Jump to content
The Weather Forums

Jan- February Mid-long Range Discussion


Recommended Posts

The third week of February has potential (following the thaw pattern beforehand), and possibly the first week of March as well. Assuming nothing fluky happens when the MJO/ERW recoupe across the IPWP.

  • Like 1
Link to comment
Share on other sites

The Friday system has weakened with 1/2" max snowfall potential.

 

February brings return flow with rain being the primary p-type. How warm will it get? Mid to upper 50's are possible. There is a likely scenario with the cold ground, fog could develop and the warmest air could pass by above 3000 ft.

 

Around February 6th could air will return. FV3-GFS has the best snow friendly solution.

 

fv3p_mslp_pcpn_frzn_us_35.png

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

Friday system should become more clear today. Precip fields on the 06z NAM already a bust. It does pick up on low clouds and fog for Sunday afternoon. This keeps temps in the low-mid 30's Sunday under in-situ CAD. Image below.

 

February is prime-time for winter storms. All models agree on cold air return end of first week. GFS and CMS look better with trof to west but not as amplified. Euro picks it up at 192hrs then it vanishes. FV3 most consistent with potential winter storm. Images below.

 

 

namconus_T2m_neus_53.png

 

fv3p_mslp_pcpn_frzn_us_40.png

 

fv3p_mslp_pcpn_frzn_us_43.png

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

The down side to epic cold waves is atmospheric equilibrium. It will take a while for instability to return to the east coast. Expect model volatility next seven days.

 

Some mitigating factors: Well developed snow pack northwest, opportunities for CAD development.

 

Aggravating factor: Prolonged warm periods of up to two weeks have been the pattern this season.

 

There will be cold air return as early as 5 days. Two main models depict mid-atlantic snow, images below. In the mean time, we can watch the news that will show the massive automobile crashes from freezing rain in the Great Lakes (pray for their safety), or the epic snowfall in the Rockies.

 

Ice threats

 

ZR_000-240_0000.gif

 

10 day snow maps

 

gem_asnow_neus_40.png

 

fv3p_asnow_neus_41.png

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

Forecasts models diverge at 72hrs, this will be the tipping point. How strong will the ridge be from eastern Canada down the east side of the moutains? How amplified will the 500mb trof be?

 

The NAM has been the most consistent and benign. Other models are amplifying to a dangerous level with subtropical air advecting off the Gulf coast. If this verified we could be looking at a Spring type severe weather outbreak in the South.

 

Tuesday will produce extreme temperature gradients from Virginia north, temps in upper 60's to 70 in Virginia, mid 40's in NE Maryland. Until this is resolved all mid and long range patterns will continue to literally blow in the wind.

 

namconus_ref_frzn_us_52.png

 

gfs_mslp_pcpn_frzn_us_18.png

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

12z still has the battle of the ridges. One along the east slopes of the Rockies, one on the east coast. Those in the convergence zone get to enjoy the ebb and flow for another 48hrs.

 

NAM still most consistent, bit hints of amplification. If the Atlantic ridge holds this would nessasarily happen. The question sill remains is to how far the warm air advection goes in the Ohio Valley. The disparities in the global and mesoscale remain. NAM much more aggressive still with CAD potential. 18z isotherms for 78hrs image below..

 

namconus_T2m_contour_us_51.png

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

After the great thaw, all models have snow returning to mid-atlantic 150-180hrs. Euro most aggressive with 8-24".

alot of forums are declaring Winter over Im not sold based on the fact the last few years after a warm beginning of February winter came back mid late February and lasted through mid late March I can very easily see that happen once again.one thing for sure it has not been a very friendly winter for promets and long-range forecasters alot of promets even the most repectful ones have really scratched there heads on how this winter has behaved.you always get one where it throws everyone off at times.just gos to show while forecasting is getting better it not perfect and it still can humble you in the end.
Link to comment
Share on other sites

It’s a complicated evolution so the large scale players need to settle before we can derive conclusions re: CAD.

 

However, global models (esp the GFS) will underestimate the CAD duration. Sometimes by a lot. So *if* this ends up being a legit wedge event, it will be colder than global models depict. But the setup needs to favor a wedge first.

Link to comment
Share on other sites

Looks like a front side storm for sure. 06z CMC doubled down on CAD. 12z NAM colder, precip fields continued their SE slide. Oklahoma surface low more compressed as high builds in eastern Canada.

 

Its good to be in the game...

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

12z GFS, starting to bow. Expect cooling as reality nears.

 

There is no way to interpret models without a knowledge of climatology for a specific region.

 

We have been tracking this storm a long time. Next 24 hrs crucial.

 

Good to be in February, at home....

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

Several big cutter cyclones on the way with this pattern.

 

These are usually mixers but CAD/ice + pressure surges/high winds behind them can be rough on trees/infrastructure. Some of the upcoming systems look heavy duty..980mb lows don’t usually pass quietly..

Link to comment
Share on other sites

Several big cutter cyclones on the way with this pattern.

These are usually mixers but CAD/ice + pressure surges/high winds behind them can be rough on trees/infrastructure. Some of the upcoming systems look heavy duty..980mb lows don’t usually pass quietly..

this entire winter has been absurd the fact north Carolina and va have more snow then Boston this year is pretty laughable hect we even have more then Boston so far and that not saying much as so far it has been over all pretty pathica :lol: :lol:
Link to comment
Share on other sites

There is a series of systems that could bring snow to the DELMARVA next 10 days. This phenomenon has been coined, "Presidents Day Swarm." There is usually several small or one big storm.

 

Looks like mostly snow. Some ice may mix in, but no "Ice Storms." Famous last words.

 

GFS and Euro leading the way with 12-20 Inches of snow. Its climatological

prime-time. Get some candles...

 

gfs_asnow_neus_41.png

  • Like 1

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

Have been monitoring the three systems. Number one has become nothing but a wave, some wet snow DC south. Number two has weakened and will bring a few showers with passing Sunday night. So if first two bust...

 

Number three is shaping up to be a major storm. A strong CAD potential. The front side could have big punch, heavy snow followed by sleet/ice. There could be a long period of freezing rain. I usually am not alarmed until the Icon and FV3 agree.

 

When all models agree five days out, its going to be big.

 

ZR_120-240_0000.gif

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

FWIW, five days out is more than enough time for a CAD event to completely disappear. That kind of stuff is fickle in the extended range.

  • Like 1
Link to comment
Share on other sites

FWIW, five days out is more than enough time for a CAD event to completely disappear. That kind of stuff is fickle in the extended range.

That's why I posted in the long-range discussion. So we could discuss. I am still gun shy, from the ice event afew days ago.

 

Mid 60's today. That's a sign cold air is heading south. It could end up here 120-144 hrs. A long duration storm. Image below.

 

ecmwf_z500_mslp_us_7.png

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

If the GFS is bullish on CAD, then yeah that’s a reason to worry since that model can’t simulate it to save its life to the FV3, lol. But I’d want to get closer to go-time first.

Link to comment
Share on other sites

If the GFS is bullish on CAD, then yeah that’s a reason to worry since that model can’t simulate it to save its life to the FV3, lol. But I’d want to get closer to go-time first.

Yea plenty of time. 12z Euro dropped 850mb temps by 7C to -4C at BWI 120hrs. New surface depiction below...

 

ecmwf_z500_mslp_us_6.png

  • Like 1

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

Yeah, the Euro would be a legit hammering..5-8” of snow followed by 1-2” of sleet than an inch of ZR. I’d love to see that verify, but we have a ways to go still.

 

If it’s not gonna go big, then I’m ready for spring weather and thunderstorms. So many letdowns this winter so I’m setting my expectations low until 48hrs out.

  • Like 1
Link to comment
Share on other sites

My criteria for getting excited in 5 day models are as follows. It needs to be a big system, only really big storms can be seen that far out. All models must have the system depicted with the same genesis. There must be a consistency over many runs. Cold air must be supplied.

 

Gulf low, large high to north, mid February. Good formula.

 

GFS a little colder..

 

gfs_mslp_pcpn_frzn_us_19.png

  • Like 1

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

Yeah, the Euro would be a legit hammering..5-8” of snow followed by 1-2” of sleet than an inch of ZR. I’d love to see that verify, but we have a ways to go still.

If it’s not gonna go big, then I’m ready for spring weather and thunderstorms. So many letdowns this winter so I’m setting my expectations low until 48hrs out.

agreed if it not going to happen let have a real spring and move on from this debacle of a winter then maybe we get our solar min El nino and next winter proves to be the big one.
Link to comment
Share on other sites

agreed if it not going to happen let have a real spring and move on from this debacle of a winter then maybe we get our solar min El nino and next winter proves to be the big one.

Yeah, however I gut tells me we’re not done yet..+ENSO winters (that aren’t perpetual torches) rarely end early.

 

I think this one has a chance to be legit.

  • Like 1
Link to comment
Share on other sites

Latest runs a little warmer as 500mb trof amps, 06Z CMC hints at cuting off. Then it is a question of how much confluence NE.

 

In regards to winters end. I have seen three of my my top 5 biggest Strom's in March. As someone said, "It ain't over, til its over."

  • Like 1

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

Latest runs a little warmer as 500mb trof amps, 06Z CMC hints at cuting off. Then it is a question of how much confluence NE.

 

In regards to winters end. I have seen three of my my top 5 biggest Strom's in March. As someone said, "It ain't over, til its over."

The 00z CMC was colder than yesterday’s 12z. The 00z Euro did trend warmer but it was a big cold outlier yesterday anyway. The GFS is the warmest of all guidance, as is usually the case w/ CAD.

 

Still far out enough that this could evaporate, or trend into a significant snow-to-freezing rain event.

  • Like 1
Link to comment
Share on other sites

The one trend that could be problematic for us winter weenies (if it continues) is the delaying of the start time until after sunrise.

 

Assuming the system structure remains as is, there shouldn’t be too many thermal issues if precipitation starts ~ 9-10AM, but anything later allows insolation to get more work in. We’re two months removed from the solstice below 40N..the Sun is definitely a factor now.

Link to comment
Share on other sites

The one trend that could be problematic for us winter weenies (if it continues) is the delaying of the start time until after sunrise.

Assuming the system structure remains as is, there shouldn’t be too many thermal issues if precipitation starts ~ 9-10AM, but anything later allows insolation to get more work in. We’re two months removed from the solstice below 40N..the Sun is definitely a factor now.

also I also wonder if the models are erroring in the opposite fashion then they have been this winter.as the data seems to be catching up to the fact that the mjo maybe going into phases 8 through 1 along with the growing - sol if so perhaps we see a big ending in early march before the pattern gos to a true spring one mid march and after.but would be ironic how all winter models showed cold and storms and it never varifed and when they were not showing cold a few days ago and we finally get it :lol: would be a fitting end of this winter

Link to comment
Share on other sites

I thinkTexas will be on the usual cold rain train for our winter.

 

But I’ll take rain as we could be crying for it this summer.

  • Like 1

Before You Diagnose Yourself With Depression or Low Self-Esteem,...First Make Sure You Are Not In Fact, Just Surrounded By A$$holes.

 

2018 Rainfall - 62.65" High Temp. - 110.03* Low Temp. - 8.4*

Link to comment
Share on other sites

06Z run looks good. GFS a lot better with the coastal trof and ridge placement.

 

All models have depicted a heavy precip band, the GFS depicts a very heavy snow band producing 12+ inches of snow. This band has been migrating north last 48 hrs. This looks convective, so a little thunder and cloud to cloud lighting not out of the question. Still a while to go.

 

Curiosity Phil, you said you were ready for thunderstorms...

 

Images below.

 

gfs_mslp_pcpn_frzn_us_13.png

 

gfs_mslp_pcpn_frzn_us_14.png

 

gfs_asnow_neus_20.png

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

12Z NAM is running with heavy precip banding. Heavy snow, then sleet and freezing rain. NAM holds CAD till end of run with weak coastal low. Some of the ptype totals are epic.

 

If you divide them in half, your talking a significant Winter Storm.

 

Images below:

 

 

 

namconus_asnow_neus_29.png

 

namconus_ref_frzn_neus_51.png

A Navy Chief said, "Never change your forecast. That way you can only be wrong once."

Link to comment
Share on other sites

FWIW while the 12km NAM was much too cold here for the last CAD event, the 4km NAM and the GFS both busted warm (the former surprised me, as it’s usually pretty good with CAD).

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...