Monday Afternoon Tropical Storm Isaias Discussion

With Tropical Storm Warnings posted for the lower half of the Hudson Valley (Orange, Rockland, Putnam Westchester), it’s likely that many of you may be feeling a bit of angst and uncertainty this afternoon. This short discussion will try to clear up a few basic points.
– Rain… heavy at times Tuesday afternoon.
– Increasing winds of 10mph to 25mph, gusting over 35mph
– localized wind gusts over 50mph possible
– Rainfall amounts of 2 to 4 inches… locally 5″+ possible
– 6am to 2pm : Rain showers likely, periods of heavier rain possible
– 2pm to 6pm : Isaias approaches, increasing gusts and downpours
– 4pm to 10pm : Worst of the storm, periods of torrential downpours
as well as howling winds, gusting 35 to 50mph (possibly over 50mph)
– The entire region will experience the affects of Isaias
– Heavy rains expected for all locations
– Gusty winds over 30mph possible for entire HV
– Strongest wind gusts (over 50mph) likely south of I-84
Tropical Storm Isaias will likely undergo a brief period of strengthening before making landfall near the NC/SC border. From there, it will push NNE and head toward the Hudson Valley. It will spread rain northward, well in advance of the center of rotation, so rain showers are likely most of the day on Tuesday. The storm will approach the region between 2pm and 8pm. The winds will increase in that time frame, gusting over 30mph at times, mainly as the outer bands of Isaias rotate into the region. The worst conditions will likely be from 2pm to 10pm on Tuesday. During that time, gusts over 35mph are possible, with the highest chances for damaging wind gusts over 50mph being in areas east of the Hudson River, and also in areas further south (south of I-84). The effects of this storm for the region will be like a powerful nor’easter… with some potential for wind gusts that could exceed 40mph, which is what has prompted the Tropical Storm Warning for portions of the area.
We would like to stress, that while some details have changed, the general expectations with Tropical Storm Isaias have not changed. The expectation of a track further west has resulted in expectations for slightly stronger wind gusts than we were initially projecting. This continues to be a potentially significant event, and bares watching. We will try to have more frequent updates as we approach the storm’s arrival.

Sunday Night Tropical Storm Isaias Update

Currently Isaias sits off the East coast of Florida, it has been looking healthier today as it was able to escape dry air, sheer and the higher terrain of Hispaniola and is now within the favorable warmer Gulf Stream waters.
A strong high pressure in the central Atlantic coupled with a large trough over the Eastern Conus will leave very little options for the further track of Isaias. All model guidance is locked in on a track that brings the center of circulation up the eastern seaboard and potentially through parts of our region.
Here are the rainfall projections from the GFS and European models…
GFS Rainfall Projection
European Rainfall Projection:
As you can see there are only small track variances between them, only thing we can be confident on, is the fact that a widespread heavy rainfall is likely, with rainfall amounts between 2”-6” possible. Something that will bare watching is the chance for a “PRE” which is short for a Predecessor Rain Event which if you are bored and want to geek out, you can read about here….
In laymen’s terms this is an event in which heavy rainfall breaks out ahead of an incoming tropical system, this is further enhanced by the trough that is draped across the region as it causes moisture and heavy rain to surge along this boundary, any heavy rain that occurs Tuesday in advance of the main rain shield associated with the system, may exacerbate any potential for flooding and would need to be monitored.
In terms of wind gusts, the friction of land will always keep the worst of the wind along the coast, but the models are supporting tropical force wind gusts across our southern and eastern counties, this combined with soaking rainfall may lead to scattered outages.
GFS Model Wind Gusts
European Model Wind Gusts:
The final track and intensity will determine if our impacts are on the high end or low end of this evenings guidance. With the threat of today’s severe weather behind us we are now moving on to tropical storm coverage.
If you have plans for Tuesday please factor this into those plans, most of Tuesday looks unsettled with rain and wind intensifying by later in the day. Stay tuned for more updates.

Sunday Afternoon T-Storm Potential

The humidity is very high across the region this afternoon. Temperatures have been holding in the mid and upper 70s, thanks to the morning rain showers… but it feels quite uncomfortable. Now we’re beginning to see the sky brighten a bit, and even some breaks in the clouds. That’s allowing temperatures to climb, and we’ll be into the 80s before long.
This will cause our T-Storm threat to increase over the next few hours. Some guidance does suggest that a few supercell T-Storms could develop randomly around the Hudson Valley.
There is considerable atmospheric sheer today, which could lead to rotation within those storms. As a result, the threat for a stray tornado cannot be ruled out. These storms are equally possible no matter where you are located within the HV today. For context and perspective, the threat of severe weather occurring within 30 miles of your location is less than 30%… and the threat for a tornado occurring is less than 5%. However, the potential for severe weather is present today, and everyone should exercise measured caution, and remain alert.
We will try to share any alerts that are issued this afternoon. This is a tricky forecasting situation, because the clouds and showers from this morning may have stabilized the atmosphere enough to where nothing develops. However, it’s always best to be cautious, and the rest of the atmospheric conditions are favorable for severe weather. So keep your eyes and ears open this afternoon.

Sunday Discussion : A Complex Severe Threat

Isolated thunderstorms will be possible Sunday afternoon through early evening ahead of a cold front. Recently, some data has been hinting toward a potentially severe event. Unlike past events, this is an extremely complex forecast with many driving factors. While potentially widespread, conditions leading up to the event may very well also hinder development. The main question will be whether storms materialize or not.

Timing: The main severe threat appears to be anytime after 12:00 noon through sunset.

Main Threats: All modes of severe weather are possible, including damaging winds, large hail, heavy rainfall, and an isolated tornado.

Midday tomorrow will feature an advancing warm front, which will cause clouds and scattered showers throughout the region. Behind the warm front will be an extremely moist air mass (dew points in the mid-upper 70’s). This will help result in high CAPE (Convective Available Potential Energy) values of up to ~3,000 J/kg, which is extremely favorable for severe weather development. Also, there will be a good deal of shear, which could allow for a few cells to rotate, resulting in an isolated tornado or two. While likely not a widespread tornadic event, it cannot be completely ruled out at any given location. The Storm Prediction Center has placed nearly our entire region in a slight risk (level 2 out of 5) for severe thunderstorms.

Simulated radar for Sunday (Aug 2nd) :

Conflictingly, many model runs show lingering cloud cover after the warm front passes, which will put a cap on any convection. Also, widespread cloud cover will not allow for surface heating, which is essential for updrafts. This appears to be the case on the most recent run of the Nam 3 km, which doesn’t show much convective development due to cloud cover. While a possible solution, it will only take a couple of breaks of sunshine to create a very unstable atmosphere, resulting in severe thunderstorm development. Like always, we will monitor this situation and give updates as we get closer in time.

Have a great evening!


Weekend Discussion : Eyes on Isaias

Our weekend weather appears rather quiet.  Some standard summer weather to open the first few days of August.  Nothing that should have major impacts on your weekend plans.

So as we turn the calendar to August in the Hudson Valley, it’s the tropics that will grab our local attention.  On Friday, Hurricane Isaias formed in the Caribbean, and as you can see by the 11pm Friday advisory… it’s got the eastern US within its sights.  The ‘cone of uncertainty’ with Isaias is relatively narrow… which means that we have a fairly good idea of what to expect with the track.

You’ll easily notice the upper air pattern provides a path right up the eastern seaboard for Isaias.  An approaching upper level trough will push toward the east coast ahead of Isaias.  At the same time, a large upper level ridge over the Atlantic will be sliding further east.  The area between the two features will be where Isaias makes it’s path.  The biggest uncertainty, is exactly where these features shown above are positioned.  This will mean the difference of a few hundred miles in the track, and the position of the heaviest rains in the coming days.

As it stands right now, this could be the rainfall scenario for the Hudson Valley between Monday and Wednesday…

A period of rain and thunderstorms could develop out ahead of Isaias on Monday, followed by the remnants of Hurricane Isaias on Tuesday.  All told, 2 to 5 inches or rainfall could be possible… with localized amounts over 6″.  The key to everything, is the track.  Which we just mentioned could shift a couple hundred miles either way as it moves up the east coast.  You’ll see in the graphic above, the rainfall swath is now extremely wide… so the amount of projected rainfall is dependent on the path of Isaias.  For that reason, you’ll want to keep an eye on the forecast as we are able to focus in on the details a bit better.

Finally, just to bring some piece of mind to some of you.  Any time we are talking about a tropical storm, one of the first things some people think of, is wind damage.  For the Hudson Valley, Isaias does not present a major concern with regard to wind.

This map shows the maximum wind gusts up and down the east coast from what would be Tropical Storm Isaias.  There are a few hurricane force gusts into parts of Virginia and North Carolina… but further north, gusts up to 50 or 60 mph are possible.  The black curve represents the track Isaias takes on this solution.  This is probably about as far west as Isaias is expected to track (but once again, we need to monitor it closely).  Notice how the strongest wind gusts are to the east of the center of circulation.  So unless Isaias were to take a track even further inland (which the cone of uncertainty suggests is not likely), the strongest wind gusts over 35mph, would be east of our area… mainly over Connecticut and Long Island.  So as you can see, wind damage is not the real concern at this moment… it’s rainfall.

But as always with a situation like this, the details should come into clearer view as we get closer to the event.  Be sure to check back for updates as we get closer.  Have a great weekend!

Tuesday Discussion : “Dog Days” Of Summer

Today will be another hot one throughout the Hudson Valley. Southern regions will see highs in the mid-80’s to near 90° with dew points in the low 70’s. As a result, a heat advisory is in effect for Orange, Putnam, Rockland & Westchester Counties, with heat indexes in the mid-90’s this afternoon. Northern areas will likely stay slightly cooler, especially in the Catskills, with highs near 80°.

A few isolated thunderstorms are possible this afternoon ahead of a cold front (30-40%). Timing appears to be anywhere between 1-7 pm. This will not be a widespread event and while most locations will stay dry, any storm that does form could produce gusty winds and heavy downpours. The Storm Prediction Center has placed our region in a marginal risk (level 1 out of 5) for severe thunderstorms today as a storm or two may approach severe thresholds.

Enjoy your Tuesday!


Monday Discussion : More Heat and Humidity

Mid summer heat across the Hudson Valley on this Sunday afternoon… with temperatures in the upper 80s to low 90s.
3pm Temperatures:
– Montgomery : 86° feels like 91°
– Poughkeepsie : 90° feels like 92°
– Newburgh : 88° feels like 89°
Temps tonight will not cool down too much, with lows in the low to mid 70s expected, with elevating humidity levels. That sets the stage for a hot and humid Monday around the region.
Clouds will mix with sunshine, and highs between 90° and 95° are expected. The humidity levels will increase a bit, making it feel like the mid 90s around the region. There is a roughly 30% to 40% chance of a broken line of late afternoon T-Storms to develop. We’ll have to monitor the threat as things unfold Monday. But we expect a hot and humid start to the week around the Hudson Valley.

Weekend Outlook : Get Out and Enjoy

Somehow, it’s the last weekend of July.  This time of year is statistically the hottest time of the year, with the average high being 85° in the Poughkeepsie area.  So when we look at the weather for this coming weekend, it looks like we’ll be a few degrees above average with comfortable humidity levels for the middle of summer.  Here are your projected high temperatures for NY state on Saturday, Sunday and Monday

Projected High Temperatures: Saturday, Sunday & Monday

You can see the Hudson Valley in the lower right quadrant of the graphic.  Highs in Poughkeepsie projected to be 89° Saturday, 91° on Saturday, and 92° on Monday.  The good news, is that with winds out of the west, humidity levels should be reasonably comfortable.  That means ‘real feel’ heat index values very close to the actual air temperature.  Each day looks to be rather dry, with hardly any rainfall projected by the European model.

So in short… it looks like a great summer weekend on tap for the Hudson Valley!  A fair amount of sunshine… slightly above average summer heat… and comfortable humidity levels.  If you have weekend plans, you should be very happy with what is in store.

Drought Situation

The last few months have been quite dry across the Northeast US.  Much of the rainfall has been dependent on summer afternoon T-Storms.  That means considerable variance from one area to the next.

You can see that the SW half of the Hudson Valley is not in a drought condition.  That’s due to recent rainfall from T-Storms, giving those areas near normal rainfall amounts over the past month or so.  However, the northeastern half of the valley has not seen as much of that rainfall, and is anywhere from abnormally dry, to even in a moderate drought condition as you head into NE Dutchess and Columbia counties.  With minimal rainfall expected over the next few days… that will only intensify drought conditions where it’s already being felt.

The good news, is that there may be some thunderstorms on Tuesday or Wednesday with a cold front.  But we’ll have to continue to monitor that situation as the weekend progresses.

Long Range Discussion

So far in the month of July, temperatures have been quite warm compared to average.  Not hot… but definitely 2° to 5° above average, during the statistically hottest time of the year.

Looking at the next 14 days, into early August… it appears that the focal point of the ridge in the jet stream could shift a bit further west.  This could shift temperatures closer to average for this time of year.

We’ll have to see how the details iron out… but the clear thing to state appears to be that we don’t expect a major cool down at this point.  Summer is here for the Hudson Valley, and while we don’t see any cooler than average weather, we also don’t see any intense heat waves in the next 2 weeks either.

Have a great weekend!!

Thursday Discussion : Unsettled Pattern Continues

Similar to yesterday, today will feature uncomfortably high humidity with a chance of afternoon/evening thunderstorms triggered by a cold front approaching from our west. More clouds than sunshine are expected today, but breaks of sunshine are likely to occur periodically throughout the day, which could cause locally high instability throughout portions of the Hudson Valley.

With temperatures in the mid-upper 80s and dew points in the mid-70s, heat indexes are expected to approach the mid-upper 90s in our southern locations while upper 80s-90° in northern locations, especially the Catskills. Along with very muggy conditions, these ingredients combined will result in a severe threat this afternoon.

Current model guidance suggests storms will begin to develop between 1-3 pm. Storms will move east southeast throughout the remainder of the afternoon into the early evening. The primary threats will be strong gusty winds, small hail, and locally heavy rainfall, which may lead to ponding of water in low lying areas. Currently, the Storm Prediction Center has placed our entire region in a slight risk (level 2 out of 5) for severe thunderstorms today.

Below is a simulated radar for this afternoon (noon-11pm):

Today’s Storm Prediction Center Convective Outlook:

Today’s projected 2 pm heat index values:

Wednesday Discussion : Heat, Humidity & Sct Afternoon T’storms

Another hot day with more humidity than yesterday is expected today across the Hudson Valley. Highs in the upper 80s, approaching 90° along with dew points in the low 70s will result in an uncomfortable air mass. Heat indexes will range anywhere between 90-95° in valley locations. The Catskills will remain slightly cooler with highs in the mid-80s.

Below are projected heat indexes at 4 pm today:

After a few showers late last night into early this morning, breaks of sunshine are expected, which will help further destabilize an already buoyant atmosphere, setting the stage for scattered afternoon thunderstorms. A few storms may be severe with heavy rainfall and strong gusty winds being the main threats. Current model guidance suggests storms will begin to move into western locations between 3-5 pm and will evolve eastward throughout the remainder of the afternoon and evening. The Storm Prediction Center has placed our entire region in a slight risk (level 2 out of 5) for severe thunderstorms. While not everyone will experience severe weather today, always remember to stay weather aware.

Unfortunately, mugginess and unsettled weather will continue on Thursday, with another chance of afternoon/evening storms.

Below is a simulated radar for this afternoon/evening (1-11 pm):

Today’s Storm Prediction Center’s Convective Outlook: