February 1-15: A Snowy Pattern Unfolds

[donsutherland1]

If this info. was posted during the past few days, I apologize for the duplication, as I missed it.

In another indication that the long-awaited pattern change could bring a period of below normal readings to the eastern United States, the ECPC/NCEP GSM model has now swung to cold anomalies for the eastern U.S. for the 2/11-18 week. The following week also is forecast to be somewhat colder than normal. The earlier run had the 2/11-18 period warmer than normal.

1/21/2006 Run:


1/28/2006 Run:


All said, this development and the colder ideas on the 2/1 12z ECMWF, etc., increase my confidence that the pattern will be evolving toward a snowier and colder one, especially from near the end of the first week in February onward.

[Portastorm]

Thanks Don! I really appreciate your posts.

Hope you had a great vacation.

[Stephanie]

I agree. This is the first end of January in at least ten years that I can still see my front lawn. I was able to take down my Christmas decorations yesterday. Which I usually can't do because the ones on the ground are buried in snow and ice up to the middle of March, or sometimes later. I'm with you on this one, I'm not complaining.

Well, it was quite short-lived, wasn't it? I saw your post about that blizzard.

[Hybridstorm_November2001]

Doesn't seem to snowy to me Is actually raining here with mild temps currently, and in the long range it only shows cold though not bitterly so, and flurries over the Eastern sea board and back through the Great Lakes .

[donsutherland1]

Brief update: Colder Pattern Has Arrived, Snowier One Likely to Develop

On January 25, I posted the following expectations for the February 1-15 period:

∙ February 1-7: Temperatures from Washington, DC to Boston should average near normal to somewhat above normal. As previously discussed, the cooldown is likely to be gradual.
∙ February 8-15: Overall readings in the Richmond to Boston areas should be somewhat below normal.. There is a chance of at least one or more days lows < 20° from Richmond to Boston.
∙ Washington, DC, Philadelphia, New York City, and Boston should all see some accumulations snow in the first week in February. More significant accumulations are possible during the second week.


I also noted that I expected above normal snowfall for the month as a whole with the following monthly estimates:

Boston: 12” or more
New York City: 10” or more
Philadelphia: 10” or more
Washington, DC (DCA): 8” or more

So far, it appears that things are just a little behind schedule. First, I expected the Feb. 1-7 period to see near normal to somewhat above normal temperatures. It was not yet supposed to become cold. Readings in the East will probably run 9° above normal +/- 2° depending on location. So the warmth was stronger and a little more persistent than I had expected.

Hence, the idea of at least a little snow in the first week of February for parts of the East will likely prove incorrect.

So does this mean that the entire idea of a turn to below normal readings and then a snowy February is in jeopardy?

I strongly believe it does not for several reasons:

1) The overall trend of a cooldown is real and is underway. The February 8-15 period per the latest guidance looks to see at least somewhat below normal readings. So on that end, the pattern should "catch up" to where I had expected.

2) Some of the ensemble members and guidance points to a potential storm to impact parts of the East Coast next weekend (Sunday-Monday?). Details remain to be resolved, but at least there's a potential event on the proverbial playing field. With plenty of cold nearby, accumulating snow could be a threat. Even if this event doesn't work out, more opportunities appear likely.

3) After mid-month, the NCEP ensemble mean 500 mb anomalies have persistently been showing the development of a pattern that is favorable for overrunning snows. In fact, in the longer-range, the ensembles hint at a pattern that is remarkably similar to that of around February 8, 1994, which featured one of the great overruning patterns of the 20th century. One difference is that perhaps the boundary for snow would run somewhat farther to the south than in 1994. This is not a guarantee of such snows, but a hint of where the pattern might be headed in terms of snowfall potential.

NCEP ensemble mean 500 mb anomalies for 2/19 0z:


500 mb height anomalies on February 8, 1994:


Conclusion:
In spite of the early stumble--readings were warmer than I had expected and no snow is likely across much of the East (maybe limited snow showers in some spots) through Feb. 7--things remain on track for what I continue to believe will be a snowier than normal February in the Mid-Atlantic and Northeast.

[Hybridstorm_November2001]

000
FXUS61 KCAR 061908
AFDCAR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
208 PM EST MON FEB 6 2006

.SYNOPSIS...LOW PRESSURE WILL DRIFT SLOWLY NORTH INTO LABRADOR
WHICH WILL PROVIDE PLENTY OF CLOUDS AND POSSIBLE SNOW SHOWERS
THROUGH MID WEEK...ESPECIALLY ACROSS NORTHERN MAINE. HIGH PRESSURE
WILL BUILD ACROSS THE REGION BY THURSDAY GIVING PARTLY CLOUDY
SKIES REGION WIDE. WEAK LOW PRESSURE MOVING EAST FROM THE GREAT
LAKES COULD BRING ANOTHER CHANCE OF SNOW SHOWERS TO THE REGION
THIS WEEKEND.

&&

.SHORT TERM (TONIGHT THROUGH WEDNESDAY)...
EXPECT THE FORECAST AREA TO BE IN CYCLONIC FLOW AND UNDER UPPER
TROF THRU THE SHORT TERM PERIOD. BOTH NAM AND GFS SEEM TO DO A
GOOD OVERALL JOB OF HANDLING THIS. STRATEGY IS TO BLEND GFS/NAM.
FOR TEMPERATURES...DEW POINT AND WINDS OVER LAND HAVE POPULATED
GRIDS WITH MAV/MET MOS. OVER THE COASTAL WATERS HAVE USED NAM12
GUIDANCE. HAVE USED GFS SKY COVER. FOR POP HAVE USED MAV/MET MOS
BUT HAVE INCREASED POPS AROUND 06Z TONIGHT WITH A SHORT WAVE
MOVING THRU...OTHER WISE HAVE HIGHEST POPS ACROSS THE NORTH AND
HIGHER TERRAIN DURING THE REMAINDER OF THE SHORT TERM PERIOD.
SHORT WAVES MOVING THRU IN THE CYCLONIC FLOW NEXT SEVERAL DAYS
WILL BE DIFFICULT TO TIME. FOR QPF HAVE USED 50/50 BLEND OF
GFS/NAM. MOST QPF MINIMAL BUT HAVE USED SNOW DENSITY TOOL FOR SNOW
ACCUMULATION.

&&

.LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...
LONGER RANGE MODELS CONT TO BE CONSISTENT WITH INDICATING A MAINLY
DRY WNW FLOW PATTERN...WITH FAST MOVING WEAK S/WVS. DUE TO DAY TO
DAY DIFFERENCES OF TIMING OF THESE S/WVS...CLDS AND POPS HAVE TO
BE RE-DONE. IN ANY EVENT...WE DO NOT INDICATE GREATER THAN CHC
SN SHWR POPS ATTM. AGAIN WENT WITH A MIX OF HPC AND 06Z GFS DATA
FOR OUR GRIDS...WITH 12Z GFS/NAM ADDED FOR PDS 5 THRU 7 TO
TRANSITION FROM THE SHORT RANGE GRIDS. USED A BLEND OF HPC AND GFS
ENSEMBLE DATA FOR HI/LOW TEMPS IN THE LONG TERM.


Source: http://www.nws.noaa.gov/data/CAR/AFDCAR

[Hybridstorm_November2001]

The above is the forecast discussion for my general area. If your prediction of a snowy February 1-15 is to come true, things are going to have to drastically change pattern wise, and soon.


Sorry, but I just don't see that in the cards. At least not before the start or middle of next week (13th - 15th) at the earliest.

[donsutherland1]

Hybridstorm_November2001,

The snowfall totals are for all of February. I expect things to grow snowier beginning in the Feb. 8-15 period. Afterward, the GFS ensembles continue to point to a potentially potent overrunning period, but that's just beyond mid-month and too speculative to embrace just yet.

[Stephanie]

Well, the cold is back - right on schedule don!

I'm too used to the warm air! I've been very spoiled so far.

[AnthonyC]

Don,

What are your thoughts for the PNW regarding retrogression and a colder pattern? Most models agree a negative PNA will evolve and retrogression will happen in about a week. Do you think this will happen? Do you see arctic cold/snow for the lowlands of the PNW?

Anthony

[bob rulz]

How cold and snowy do you see it getting for the Intermountain West? I haven't heard anything about it, just about how cold and snowy it's getting for the east.

[donsutherland1]

AnthonyC,

Through February 15, I believe the Pacific Northwest will continue to experience above normal readings. However, afterward, a colder pattern should set in and there may well be a chance that parts of the Pacific Northwest (including Seattle and Vancouver) might at least have the opportunity for some snowfall. It appears that the below normal temperature regime will probably last at least a week but I'm not yet sure about the magnitude of the cold.

[donsutherland1]

Bob rulz,

This is still not a high-confidence matter. While some cold could seep into northern and eastern areas of the Intermountain West, the coldest air might avoid this area. In fact, the NCEP ensemble means continue to argue for normal to somewhat above normal readings, especially the farther south one goes. It's a very tough call right now.

[donsutherland1]

Stephanie,

Now let's see if the snow can come back. I still strongly believe that the pattern evolution will lead to the potential for cold and a lot of snow (e.g., I still have strong confidence that Philadelphia will finish with 10" or more by the time February comes to a close).

[Stephanie]

We still have alot of February left don. Anything is possible!

[Dave C]

The latest discussion from Taunton, Mass NWS looking very interesting!!
http://www.erh.noaa.gov/box/products/BOSAFDBOX

[JBG]

The latest discussion from Taunton, Mass NWS looking very interesting!!
http://www.erh.noaa.gov/box/products/BOSAFDBOX

See this one:

See this one (Link)
048
fxus61 kokx 082031
afdokx


Area forecast discussion
National Weather Service Upton New York
331 PM EST Wednesday Feb 8 2006


Short term (tonight and thursday)... yet another trough of low
pressure/weak cold front is sinking south through the region this
afternoon/evening producing some scattered flurries as it passes.
Will reflect the remainder of this afternoon in the zones to
reflect scattered flurries. With loss of solar heating clouds should
thin out this evening (where the exist over western portions of County Warning Area
now) and winds should diminish to around 5 miles per hour or so. The
relatively light winds and minimal sky cover should allow for
decent (though not ideal) radiational cooling to set up...ad given
dew points around 10 by sunrise...expect most locations in New Jersey/CT
and inland New York locations to have lows generally 15-20 (along west/ the lifted index
Pine barrens)...W/ lows 20-25 New York metropolitan and most of Long Island
(consistent west/ blend mav/met/FWC guidance).


With low level thickness prognosticated to be about the same (maybe a tad
cooler) than this afternoons values...expect highs around
todays...and consistent with blend of mav/met/FWC guidance. Do
expect low level downslope flow and increasing subsidence as high
builds in from SW to have sky conditions trend to M sunny by
afternoon.


&&


Short term (thursday night through saturday)...
as things in the longer term are trending towards a European model (ecmwf)/GFS
blend (more on this below)...leaned more towards GFS in the short
term. Thursday night should be dry as high pressure builds offshore to our
S...W/ lows generally a tad warmer than tonight as west-SW return flow
sets up late (once again blend of mav/met/FWC guidance used for
low temperatures). Because of phasing insouthernated west/ southern stream GFS has clipper
like system for Friday/Friday night passing slowly to our N/W...as a
result will be under a prolong period of weak middle level warm air advection and
positive vorticity advection...but with SW flow in low levels (typically a drier
flow)...have only gone with slight chance probability of precipitation for snow Friday and Friday
night. While it appears precipitation likely should end late Friday
night...overall uncertainty warrants having slight chance probability of precipitation
all of Friday night.


Given expected cloud cover went with cooler FWC numbers for highs
Friday (mainly m30s west/ some areas across north/west zones a30)...and with lean
towards GFS used mav numbers for lows Friday night. Should be between
the clipper and potential coastal storm Saturday...however given
expected passage (regardless of model) of weak 500 mb short wave...have
slight chance probability of precipitation all day Sat...though did transition form SW to S
in the afternoon to reflect possibility of steadier precipitation
developing ahead of potential coastal low...though it appears that
regardless of model that any snow fall received on Saturday would
be very light...probably not even amounting to a dusting.


&&


Long term (saturday night through wednesday)...
basically 2 model camps the Canadian/NOGAPS/extension of NAM west/ a
weaker system passing well offshore (but quite a bit slower than
other camp)...this would spell no precipitation for the
region...just continued cold. The other Camp is the
GFS/UKMET/ECMWF which have a coastal low deepen off near the southeast
then middle Atlantic coasts Sat and Sat night and then pass somewhere
southeast of Cape Cod from Sunday into Sunday night. Have opted for the
latter Camp for now as most models have trended in this direction
over their past few runs.


For now European model (ecmwf) is in between UKMET and GFS track (and a tad slower
and weaker)...so basically followed as a compromise...but note
that many GFS ensemble members support the operational 12z GFS
solution so the situation bears close watching. For now have gone
with chance probability of precipitation for snow Sat night and Sunday...then slight
chance probability of precipitation eastern 1/3 Sunday night as storm departs. While there is
the potential for significant snows...especially across eastern
portions of the area...there is too much uncertainty to issue any
statements at this time...especially when the chance that we could
get nothing is running about 30-40 percent in my opinion. The only
place regardless of model chosen where p-type might be an issue is
well offshore (20+ miles out so went with mix r/S there).


Behind the storm high pressure builds in from the west to our S Monday
and Tuesday then moves offshore Wednesday...keeping conditions dry and
allowing for a gradually warming to the 40s by the middle of next
week. Throughout the extended period used cooler men (mex ensemble
mean) numbers for high/low temperatures.


Thanks box/hpc/aly for excellent coordinate on extended.


&&


Aviation...
VFR conditions at all terminals through 18z Thursday. Lead short wave
moving through the middle Atlantic this afternoon has generated a
widespread middle level cumulus field and even a few snow flurries...although
most of the activity is remaining virga due to dry low levels. In
any case...expect ceilings/visibilities to remain well above VFR mins through
the period. A series of additional weak shortwaves will keep scattered-broken
middle level clouds around the area...but do not expect any significant
precipitation for tonight or Thursday.


&&


Marine...
winds and seas will remain below Small Craft Advisory criteria through
Thursday night on a light westerly flow. Seas will increase to
just below Small Craft Advisory levels on ocean waters late Thursday afternoon as
the waters will be sandwiched between high pressure to the south
and low pressure to the north. Seas will continue to be near
marginal Small Craft Advisory levels through Friday night. A coastal storm is
expected to develop Saturday south of the region and track
northeast through Sunday. Latest wna guidance is showing 18 feet
waves for the ocean waters...have cut those numbers back to 8 to
12 feet. In addition...gale force winds may be possible over the
weekend.


&&


Hydrology...
no significant precipitation expected through Saturday. There is the
potential for significant liquid equivalent to fall Sat night into
sun (however this should be in the form of snow - if precipitation
falls - and have minimal hydrologic impact)...but given the
uncertainty will just to continue to monitor for now.


A Flood Warning continues for low lying sections along the lower
Connecticut River...including Cromwell...Middletown and Portland.
The flooding is expected to be minor...and the river should fall
below flood stage at Middletown by 7 PM this evening.


&&


Okx watches/warnings/advisories...
CT...none.
New Jersey...none.
New York...none.
Marine...none.
&&


$$


Short/long term...pfm
aviation...cj
marien...British Columbia

[bob rulz]

Bob rulz,

This is still not a high-confidence matter. While some cold could seep into northern and eastern areas of the Intermountain West, the coldest air might avoid this area. In fact, the NCEP ensemble means continue to argue for normal to somewhat above normal readings, especially the farther south one goes. It's a very tough call right now.

Damn. I'm in the eastern and edge of the Intermountain West but closer to the center north-south (inland Washington and Oregon count as the Intermountain West right?). Hopefully that cold hits here. I love cold weather, we haven't gotten enough of it in the last few years. What about the probability for precipitation here?

Also, AccuWeather is pointing to the possibility of a major Nor'Easter this weekend. Yes, I know, it's AccuWeather, but their headlines are usually accurate (as opposed to their actual forecasts, which suck).

[Hybridstorm_November2001]

Looks like I could be eating crow My hat is off to you donsutherland1. Bravo on the great long range forecast!

[AnthonyC]

Thanks Don!

If you have any further information regarding this possible pattern change for the PNW, keep us informed!

Anthony