Aug 21, 2013: Stormier Pattern Next Week

Forecast Highlights:

patternAnother day of warmer than average temperatures is expected across the area today, with temperatures in the immediate NYC area climbing to near or slightly above 90 degrees. A cold front will move through on Thursday night, producing scattered thunderstorms during the day, followed by a cooler, dry and mostly sunny weekend. A pattern change currently underway, however, will lead to a more active and stormier pattern next week as the region sits near the boundary between a significant heat wave to the west and cooler temps to the east.


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Tuesday, August 20 Observations:

8.20.13As a high pressure built back into the region, a warmer air mass returned with temperatures returning to above average levels along with slightly more humid conditions. Partly sunny skies were observed on Tuesday across the area with temperatures warming up to the mid to upper 80s for most, peaking at 90 degrees in Newark, making it the first time in nearly a month that Newark reached 90 degrees. The coolest high temperature was 83 degrees in Port Jervis, NY and Danbury, CT. The rest of NYC fell just short of the 90 degree mark, with LaGuardia peaking at 89 and Central Park at 88.




Today – Weekend: Some Storms, Then Cooler Weekend

The high pressure will remain in place near the region today, with mostly to partly sunny skies, southwest winds, and temperatures warming up again into the mid to upper 80s across the area, with parts of the immediate NYC area near or slightly over 90 degrees. While this marks the warmest time frame of the month so far considering most of the month has seen near-below average temperatures, these temperatures are not unusual for this time of the year in August. A pre-frontal trough will move through the area on Thursday, triggering scattered non-severe thunderstorms, which should result in slightly cooler high temperatures, in the mid 80s for most and the mid to upper 80s in the immediate NYC area.

The cold front will move through on Thursday night, with drier conditions returning for Friday and the weekend. Mostly sunny skies are expected on Friday with highs in the low to mid 80s along with a north wind. Partly cloudy skies are expected overnight with lows falling into the low-mid 60s in NYC and the immediate coast, low-mid 50s inland, and the mid-upper 50s elsewhere. Mostly sunny skies will return for Saturday and Sunday with a NE wind and highs reaching the mid 70s inland and the upper 70s to near 80 degrees for the rest of the area. The coolest overnight lows are expected on Saturday night, with mostly clear skies, lighter winds, and lows falling into the upper 40s-low 50s inland, mid 50s in the north/west suburbs, south CT and east-central Long Island, and the low 60s in NYC and the immediate coast.

Next Week: Stormier Pattern Develops

patternAs noted with yesterday’s forecast update, an increasingly amplified pattern is developing for next week, consisting of strong ridging centered over the central US resulting in a significant heat wave with widespread high temperatures in the 90s and 100s, making it the most widespread heat wave of the summer in that region which has seen a relative absence of sustained heat compared to last year. The northeast US region will be kept under a northwest flow aloft, sitting in between the ridging to the west and a trough pattern to the east in southeastern Canada, which will result in a stormy ending to August as shortwaves ride along the northern end of the ridge then dive southeast into the region, bringing brief surges of strong heat focusing primarily west and south of the area, followed by frontal passages bringing rain and thunderstorms, possibly strong/severe for some, and cooler temperatures especially further north and east. The main uncertainty in the pattern is regarding how far east the ridging extends, which will determine the risk of rain/thunderstorms for the area and how warm temperatures end up.

The first storm is indicated to affect the area towards the Tuesday-Thursday time frame, with a surge of heat focusing in the Mid Atlantic bringing temperatures into the upper 80s and 90s, while rain and thunderstorms spread into the Northeast US and the NYC area. At this time, temperatures are likely to reach the mid to upper 80s in the area, especially west of NYC, although as previously mentioned there is some uncertainty regarding the eastern extent of the heat, and some 90s cannot be ruled out. Stay tuned for more information on next week’s outlook over the next few days.

12 thoughts on “Aug 21, 2013: Stormier Pattern Next Week

  1. Eduardo Berroa Reply

    Recntly, I’ve caught an very loud airmass t’storm rapidly weakened near and then suddenly exploded over the Bronx… Nearly windswept torrential downpours, 10-20 mph winds and occasional-to-frequent rumbles of thunder and cloud-to-ground lightning flashes and strikes. According to the Current Data from Wunderground, rainfall were estimated up to 1.27 inches and however, I’d bet some local thunderstorms are possible later today I’ve guess.

    • NYC Area Weather Post authorReply

      Some of the storms in the area, especially near and south of NYC, have produced totals locally up to 1-3 inches. This round of storms should end by 1-2 PM, with a few isolated storms possible later in the evening but with additional widespread storm activity like this morning is unlikely.

    • NYC Area Weather Post authorReply

      Additional isolated storms are possible later this afternoon and evening especially inland, but with otherwise no additional widespread heavy thunderstorms likely.

    • NYC Area Weather Post authorReply

      Mostly in the mainland, especially towards western NJ and SE NY where additional scattered activity is possible; most of the short range models keep Long Island and southern CT dry for the rest of today, although a few isolated showers/storms can’t be ruled out towards central-west LI.

  2. Anonymous Reply

    Thank you! I am just having vacation on Long Island now that I need to know the weather well.

  3. Anonymous Reply

    Oh, and by the way, could you please tell me if there are any showers expected in Suffolk County, Long Island tomorrow (Friday)?

    • NYC Area Weather Post authorReply

      Tomorrow should be mainly dry across the area as a whole, although a few isolated showers are possible in Long Island towards the evening/early night hours.

  4. Anonymous Reply

    About at what time will the chance of showers start in Long Island?

    • NYC Area Weather Post authorReply

      If light rain does fall tomorrow, it would likely be after at least 6-8 PM based on the latest model guidance; most don’t show any rain, and the probability of showers is lower than today as the cold front will already be offshore by then, although with a weak vorticity max moving through I can’t completely rule out at least isolated showers.

  5. Anonymous Reply

    Thank you very much for letting me know! My vacation ends tomorrow; your weather updates greatly informed me!

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