When air flows are blocked by obstructions, such as buildings, trees, mountain ranges, or in this case, a mountainous island, all sorts of interesting effects can occur. Just as flowing water hitting a rock will form swirling eddies, flowing air has the same tendency, which you can plainly see int he image above. We’re usually not able to see these effects so vividly, though you’ll often feel them in the form of turbulence.
One of the lead forecasters at WPC was taking a look at the visible satellite imagery in the Pacific near the Baja California Peninsula and noticed some swirly action. If you take a look, there’s several swirls being caused by a volcanic island called Isla de Guadalupe. There’s also one right next to the coastline. How many can you count!?
We have satellite and radar imagery on our webpage alongside the surface analysis–if you want to take a look, visit our website (www.wpc.ncep.noaa.gov) and take a look under the current weather!
An unsettled week is in store for us after a spectacular stretch of warm, sunny conditions this past weekend. The good news is, it looks as though the pattern of rain during the week, but clearing and warm weekends is set to continue.
Tuesday – a high pressure center over New England will swing a backdoor cold front through tomorrow. This will lead to a chance of showers during the afternoon hours, with cloudy conditions otherwise and highs in the mid-upper 70s.
Wednesday – essentially a repeat of Tuesday in terms of sensible weather. A stationary front will sit just south of NYC and allow for an increasing chance of showers and possibly a few scattered thunderstorms. Temperatures will be in the same range as Tuesday.
Thursday will probably bring the best chance of significant showers and thunderstorms coming ahead of an approaching warm front. Cloudy again, with a chance of showers and thunderstorms throughout the day, and a high in the upper 70s.Friday – the warm front mentioned above will slowly progress through the area during the day Friday, once again bringing a chance for showers and thunderstorms, with mostly cloudy skies and highs once again in the upper 70s.
High pressure finally builds in during the day Saturday, which should lead to diminishing clouds, eventually mostly sunny skies for the rest of the weekend, and warmer temperatures in the low 80s.
A lot of you may be going down to Governor’s Island this weekend to check out the Governor’s Ball this weekend, which promises to have spectacular weather for an outdoor music festival!
Today – winds from the north will diminish today as an area of high pressure builds in over NYC from the Ohio Valley. Temperatures will be seasonable near 80 with mostly sunny skies. If you’re on Governor’s Island itself, you might experience slightly cooler temperatures due to breezes off the harbor.
Saturday – day two of a weekend of glorious weather, as temperatures continue to climb with the high pressure sits right over us. Expect clear skies with warm highs in the mid 80s. Excellent weather for a grill out or just any outdoor activity period.
Sunday – yep, you guessed it, yet another day of ridiculously nice weather, with highs in the low-mid 80s, and a mostly sunny sky.
Next chance for rain and thunderstorms comes Monday in advance of a complex frontal system.
NWS Weather Prediction Center’s forecast for Sunday
Yesterday marked the official start to the 2014 Atlantic Hurricane season (June 1 – November 30), so this is as good a day as any to talk about the forecast for this season. The graphic below shows the National Hurricane Center’s official 2014 Hurricane Season Outlook that was released last month. This forecast is probabilistic, i.e. it gives a range of numbers and chances that this season will either exceed or fall below the forecast total.
National Weather Service National Hurricane Center’s forecast summary for 2014
Explanation
In the NHC’s parlance, Named Storms refers to tropical or subtropical storms that produce sustained winds in excess of 39mph (this is the criteria for a tropical or subtropical storm) at any point in their life cycle. Hurricanes refer to the named storms that end up producing sustained winds in excess of 74mph, and Major Hurricanes refer to hurricanes that make it to Category 3 or higher on the Saffir-Simpson classification scale. Accumulated Cyclone Energy (ACE) is a rough measure for the overall intensity of a tropical cyclone and is calculated as follows:
The ACE of a season is calculated by summing the squares of the estimated maximum sustained velocity of every active tropical storm (wind speed 35 knots (65 km/h) or higher), at six-hour intervals. Since the calculation is sensitive to the starting point of the six-hour intervals, the convention is to use 0000, 0600, 1200, and 1800 UTC. If any storms of a season happen to cross years, the storm’s ACE counts for the previous year.[2] The numbers are usually divided by 10,000 to make them more manageable. The unit of ACE is 104kn2, and for use as an index the unit is assumed. Thus:
where vmax is estimated sustained wind speed in knots. (Source – Wikipedia)
Hence, a high ACE number corresponds to a very intense storm or storm(s).
Outlook
As you can see from the above image, the NHC is calling for a normal to slightly below normal season for the Atlantic with 8-13 named storms, 3-6 hurricanes, and 1-2 major hurricanes. Despite the fact that the forecast calls for a normal to below normal season, it only takes one landfalling hurricane or major hurricane to inflict serious damage to a coastal area. Even with just tropical storms, huge amounts of rain can fall leading to major flooding.
El Niño’s Impact
One of the reasons why the forecast is calling for a normal to below normal season is that it appears an El Niño event is initiating and forecast to increase in intensity. El Niño refers to a phenomenon that occurs when the ocean surface of the Eastern Pacific Ocean becomes abnormally warm (La Niña refers to the opposite effect, when the Eastern Pacific cools abnormally).
This anomalous warming of the Eastern Pacific leads to all sorts of global climate impacts. Among these is a noticeable decrease in the incidence of Atlantic hurricanes, and an increase in the number of Eastern Pacific hurricanes. In fact, you can see in the same outlook, NHC is calling for a near normal to above normal hurricane season for both the Eastern and Central Pacific. The reason behind this is simple: hurricanes feed on heat to grow, so the warmer the water below a storm, the greater the potential for that storm to grow.
Map of sea surface temperature anomalies as of 6/2/2014
As you can see from the map above, there is a region of abnormally warm sea surface temperatures extending west into the Eastern Pacific from the coast of Ecuador and Peru (yellow & orange). At the same time, there is a large area of much cooler than normal sea surface temperatures extending from the west coast of Africa into the Central Atlantic (light and dark blue). Incidentally, these cool temperatures off the coast of Africa are in a region that is notable for spawning some of the strongest hurricanes, the Cape Verde type hurricane. Clearly, if this temperature anomaly keeps up, it will serve to inhibit the formation of tropical storms and hurricanes in that region.
Great day to start the week, with warm temperatures and sunny skies. Highs will top out in the low 80s today.
Tuesday, clouds will begin to build in ahead of a cold front approaching from the Great Lakes. Temperatures will remain warm with southwest flow and the cold front pushing warm air ahead of it. High temperatures should be around the low 80s with a chance of rain increasing into the afternoon.
Wednesday – a chance of showers and embedded thunderstorms persist through the Wednesday and Thursday timeframe. Temperatures will again be warm in the low 80s ahead of the cold front. Otherwise, generally mostly cloudy skies.
Thursday – the cold front is finally expected to pass through NYC on Thursday. This should set the stage for the best chance of significant precipitation this week. We may again see some thunderstorms, though none severe. Temperatures will cool off a bit with the rain and in the wake of the cold front, with high temperatures in the upper 70s.
Friday – high pressure builds in for Friday, remaining anchored and increasing in intensity over the weekend. This will translate to another splendid weekend of seasonable temperatures and sunny skies. Highs will be in the upper 70s to low 80s.
The Weekend – as mentioned above, high pressure will set the stage for seasonable temperatures and pleasant conditions during the weekend. Expecting high temperatures in the low 80s with mostly sunny skies. The high pressure will also block a storm system forecast to develop over the plains from entering our area until next week.
For the remainder of today, temperatures will be in the low-mid 70s. A cold front is forecast to pass through the region later this evening into the overnight hours. Ahead of the frontal boundary, some scattered showers and a few thunderstorms are possible during the afternoon hours. Coverage will be sparse and any storms should be short in duration.
Saturday enough instability may linger in the wake of this cold front to allow for the development of PM pop up thunderstorms/showers. Again, coverage will be widely scattered and intensity of these storms would not be too great. Otherwise, partly cloudy with high temperatures will be slightly warmer in the mid-upper 70s.
Sunday will be the best day of the weekend with high pressure beginning to build into the area. This high pressure center is forecast to sit to the south of us, allowing a warmer airmass to circulate clockwise around it. This should translate to warmer temperatures in the upper 70s to low 80s (especially inland) across the area. Fair weather with mostly sunny to clear skies.
This warm trend should continue into Monday of next week, when highs again will push 80n across the area under mostly sunny skies. Next chance at rain will be Tuesday.
What fantastic weather for the Memorial Day weekend! We topped off in the mid-80s across the area yesterday, and we’re likely to see another day with temperatures in the mid-upper 80s across the region (esp in interior portions of New Jersey).
Sadly, our stretch of summer-like temperatures is about to come to an end as a backdoor cold front (a front that does not approach from the west like most fronts do over this area) approaches the area from the north. Ahead of this cold front, temperatures are in the mid-80s and there is robust moisture in the atmosphere. This will provide the right ingredients for the possibility of severe thunderstorms later this afternoon and evening.
Possibility of Severe Thunderstorms This Afternoon
Current thinking is that these storms approach the NYC metro around 4-7PM during the evening rush hour. The Storm Prediction Center has placed NYC, western Long Island, Northern New Jersey, and much of the Hudson Valley under a slight risk area for severe weather this afternoon. By the way, slight risk in this context does not indicate that storms which occur will not be that severe, rather, it is denoting that the probability for severe storms is on the low side, and that coverage is not expected to be widespread. Just so you all are clear, the National Weather Service defines a severe thunderstorm as producing one or more of the following:
Wind gusts greater than 58mph
Hail greater than 3/4″ in diameter
A funnel cloud or tornado
A severe thunderstorm or tornado watch means that conditions are favorable over an area for the development of these types of weather hazards, however, no immediate threat has yet been identified. A warning means that a severe thunderstorm or tornado is imminent or already ongoing, which is understandably a much more dangerous situation. Anyway, the most likely threat for our immediate area are damaging wind gusts and hail, although a few isolated tornadic supercells cannot be ruled out.
Storm Prediction Center Day 1 Convective Outlook – we are in the slight risk area highlighted in yellow
Wednesday – by tomorrow, the cold front responsible for the possible thunderstorms later today will have moved through our area, however, there is still a chance for lingering showers on the backside of this frontal boundary. Also, since this is a backdoor cold front, temperatures will be significantly cooler tomorrow than today with an onshore easterly wind keeping high temperatures only in the mid 60s (about 20 degrees cooler than today).
Thursday – an area of high pressure will build into the area, but due to its position to our northeast, it will also continue to usher in onshore easterly/northeasterly winds that will keep our high temperatures below normal in the upper 60s. Otherwise, it will be a nice, sunny day.
Friday – another cold front will approach the region from the west and bring in the possibility for afternoon showers and thunderstorms. Slightly warmer with cloudy conditions and a high temperature near 70.
Saturday – high pressure will once again build in across the region and remain in place through the weekend. Therefore, am expecting pleasant, sunny conditions with about average temperatures in the mid-70s.
About that meteor shower… so as it turned out, the Camelopardalis meteor showers were a dud. Astronomers may have miscalculated the timing and/or amount of debris accumulated. Hey, it was the first time this particular shower was supposed to go down, so I guess you can’t blame them for not getting it right.
Just a quick update on your Memorial Day Weekend weather.
Saturday, still looks like there’s a chance for showers and isolated thunderstorms in the NYC metro area in the afternoon hours of Saturday. High temperatures will be mild in the low 70s under mostly cloudy skies.
In Oberlin, temperatures will be around the same in the low 70s, but skies will be clear and sunny.
Sunday will see clearing skies for the NYC metro area and warmer temps in the upper 70s and even low 80s particularly inland. Cooler at the shore with some (especially the south facing shore of Long Island) with a sea breeze and highs in the low-mid 70s. Still, an all around excellent beach day.
Oberlin will remain sunny with clear skies and highs in the upper 70s.
Monday will be the warmest day of the weekend with highs in the low 80s in the NYC area and mostly sunny skies.
Oberlin may see some clouds building in over the course of the day with an approaching storm system, but not expecting any rain. Highs in the upper 70s.
Visibility for Tonight’s Meteor Showers
Again, it is looking like the NYC area will miss out on the chance to see these meteor showers with cloud cover expected to be widespread. Good viewing for Oberlin though!
Cloud cover forecast for select locations (blue line). Red box indicates best viewing window for the meteor showers.
Today was an active weather day for the NYC area, particularly over New Jersey and upstate. A funnel cloud was spotted up in the Albany area, and a few severe thunderstorms exhibiting strong rotation (the strongest thunderstorms-supercells-often feature a single internal circulation called a mesocyclone) formed ahead of a cold front that’s still slowly pushing its way over western New Jersey. Some of these storms produced large hail over interior parts of the NYC metro area.
Friday there will continue to be a risk for thunderstorms during the afternoon hours, otherwise it should be a mostly cloudy day with his right around 70.
In Oberlin, tomorrow should see skies gradually clearing with his in the mid-upper 60s.
NAM model simulated radar image for 5PM EDT Friday, May 23, 2014
Saturday still cannot rule out a lingering risk of thunderstorms and showers in the PM hours on Saturday as shortwaves (impulses of energy) continue to spin around the backside of the departing low pressure system that’s brought us this period of unsettled weather. Highs will again be around 70, depending on if breaks in clouds develop.
By Saturday, skies should clear out over Oberlin, allowing temperatures to rise into the low 70s.
NAM model simulated radar image for 2PM EDT Saturday, May 24, 2014
Sunday and Monday are still on track to be the best days of the Memorial Day weekend with temperatures in the upper 70s Sunday and low 80s Monday.
Camelopardalis Meteor Shower Visibility
Now about that meteor shower, will you be able to see it in NYC? Sadly, the answer is probably not, due to a forecast that calls for mostly cloudy skies. With cloudy conditions, light pollution is amplified as the light cast off from the city gets reflected back down even more. It will be a different story for Oberlin, though, where skies are forecast to clear due to the influence of building high pressure well before the anticipated peak of the meteor showers.
NWS hour by hour graphical forecasts. Red boxes indicate the forecast peak for the new Comet 209P/LINEAR Camelopardalis meteor shower. The blue line represents the percentage of the sky that’s forecast to be covered with clouds.
The Storm Prediction Center in Norman, OK has placed western portions of our region under a slight risk for severe weather this afternoon, with the primary threat being damaging winds and hail.
Mid-upper level conditions are favorable for the development of thunderstorms with some rotating updrafts. Unidirectional winds at various levels, as well as wind speed shear, could impart enough rotation on storm cells to cause marginally severe wind damage and some hail. The highest potential will be over Eastern Pennsylvania and New Jersey where sufficient solar heating could produce CAPE (Convective Available Potential Energy, measured in joules per cubic kilogram) values of between 1000-1500 J/kg^3.
Storm Prediction Center in Norman, OK has placed western portions of our region in a slight risk area for severe weather this afternoon
A small cluster of thunderstorms is already initiating along the western New York/Pennsylvania border ahead of a weak cold front. These storms should expand in coverage and increase in intensity as skies are clear ahead of the frontal boundary, allowing for a good influx of energy for storms to feed off of. The current thinking is that isolated severe thunderstorms reach our region by around the 4-6PM time frame. The chances of these storms remaining severe over NYC and coastal areas is low, since there will be a stabilizing influence from the cool marine layer offshore.
