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Medium Range Thread


tombo82685

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Would April 16 or 17 count if it happened? Funny thing the leaf out has slowed a bit because of the chilly recent weather, but we have been so bone dry that we have easily been doing +16 to +17C over 850mb temps.

Wouldn't count for the bet, but I would take it as a forecast win that far out. I think we'll probably top out in the upper 80s, but we'll see. Tropical signs are still there for more warmth the last week of April, too.

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Would April 16 or 17 count if it happened? Funny thing the leaf out has slowed a bit because of the chilly recent weather, but we have been so bone dry that we have easily been doing +16 to +17C over 850mb temps.

Lol...i was going to bump his post also....euro has 90 in phl on Monday....soil is real dry...see no reason we dont do it.....adam has been good in long range this year

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Since 1998 philly has'nt had a below normal april except in 2007, all others have been around normal or above to well above. The last 4 aprils have been about 3.5 above average. The trend has gone on long enough to say that above average is average at least for march and april.

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Forecasts

Apr 1-15: +2

Apr 16-30: +9

Last Friday, I made a bet with my boss that PHL will see 90 between Apr 20-30. We'll see how that goes...

April 1-15 Verification: +4.24. The 14th and 15th took the anomaly from +3.04 to +4.24.

Apr 16-30: +6

May 1-15: +1

I'm not too confident in either of these forecasts. I'm above the Euro ENS for the April 16-30 period, mainly because I think we'll be warmer in the last 5 days of the month than what the Euro has. Early May is a tough forecast. Models are losing the MJO signal and the ENSO signal is weakening as well. Without those two dominant teleconnections, it's tough to make a call.

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And Grothar would be happy.

So, how did the Euro do 5 days out on the Sunday AM, pathetic, disintegrating showers?

honestly, i have no clue, really havent been keeping a track record. Though i know last week it had a good rain event for wednesday and now that looks like a tenth or less from a low that scoots out off nc

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This could be an interesting week of watching the models multiple models putting out a large system heck this 12z GFS run might be the biggest storm it has had yet. As for the euro last week it did have a mid week rain event of 0.50 to 0.75 or so last week but that is no longer happening not sure what has been wrong with it lately. The pattern ahead finally does support rain for this weekend but after this potential storm this weekend it is anyone's guess. Long range of the EURO and GFS has been garbage which is typical for this time of year.

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AAM and Mountain Torques are falling right now, likely in response to the current MJO phase. Usually, that would mean +EPO and +NAO in 10-15 days. I'd also guess the MJO will be weakly in P5 in a week to 10 days, which is also a warm signal. I backed off the April 16-30 forecast because of the modeling, but the teleconnection signals are there for continued warm/dry at the end of the month.

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AAM and Mountain Torques are falling right now, likely in response to the current MJO phase. Usually, that would mean +EPO and +NAO in 10-15 days. I'd also guess the MJO will be weakly in P5 in a week to 10 days, which is also a warm signal. I backed off the April 16-30 forecast because of the modeling, but the teleconnection signals are there for continued warm/dry at the end of the month.

Yeah rolling CPC analogs ahead and the gefs analogs centered on April 27th show another expansive warm shot moving in for the end of the month. So while this cutoff could screw things up making it cool for a few days, I'm still very confident 16-30th finishes above normal...Early May would stay warm as well according to those analogs.

As for the MJO, are you buying into the GEFS looping it back into phase 8? Euro obviously keeps it dead but the ukmet seemed to be siding on the GEFS near the end of the 2 week period. In my long range forecast a couple weeks back I was sort of depending/hoping on the MJO emerging back into those warm phases you mentioned by the end of April/beginning of May.

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As for the MJO, are you buying into the GEFS looping it back into phase 8? Euro obviously keeps it dead but the ukmet seemed to be siding on the GEFS near the end of the 2 week period. In my long range forecast a couple weeks back I was sort of depending/hoping on the MJO emerging back into those warm phases you mentioned by the end of April/beginning of May.

The modelling is why I backed off, but the two stat forecasts I use still show a clear signal into the warm phases:

http://www.atmos.albany.edu/facstaff/roundy/waves/hovsdet/7.5S_7.5N/2012.png

http://cawcr.gov.au/...ps.5day.MJO.gif

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Through 162 of the 12z euro west of the area must be 2-3 maybe 4 inches of rain looks like maybe 1-1.5 so far for Philadelphia area with this run for the system looks like the trends on euro and gfs is stronger still. would defiantly take care of the pollen and drought.

Many of the model runs look similar to the nor'easter of April 2007. If the GFS and Euro models do pan out, that will provide some relief but it is not a drought buster. We are just too far in the hole right now for precip and the groundwater tables continue to fall rapidly. Anything over an inch or so will runoff especially if the the storm event produces quick hitter t storms. Long duration rains over days with cool conditions will help. I do not see this with this possible event. I see us in the warm sector of the storm event with heavy t-storms that just temporarily replenishes the existing base flows of the streams. Lets hope for a long duration event with a retrograding LP off the Rhode Island coast. Now that will help.

http://en.wikipedia.org/wiki/April_2007_nor'easter

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The modelling is why I backed off, but the two stat forecasts I use still show a clear signal into the warm phases:

http://www.atmos.albany.edu/facstaff/roundy/waves/hovsdet/7.5S_7.5N/2012.png

http://cawcr.gov.au/...ps.5day.MJO.gif

How has Roundy been verifying of late? I'm not sure if I'm interpreting the OLR predictions completely correctly, but it would appear he keeps the wave low amplitude into phase 5 like you said, instead of bringing it into the circle.

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How has Roundy been verifying of late? I'm not sure if I'm interpreting the OLR predictions completely correctly, but it would appear he keeps the wave low amplitude into phase 5 like you said, instead of bringing it into the circle.

I usually weight the Roundy forecast about 70% and Euro weeklies about 30% for my MJO forecast. IMO, the Euro is often too quick to dampen the wave.

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Through 162 of the 12z euro west of the area must be 2-3 maybe 4 inches of rain looks like maybe 1-1.5 so far for Philadelphia area with this run for the system looks like the trends on euro and gfs is stronger still. would defiantly take care of the pollen and drought.

The Euro has shifted the heaviest rains offshore in last night's runs. Still could get an inch plus 95 and east if the model is right.

GFS has the axis of heaviest rains along and east of 95 but across South Jersey (2"+).

IF that verifies, it will help...but this isn't the first time the models have had a robust rain event 5-6 days out...we had one in March that underperformed quite a bit from projections in the D5-D6 range...not saying the models are wrong but in these dry spell patterns I need to see it a lot closer to D2 before I get giddy.

BTW, it won't take care of the pollen for long...we're nearing peak tree pollen pumping time.

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The powerhouse storm this weekend seems like it's going to be quite the game changer for how the final days of the month play out...

Makes zero sense from a teleconnection point of view. I'm waiting for someone to explain what is forcing this pattern, because it isn't the "normal" stuff.

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Makes zero sense from a teleconnection point of view. I'm waiting for someone to explain what is forcing this pattern, because it isn't the "normal" stuff.

Is it the down stream effects of the MJO being in phase 8&1 for about 2.5 weeks?

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Is it the down stream effects of the MJO being in phase 8&1 for about 2.5 weeks?

I don't think so. The forcing is over the IO now, which isn't a supertorch or anything, but isn't a monster storm either. The only thing that was remotely positive for this event, imo, was the big Rockies mountain torque 10 days ago, but everything else says flat or warm. I mean, the AAM has just been sitting phase 2 for about 10 days, which is usually a SE ridge. I don't get it.

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Makes zero sense from a teleconnection point of view. I'm waiting for someone to explain what is forcing this pattern, because it isn't the "normal" stuff.

I'm pretty lost myself with regards to that...Liked the warm idea too (i guess we get the warm shot in early may?)..but it looks like your concern over the cooler long range euro ensembles earlier this week was warranted.

Perhaps shorter wavelengths late in the season aren't correlating the usual signals to sensible weather? The big storm does seem to be pure chaos

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