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Our first torch of 2011 April 11-12th


Damage In Tolland

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I notice a lot of people are hyperventilating over the 850 mb temperature. This value can be misleading. It is true that as the sun angle and day length increase, the solar heating of a sunny day makes it easier to mix up to 850 mb. But even in April this is not a slam-dunk. There are other mechanisms to consider, such as the strength of warm advection at that level compared with the lower level heating. Onshore flow may also buffer the lower level heating. The 00z 4/7 GFS forecast for Monday showed 15-17c at 850 mb...but forecast soundings for that Monday afternoon showed mixing depths were only to around 3000 feet. With that in place, the 925 mb temps would be far more relevant (take off 7-8C to get the dry adiabatic equivilent at 850 mb).

Then there is the other extreme, which we can see in June-July-August. The mixing depth may extend well above 850 mb. In this case, the temps at 800 mb (occasionally higher) will be more relevant.

That's why some of us talk about "equivilent 850 temps" as much as "850 temps" in our discussions. Bottom line...consider potential mixing depth before obsessing on forecast 850 mb temperatures.

Agree, but the models seem to really underestimate the mixing heights at times this time of year over the lower interior...especially with no foliage on the trees yet and brown fields.

This is the 4d GFS sounding for MHT (Monday 18z). I find it hard to believe MHT would only mix up to 900-925mb with a SW flow and very dry air in the mid-levels. It will obviously be iffier for coastal areas and far SNE (heck maybe the warm front gets hung up a bit more than modeled and Tue ends up the warmest day), but I think this sounding would be an easy 80+ for MHT-ASH.

post-3-0-89456900-1302227216.gif

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It has a weak wave of low pressure forming off the NJ coast, causing the warm front to temporarily stall from between BGM and ALB to just south of LI. Not an uncommon scenario this time of year. I think Tues will be at least 5 degrees warmer than Mon over most of SNE (aside from the Litchfield Hills and Berkshires) as winds turn more westerly.

Look how cool the 6z NAM 2M temps are for 18z Monday over SNE. Weird.

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It has a weak wave of low pressure forming off the NJ coast, causing the warm front to temporarily stall from between BGM and ALB to just south of LI. Not an uncommon scenario this time of year. I think Tues will be at least 5 degrees warmer than Mon over most of SNE (aside from the Litchfield Hills and Berkshires) as winds turn more westerly.

Certainly possible I still think places like BDL and DXR get very warm on Monday. East of there it's uncertain.

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Geez nice TStorm profile Mon AM On the GFS

Showalter Index: -2.62 C Risk: Severe thunderstorms possible

Total Totals Index: 52.57 C Risk: Scattered heavy thunderstorms

Vertical Totals Index: 27.02 C

Cross Totals Index: 25.55 C

K Index: 25.69 Risk: 40-60 % chance of thunderstorms

Sweat Index: 326.80 Risk: Showers and thunderstorms possible

Energy Index: -2.03 Risk: Severe Thunderstorms probable

Yes, definitely an anomalous set up for April in New England. Interestingly enough, IF we can get less SSW component late Monday, I like the severe chances for that day just on the synoptic appeal. I am going to be getting my video recorder squared away with fresh bats and memory just in case.

00z Euro continues with warm synoptic vibe overall, and really hits it hard for Monday. This may or may not be reflected in the MOS product… One thing, if the winds are more SSW than and real warm potential will be shunted back to W of EEN-CEF (Westfield – Keene) line… RI would get really screwed. If the wind is SW, the warmth edges E to BED-ORH and points west – mind you we are talking about where the gradient between continental heat and marine contamination aligns. If the wind is more WSW, then everyone cooks save for the Cape and Island and eastern LI.

Again, no sub-zero’s at 850mb once this clears the boards overnight into Tuesday… Frontalysis (weakening cold front) offers a transition from a single day heat pop on Monday, to something of a 66 to 72F if/when full sun sort of air mass. I.e., real spring about to sprung. Thereafter, who knows, but my sense on things is that we are finally on the door-stop of leaving the realm of cooler than normal behind – at least for a 7-10 day period. This sort of transition happened last year, though perhaps a month earlier, but also after a predominating –NAO winter. Interesting. We’ll see how this parlays out in time. Just for sh ts and giggles … the 360 hour 06z GFS has a 590dm height node/ridge axis parked over VA, with the rim of the 582 N of BOS! If that were a day 5 chart we’d be talking a heat wave. Last April we had a string of 4, 90+ afternoons –

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I see the NWS folks are limiting the BL heights on Monday - not sure I agree with this. They make the statement, but don't back it with any reasoning. They may be right - but I'd like to know what they are basing that on.

My experience with these pop into warm sector scenarios, when you have a decent gradient between CC and western NY, the mixing depth exceeds expectation most times - particularly when RH fields dry out (00z Euro) and you open up to sunshine at this time of year.

Interesting.

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meh...indices may look good for Monday but they will be going to waste, there is not much in the way of lift in our area and we will be drying out aloft as the day goes on. IF there was better lift around I could certainly see thunderstorms and severe wx out across NYS, possibly into parts of northern New England but I don't think we are going to see much in the way of precip on Monday afternoon or during the evening.

Perhaps we see some showers...maybe some thunder on Sunday with the warm front lifting northward but I think right now QPF is a bit overdone.

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I see the NWS folks are limiting the BL heights on Monday - not sure I agree with this. They make the statement, but don't back it with any reasoning. They may be right - but I'd like to know what they are basing that on.

My experience with these pop into warm sector scenarios, when you have a decent gradient between CC and western NY, the mixing depth exceeds expectation most times - particularly when RH fields dry out (00z Euro) and you open up to sunshine at this time of year.

Interesting.

This, and also this time of the year with a lack of foliage, surface heating can over-perform, with greater mixing, pushing BL heights higher than progged

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That's way ahead of here then. That sounds about like where they were around Reading, PA earlier this week when I drove north through PA.

Around DC the forsythia were getting a little past their best and cherry blossoms, while very nice, were a few days past their prime.

Saw a magnolia just starting to bloom and a forsythia starting to bloom as well.

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12z NAM looks like it may have several rounds of elevated convection if not MCS activity overnight Sunday ahead of the warm front. It also hangs the boundary up over NE Mass like Scott was pointing out yesterday.

That could be interesting for Middlesex Co later Monday afternoon if there is any DP pooling on the SW side - eh, if that configuraiton actually verifies. I noticed that some of the longer range MOS products were into the mid 70s and over 50 for DP as of the 00z suite, so perhaps we are shedding climo on those products.

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probably not. why?

Eventhough( i believe ) their funding comes from congressional appropriations, which would require they be furloughed , they are likely to "excepted" i.e. deemed essential. OMB guidelines for determining essential is (to paraphrase) "associated with constitutional responsibilities, the protection of human life or the protection of property". given those guideline i would think they would be excepted .

Would the governmental shut-down affect NCEP?

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biggest snow storm in 50 years for mt tolland on the 18z gfs

gfs_pcp_204m.gif

It does go to rain. I would doubt a large april 17th snowstorm for MT Tolland if 5 models showed it 48 hrs out. At this time of year it's hard to get any snow that survives past 10:00 AM the next day. Even 96 melted pretty fast.

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meh

Yea helluva way to run a torch

Tonight: Partly cloudy, with a low around 30. South wind at 6 mph becoming east.

Saturday: Sunny, with a high near 55. Northeast wind at 9 mph becoming south.

Saturday Night: Mostly cloudy, with a low around 34. South wind between 3 and 7 mph.

Sunday: A slight chance of light rain after 10am. Mostly cloudy, with a high near 54. South wind between 5 and 14 mph. Chance of precipitation is 20%.

Sunday Night: A chance of rain or drizzle, mainly after 10pm. Patchy fog after 2am. Otherwise, cloudy, with a low around 46. South wind around 11 mph. Chance of precipitation is 40%.

Monday: A slight chance of showers. Mostly cloudy, with a high near 68. Chance of precipitation is 20%.

Monday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 50. Chance of precipitation is 50%.

Tuesday: A chance of showers and thunderstorms. Mostly cloudy, with a high near 60. Chance of precipitation is 50%.

Tuesday Night: Partly cloudy, with a low around 42.

Wednesday: Mostly sunny, with a high near 57.

Wednesday Night: Partly cloudy, with a low around 40.

Thursday: Mostly sunny, with a high near 56.

Thursday Night: Mostly cloudy, with a low around 41.

Friday: Partly sunny, with a high near 56.

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