Winter in Noord-Amerika 2015/2016

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Op vrijdag 15 januari 2016 21:02 schreef aloa het volgende:

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dat idd. Het gaat om het verschil in temperatuur. De koude poollicht die over de warmere meren gaat.

twitter:

reedtimmerTVN twitterde op maandag 18-01-2016 om 13:42:50 Confidence increasing for major nor'easter to impact parts of Northeast U.S. Friday PM to Sat incl. DC, NYC, Boston! https://t.co/Ppa4ibW8QE reageer retweet

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Op zaterdag 16 januari 2016 10:16 schreef aloa het volgende:

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Voor veel sneeuw wel.

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'Potential greatest snowstorms in decades'
For an event still several days out, computer models were in remarkable agreement late Tuesday on what could be one of the greatest snowstorms in decades for the region around Washington, D.C. It’s difficult to convey what the models are projecting without appearing to sensationalize the event, but here goes: there is every indication that snow totals on the order of two feet are quite possible across parts of the greater D.C./Baltimore area, with the potential for almost as much in Philadelphia and perhaps a foot toward New York City. Anything over 20” at Washington National Airport would be the greatest snowfall for D.C.’s official reporting station in almost a century (see below).

Although it’s too soon to get too precise about exact amounts and locations, confidence is uncommonly high for a high-impact event in the mid-Atlantic. The 0Z Wednesday run of the GFS doubled down on the prognosis, with projected snowfall amounts exceeding 30” within commuting distance of the district (see Figure 1). As a group, the ensemble members with this GFS run weren’t quite as bullish, but as noted by Capital Weather Gang, the ensemble average still projects a widespread 20” or more over much of the D.C. area. At this writing, the 0Z operational run of the ECMWF model was just coming in, and it appeared just as compelling as the GFS output below in terms of a potential record-breaking storm for the D.C. area.

The making of a winter blockbuster
The impetus for the storm is an upper-level impulse that was moving into the Pacific Northwest late Tuesday. The jet-stream energy will sweep across the mid-South on Thursday into Friday, helping produce a quick shot of snow and ice for parts of Arkansas, Kentucky, and Tennessee. Snow could begin as soon as midday Friday ahead of this impulse over the D.C. area. Then, as the jet-stream energy carves out a powerhouse upper low, a surface cyclone should intensify on Saturday off the Virginia coast--a prime location for big mid-Atlantic snowstorms. In classic fashion, the low-level cyclone will funnel warm, moist air from the tropical Atlantic into the region, with the air mass cooling and generating snow as it rises.

The storm’s expected evolution is “textbook,” said NOAA’s Paul Kocin in an NWS forecast discussion on Tuesday. Kocin would know: he literally wrote the book on the subject with NWS director Louis Uccellini, the classic two-volume ”Northeast Snowstorms”.

There are many failure modes for big mid-Atlantic snowstorms. For example, warm air wrapping around the surface cyclone can turn the snow to rain or sleet, or a dry slot can develop south of the surface low--and of course, the location of key features can shift. At least for the time being, the model depictions are threading the needle around these frequent storm-killers, keeping alive the possibility of a once-in-a-generation event for at least some areas. Snow could fall more or less continuously for an unusually long span of 36 hours or more, heightening the chance of big accumulations.

A serious flood threat for the mid-Atlantic coast
There is more than snow in the works with this storm. The ferocious dynamics at play during the storm’s height could produce winds of 40-50 mph or more, which would lead to blizzard conditions and huge drifts. On top of that, strong onshore winds may produce waves up to 20 feet and major coastal flooding, especially from New Jersey to the Delmarva Peninsula. The full moon on Saturday will only add to the risk of significant flood impacts. In addition, sea-surface temperatures running 5 - 7°F above average should keep the offshore surface air relatively warm, allowing strong winds aloft to mix to the surface more readily than usual for a midwinter nor’easter, as noted by the NWS/Philadelphia office in a weather discussion on Tuesday night. The risk of damaging coastal flooding will need to be watched with the same vigilance as the potential for crippling snowfall just inland.

twitter:

weatherchannel twitterde op dinsdag 02-02-2016 om 13:24:28 #Punxsutawney Phil does not see his shadow, and predicts #spring comes 6 weeks early! #GroundhogDay @AMHQ https://t.co/e2dSGWFZwT reageer retweet

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Op dinsdag 2 februari 2016 13:25 schreef Houtenbeen het volgende:

twitter:

weatherchannel twitterde op dinsdag 02-02-2016 om 13:24:28 #Punxsutawney Phil does not see his shadow, and predicts #spring comes 6 weeks early! #GroundhogDay @AMHQ https://t.co/e2dSGWFZwT reageer retweet

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An extremely dangerous fire weather day is possible on Thursday. Equivalent of a High Risk for severe storms.

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"The highest 24 hour snowfall accumulation for Ottawa was recorded Tuesday with a whopping 51 cm of snow," says Weather Network meteorologist Erin Wenckstern. "That smashed the old record of 40.6 cm of snow set back on March 2, 1947."

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Op dinsdag 5 april 2016 03:04 schreef aloa het volgende:
Nog meer kou deze week en komend weekend.

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http://www.accuweather.co(...)nd-of-april/56489853

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Op dinsdag 5 april 2016 03:04 schreef aloa het volgende:
Nog meer kou deze week en komend weekend.

[ afbeelding ]

http://www.accuweather.co(...)nd-of-april/56489853