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irishbri74

April/May Meteorological Pattern Discussion

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This year’s April looks different from last years forecasted April , given the high latitude pattern. (Lack of -NAO). Woo holding strong, but zonal flow should let us have 50/50 shot at warmer vs colder weather. 

CBD48336-FDB3-4DFB-8F15-BE704518C27D.jpeg

 

9DCD373D-C8E4-4B28-AFD2-D7C688A88BE9.png

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Brian, I started a new pattern topic and moved your post here.  Your map looks like it's from 2016 although given how last April went, it probably is close anyway.

 

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7 hours ago, Rainshadow said:

Brian, I started a new pattern topic and moved your post here.  Your map looks like it's from 2016 although given how last April went, it probably is close anyway.

 

How bout that... it came up on my Facebook memory, thought it was last year (mirror images for 2 marches in a row !). Brain is fried from this wedding planning!  My apologies folks! 

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39 minutes ago, irishbri74 said:

How bout that... it came up on my Facebook memory, thought it was last year (mirror images for 2 marches in a row !). Brain is fried from this wedding planning!  My apologies folks! 

Just remember to say I do on the big day and always remember to say you are right & I am wrong and you will do fine.  :)

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Now that the wavelengths are getting shorter, MJO influence on our temperatures have less statistical significance.  The only ones that may have some weight because of higher confidence closer by are phases 3 for cold and 6 for warm.  

combined_image.png.3dcdf867a1bab4b60aa2edf53ba4a08b.png

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With el nino rebounding to a healthier around +1.0C value, dynamical/statistical models are outlooking it to persist through the summer and into next winter?

figure4.png.7b2410f299b48660df6853d350838ee8.png

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42 minutes ago, Rainshadow said:

With el nino rebounding to a healthier around +1.0C value, dynamical/statistical models are outlooking it to persist through the summer and into next winter?

figure4.png.7b2410f299b48660df6853d350838ee8.png

Calling it now modoki

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00z March 18th GEFS

Positive PNA below normal 500mb heights last til the 20th and then come back with offshore/east development on the 21st thru 23rd.  As the +PNA ridging moves eastward across NOAM, above normal heights return on the 24th (one day later than the outlook from four days ago).  A negative NAO is outlooked to develop and heights return to near normal on the 26th. the long run of above normal heights gone. On the 26th there is the -NAO E and neutral looking PNA (maybe index positive) with trofs across the southwest & southeast CONUS. Latter with latest day 9 Euro snow.  As that SE trof exits, above normal heights briefly return on the 29th & 30th, +NAO at that point. Til the end of its run on April 2nd, we drift in/out of normal and slightly below normal heights with mainly a zonal flow.

NAEFS for the week of 3/26-4/2 has pretty high confidence of above normal temperatures. So much for the GEFS thoughts. EPS does not look that cold either.

MJO is in Phase 5.  COD location I am guessing because of 200mb winds, but convection still looks rather robust and that is what drives the latent heat release.  So warmer phases on the way until maybe a real COD after phase 6 or 7.  A warmer than average send off to Smarch still looks there.

 

00z March 20th GEFS

Brief above normal 500mb heights until neg tilt trof (below) on the 21st.  As the +PNA ridging moves eastward across NOAM, above normal heights return on the 24th (same as two days ago).  A negative NAO E develops and heights return to near normal sooner on the 25th. Rockies PNA ridging/ -NAO E bring below normal heights to our period of interest late on the 25th.  Breakdown of the -NAO E/ PNA ridge brings above normal heights back on the 28th. This persists to the end of March. As Sapril starts a series of Pacific trofs bring an el nino look with below normal heights across the southern & southwestern conus. Our heights return to above normal on April 3rd & 4th (end of run).

NAEFS for the week of 3/28-4/4 is weakly confidence of above normal temperatures. 

MJO as far as convection goes is in Phase 5 almost phase 6.  The amount of convection and the 850mb & esp 200mb push into the COD.  The models were right (I was wrong) about it weakening. Although convection is not nil and any convective forcing would assist in warmer phase solutions going forward. I like the split of different MJO factors as convection still drives the ridging bus. Granted if there is not support aloft, it won't be easy going forward.

 

00z March 24th GEFS

The GEFS made this easy, after a brief interlude with near normal heights returning, they are outlooking above normal 500mb heights from March 27th thru the end of its run on April 8th.  First the NAO is outlooked to be positive throughout. Second a Rex block is outlooked for the eastern half of the Pacific with a closed ridge over Alaska that eventually retrogrades to Siberia. So there is an angle of cold issue with the usual suspects, EPS farther east, GEPS and GEFS farther west as April begins. This downstream ridging effect keeps the PNA positive, but some of this is due to normal or below normal heights SERN Conus. Eventually (la la land) the models are all in agreement of the unraveling of the Rex Block results in eastern Pacific / western NOAM troffing and a stout +EPO.  With energy coming east, severe weather (la la land) should get off to an above average start first week of April.  

NAEFS for the week of 4/1-4/8 is moderately confidence of above normal temperatures.  Coldest location central plains. 

MJO as far as convection goes is in Phase 6.  Now with more convection, the GEFS is riding the outer part of the COD (again being kept in the COD mainly due to 200mb winds) than the silly crisscrossing deeper within the COD. So the toasty end to March has legs.  With wavelengths shortening, MJO stat confidence is waning this far east.  Phase 7 centered on April is colder, but 8 is now confidently warm northern plains and 1-3 are coldest phases with the greatest significance in our area phase 3.  So the idea of the EPS colder shot has some MJO legs as does the warm up following. Of course the models still keep the MJO in the COD regardless.

 

 

 

4indices.png

am_ir_monthly_60E_1.gif

twc_globe_mjo_vp200.png

wh04.mjo.component.png

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1 hour ago, Rainshadow said:

CFS2 is all torchy about April:

summaryCFSv2.NaT2m.201904.gif.573c669c17ac1c86f4bc11ef18390e18.gif

Apologies to Tom in advance, but Hallelujah!

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8 hours ago, snowlurker said:

Apologies to Tom in advance, but Hallelujah!

I'm for that, torch in april is like 65-70, we take. Now torch in june-august no thanks

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1 hour ago, tombo82685 said:

I'm for that, torch in april is like 65-70, we take. Now torch in june-august no thanks

Now you're talking, Tom!

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1 hour ago, tombo82685 said:

I'm for that, torch in april is like 65-70, we take. Now torch in june-august no thanks

Average in April is 65-70, at least in the latter half, torch can be 1976 - I was pumping gas, leaves weren't out on the trees yet, hot as b*lls...

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26 minutes ago, iceman56 said:

Average in April is 65-70, at least in the latter half, torch can be 1976 - I was pumping gas, leaves weren't out on the trees yet, hot as b*lls...

True, I remember early or mid 1990s where it was in the 90s for 3 straight days. 

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2 hours ago, iceman56 said:

Average in April is 65-70, at least in the latter half, torch can be 1976 - I was pumping gas, leaves weren't out on the trees yet, hot as b*lls...

For Philadelphia the hottest weather during 1976 occurred in April, 94 degrees - impressive stat

more recently we came very close in 2009, only (2) 95 days in AUG were hotter than the April 93 degrees

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00z March 20th GEFS

Brief above normal 500mb heights until neg tilt trof (below) on the 21st.  As the +PNA ridging moves eastward across NOAM, above normal heights return on the 24th (same as two days ago).  A negative NAO E develops and heights return to near normal sooner on the 25th. Rockies PNA ridging/ -NAO E bring below normal heights to our period of interest late on the 25th.  Breakdown of the -NAO E/ PNA ridge brings above normal heights back on the 28th. This persists to the end of March. As Sapril starts a series of Pacific trofs bring an el nino look with below normal heights across the southern & southwestern conus. Our heights return to above normal on April 3rd & 4th (end of run).

NAEFS for the week of 3/28-4/4 is weakly confidence of above normal temperatures. 

MJO as far as convection goes is in Phase 5 almost phase 6.  The amount of convection and the 850mb & esp 200mb push into the COD.  The models were right (I was wrong) about it weakening. Although convection is not nil and any convective forcing would assist in warmer phase solutions going forward. I like the split of different MJO factors as convection still drives the ridging bus. Granted if there is not support aloft, it won't be easy going forward.

 

00z March 24th GEFS

The GEFS made this easy, after a brief interlude with near normal heights returning, they are outlooking above normal 500mb heights from March 27th thru the end of its run on April 8th.  First the NAO is outlooked to be positive throughout. Second a Rex block is outlooked for the eastern half of the Pacific with a closed ridge over Alaska that eventually retrogrades to Siberia. So there is an angle of cold issue with the usual suspects, EPS farther east, GEPS and GEFS farther west as April begins. This downstream ridging effect keeps the PNA positive, but some of this is due to normal or below normal heights SERN Conus. Eventually (la la land) the models are all in agreement of the unraveling of the Rex Block results in eastern Pacific / western NOAM troffing and a stout +EPO.  With energy coming east, severe weather (la la land) should get off to an above average start first week of April.  

NAEFS for the week of 4/1-4/8 is moderately confidence of above normal temperatures.  Coldest location central plains. 

MJO as far as convection goes is in Phase 6.  Now with more convection, the GEFS is riding the outer part of the COD (again being kept in the COD mainly due to 200mb winds) than the silly crisscrossing deeper within the COD. So the toasty end to March has legs.  With wavelengths shortening, MJO stat confidence is waning this far east.  Phase 7 centered on April is colder, but 8 is now confidently warm northern plains and 1-3 are coldest phases with the greatest significance in our area phase 3.  So the idea of the EPS colder shot has some MJO legs as does the warm up following. Of course the models still keep the MJO in the COD regardless.

 

00z March 27th GEFS

Above normal 500mb heights start the run and continue until early on Sunday March 31st. With a bow to the EPS below normal heights return briefly around April Fool's Day.  On April 1st we have a -EPO (big 500mb ridge in Alaska), +PNA & +NAO. A prolonged stretch of above normal 500mb heights returns on April 4th to the end of its run on April 11th as the 500mb Alaska ridge is outlooked to retrograde and swrn CONUS and then eastern Pacific troffing predominate.   IDK if the GEFS has already gone into its always warm warmer half of the year mode yet, but the EPS is on board too.  It does look cooler at the end of its run than the GEFS and the GEPS has a somewhat cooler flow overall. 

NAEFS for the week of 4/4-4/11 is somewhat confident of above normal temperatures.  Only slivers of cold confidence in Maine and North Dakota. 

MJO has weakened. COD looks justified. Phase 6/7 if anything. Tropical system off of South America coast gives it a bifurcated look, but Pacific convection is not that much regardless.  Hard to say what drives the bus going forward. Current MJO phase is warm for us, but after that one would need it to come out of COD for colder phases to possibly have an impact on us. Either way this has the look of most recent Aprils which have been warm and not the SSW impacted Sapril we had last year.

 

am_ir_monthly_60E_1.gif

sst.daily.anom.gif

wh04.mjo.component.png

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The more progressive pattern is leaning toward the gfs/ukmet for next week system:

 

a.JPG

b.JPG

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00z March 20th GEFS

Brief above normal 500mb heights until neg tilt trof (below) on the 21st.  As the +PNA ridging moves eastward across NOAM, above normal heights return on the 24th (same as two days ago).  A negative NAO E develops and heights return to near normal sooner on the 25th. Rockies PNA ridging/ -NAO E bring below normal heights to our period of interest late on the 25th.  Breakdown of the -NAO E/ PNA ridge brings above normal heights back on the 28th. This persists to the end of March. As Sapril starts a series of Pacific trofs bring an el nino look with below normal heights across the southern & southwestern conus. Our heights return to above normal on April 3rd & 4th (end of run).

NAEFS for the week of 3/28-4/4 is weakly confidence of above normal temperatures. 

MJO as far as convection goes is in Phase 5 almost phase 6.  The amount of convection and the 850mb & esp 200mb push into the COD.  The models were right (I was wrong) about it weakening. Although convection is not nil and any convective forcing would assist in warmer phase solutions going forward. I like the split of different MJO factors as convection still drives the ridging bus. Granted if there is not support aloft, it won't be easy going forward.

 

00z March 24th GEFS

The GEFS made this easy, after a brief interlude with near normal heights returning, they are outlooking above normal 500mb heights from March 27th thru the end of its run on April 8th.  First the NAO is outlooked to be positive throughout. Second a Rex block is outlooked for the eastern half of the Pacific with a closed ridge over Alaska that eventually retrogrades to Siberia. So there is an angle of cold issue with the usual suspects, EPS farther east, GEPS and GEFS farther west as April begins. This downstream ridging effect keeps the PNA positive, but some of this is due to normal or below normal heights SERN Conus. Eventually (la la land) the models are all in agreement of the unraveling of the Rex Block results in eastern Pacific / western NOAM troffing and a stout +EPO.  With energy coming east, severe weather (la la land) should get off to an above average start first week of April.  

NAEFS for the week of 4/1-4/8 is moderately confidence of above normal temperatures.  Coldest location central plains. 

MJO as far as convection goes is in Phase 6.  Now with more convection, the GEFS is riding the outer part of the COD (again being kept in the COD mainly due to 200mb winds) than the silly crisscrossing deeper within the COD. So the toasty end to March has legs.  With wavelengths shortening, MJO stat confidence is waning this far east.  Phase 7 centered on April is colder, but 8 is now confidently warm northern plains and 1-3 are coldest phases with the greatest significance in our area phase 3.  So the idea of the EPS colder shot has some MJO legs as does the warm up following. Of course the models still keep the MJO in the COD regardless.

 

00z March 27th GEFS

Above normal 500mb heights start the run and continue until early on Sunday March 31st. With a bow to the EPS below normal heights return briefly around April Fool's Day.  On April 1st we have a -EPO (big 500mb ridge in Alaska), +PNA & +NAO. A prolonged stretch of above normal 500mb heights returns on April 4th to the end of its run on April 11th as the 500mb Alaska ridge is outlooked to retrograde and swrn CONUS and then eastern Pacific troffing predominate.   IDK if the GEFS has already gone into its always warm warmer half of the year mode yet, but the EPS is on board too.  It does look cooler at the end of its run than the GEFS and the GEPS has a somewhat cooler flow overall. 

NAEFS for the week of 4/4-4/11 is somewhat confident of above normal temperatures.  Only slivers of cold confidence in Maine and North Dakota. 

MJO has weakened. COD looks justified. Phase 6/7 if anything. Tropical system off of South America coast gives it a bifurcated look, but Pacific convection is not that much regardless.  Hard to say what drives the bus going forward. Current MJO phase is warm for us, but after that one would need it to come out of COD for colder phases to possibly have an impact on us. Either way this has the look of most recent Aprils which have been warm and not the SSW impacted Sapril we had last year.

 

00z March 31st GEFS

Negative tilt below normal 500mb heights start April. Near normal heights return as coastal low closed low ejects southeast of us. -EPO ridge retrograding to Siberia.  Above normal heights return on April 3rd (a day earlier than 3/27 GEFS).  Stout subtropical positive EPO jet brings closed low and trof to eastern Pacific as above normal 500mb heights encompass the CONUS through April 9th.  Then a -NAO (no I can't make this stuff up) and dissipation of eastern Pacific trof brings near normal heights back into our area.  Above normal heights return on the 11th-14th as troffing is outlooked for the sw CONUS.  -NAO brings near normal heights back at end of the run (15th) with ridging in the central CONUS. 

NAEFS for the week of 4/8-4/15 is HIGHLY confident of above normal temperatures. 

MJO based on convection alone was in Phase 7 on 3/29 (last CPC update).  Mike's page looks like a COD phase 8. Either way outlook is for the MJO to remain in the COD. Phase 7 is warm for us, Phase 8 is warm for most of the CONUS in April.  Phases 1-3 are cold for April, but with a COD outlook we may bypass it.  The GWO AAM is strongly positive (hello el nino), and is outlooked to remain so.

4indices.png.65bfb50058d42860b63ee0769140022a.png

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On 3/25/2019 at 9:10 AM, Rainshadow said:

CFS2 is all torchy about April:

Stayed torchy through the end of the month and turned dry in the NE

summaryCFSv2.NaPrec.201904.gif

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3 hours ago, Chubbs said:

Stayed torchy through the end of the month and turned dry in the NE

summaryCFSv2.NaPrec.201904.gif

After Monday & Tuesday, it is going to get off to a good start.

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One thing that may throw a wrench into the torchy April forecast is what the eps are showing in extended. Usual caveats here as pertaining to any nao forecast outside 7 days and esp 10 days. They do build a pretty robust nao signal end of next week into mid april. If that were the case it could lead to backdoor fronts and below normal temps

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So I guess that -NAO will finally verify next week so we can get some drizzly 40's.   

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So, should we place our guesses for rain fall this Spring/Summer like we do with snowfall?

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12 hours ago, cbelke said:

So, should we place our guesses for rain fall this Spring/Summer like we do with snowfall?

Charlie, Al & I do a summer outlook golf round in Mayish. You might have to be "sick" one day and make the 120 mile trip and be part of the official outlook. I think it coincidentally worked last year.  We miss Tom's blue ball during this outlook, but he makes the important winter one.

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