You’ve felt the air warm up and become more humid as the warm front that brought our first round of rain passed through earlier today. Now, we’re getting set for a second round of heavy showers and thunderstorms associated with a pre-frontal trough that’s slowly progressing east towards the area from Eastern Pennsylvania.
Ahead of this line of showers and thunderstorms, the air has destabilized readily with the ample sunshine earlier this afternoon. CAPE (Convective Available Potential Energy – a measure of how much fuel there is for thunderstorms to feed off of) is between 1000-1500 J/Kg over Northeastern New Jersey and NYC. This should allow for this line of storms to hold up and perhaps strengthen before hitting NYC. In fact, a couple sever thunderstorm warnings have already been posted for cells over Northeastern New Jersey.
Two part update today – first to address NYC weather, and then to discuss the outlook for next week down in Brazil during the opening week of the FIFA World Cup.
Friday – the work week closes out with the wettest day so far with a warm front passing through tonight, and then a cold front following shortly thereafter tomorrow. This will translate to mostly cloudy skies, with a round of rain tonight, followed by a period of scattered rain showers and thunderstorms, and then ending with another round of heavier rain and thunderstorms Friday night. Temperatures will be much warmer than today after the passage of the warm front with highs in the low 80s.
NAM model output simulated radar image for Friday morning @ 5AM
Luckily for us, the cold front passes through quickly Friday and leads to a splendid stretch of weather beginning with a sunny, mild and pleasant Saturday and Sunday. High temperatures will be in the low 80s both days under clear skies. This is due to an area of high pressure building in from the west behind the cold front.
Warm Spell Next Week
This same high pressure area will track to the southeast during the weekend. By mid-week next week, the high pressure center will be offshore of the Southeastern US, and link up with the Bermuda High. As you may know, Bermuda Highs typically cause hot, humid weather in our region, and this will be no exception. Temperatures will steadily increase each day Monday, Tuesday, and Wednesday, such that by Wednesday, we’ll be looking at highs in the mid-upper 80s. This area of high pressure will also block any precipitation from impacting us until at least next Thursday into Friday when a low pressure system with a trailing cold front is forecast to pass through the Great Lakes.
GFS model output for next Tuesday
World Cup Weather
The World Cup is upon us!!! With opening kickoff just a few minutes away, I thought it’d be useful to talk about weather down in the host country, Brazil. As you know, it’s currently autumn in the Southern Hemisphere, but you wouldn’t be able to tell based on the forecast high temperatures for most of the Brazilian cities with games going on next week. High temperatures will range from the upper 70s-upper 80s depending on where you are.
The highest temperatures will be in Manaus, which not surprisingly sits in the Amazon basin. That’s also the city where you can expect the highest likelihood of rain and thunderstorms. Most of the coastal Brazilian cities that are hosting games will have pleasant conditions and high temperatures in the low 80s this week. Fair weather should be the story as high pressure will tend to dominate this week.
GFS model output for S. America on Tuesday
For your reference, here’s a map with dates of games being held in each host city. I’ll be keeping an eye on the weather and posting any relevant updates as they come up.
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.
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.
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.
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.
Weather conditions will gradually deteriorate through the course of the day today as an approaching storm system draws closer to our area. Cloud coverage, scattered showers, and possible thunderstorms associated with a warm front should increase in coverage during the course of the day. High temperatures should be on the mild side in the mid-70s.
Thursday – as of now, the National Weather Service calls for the aforementioned warm front to approach but not clear our region by Thursday morning. As such, cooler southeast and easterly winds off the ocean will keep temperatures on the cool side with highs only in the mid-upper 60s. There will be a persistence chance for showers and thunderstorms as multiple impulses of energy ride up and along the frontal system, with a break probably occurring between early Thursday morning and later Thursday afternoon/evening.
Friday – in NYC, although the warm and cold fronts associated with this latest storm are forecast to have cleared through the area by Friday, an upper level low situated over the Canadian Maritimes will continue to allow impulses of energy (shortwaves) to rotate into our area providing the spark for a continued chance of showers and thunderstorms, especially Friday afternoon and evening. This upper low will be slow to move east due to a strong blocking “omega” high pressure center located over the central North Atlantic. High temperatures will again be around the upper 60s.
For Oberlin, conditions will begin to improve earlier with the chance of rain ending by Thursday, partly sunny skies Friday with gradual clearing and highs in the upper 60s.
NAM output simulated radar image for Friday at 2PM EDTGFS model output of 500 mb heights and absolute vorticity for Friday at 2PM EDT
Saturday – we’ll see an tenuous area of high pressure trying to build in from our west. However, there may still be a marginal chance of PM showers. Otherwise, expect gradually improving conditions with temperatures climbing back up into the low 70s.
Sunday and Monday (Memorial Day) – These will be the best days of the weekend with dry, mostly sunny, and warm conditions. High temperatures will continue to climb into the mid-upper 70s Sunday and possibly topping 80 Monday (this applies to both Oberlin and NYC). Next chance at rain will be Tuesday.
A New and Spectacular May Meteor Shower? – About Comet 209P/LINEAR & Camelopardalis
A friend of mine brought to my attention that a newly discovered and possibly brilliant meteor shower is forecast to take place in the early morning hours of Saturday, May 24th.
In brief, Earth is forecast to pass through the debris trail of a comet “Comet 209P/LINEAR” (discovered in 2004) during the overnight hours Friday into Saturday. Researchers are forecasting that the debris trail Earth passes through is one that has accumulated dust from as early as 1800 to 1924. As such, expectations are that we could see about an average of 200-400 meteors an hour (some estimates call for a meteor storm of 1000 meteors an hour!), i.e. between about 3-7 meteors per minute. Furthermore, the setup for this event is such that Southern Canada and the East Coast of the U.S. are ideally positioned to view this event. In the image below, the red line represents the forecast position of the radiant line (point from which meteors appear to emanate and where you would see the highest number of meteors), note that this line runs almost direct over Washington DC. Also, notice that the moon is in waxing gibbous phase, reducing its potential to overpower the meteor shower.
Timing and Visibility
The forecast zenith of this meteor shower is between 2AM-4AM Eastern Daylight Savings Time on Saturday, May 24th. Right now, the forecast for this time window calls for mostly cloudy skies over NYC as well as points east and north (i.e. New England). Partly cloudy skies are forecast the points further south and west (i.e. along the Jersey Shore, Washington DC/Northern, Eastern Virginia, Western Pennsylvania), with the best viewing conditions being in the DC metro area and Eastern Virginia where mostly clear skies are forecast. A word of caution: cloud cover forecasts even this close to the day of are notoriously difficult to pin down due to the fact that even small changes in initial conditions can lead to large shifts in a forecast. However, with high pressure building over the east coast throughout the course of the weekend, we should have generally good chances to view this shower.
My recommendation is that you go check this out in an area with minimal light pollution if you can. I think we’re in for a what I hope will be a good show!
Where to Look
The radiant point for this forecast meteor shower will be situated in the relatively obscure constellation Camelopardalis (named by the Romans for a hybrid animal that looks like both a camel and leopard, now known as a giraffe). As you’ll see below, this constellation is located slightly below the North Star (Polaris), and a bit to the right of the Big Dipper.
You can read a more in-depth analysis of this meteor shower here. I’ve grabbed and edited a couple images from this entry.
All preliminary indications are that this Memorial Day weekend should see fairly good weather, as you can read in the detailed discussion below. First, for your work week forecast:
For the remainder of the day today, there is a slight chance of a pop up shower or thunderstorm as cumulus clouds continue to build. This risk will cease as the sun begins to go down, and cuts off the heat source for these clouds. Overnight lows will fall into the low 50s in the city (not as cold as last night, as some clouds are expected to stick around early and stunt the potential for good radiational cooling), with 40s in the interior.
Tuesday will be the best day of the week, with high pressure briefly building in from the west. This will lead to mostly clear skies and warm temperatures in the upper 70s (also partially due to an incoming warm front).
Beginning Wednesday, we will see a period of unsettled weather as a relatively slow moving storm system approaches. This system will develop over the Great Lakes, and a warm front is forecast to be approaching our area during the day Wednesday. There will be an increasing chance of showers throughout the day as the warm front nears, with the best chance for precipitation in the late evening and overnight hours. Temperatures will be slightly lower than Tuesday in the mid-70s.
HPC’s Day 3 forecast for the US
Thursday there is a bit of uncertainty regarding the eastward progression of the warm front mentioned above. If the warm front has already passed over us, then we’ll be in the warm sector between the warm front and approaching cold front. This would lead to favorable conditions for some thunderstorms. Otherwise, we would expect mostly cloudy skies and a chance for more showery precipitation. High temperatures will be similar to Wednesday.
Friday, with the cold front Thursday having moved through and high pressure slowly building in, we would expect a good day weather-wise. However, as you see in the following image, the center of the now occluded low pressure is forecast to remain nearly stationary off the coast of New England. This is due to a blocking high over the North Atlantic (not pictured). Therefore, a chance of showers is forecast for both Friday and Saturday, with skies gradually clearing from mostly cloudy to mostly sunny Saturday. High temperatures Friday is forecast to be in the low 70s.
Now, the all important initial weekend forecast: as depicted above, high pressure building over the Great Lakes should progress generally southeast towards the Carolinas during the weekend. This should translate into improving weather each day during the weekend and increasing temperatures. Saturday, Sunday, and Monday should see high temperatures climbing from the low to mid 70s, and skies clearing to become mostly sunny.
For those of you reading this forecast who are traveling towards Oberlin and points west, the forecast for those parts is actually even better than for New York City in terms of sunshine, although, as you know temperatures will be slightly cooler in Ohio than here.
First for weather headline that will be dominating today: the storm system that is set to bring us heavy, potentially flooding rain later today and into the overnight hours. Currently, temperatures in our area are generally in the mid-upper 60s with a strong south to southeasterly wind. This is leading to an influx deep moisture ahead of the approaching cold front. We are firmly entrenched in what meteorologists refer to as a warm sector. This will provide the necessary conditions for heavy rain and some possible embedded thunderstorms to form later.
NOAA NCEP surface analysis as of 9AM EDT. Note the cold front sitting just off to our west with an elongated area of moderate to heavy rain.
Based on the latest output from GFS and NAM models, it would appear the heaviest of the rain will arrive in our area during the PM rush and last through the evening into the early morning hours. So, if you’re going to be heading out this evening, grab an umbrella and appropriate rain gear.
NCEP’s forecast for quantitative precipitation totals over the next 24 hours.
One of the major hazards with this storm is flash flooding and flooding in general. Because a high amount of precipitation is anticipated to fall in a relatively short time window, flash flooding is a real concern especially in urban areas and small streams. This will make for a sloppy and slow evening commute. The flip side of the fast moving nature of this storm system is that it should clear the area fairly quickly, meaning that you runners out there should have slightly better conditions than previously forecast for the start and duration of the Brooklyn Half Marathon.
NAM high resolution model output showing the cold front and storm system to have pushed through our area by about 5AM EDT
Saturday after the cold front passes through and the rains subside, we should be looking at gradually clearing skies and slightly above average temperatures in the low 70s.
Sunday through Tuesday – we will be compensated for this rainy Friday by a string of days with fair conditions and seasonable temperatures. A high pressure center will form and camp out over our area, preventing any bad weather from impacting us. As such, temperatures should be nearly steady each day during this period in the upper 60s to low 70s with mostly sunny skies.
