The above image is our outlook and is based off the latest SREF...along with the latest NAM from 00z model run.
What we see happening is several things and this is at 8 AM in the morning. We see a cold front with an area of low pressure over the dakotas with a associated trough ..this will be dropping southwards.. We also see a another series of lows over Kansas with a warm front attached to it that drapes southwards and then southeast wards . It will be these two frontal systems that will bring a chance of severe weather to the zones highlighted in the first image.
Lets look at the temperatures first off to begin..
Temperatures will mainly be in the 80s and 90s and the dew points in these same general areas will be in the 60s and the 70s
So across these areas we will be provided with a warm to hot muggy like day and if you are outdoors please drink plenty of fluids.
Convective Available Potential energy that will be available for storms to tap into ..Remember this works as fuel to a fire along with other parameters that are in place..
The CAPE ranges from 1000 to as much as 4000 + depending on where you reside in the highlighted severe zone.
There will be plenty of lift in the atmosphere as well ..
With the lift index as low as -10 to -12 ...other areas not quite as negative but once again it depends on where you reside..
Wind shear , which is detrimental to Tropical Cyclones is a needed ingredient for severe weather and you can see that we have marginal to decent wind shear in place across the region of 30 to 50 knots...
This is the SWEAT index and it is highest across Iowa, Nebraska and parts of Kansas...
And in combination with the SWEAT Index is the Energy Helicity Index and for those that are not aware it is these parameters that you look at for tornado chances..
EHI is highest across Eastern Kansas into SW Missouri. Due to the SWEAT index being so high across Iowa , Nebraska and parts of Kansas and the EHI also high in Kansas it is these areas that we would say have a chance of a Tornado or Two. If you are outside these areas but in the severe zone then your greatest threats is winds and hail . Of course with any storm you will have the threat of heavy rain as well..
A stationary front draped across the central part of the USA and a series or waves of low pressure will be riding across this front and this front should serve as the potential for severe weather ..
The above is based off the SREF severe probability outline and the parameters are based off of the 00z NAM ...
Temperatures across the area are going to be warm to hot ..
With temperatures in the 80s and 90s across majority of the severe zone..
Dew points will be anywhere from the 50s to the 60s.. across the region ..
Shear will be sufficient for severe weather with the shear from 40 to as much as 60 knots depending on where you are located...
Convective Available Potential energy will be anywhere from 1000 to 4000 depending on where you are located..
Lift in the atmosphere will be in place from anywhere from 0 to -8 or so depending on where you are located..
SWEAT index is highest across Nebraska and Kansas where it reaches as high as 500. This indicates that Tornado's could be possible across the region.
Finally EHI is highest across Nebraska which is in line with the highest SWEAT area so we think that Nebraska and Kansas have the potential to see a tornado or two across that region...
If you are outside of those regions the main threats will be Winds and Hail ...
Across the Northeast there will be showers and thunderstorms but they will be of the Non Severe Variety and the weather will continue with low humidity and average to below average temperatures..
I Think despite what NHC just said in there most recent discussion...I think the question now that needs to be answered and observed is whether or not DORIAN can survive the dry air that is to the immediate west of the system...
This has been the difference maker between the GFS and the ECM models and why one has the system virtually weakening from this point forward and the other maintains the system...
Tropical Storm Dorian the storm that was said it could not or would not develop if you read around the internet the past few days. Of course we had said on our Facebook page that this would be the next Tropical Depression which it became and then upgraded to a tropical storm.
As you can see tropical storm Dorian looks pretty good in this early part of the overnight... Considering that Dorian is not really over any TCHP and also cooler waters are being straddled.. we think she looks fairly good and should more then likely be increased in intensity with the next update...
TCHP
TCHP increases as it would head towards the Lesser Antilles ...and the sea surface temps...
Again it is straddling the cooler waters but then there is warmer waters ahead of it .. we think that the speed that the system is traveling at the present time will be fast enough that it will have little effect on Dorian. Dorian as of 11 PM was moving 20 MPH to the WNW and this is to the south of a mid level ridge.. And the steering currents would keep this west to northwest to west track in place..
You can also see looking at the vorticities in the 850 mb level, 700 mb level and 500 mb level that they are stacked and vertically aligned...
A little stretched out to the southwest at 850 mbs ..
So this is just another reason why Dorian is looking pretty good tonight. The question really becomes what is ahead.. Well lets take a look at some more images before we get to the guidance...
While Dorian is just out of the picture here you can see that the wind shear presently is light at about 5-10 mph. This is conducive for further strengthening.. You can see that the shear has been dropping around the system by looking at the shear tendency map which tells you whether shear is increasing or decreasing..
So wind shear right now is favorable.
You can also see that the system is moving into decent convergence and the same can be said about divergence as well..
So this is just another factor that would favor some intensification of the system.
Track wise ... fairly well clustered at the 00z time frame..
Majority of the guidance has this moving west northwest to west and missing the shredder islands.. this is a good thing for those who would like to see if Dorian can make it to the East Coast...
Intensity however is divided as some weaken the system and some strengthen the system..
The GFS says that the Southeast should keep an eye out on this system...
The above is 192 hours and its interesting to note that the GFS must have really weak steering currents because the run just meanders Dorian towards the Southeast coast because this is 240 hours out below..
We think right now its not really all that important as to "where this may end up" because the question is whether or not the intensity of the system holds in check with the questionable TCHP and the cooler waters.
We think for the near term and time being that conditions are pretty much ideal otherwise for this system to at least maintain if not gain some in intensity and if the guidance continues to suggest the Bahamas and then the Southeast region and the system continues to maintain or increase ...at that time we would suggest that we would have to keep an eye out for the Southeast coast or somewhere on the east coast.
We would like to see some other of the global guidance come around to what the GFS is showing. Though we are not sure we buy the meandering of the system beyond 192 hours but remember this is where the GFS loses resolution even further.
A cold front is dropping thru the central part of the country and this cold front could bring severe weather along its boundary. At the very least there will be heavy rain associated with this cold front.
Presently some very heavy rain is falling across the PA area with some non severe thunderstorms as well. However..tomorrow we think there will be a wind potential along with the possibility of a tornado or two and we will highlight where we think that could happen..
Lets start with the temperatures which will be in the 70s to 90s depending on where you are located ...but as has been the case the dew points will be on the sticky side
With the dps being in the 60s and 70s so that will make it feel more hot then what the actual air temperature is.
When we look at the Convective Available Potential Energy we see some pretty high numbers with the CAPE going all the way to 5000-6000 in a small isolated area..but never the less quite high elsewhere as well.
Lift index is also going to be quite negative showing plenty of lift in the atmosphere with numbers of -8 to negative 12 over a large area..
Wind shear will be in place from about 30 knots to as much as 60 knots across the region..
With the SWEAT index as high as what it is showing into Kanas & Missouri and parts of ARK (Northern) this is the region where there could be a tornado or two to occur ...
Also the EHI is highest over Kansas..
So with the severe weather parameters in place .. we are highlighting the following region...
Again the main threats are going to be damaging winds but some tornado's are possible in the areas mentioned above...
The cold front that we mentioned yesterday is continuing to move its way towards the south and east and this is the position it is expected to be in by 8 AM early morning friday. This is also the cold front that we anticipate will serve as a trigger for severe storms as it moves to the south and east. Yesterday the CAP ended up being a little stronger then anticipated while there was severe there was nothing in the way of Major severe or no tornados had occurred despite the parameters that were in place.
Today will continue to be a hot and humid day and it should be the day where the heat "peaks". Temperatures once again will be in the 80s and the 90s....with the dewpoints in the 60s and 70s..
Where the temperatures are in the 90s with the dewpoints in the 70s the heat indexes will be between 100-105 degrees.
Convective Available Potential energy is anywhere from 1000 to as high as 4000 .
Lift in the atmosphere is as low as negative 8...
NAM shows the greatest SWEAT being across the Northeast part of the country along with MI and Wisconsin..
EHI is highest over Maine... and the greatest shear still lies across the northern tier into MAINE as well..
We think that today will be mainly a wind threat however with high SWEAT showing up over parts of the NE and high EHI showing up over parts of Maine we would not rule out an isolated tornado in those locations. Also a chance of a tornado or two in Lower MI...
Despite the chance of severe weather we think that the biggest story to draw the attention will be the continuation of the heat and humidity. Once again we urge all our readers in this hot and humid air mass to drink plenty of liquids and wear light , loose colored clothing....Stay safe and stay indoors in the AC if at all possible!
