moist atmosphere along with some very warm to hot temperatures.

At the surface there is a stationary front across the southeast with an area of low pressure off the southeast coast over the atlantic. By this evening there is expected to be multiple pieces of energy which are expected to move off to the Northeast.

By tomorrow evening there should be a cold front stretching SW from a low pressure in southern canada. As this low moves east it will drag and drop the cold front south . It is the combination of this trough moving south and east over the lakes and the cold front dropping south and east that will bring the potential for showers and thunderstorms some of which could be severe into the Northeast.

Further west it will be the multiple shortwave troughs moving from the southwest towards the Northeast into a very warm and moist air mass.

The main threats will be winds and hail with any of these storms ..however..an isolated tornado can not be ruled out. As the evening progresses the lower level jet is anticipated to strengthen so this could keep severe weather going into the overnight hours in areas off to the west particularly in the mid Missouri Valley region.

Stay tuned for more information.