With Hurricane Season fast approaching us ..we have decided to do a little research into this hurricane season and come out with a outlook for named storms, hurricanes and Major Hurricanes.
One of the first things we look at is the ENSO Status and we see that currently we are in a neutral ENSO status and this looks to be the case with majority of the guidance though there are a few models that take us into an El Nino and a few that take us into a La Nina but the over all clustering of models keeps us in Neutral conditions.
So we take a look back thru the years going back to 1950 to see what those Neutral Seasons looked like to get a rough picture of how many systems form during Neutral years and the # is rather quite low ..between 7 and roughly 11 .. Lets look at the years
1952 Neutral Year result 7 storms
1959 Neutral Year 11 storms
1960 Neutral Year 7 storms
Perhaps an important thing to note in here is that each of the years so far had storms that impacted the east coast.
1961 Neutral Year 11 storms
1962 Neutral Year 5 storms
1966 Neutral Year 11 storms
1967 Neutral Year 8 storms
1978 Neutral year 11 storms
1979 Neutral Year 8 storms
1980 Neutral Year 11 storms
1981 Neutral Year 11 storms
1990 Neutral Year 14 storms
1993 Neutral Year 8 storms
Last but not least is the year 2012 which was also a neutral year and that had an astonishing 19 named systems..
Looking back thru history to 1950 at Neutral years you can see that the main two regions that were under the gun were the GOM region and storms up the eastern seaboard. The other interesting thing we note is that all the neutral years were relatively low on the storm numbers until we got to the year 2012 when we seen a substantial jump.
We think this can be largely contributed to the fact that since 1995 we have been in a positive phase of the AMO.
In the positive phase of the AMO the water temperatures tend to run higher and this adds fuel to the fire when it comes to tropical cyclone formation. You can see the sea surface temperatures here as of the 25th and how along the coast they are running warmer then normal..
Interestingly enough we also find that the Caribbean has already obtained substantial Tropical Cyclone heat potential.
So the things that we see standing out that is since 1995 cyclones have been on the rise as far as quantity but not necessarily quality. We also see that the GOM and the east coast were in play quite frequently so we are thinking that at least another storm along the east coast will occur this Tropical season. We also see things were relatively below average to average up until 2012 but since 95 they have been increasing despite the ENSO and that we feel is AMO related.
So with the AMO in a positive phase..the Atlantic waters warmer then normal.. ENSO status being neutral we think that this year could be a rather active year with 13-16 Named Storms ..which 5-7 would be hurricanes and 3-4 would become Major Hurricanes. We also with looking back at past history think that the East Coast could come into play once again..and the GOM would be the other hot spot. Of course we will also be dealing with the disappointing recurves that effect nothing but the ocean.
All and all looks to be another active season on tap for the 2013 hurricane season..
Stay tuned as we will be covering each and every season and pinpointing where we think the storms will make landfall..
Those of you who follow this blog know that we been talking about the pattern and how we are in a historical time frame for the AO being so negative and usually a - AO has two effects on the weather. It makes the weather colder then normal and allows in tandem with a negative NAO to form what we call atmospheric blocking. When this happens there is confluence across the Northeast.. and this confluence can press south with dry air and as precipitation advances into it ..it has trouble reaching the ground...
As you can see via the current radar it is showing snow falling across a good chunk of PA..
Never the less when you look at observations for the midnight hour you see the following...
SOUTHERN NEW JERSEY
CITY SKY/WX TMP DP RH WIND PRES REMARKS
POMONA CLOUDY 37 27 67 E8 29.67F WCI 31
RIO GRANDE* CLOUDY 37 28 70 E9 29.70R WCI 31
MILLVILLE CLOUDY 37 26 64 CALM 29.71R
WRIGHTSTOWN CLOUDY 36 26 67 NE5 29.67F WCI 32
LAKEHURST CLOUDY 47 27 45 NE5 29.68F
MOUNT HOLLY CLOUDY 37 27 67 CALM 29.69F
TRENTON CLOUDY 37 25 61 SE5 29.69F WCI 33
$$
NJZ001>014-250500-
NORTHERN NEW JERSEY
CITY SKY/WX TMP DP RH WIND PRES REMARKS
SUSSEX CLOUDY 37 22 54 NE7 29.71F WCI 32
MORRISTOWN CLOUDY 41 25 52 CALM 29.71F
NEWARK CLOUDY 41 24 51 CALM 29.72F
TETERBORO CLOUDY 40 27 59 CALM 29.71F
CALDWELL CLOUDY 39 25 57 CALM 29.71F
SOMERVILLE CLOUDY 39 25 57 CALM 29.69F
ALLAIRE* CLOUDY 37 27 65 E5 29.71F WCI 34
$$
PAZ043-044-047-054-055-060>062-066>071-250500-
EASTERN PENNSYLVANIA
CITY SKY/WX TMP DP RH WIND PRES REMARKS
PHILADELPHIA CLOUDY 39 24 55 E6 29.71F WCI 35
NORTH PHILA CLOUDY 37 25 61 E5 29.71F WCI 33
BLUE BELL CLOUDY 37 27 65 E3 29.67F
DOYLESTOWN CLOUDY 36 24 62 CALM 29.68F
POTTSTOWN CLOUDY 38 25 59 CALM 29.70F
LANCASTER CLOUDY 37 25 61 SE3 29.68R
COATESVILLE CLOUDY 36 28 75 CALM 29.70R
READING CLOUDY 40 25 55 SE9 29.67S WCI 34
ALLENTOWN CLOUDY 40 24 53 SE7 29.68F
MOUNT POCONO CLOUDY 32 20 61 E12 29.63F WCI 23
WILKES BARRE CLOUDY 36 21 54 VRB5 29.67F WCI 32
Cloudy skies being reported in locations where you see precipitation on the radar.
Presently we have a primary area of low pressure and the secondary developing as the guidance suggested would... We can see this looking at the pressure falls..
Guidance over the past 24 hours has really cut back on QPF with this storm system.
The GFS at 24 hours above. The NAM which at one point was showing a foot of snow now looks like this..
The RGEM looks like this...
Guidance is in agreement that the heaviest QPF is going to be along the coast of New Jersey.
So what we have done is we have taken a blend of the guidance and used a few factors in addition to this.
Factor #1 Majority of the precipitation is going to be falling during the daylight hours today.. This in combination with lighter intensity (exception along the coast) and the area closer to the primary ...the snowfall will have a hard time accumulating on anything other then the grassy areas. Again ..new Jersey and the area out west are exceptions.
Factor #2 The confluence with the dry air.. This means we are going to lose precipitation to the dry air. It will look like its snowing on radar but when you look out your window you might not see anything ...*again new jersey and the area to the west are the exception cause of heavier intensity..
Factor #3 This storm system is going to be sliding further south and east then what the models were showing previously and with the confluence pressing south moisture will have a difficult time making it North....
So into places like NYC we are only expecting a Trace to an inch or so.
The End Result...
If you are across south central PA into SW PA this will be a decent event but it is a far cry from what the models were suggesting a few days ago and a far cry from the HYPE of some weather outlets that thought just because we had a - AO it would result in a huge storm.
For late March and into spring though this will end up respectable in areas to the east (New Jersey) and areas west..
We are not seeing the severe weather threat as far north as what the SPC was going with in there day 2 outlook. SREF does not agree with that far north and neither does the NAM which we are going to show here..
First of all lets look at the CAPE..
You can see that the greatest CAPE is down along the Gulf of Mexico.
This coincides with the area of greatest Lift as well..As to the north there is virtually no lift in the atmosphere..
The greatest EHI is also down along the Gulf coast with Lousiana being the prime region for EHI at 1 or above along with over into Florida.
Helicity is also a non factor in areas further to the north.
The only severe parameter that is a factor for severe weather in regions further to the north is the shear. However, with all the other parameters being low with little if any CAPE ..there is no fuel to feed the storms.. so further north we think that it will be mainly rains and garden variety type storms so did not include them in the outlook.
Further south into LA we think it is possible that this area could experience some supercells along with tornado potential with the EHI above 1.
It will also be across the southeast where the trigger will be which is a stationary front and this is where the convection should focus along.
Also the temperatures further north will be cooler with only 40s and 50s while along the gulf coast temperatures will be in the 60s and 70 to 80 degree range.
Warm front has already lifted thru the region of TN but will continue to lift north. Low pressure along this front will continue to lift east northeast thru the region. The main action thru out the day yesterday and this early morning has been north of this warm front as the radar will currently show..
However.. there are showers and garden variety storms developing closer to the low pressure area to the west of KY pressing off to the ENE ..
Looking at severe parameters we are not very impressed with the severe weather chances as the only parameter that is really favorable for severe would be the lower level shear..
So shear of 30-40 knots across the region would be favorable for severe weather. The problem at least as far as TN/KY is concerned is that the CAPE is just not all that impressive with about 500 CAPE available. Remember CAPE is like fuel that feeds the atmosphere to help create severe weather..
The greatest CAPE is well to the south of those areas along the gulf coast. This also lines up with the area of greatest lift in the atmosphere..
Which also lines up with the greatest EHI
So as you can see the greatest severe weather parameters from CAPE to LI index to EHI is over the Gulf coast region. Over all as we said we are not to impressed with the severe weather chances but we think that any severe greatest threat would be south of KY and TN with KY and TN experiencing more in the way of heavy rainfall and garden variety thunderstorms. The timing essentially is another factor against severe weather as some showers etc are moving towards the region now. Due to the shear there could be some severe in TN/KY but with the other mitigating factors we see that being only strong gusty winds..along with some possible hail.
If any tornados were to occur we think the greatest chance would be further south of there where the EHI is more supportive of them even though Helicity is not that favorable.
So with all that said above this is the outlook for today!.
Low pressure in the south central region in tandem with a low pressure in the midwest are going to essentially join forces and bring a potpourri of weather to the region. A secondary will also develop along the jersey coast.
Initally the lower level cold air will be in place as the precipitation moves in from the southwest. Temperatures will rise aloft and this will allow the precipitation initially to start as snow but change to a sleet/freezing rain scenario before changing to rain (in all but the highest elevations in PA) ..the heaviest snows will be from NY state Northwards ..but even NY state can see a change over to freezing rain .. Outside of NW NJ precipitation should be mainly rain in New Jersey..
And NY State..
This same system will be responsible for some severe weather and this will come out shortly..
Lets take a look at where we have been so far for the month of March
For the most part the month of March has been seasonal to above normal in the Northeast with the exception of SW PA and SE NJ and then the southeast.
Now this is important as we try and figure out where we are headed for the future weather wise. If you look at the above chart you will see that the AO has been negative and still is negative but as the temperature departure map shows we have still been seasonal to above seasonal values. Normally when you have a - AO this allows a discharge of colder air into the USA but as we have pointed out in times past you can not figure out WHERE this discharge of cold air will end up just by looking at the AO. You have to look at other teleconnections..
The NAO was negative but recently has risen to the neutral value but it is shown to go back negative before once again rising towards neutral or positive. So you can see why the temperatures in the southeast were below normal due to the NAO being negative it allowed the discharge of colder air into the southeast.
Factor in the PNA and you can see that it was quite positive ..so the - AO - NAO and positive PNA allowed the colder air to discharge into the southeast part of the USA.
However, and this is important you notice that the PNA has since gone negative.. so when the PNA declined ..and the NAO rose to neutral ..despite the AO remaining negative ..temperatures were well above normal.. and you can see this in the last 7 day departures..
There is still one more teleconnection we have to look at and that is the MJO
You can see the the MJO was in phase 7 and if you look below you can also see why the southeast was cooler
However now the MJO is back into phase 6 and this shows you once again why the temperatures have become warmer.
So when we go back and look at the teleconnections they pretty much show why what has occurred has occurred. Now when we look into the future we see the NAO going negative , the AO going extremely negative (both these signals indicate a discharge of colder air into the USA but remember now we are in the month of March and the averages are now higher then they were in say December and Jan ) but we still need to go back and look at the PNA and this is expected for the time being to stay negative and actually get more negative. So what this implies is that the discharge of colder air will be more central and west based then east based as long as the MJO is in phase 6.
Forecasts are showing the MJO to go thru phase 7 again so when this occurs temperatures once again would become colder then normal with the other teleconnections already in place..but as long as the PNA remains negative the brunt of the coldest would be central and west based. If the PNA were to go positive with the AO so negative and the NAO going negative this would once again put a trough over the eastern part of the country.
Keep in mind that colder then normal does not necessarily mean temperatures supportive of snowfall if and when the PNA goes positive. Normal high temperature at ABE for example is 48 degrees...all it would imply is temperatures below normal which could mean the upper 30s or lower and mid 40s.
Also keep in mind that when the MJO is in phase 6 this also involves the southeast ridge and gives a much more likely hood of storms cutting to the west of the region which is what we see on the model guidance for around the 18th to the 20th. When a storm system cuts west of the region it allows for warm air advections and mid levels to warm and while it may initially start off as frozen likely hood with a western track is for the system to change over to a cold rainfall.
Heaviest amounts of snow will be confined further to the south where heavier precipitation rates will occur which will allow dynamical cooling to take effect and draw down the colder air from above to the surface. Further north the boundary layer may be an issue and so you see the snow totals start to go down.. Matter of fact in the eastern Part of the state of PA into the NE Part ..we may be dealing with a rain snow mixture for some time..
We are not putting much weight of the GFS/NAM into the scenario because they seem to be to out of harmony with the rest of the guidance.
If you are on the northern fringes of the precipitation shield you will be dealing with lighter rates and boundary layer issues..
Since we created this map the GFS has now come into better agreement with the rest of the guidance..
This storm will be more of a nuisance above southern PA and a hindrance for those from southern central PA south into MD and VA where the heaviest snows will fall..
