MID ATLANTIC NY PA NJ DE MD DC MID ATLANTIC NY PA NJ DE MD DC

DEC 16 5:00PM Storm #1 This weekend. Houston we have a cold air problem.

Discussion started by robweather 2 years ago

We are still under the influence of a maritime Pacific air mass and this once again creates marginal temps at the lowest 1000 feet of the atmosphere. Throw in no blocking from high pressure in Canada or New England and you get a storm wanna be.

Screen Shot 2014-12-16 at 5.01.32 PM

MARITIME POLAR AIR MASS

The source region for mP air is over cold ocean currents or high latitude ocean waters. This air does not have as much moisture content as mT air. Since mP air is always near saturation, orographic lifting of the air mass can produce widespread rain or snow.

This air mass is notorious for producing fog, drizzle, cloudy weather and long lasting light to moderate rain. The temperature of mP air ranges from just above freezing to below 70 degrees F. mP air is modified as it moves over elevated terrain.

On the windward side of mountain ranges, mP air can produce an abundance of rain and snow. Once on the lee side of mountains, the mP airmass modifies into a continental airmass.

These air masses produce cold fronts but the air is not as cold as polar or arctic fronts. They are often termed "Pacific fronts" or "back-door cold fronts". Maritime Polar air occurs frequently in the Pacific Northwest and to a lesser degree in New England.

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MARTIME NOW...ARCTIC LATER

Screen Shot 2014-12-16 at 5.46.05 PM

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MODELS MODELS MODELS

If this storm ends as nothing more than a light event offshore the GFS will win the mid and long range model war on this one. The Europoean model took the early lead this fall with the mid and long range game so this would make it 1 for the GFS and 2 for the Euro.

Screen Shot 2014-12-16 at 6.07.17 PM

The Operational European model above shows just enough cold air to support some wet snow but this model may be 1-2 degrees too cold. Even if this is snow the this model only shows the following precip for the event. 

Philadelphia .13" (Sat Night into Sunday AM) 

Allentown .18" (Sat Night into Sunday AM) 

Wilmington .14" (Sat night into Sunday AM)

Baltimore .15" (Sat. Evening into Sunday AM)

DC Metro .17" (Sat. late day into Early Sunday)

NYC Metro .20" (Sunday early AM to Sunday PM)

Temps are warmer at the surface at 34-37 at night and 42 during the day. This would mean the wet snow, if it's all wet snow, would be not sticking to the ground.

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Screen Shot 2014-12-16 at 9.59.06 PM

The Euro ensembles added the moisture but it still a marginal temp event. The coldest air is in the lightest moisture so this overall is still not a huge event.  The map on the right is the temps at 5,500 feet and the rain snow line is the blue dotted line on the left map.

 

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toNY
toNY
Well if the storm rides up the coast like the euro 0z run just showed than we may indeed trend towards a -NAO. It's possible we could get a miller A storm snowstorm in our hands this weekend.
2 years ago
robweather
robweather
The key is the trending of the NAO and AO. Pop those in the right spot the moisture will be there. The moisture will be here all winter…I have the need for the Arctic Freeze.
2 years ago
FreezeMizer
FreezeMizer
I hear you. Work has been brutal this entire year. And next year is shaping up to be worse. So maybe there is a correlation between that and our crushing winters?? Hahaha...

The NAO is the wild card this year. Everything else looks like they want to play in the same sandbox.
2 years ago
WildWeather
WildWeather
Hey Freeze and all sorry for not being on. I have been super busy at school.... Yes things are going to get really interesting after Saturday Night looking into next week. El Nino means the Child in Spanish. El Nino typically begins to be realized around Christmas which is why it has been named El Nino correct me if I am wrong.

I love our chances this year of seeing a few biggies just have to time up everything perfectly and a -NAO must be a part of the equation or our snow chances become rain chances off the relatively warmer than normal Atlantic Ocean.

The Atlantic this year will giveth or taketh away!!
2 years ago
FreezeMizer
FreezeMizer
Hey Kevin - how's it going?

yes. yes. yes. we've seen this many times. It's getting very interesting....finally.
2 years ago
WildWeather
WildWeather
No doubt this storm is the lead blocker as you say Rob for a more significant storm in time for Christmas Day!! In this new pattern that is pending we will need the NAO to be negative to get the big snows mark my words. This pattern is not a repeat of last year where it will snow despite having a +NAO.

I truly think we get most of our snow this year from 2 or perhaps 3 big storms dropping 8+ inches the reason why I was going with a range this year of 16-26" or so.

The NAO playing along side the developing weak El Nino will tell the tale of this Winter 2014-2015. The writing is on the wall before it happens!
2 years ago
ballz97fm
ballz97fm
Removed
2 years ago
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