Tag Archives: tropical wx

NYC Weekend Weather – Sept 7, 2018

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Cooler temperatures are finally upon us after a very hot and humid week. However, the cooler weather also brings a prolonged period of cloudy conditions, with chances for showers each day this weekend. Rain chances continue into the beginning of next week with a storm system approaching. Long-term, we look towards the tropics, as Tropical Storm Florence continues to have the potential for bringing some impacts to the area.

Rest of today – overcast, with much cooler high temperatures in the mid-70s. Chances for showers, especially later in the day.

Saturday – cloudy with high temperatures remain cool in the low-mid 70s with northeasterly onshore flow behind a cold front draped west-east south of us. This front (which passed through yesterday) will become stationary. Multiple impulses of energy will run along this boundary and allow for continued slight chances of showers.

Sunday – yet another cool, cloudy day with chances for rain. High temperatures around 70°F.

Monday – the stationary front stalled out south of us will return north as a warm front. As this happens, chances for rain increase, along with temperatures rising back into the mid-upper 70s.

Will Tropical Storm Florence Impact the East Coast?

Tropical Storm Florence has been active over the eastern and central North Atlantic for over a week now. Within the last few days, Florence underwent a rapid intensification that brought it up to Category 3 status, making it the first major hurricane of the 2018 Atlantic hurricane season. Subsequently, it has weakened to a tropical storm under relentless strong shear. However, it is expected to reintensify into a major hurricane once shear subsides. Worrying trends in the track forecast for Florence continue to allow for the possibility of landfall on the East Coast, or at the very least, substantial coastal impacts like dangerous surf and beach erosion. However, the National Hurricane Center continues to note that there is considerable uncertainty to the track forecast for Florence, such that it is still too early to determine what effects it will have on the East Coast. This storm will warrant careful observation over the coming days and I will have subsequent updates on it.

NYC Weekend Weather – Jun 19, 2015

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In contrast to last weekend, where Sunday was the better half, the reverse will be true this weekend. Remnants of Tropical Depression Bill will be moving over us on Sunday, bringing the potential for extended periods of showers and heavy rain. It is hoped that this much needed rain will put a dent in the persistent moderate drought conditions in the region.

Rest of today – there is a small chance for thunderstorms up until around lunchtime today, after which skies should gradually clear. High temperatures are expected to top out in the upper-80s to near 90.

Saturday – high pressure will be shifting to the east, bringing in an onshore flow, keeping temperatures cooler in the upper-70s under partly sunny skies. Chances for rain will be increasing steadily through the evening such that by the overnight hours, periods of steady rain should be the norm.

Sunday – As referenced above, remnants of Tropical Depression Bill, still carrying tropical moisture, will be moving over the region. There is still some uncertainty as to whether the areas of heaviest rain will move further south and over the ocean, however, at this point it seems likely that Sunday will feature periods of steady rain, heavy at times. Rainfall probability and rainfall totals will drop precipitously from south to north, since the storm center is expected to track to our south. We could pick up as much as 1″-1.5″ of rain over Long Island, which would be a blessing since this area is still in the grip of moderate drought conditions. With clouds and rain, high temperatures should top out around 80.

Quantitative Precipitation Forecast for Sunday
Quantitative Precipitation Forecast for Sunday
North American Model high resolution output for Sunday at 11AM EDT
North American Model high resolution output for Sunday at 11AM EDT 
Drought coverage in New York as of this week
Drought coverage in New York as of this week

Monday – conditions improve following the passage of the storm on Sunday, with high temperatures rebounding into the mid-upper 80s under mostly sunny skies.

Tropical Weather Update | Typhoon Hagupit – Dec 5, 2014

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A potent and massive typhoon is taking aim at the northern Philippines, in particular, Samar Island. Some of these areas were devastated by Category 5 Super Typhoon Haiyan less than one year ago, which broke the record for strongest landfalling tropical cyclone with wind speeds measured in Tacloban of 190mph. If you have friends or family in the Northern Philippines, Hagupit certainly bears keeping an eye on. Luckily for Tacloban, the current forecast track should take the center and northern semicircle (the stronger portion) of the storm north of the area, which should spare the area worst hit by Haiyan from another direct hit and the worst effects of a typhoon.

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Infrared satellite imagery of Typhoon Hagupit – note the symmetrical appearance of the inner portion of the storm, along with a well-defined eye (classic signs of a very strong storm).

Forecast Track

From the image below, you’ll see that Hagupit is currently forecast to move slowly west-northwestwards over the next 48 hours. Due to the strength of the storm, and the uncertainty surrounding the steering mechanisms in place (a subtropical ridge – high pressure area to the north weakening, and a frontal boundary), there is a low degree of confidence over the overall track forecast. However, it does appear, even with the uncertainty factored in that the storm center will pass to the north of Leyte Island and Tacloban, which was devastated by Super Typhoon Haiyan. That’s good news, since this would mean the weaker, southern semicircle of Hagupit would pass over the Leyte Gulf area. This would significantly reduce the effect of a devastating storm surge, since the winds from the storm would not have the best fetch (distance over open water) to build up a storm surge. In effect, with the current track, the strongest winds would be deflected by the terrain of Samar Island, sparing Leyte Island.

It is worth noting, based on this current track, that Legazpi City in extreme southeastern Luzon Island would bear the worst of the storm, including what could be a devastating storm surge. The bay east of Legazpi could serve to funnel storm surge westward under the right conditions, amplifying the effect of the surge in a similar (though less intense) manner as Leyte Gulf and San Pedro and San Pablo Bay did for Tacloban in Haiyan.

wp201422_5day

 

Haiyan_2013_track
For comparison, the track of Super Typhoon Haiyan in November 2013. Dots indicate position of the center of the storm every 6 hours, the colors indicate strength, with red indicating Category 5.

Intensity Forecast

Typhoon Hagupit has well-established outflow in the northern quadrant, as you can see from the satellite image above (white streaks fanning out from the center of the storm). It is being affected by easterly vertical wind shear, hence the absence of the same outflow bands in that sector of the storm. Hagupit has already weakened from a Category 5 Super Typhoon, but is still forecast to approach the Philippines as either a strong Category 3 or weak Category 4 storm, which would mean wind speeds likely in the range of 110-120mph. After landfall, Hagupit should weaken dramatically as interaction with the mountainous terrain of the Philippines disrupts the typhoon’s dynamics.

Weekend Weather, Hurricane Arthur Update – Jul 4, 2014 @ 10AM EDT

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As of 9AM EDT, Hurricane Arthur has weakened somewhat from its peak intensity as a Category 2, and sustained winds have declined to 90mph. However, its eye is still clearly visible, and as you can see below, the storm is maintaining a symmetrical appearance with good outflow in all quadrants, meaning this is still quite a powerful storm. As Arthur continues moving northeast, it is expected to weaken rapidly upon entering much cooler waters and with increasing vertical shear from the codl front seen below.
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Track Forecast

Forecast models are in very close agreement about Arthur’s track over the next 12 hours or so. As you see below, they are tightly clustered around the 40N, 70W benchmark. Hence, forecast reasoning has not changed much since yesterday night. Arthur is expected to continue its northeast track and speed up under the influence of the cold front depicted above, moving offshore of New England and into the Canadian Maritimes as it makes extratropical transition.

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What This Means for Us

As expected, Arthur will be bringing multiple rounds of rain to the entire Northeast over the course of the day today. You can already see Arthur’s outer rain bands on our regional radar (you’d see it in the standard 124 nautical mile radar, but I’ve inserted an image of 248 nautical mile range radar image to see the storm better). As Arthur accelerates and makes its closest pass to this part of the country, we’ll see repeated bands of rain moving on shore. You can expect periods of heavy rain and thunderstorms, interspersed with some dry spells under cloudy skies.

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The Rest of the Weekend

Once Arthur and the cold front clear the Northeast, we will see a return to a spectacular weekend with high pressure building back in. Sunny skies, mild, and dry conditions will prevail across the entire region with high temperatures in the low-mid 80s on both Saturday and Sunday. As the high pressure moves to our southeast, we’ll see a return flow from the backside of the high pressure ushering in another warm, humid airmass for the beginning of next week.

 

Tropical Storm Arthur Update – Jul 2, 2014 @ 18:00 EDT

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Current satellite imagery of Tropical Storm Arthur shows a storm that is increasingly organized, with well established outflow in all quadrants, a symmetrical appearance, and spiral bands around the whole storm. An eye feature continues to grow more clear. The National Hurricane Center current analysis of Arthur indicates a storm with sustained winds of 70mph, just below the 75mph criteria for a Category 1 hurricane.

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Intensity Forecast

Current forecast reasoning shows low wind shear conditions over the next 48 hours, which should allow Arthur to continuously strengthen. Max winds are currently forecast at 85mph.

Track Forecast

As of right now, it seems Arthur has taken a jog to the west, so model forecasts have been pushed west as well. As a result, portions of the Outer Banks in North Carolina have now been placed under a hurricane warning. This slightly more westerly route also means increased potential for impacts in southeastern New England late Friday into Friday night. For NYC, we’ll be looking at soaking rains from the tropical moisture brought up by this storm tomorrow as well as Friday, however, confidence is decreasing that Arthur will rain out our fireworks in NYC.

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