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Rainshadow

February/March Meteorological Pattern Discussion.

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00z Jan 19th GEFS

Above normal 500mb heights return on the 22nd thru the 24th preceding the next system.  On the 25th when below normal heights return (been consistent for a week). We still have an Aleutian trof, eastern Pacific ridging, eastern NOAM troffing, -NAO and Hudson Bay TPV outlooked.  Angle of the coldest looks west of us.  This is pretty much the same story through its run (NAO may become more negative, well anyway outlooked).  But starting about February 1st, the Pacific flow looks more zonal even with our heights still below normal.  the above normal SE heights are gone.  Our heights return to near normal at the very end on February 3rd.  If the GEFS bias is consistent, this is probably a week too fast at flattening the Pacific.  We will follow the can.

NAEFS for the week of 1/27-2/3 is finally confident of below normal temps here.

 

00z Jan 21st GEFS

Above normal heights return on the 22nd thru the 24th preceding the next system.  On the 25th when below normal heights return.  Can see the double barrel energy in the troffing and the early next week system with a neg tilt look to it.  On the 28th the NAO (as an index) looks positive, there is an Eastern Pacific Ridge and the PV in Hudson Bay not as great looking as earlier.  Rest of January pattern is retrogressing (ridging thru Alaska on the 31st) as above normal heights return to our area.  Angle of cold outlooked farther west.  This is faster than two days ago. As February starts, the flow over the Pacific becomes more zonal, tight atypical nino pattern with below normal heights in Canada and above normal heights southern conus. 3rd thru the 5th our heights are near normal. South of Alaska troffing is outlooked at end of the run.

NAEFS for the week of 1/29-2/5 is confident of below normal temps starting just north & west of the Philly metro area westward thru the Northern Plains.

 

00z Jan 23rd GEFS

Current above normal 500mb heights are replaced by below normal heights on the 25th.  This persists thru the 30th, although the > of the cold gets farther west as a northwest Atlantic ridge tries to retrograde west.  Above normal heights eke to the west into our area as February starts.  This is a day later than two days ago.  On February 1st, we see a closed ridge over the Bering Sea; a zonal looking ridge/trof/ridge pattern across the conus.  The EPO looks weakly positive, the nao is negative and a weaker TPV over northern Hudson Bay.   Our 500mb heights are near normal until the 4th (below) by product of a cold shot. The Pacific does not look cold with ridging in the Aleutians and troffing across the eastern Pacific. Above normal heights (yeah la la la la la land)  envelope most of NOAM at the end of the run on the 6th and 7th.

Personally though I can see this happening as a reboot or change given this is about the 3 week mark of the SSW vs what the GEFS was previously pushing about this occurring a week earlier.  Granted by then the MJO could be in colder phases and thus negate it altogether.

NAEFS for the week of 1/31-2/7 is slight confident of below normal temps in our area, guessing cold weighted to the start of the week now that the GEFS has chilled.

 

00z Jan 26th GEFS

Current below normal 500mb heights pretty much persist through February 2nd.  The TPV passing to our north re-inforces this.  Above normal heights arrive from the west on February 3rd. It is a net loss of two days from the previous post (three days). Dollar cost averaging or not, this is a pretty zonal looking flow as of February 3rd with the epo weakly negative (no ridge thru Alaska), +nao, -pna and TPV retraction to Baffin island.  Above normal heights persist into February 9th until the TPV starts sinking to Hudson Bay again.   The EPS & GEPS do not look like non stop warmth from February 4th thru the 10th, but they do show an overall warmer pattern relaxation.

NAEFS for the week of 2/3-2/10 is confident of near normal temps in our area.  Given the way this has worked this winter, i'd say that 8 day period would average above if the ensembles are semi-close.

MJO is currently in Phase 5 (from Mike's site), new outlook is for a more stout MJO for the umpteenth time this winter. Using a two week lag rule, this would support that relaxation depicted and a MJO related return to colder weather thereafter.

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We are closing in on page 50 on the previous thread, so new one needed. I like to keep these threads within the met seasons, but we will see how interesting the weather is entering March and what Tom wants to do.

 

 

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I'm assuming we will be talking about gusty winds similar to last artic front, so wind chills will be an issue?

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18 minutes ago, SalemCountyNJ said:

I'm assuming we will be talking about gusty winds similar to last artic front, so wind chills will be an issue?

Yea, thurs AM looks the worst right now. 

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Euro carves a deep western trough and brings a taste of spring over us.  Flopping all over past d7, this is a drastic change in 1 day and will likely change again.  Long and short, can't trust long range, story all winter long

ecmwf_z500a_namer_fh192_trend.gif

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45 minutes ago, susqushawn said:

Euro carves a deep western trough and brings a taste of spring over us.  Flopping all over past d7, this is a drastic change in 1 day and will likely change again.  Long and short, can't trust long range, story all winter long

ecmwf_z500a_namer_fh192_trend.gif

EPS seems to support the taste of spring.

 

image.png.d26dd390ebcc25f9f94f382261cb3934.png

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6 minutes ago, Harbourton said:

EPS seems to support the taste of spring.

 

image.png.d26dd390ebcc25f9f94f382261cb3934.png

Yep, definitely a torch start to February. Break out the shorts if this is correct 

4770EC75-A83C-4493-8BC5-FA02AA7C9878.png

721E1847-B19B-4CA8-9449-EF4786498A19.png

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45 minutes ago, susqushawn said:

Euro carves a deep western trough and brings a taste of spring over us.  Flopping all over past d7, this is a drastic change in 1 day and will likely change again.  Long and short, can't trust long range, story all winter long

ecmwf_z500a_namer_fh192_trend.gif

I think we warm but it's transient. Euro and CFS2 weeklies show a mean, which certainly will not pick up short term blips. And "yes", that does mean that I assume both weeklies to be more right than wrong...at some point!  Lol

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1 minute ago, Allsnow said:

Yep, definitely a torch start to February. Break out the shorts if this is correct 

4770EC75-A83C-4493-8BC5-FA02AA7C9878.png

A late January thaw followed by the winter we've all been waiting for. 

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3 minutes ago, Mitchnick said:

A late January thaw followed by the winter we've all been waiting for. 

In Smarch we trust

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For the members who are stastically challenged like myself, I can't remember any winter with above normal snowfall around the I95 corridor when it snows in November. Does anyone have other thoughts?

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Just now, phillysports11 said:

I was thinking the same as well, when it snowed in October on Halloween I can't recall how the winter played out for the 95 corridor.  

it was very bad

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Just now, phillysports11 said:

What year was that again? I'm curious what our snowfall totals were for that winter. 

2011-2012. I believe it was less than 8"

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I feel for you all. The pattern in the 7-15 looks horrid now, cutter city. I suspect the MJO is finally winning out for a time in the grinchy phases. Models look like they are picking up on a phase 6/7 for the first week of Feb. Once again I look like a good spot Tuesday night then whatever it late next week is suppressed to the south. I'd say the first half of February is now above normal with a few weeks of opportunity from the middle of Feb into Mar as the MJO goes into 8,1,2,3. We got lucky this week the strat dominated a phase 5/6. The worst Philly could finish (assuming no measurable snow) through the end of Feb would be the 8th least snowiest meteorological winter. 2011-12 had 3.7 inches for the whole winter ( Dec-Feb). 

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1 hour ago, SalemCountyNJ said:

For the members who are stastically challenged like myself, I can't remember any winter with above normal snowfall around the I95 corridor when it snows in November. Does anyone have other thoughts?

Just off the top of my head, big time winters that had November snow:

1995-96

1898-99

1977-78

1978-79

Nov snow at PHL is rare in our recent climo

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I'm not ready to write off the first half of February cause the eps show a bad pattern right now. I want to re-evaluate later next week and see how things look. There is to much volatility right now between mjo and ssw effects of high lat blocking. Just 3 days ago the eps looked pretty good and then 3 days later it's a cancel first half of feb. To much wind shield wiper effect to get a good grasp to where this is headed. It does make sense the look they have with the progression of the MJO. Then to counter that you have strat effects which want to force high latitude blocking. If the mjo is indeed overwhelming the pattern than sure it could be ugly after this tpv cold shot. Right now I certainly buy the  warm up after the tpv moves out, usually always happens that we get return flow on the back side and it warms up.  Happened quite frequently in the winters of 13/14 and 14/15 where we go from single digit lows to 50s and rain. The thing is, are we looking at a 2 day warm up with a cutter back to cold or is this a more prolonged stretch as the eps indicate. So basically what I'm saying is patience, don't have a knee jerk reaction over something that is over 8 days from now. 

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6 hours ago, colonel_kurtz said:

Just off the top of my head, big time winters that had November snow:

1995-96

1898-99

1977-78

1978-79

Nov snow at PHL is rare in our recent climo

Impressive memory. Quite impressive.

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VAY down to 1 now on the latest euro. What a thing of beauty

ecmwf_t2min_nj_19.png

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5 hours ago, tombo82685 said:

VAY down to 1 now on the latest euro. What a thing of beauty

 

Those are some nice fig killing temps.🙄

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If it is any consolation CFS has one bad week, then the best snow pattern of the winter-to-date. Note in particular the NAO- and how the high heights in the Maritimes/Atlantic flip.

cfs-avg_z500aMean_nhem_fh168-672.gif

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2 hours ago, Chubbs said:

If it is any consolation CFS has one bad week, then the best snow pattern of the winter-to-date. Note in particular the NAO- and how the high heights in the Maritimes/Atlantic flip.

cfs-avg_z500aMean_nhem_fh168-672.gif

Although it has been there, I still don't trust any NAO outlook beyond 8 days.   The ridge/trof axes are farther east than our current cutting set-up, but that caveat still holds with that too.  

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