Severe Weather Potential on Sunday August 21st!

The above is based off a blend of the SREF and the latest GFS.

CAPE across the area is 500-4000

Lift index is 0 to – 6 depending on where you live within the zone marked off above.

Mid Level Lapse rates will be marginal to good from 6.0 to 7.0 depending where you live.

Precipitable water is equal to 1.5 to 2 inches across the region which essentially means that any of these storms will be capable of producing heavy rains..

Shear looks like it will be 30-50 knots mainly across the NE region..

Trigger will be a cold front that by 8 AM (today)  will be located off to the west cutting michigan in half. This cold front will continue to move east across the region..approaching NW PA by 8 AM sunday morning. The timing of this front will limit severe weather across western portions of PA and should result in rain and garden variety storms..However a low pressure will develop along this front over the lakes and this should enhance showers and thunderstorms across the area and the greatest chance will be on the eastern side of the NE which will be in the warm sector. The cold front should cross the area shortly after 8 PM and clear the coast by Monday 8 AM.

The greatest threat appears to be large hail and damaging winds in excess of 60 MPJ with the potential for isolated tornado’s if any supercells should form with sufficient shear in place.

Stay tuned for further information should it become necessary!

97 L Seems To Be Honing In On Florida!

The images above are the latest images of 97 L. Guidance is pretty much in agreement tonight on this taking aim on Florida. The only guidance that stands out from taking Aim at Florida is the GGEM which has this making landfall in Louisiana .

Lets look at the GFS/ECM at 168 hrs.

GFS has a powerful system into Florida by 168 hrs.

ECM also has 97 L taking aim on Florida. One can plainly see there is a difference in strength between the two models with the GFS painting what would be a much stronger system then the ECM.

It is IMPORTANT to keep in mind that global models while good for track and synoptic scale pattern..are not to be used for pressure of a tropical system.

So lets look at the surroundings around this system currently.

First thing we are going to look at is the dry air that is still being ingested by this system. This is one reason why development of this will be a little slower.

Second, as of 3 Z we are dealing with about 10-20 knots of wind shear. There is an upper level anti cyclone near by but this shear is still effecting 97 L.

The vorticity is still stretched out and elongated..

However, convergence and divergence at the present time is decent across the system.

We do NOT think that these conditions are going to prevent this from developing. However..we do think that this will cause development to be slower.

Current thinking really has not changed from what we stated earlier in the afternoon on our facebook R.W.S page and that is we think that this may take until Monday to become a tropical cyclone.

Keep in mind that a tropical cyclone going across cuba and or Hispanola can weaken the system or even destroy it. However..guidance does not suggest this happening. Rather the thinking is that it will remain pretty weak until it crosses these locations. The weaker the system is going across the islands the less effect it would have as long as the COC remains intact.

We are not changing any thought behind this map that once again was created on the 18th of August.

Could we have the first hurricane of the 2011 Atlantic Season?

The image above is 97 L. On the latest water vapor this does not look all that impressive at this point and time.

Latest visible implies that we are dealing with a rather broad system at the present time.

We are going to start off right from the back with this system by saying that it will be several days before this gets its act together. Possibly not until it gets thru and across the Island of Hispanola.

Before then it does not have a friendly environment despite having an upper level anti cyclone over top which is keeping shear at 5-10 knots..

Now these are based off of 18 Z data but as you can see the system has a rather broad vorticity field. Lacking convergence and divergence. And to add on top of that is the following:

You can see how much dry air is around this system and getting ingested into the system at this point and time. In fact it is almost impossible to even see the location of the invest due to the dry air.

So the environment is going to keep the system rather weak which will keep the system on a westerly track.

Now as to the guidance and what will ultimately occur with this system. All the global guidance from the GFS to the ECM to the CMC are all indicating that this storm will become a tropical cyclone and potentially the first hurricane of the Atlantic season.

Last nights ECM took the tropical cyclone into FL which is pretty much what the GFS does with the system today at 12 Z. Today, however, the ECM keeps the system further south and then it makes its way into the GOM.

We are dealing with something that is anywhere between 7-10 days out so the guidance will continue to go back and forth between solutions. The question of where this goes or the ultimate track will likely depend on the strength of the Bermuda High. A stronger bermuda high and the more west this will go and end up in the GOM . The weaker the high then a weakness would allow the system to effect FL to the carolina coast..

At the present time we have not changed our thinking from what we issued yesterday in regards to this system..

There is plenty of time to watch the development of this system. However, this system appears that if it indeed does develop could be the first potential threat to the USA..

Stay tuned for more information

The Next Invest Behind 93 L

We will have more on this later today but wanted to get this out there!

Invest 93 L Update August 18th 2011

The above is the latest look at invest 93 L which the NHC now has at  a 70% chance of developing. Folks if you go back to the 15th  we mentioned that we thought this would develop in the time frame of 48-72 hrs and that would bring us to around 11:30 AM today!. We still feel that this will be a tropical cyclone with in that original time frame given.

For starters the system has a upper level anti cyclone over top of it which is keeping light shear at 5-10 knots.

Second the convergence with this system and divergence is decent and the dry air around the system is minimal.

A couple things that are not so favorable is that the system needs to slow down and start gaining a bit of latitude in order to avoid land.

In addition to this the vorticity is a bit tilted..however..we still feel that this will become a tropical cyclone by later today!

As far as movement steering currents really suggest that this should continue to push off towards the west. This system definitely will not effect the USA…

However…there is a system that has potential to effect the USA…however that will be for an update later today!

Severe Weather Potential for the 17th of Aug 2011

Low pressure moving across south central Canada has a cold front that relays to the south to another area of low pressure which will be over Eastern KS by 2 AM . Another cold front goes back west and then NW from there and a stationary front is also extended south and then east to a low pressure over Fl at this time.

These cold fronts will slowly make there way towards the east and bring the chance for severe weather into the region shown above!

The greatest threats with this potential appear to be large hail and damaging winds!

Tropical Update for August 16th 2011

The above is the most recent images of Invest 93 L .  Latest guidance such as the ECM which was somewhat bullish on development has backed off somewhat with development of this system. However, we here at R.W.S still feel that this should become the next tropical cyclone..however it should NOT be a threat to any part of the US .

Lets look at the conditions around the invest..

The above is the wind shear, convergence and divergence. As you can see this has a fairly friendly environment to work with –light shear at 5-10 knots and decent convergence and divergence across the system.

Vorticity has increased and the circulation is evident at this loop (click here)

We still feel that this will take about another 48 hrs to become the next tropical cyclone. We keep the chance at 40%.. Once this hits the western Caribbean that is where we feel that it should develop. 

Stay tuned for further updates. The next update will be 24 hrs from now!