Archive for Gulf Coast
Hot conditions continue, Earl approaches
Posted by: | Comments09/01/10 4:54 PM
High pressure once again produced an excellent day of weather, albeit hot but at least dry. Temperatures rose into the upper 80′s to mid 90′s once again while humidity increased slightly from the previous few days.
All eyes of course are on Hurricane Earl. The forecast for Hurricane Earl is very complicated but also rather simple to see. Through today, Hurricane Earl has been under the influence of two main features. The first is a strengthen ridge to the northeast and east, which is driving Earl to the northwest and the second is a strong upper low over the eastern Gulf of Mexico, which is enhancing the southeasterly flow. This southeasterly flow is bad news for those along the Mid Atlantic coast.
The idea from the NHC and most model guidance as that Earl would reach the edge of the western Atlantic ridge, turn north around the North Carolina coastal waters, and exit into the Atlantic well east of New Jersey. As you know, I was not and still not buying that forecast. Let me explain why.
Besides looking at models, a meteorologist has to use his brain sometimes and actually look at the atmospheric set up using physics and some basic laws of meteorology. Now, the first physics problem we have here on the water vapor satellite picture is that there is a lot of dry, sinking air over the Tennessee Valley. This is important because this dry air is significantly slowing the cold front that is expected to force Earl well to the east of New Jersey. This dry air is the result of two features. The first is what we call a heat ridge or warm core ridge. The second is what we call upper level wind convergence. You see, the upper low over the Gulf Coast is creating wind convergence over the Tennessee Valley. This convergence is slowly down the base of the trough, which means our cold front is going to be a little late to it’s date with Earl. I know, Earl is going to be disappointed.
So where does this put us, the Northern Mid Atlantic?
Well, if my theory is right that Earl is going to move further west than guidance suggests, than Earl will pass 75W to the south of 30N, which would allow Earl to move through the Outer Banks of North Carolina and then due north towards the southern Delaware coast. Eventually Earl will turn northeast and I have that happening over the New Jersey coastal waters, roughly 150 miles off the New Jersey coast.
At this time, the forecast I had for this morning remains the same with the most significant impacts along the immediate New Jersey coast and along the south shores of Long Island where Tropical Storm to near Hurricane strength winds can be expected, heavy rainfall, rough surf, and coastal flooding. Further to the northwest over interior southern and central New Jersey, northeastern New Jersey, the New York City metropolitan area, and much of Connecticut, bands of heavy rain and strong winds will move through these regions, however the effects of Earl will not be a constant and I could not rule out some breaks of sun between the bands of rain. Winds will remain in the Tropical Storm strength, but mostly towards 40 mph for a short times. Further to the west, the cut off from the impacts of Earl will be sharp with little impact for Philadelphia, the Delaware River Valley, eastern Pennsylvania, interior New York and northern Connecticut.
Earl will exit into the Atlantic quickly along with a cold front on Friday night with clearing skies. A cooler Polar air mass will take hold for Saturday and Sunday with temperatures falling back into the 70′s and lower 80′s. By Monday though, lower to mid 80′s will take hold for much of the Northern Mid Atlantic. High pressure will keep the region dry through early next week once Earl exits.
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-- Weather When Posted --
- Temperature: 89°F;
- Humidity: 43%;
- Heat Index: 90°F;
- Wind Chill: 89°F;
- Pressure: 30.02 in.;
Premium Discussion Overview for Saturday, July 17 2010
Posted by: | CommentsIt’s hot and humid this morning and conditions are only going to get worse. Today, in the Premium Discussions I explain why the weather is only going to get hotter and what influences this will have on the Tropics! Are you a Premium Member? Get the details for Premium Membership here!
-- Weather When Posted --
- Temperature: 84°F;
- Humidity: 62%;
- Heat Index: 88°F;
- Wind Chill: 84°F;
- Pressure: 29.95 in.;
Get use to muggy, unsettled conditions for this week
Posted by: | Comments06/13/10 11:07 AM
For those waiting for those muggy days of summer, well your wait is over!
The key to this forecast for the whole week is the stationary front over the Ohio Valley through the southern Hudson Valley and southern New England. That stationary boundary is the dividing line between the muggy, humid conditions building over much of northern Mid Atlantic down through the Gulf Coast and the more comfortable weather conditions over the eastern Great Lakes and New England. Naturally, model guidance is having a fun time handling this feature as each disturbance will alter the exact position of this boundary via various mesoscale influences. Combined that dubious influence with mid level disturbances, and we have a forecast full of volatility and plenty of thunderstorms!
Okay, so let’s nail down some facts here. First and foremost, this pattern is not going to be going away any time soon. In other words, the northern Mid Atlantic is going to be caught in this constant battle of air masses for what I consider the foreseeable future. The ridge that is being established over the western Atlantic is gaining more and more support from various teleconnections, which I’ve been talking about for weeks in the Premium Members Long Range Thoughts discussion. So, we know that there will be a constant invasion of warm, sometimes hot, and humid weather conditions over the northern Mid Atlantic for some time. I think the hottest weather conditions will be over the Gulf Coast where the air mass will have the strongest support, so I do not expect an outbreak of 100′s for the region any time soon.
Instead, what we have at the surface is a reflection of a battle going on at 500 MB. That persistent negative NAO pattern that gave the northern Mid Atlantic plenty of winter storms a few months ago, has not gone away. Instead, the upper level pattern has simple shifted to a higher latitude, which will keep a trough over eastern Canada and the Canadian Maritimes through much of the summer. That means that cold front will continue to attempt to drive through the northern Mid Atlantic only to stall or weaken to the point where only a slightly drier air mass follows only to be quickly replaced by higher humidity once again. As a result, through this weekend and into next weekend, you can bet on the same story again and again. Variable cloud cover, risk of fog in the morning due to all the low level moisture in the air, and a risk of widely scattered to isolated thunderstorms each day.
The cold fronts in this pattern will end up being more wind shift lines rather than true air mass changes. For example, the HPC has a cold front drive south into the southern Mid Atlantic, however high temperatures are just as warm today as in Tuesday. The only real change, if any, is that the winds from the northwest and west as another high pressure system slides east. Dew points drop for one day below 60 degrees before rebound the very next day into the lower to mid 60′s once again. The influence of the new air mass is temporary, if anything. In fact, I would not be surprised if the humidity returns much faster by Tuesday evening or Wednesday morning.
The point I’m trying to make is that I believe we have our established summer pattern in place now. Sure, there will be some tweaks here and there, but you’ll find that I will be less inclined to change the overall thinking of my forecast regardless of model changes. The reason is that the pattern drivers and their characteristics have been established and what they are going to produce is a pattern that is humid and warm to hot with a constant threat of thunderstorms.
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-- Weather When Posted --
- Temperature: 77°F;
- Humidity: 65%;
- Heat Index: 79°F;
- Wind Chill: 77°F;
- Pressure: 29.88 in.;
Clearing skies this afternoon, higher humidity on the way
Posted by: | Comments06/10/10 8:45 AM
The low pressure that produced the moderate to heavy rain over the Philadelphia and New York City metropolitan area is now exiting into the Atlantic. What will follow is a rather complicated and volatile period of weather that will sure to drive the public and meteorologist absolutely crazy or just plain confused. But first, let’s deal with the good news!
The visible satellite picture this morning shows that plenty of low clouds, whether that be fog or low stratus, still dominates much of the northern Mid Atlantic. However, as dry air conditions to move in from the west, the low clouds will shrink in coverage, lift, and finally dissipate by late this morning into the early afternoon hours. Any lingering precipitation will be isolated this morning and very light. For those going to the Mets (double header!) and Phillies baseball games this afternoon and evening, weather conditions will be generally pleasant with light winds and temperatures in the 60′s and 70′s. Basically a near average temperature day for the region. Enjoy the comfortable conditions now, as this won’t be the theme going forward.
To the right is the ECMWF for Monday night. Now, there are two very important and key features at 500 MB that will impact the northern Mid Atlantic’s weather for at least the next seven days if not longer. The first is a deepening trough over northeastern Canada and Greenland, which is going to continue to be positioned anywhere from Greenland to the Canadian Maritimes. The second feature is a building ridge over the Gulf Coast and Southeast.
Now, I’m using the ECMWF as an example, not my forecast, for the two features that will influence much of the eastern United States. Note that over New England and the northern Mid Atlantic, the upper level pattern begins to converge. Also note that 850 MB temperatures (color shaded) are tightly packed for this time of year. This means that there is a surface boundary somewhere in the area, and that means trouble!
Here is how I see this pattern playing out. The warm air mass is going to strengthen in coverage and in intensity over the next several days. However, with the Arctic Oscillation going positive and the North Atlantic Oscillation remaining negative, a deep trough will be established over the northwestern Atlantic back through the Canadian Maritimes. This leads to two primary surface features, high pressure off southern Mid Atlantic coast to the Bahamas and a stationary/warm front over the northern Mid Atlantic. There in lies the problem! South of this warm front, temperatures will be in the 80′s and 90′s with humidity increasing each day as the influence of the more Tropical air mass takes hold. North of the frontal boundary, humidity will be significantly lower with temperatures in the more normal range of the 70′s for highs. The difference in the air mass will be rather stark. For example, Connecticut is setting up to be in a rather pleasant stretch of weather, especially to the northeast, with low humidity and temperatures in the 70′s in the afternoon. Meanwhile, northeastern New Jersey will be in a far more humid air mass with dew points in the 60′s and 70′s along with highs in the lower 80′s to lower 90′s. Throw in pesky mid level disturbances from the upper trough to the north, and the risk of thunderstorms, a few occasionally severe depending on the set up, will have an even more volatile impact on high temperatures south of the frontal boundary. So the forecast from Saturday on through next week is not going to be easy and I expect changes from day to day. Right now, if you live in the Philadelphia metropolitan area, prepare for a much more humid and active weather pattern. If you are more towards New England, there is a higher potential for lower humidity and temperatures near normal. Expect changes in the details of the forecast as we move forward!
So, welcome to summer of 2010!
For details on your location for the next seven days, visit the NY NJ PA Weather Seven Day Forecast!
-- Weather When Posted --
- Temperature: 60°F;
- Humidity: 82%;
- Heat Index: 60°F;
- Wind Chill: 59°F;
- Pressure: 29.89 in.;
West Based Negative NAO pattern brings about cool week
Posted by: | Comments05/10/10 7:35 AM
The low pressure system that provided the New York City and Philadelphia metropolitan area a very windy weekend will continue to have an influence on the northern Mid Atlantic through this week.
The water vapor satellite image this morning shows an impressive upper low over northern New England and the Canadian Maritimes. This upper low is associated with the strong surface low that provided the windy conditions this weekend. Note the back and red colors over the Great Lakes, Northeast, and Mid Atlantic, which shows a clear northwesterly flow that is established. This northwesterly flow is very important to this week’s forecast due to the influence this pattern will have on a strong disturbance currently over the Rockies.
The northwesterly upper level winds will initially support strong high pressure over the northern Mid Atlantic, leading to clear skies today and very chilly conditions. Freeze watches and warnings have been posted throughout the region with the potential for lows tonight to crash into the upper 20′s to lower 30′s over the interior.
For the rest of the week, think of the upper low as a road block. This road block is going to prevent a ridge that is developing over the Gulf Coast and Southeast to build and also slow the progression of the disturbance entering the Plains. The result of this road block is a stalling warm front over the northern Mid Atlantic Wednesday through Friday, which will lead to periods of rain, overcast skies, and generally cool and raw weather conditions. As the warm front stalls to the south of New Jersey and southeastern Pennsylvania, waves of low pressure will move along the warm front producing periods of moderate to heavy rain. Otherwise variable clouds, generally overcast for the most part, and drizzle can be expected with temperatures struggling in the 50′s and 60′s. So in short, the west based negative NAO pattern will lead to a marine air mass becoming established throughout the Philadelphia and New York City metropolitan areas, especially along the New Jersey coast and Long Island.
High pressure will take hold once again by next weekend as the negative NAO pattern begins to shift east once again. Moderating temperatures can be expected by Friday afternoon and continue on through next weekend along with dry conditions.
For details for your specific location, visit the seven day forecast!
-- Weather When Posted --
- Temperature: 39°F;
- Humidity: 71%;
- Heat Index: 39°F;
- Wind Chill: 33°F;
- Pressure: 30.22 in.;
One more day of summer-like conditions
Posted by: | Comments04/08/10 6:55 AM
The brief pre-view of the summer will be coming to an end by tonight, however at least through this afternoon; warm and relatively humid conditions will continue for the Philadelphia and New York City metropolitan area.
A strong southwesterly jet stream is developing from the Gulf Coast to the Mid Atlantic with plenty of low and mid level moisture racing into the northern Mid Atlantic this morning. High pressure will slowly drift to the east into the Atlantic through this afternoon with clouds increasing through the day. The increasing clouds will keep most locations cooler than the historically warm conditions experienced yesterday with highs expected to remain in the 80′s rather than push into the lower 90′s.
A strong cold front will approach from the Ohio Valley tonight with showers and thunderstorms after mid night. These thunderstorms will be enhanced by a strong 850 MB Low Level Jet Stream (LLJ) that will enhance lifting and transport deep tropical moisture into the region. As a result, the thunderstorms will have the potential to produce heavy downpours, wind gusts over 40 mph, small hail, and frequent lightning along with flash flooding, minor wind damage, and rapidly reduced visibility. The showers and thunderstorms will move through the Philadelphia and New York City metropolitan area at the height of the morning rush hour tomorrow morning, but will exit Long Island and Connecticut by noon.
A much cooler, and overall dry regime will take hold by Friday night with clear skies, falling humidity, and temperatures near normal. Tranquil and comfortable conditions can be expected on Saturday as well with highs in the 50′s and 60′s.
A northwesterly flow at 500 MB will become established over much of the Northeast and Mid Atlantic Sunday through next Thursday with weak disturbances dropping southwest from the Great Lakes creating a threat of isolated to scattered showers and thunderstorms each day. Otherwise dry and cool conditions can be expected with low humidity and rather comfortable weather conditions in the afternoon.
-- Weather When Posted --
- Temperature: 64°F;
- Humidity: 34%;
- Heat Index: 64°F;
- Wind Chill: 63°F;
- Pressure: 30.24 in.;
Much warmer times ahead
Posted by: | Comments3/31/10 5:30 PM
The massive rain storm that has produced over 2 inches of rain for most locations throughout the northern Mid Atlantic and over 4 inches along the immediate coast is now exiting into the Atlantic. Clouds and river flooding continues to remain a theme this evening, however drier air is starting to work in from the west and the rivers are starting to crest.
The great news is that high pressure along the Gulf Coast is going to continue to build throughout the Southeast, Ohio Valley, and Mid Atlantic by tomorrow morning. Note the isobars over the Ohio Valley back through the southern Plains. The southwest to northeast orientation of the isobars supports southwesterly winds and strong warm air advection developing throughout the Mid Atlantic by tomorrow.
A strong ridge will develop at 500 MB and will remain in place through Monday, which will support a very warm conditions starting tomorrow through Monday. Along the coast, a sea breeze will have the potential to develop each day and keep highs in the 60′s and lower 70′s. However, just away from the coast through the interior locations of northeastern Pennsylvania and the Hudson Valley, high temperatures will have the potential to drive into the mid to upper 70′s with even an isolated area of lower 80′s over the Delaware River Valley. In short, this weekend is going to be perfect!
The party comes to a brief end on Tuesday as a back door cold front drops south and west through the northern Mid Atlantic or at least through the New York City metropolitan area. The back door cold front will cause temperatures to hold in the 50′s for highs while to the south and west of the cold front temperatures will drive into the 60′s and 70′s. The cold front will rebound on Tuesday night with much warmer conditions for Wednesday.
A strong cold front will approach on Thursday evening with isolated strong to severe thunderstorms possible, especially over the Delaware River Valley. However, the brunt of the showers and thunderstorms with this cold front will hold off until Friday.
-- Weather When Posted --
- Temperature: 57°F;
- Humidity: 62%;
- Heat Index: 57°F;
- Wind Chill: 54°F;
- Pressure: 29.86 in.;
Significant flooding event expected for this weekend
Posted by: | Comments4:25 PM
The storm is starting to organize over the Plains, Gulf Coast, and Southeast. The model guidance at this point is in very strong agreement for a widespread heavy rainfall starting tomorrow afternoon and continuing on through Sunday morning with rainfall amounts by Monday morning ranging from 2 inches to as much as 5.5 inches of rain.
The storm is currently separated into several different pieces from the Plains to the Southeast coast. The first piece is over the southern Plains which is a disturbance that will be phasing with the second piece over the northern Plains, which is the strong upper low. Of course, not to complicate matters even more, a coastal front is forming along the East coast, while a strong Sub Tropical Jet stream is driving moisture from the Pacific right into the Southeast coast. So, does everyone got that? Okay, let’s move forward!
The storm will come in two waves. The first will develop tonight in the form of a warm front off the New Jersey coast and south of Long Island. This warm front will produce weak isentropic lifting at first, thus the widely scattered showers. However, as the upper low over the Plains dives south towards the Mississippi Valley, a new low and mid level jet stream will develop off the Atlantic and enhance the isentropic lifting. This basically means that showers will become more widespread as the day continues on Friday. This jet stream is already developing from the Carolina coastal waters into the Great Lakes and will only intensify over the next several days.
As the upper low dives towards the Tennessee Valley tomorrow afternoon, a new coastal low will form along the Virginia coast at a triple point. The triple point is the location where the warm, cold, and occluded front meets and is usually a very favorable location for low pressure development. This surface low will rapidly intensify on Friday night into Saturday along the Delaware and New Jersey coast. Heavy rain will develop from Saturday afternoon through Sunday morning throughout the Philadelphia and New York City metropolitan area along with a strong easterly wind of 15 to 30 mph over the interior and 20 to 35 mph along the coast with higher gusts over 40 mph. This storm will linger over the northern Mid Atlantic into Monday morning with scattered showers. The storm will be capable of flash flooding, which is why the National Weather Service has issued Flash Flood Watches for much of the Philadelphia and New York City metropolitan areas along with coastal flooding, minor to moderate wind damage, and significantly reduced visibility.
This storm will exit completely by Tuesday morning with high pressure in control for much of next week and into next weekend with much warmer and obviously drier conditions. However, a lot of rain will fall before getting to that point!
-- Weather When Posted --
- Temperature: 50°F;
- Humidity: 76%;
- Heat Index: 50°F;
- Wind Chill: 46°F;
- Pressure: 30.03 in.;
Warmer times ahead after glancing blow
Posted by: | Comments7:48 AM
A strong area of low pressure is rapidly developing along the Gulf Coast, however this storm is staying far enough south and east to not have a major impact on the region’s weather.
The “pattern changer” as I like to call it is not over the Gulf Coast however but the West coast as a strong disturbance from the Pacific drives east towards California. This disturbance is dislodging the once powerful ridge over the western United States and causing the entire 500 MB pattern to shift eastward. As a result, the storm track for the storm over the Gulf Coast will have to move east-northeast rather than northeast and therefore stay well south and east of the Philadelphia and New York City metropolitan area.
Clouds will increase through the day with temperatures in the upper 30′s over the interior and lower to mid 40′s along the coast. The once impressive snow pack will continue to shrink under the influence of the modifying air mass in place. The low pressure system along the North Carolina coast this evening will continue to move east-northeast tonight into tomorrow morning. Precipitation will expand as far west as the Delaware River Valley with scattered snow showers overnight and rain/snow showers along the coast. Any accumulation of the snow will be found on the usual colder surfaces like the grass and on car tops, otherwise only wet roads are expected as surface temperatures remain 2 to 4 degrees above freezing throughout the region. Further west over the interior, besides increasing clouds and a slightly strong northeasterly wind, no appreciable impacts will be felt from this storm.
High pressure will dominate thereafter from Wednesday evening on through Monday afternoon. High pressure will position itself over the southern Ohio Valley and northern Tennessee Valley through the period with dry conditions, scattered clouds, and temperatures averaging near normal. For most locations temperatures will remain in the 40′s for highs through the period, with a few shots at the lower 50′s by Sunday and Monday afternoons. A strong cold front will approach the region on Tuesday afternoon with scattered showers and a slightly colder air mass.
-- Weather When Posted --
- Temperature: 30°F;
- Humidity: 80%;
- Heat Index: 30°F;
- Wind Chill: 23°F;
- Pressure: 29.91 in.;
Minor snow threat for Tuesday night into Wednesday morning
Posted by: | Comments9:15 PM
A very energetic Sub Tropical disturbance is rapidly developing along the Gulf Coast this evening. However, a more important disturbance that will determine the forecast is actually along the West coast.
While the storm along the Gulf Coast certainly appears ominous, the progression of the Pacific storm this evening into the coast of Washington and Oregon confirm that the 500 MB pattern will be shifting east. As a result, there is rather strong support via the actual observations that the eventual storm track will be well south and west of the New Jersey coast on Wednesday morning.
Now, I’ve had a suspicion for several days now that the precipitation shield of this storm will be more expansive than the guidance was giving credit too. The model guidance of late, is starting to pick up on this idea for the immediate New Jersey coast with up to a half inch of precipitation expected. However, the other issue with this storm will be the relatively warm boundary layer in place with temperatures even on Wednesday morning roughly 4 to 6 degrees above freezing. As such, while I think that snow will be flying in the air on Wednesday morning, 99% of the snow that falls will likely melt on the majority of the surfaces. The snow that does accumulate will likely be most focused on the grass and especially cold surfaces. Otherwise, this storm is going to bring more of an impact via windy conditions on Wednesday morning than anything else.
Otherwise, the pattern will clearly be in a moderation trend over the next 10 days. While the ECMWF does suggest a strong Sub Tropical disturbance along the Gulf Coast by Thursday morning with some marginally cold air over the northern Mid Atlantic. Still there is very little support of the ECMWF solution on other guidance, but I will naturally keep an on the potential given the fact the MJO will still be in a supportive state for such a storm. As far as the cold air, that I am not convinced of.
-- Weather When Posted --
- Temperature: 37°F;
- Humidity: 64%;
- Heat Index: 37°F;
- Wind Chill: 32°F;
- Pressure: 29.86 in.;
Freehold
57°
Philadelphia
62°
Albany
59°
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