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CanisLupusArctos · 07-02-2008, 12:12 PM

Actually meteotrade, severe t-storm potential is there for tomorrow, but looks only marginal. SPC has much of the northeast circled for slight risk (level 1 of 3, where 3 is cataclysmic.) Dewpoints are low now but they'll be back on the rise tomorrow as winds turn SW. The SPC sees us getting dewpoints near 60 tomorrow. Not incredibly high, but sticky.

The limiting factor for severe potential tomorrow is the lapse rates (how quickly you would find the air cooling if you went straight up on a rocket.) The colder it is up there and the warmer/more humid it is down here (steep lapse rate) the better chance for severe weather. There are many other factors, but lapse rate is a biggie. Tomorrow's lapse rate, as SPC states in their discussion, looks only borderline for severe weather right now.

Still, a thunderstorm doesn't have to be severe in order to be dangerous on the lake. Remember a severe thunderstorm is one that has damaging wind or damaging hail. All thunderstorms have lightning, which, as we all know, is not good to get hit by. Also, non-severe thunderstorms can still generate wind gusts enough to knock you around if you're on the open lake. Sometimes a non-severe thunderstorm can get its winds into the "severe" threshold while crossing the lake, simply because there's nothing to slow down the wind on the open lake. The NWS may not be able to warn you about that-- just another reason boaters should take all thunderstorms seriously.

Tomorrow's thunderstorm threat - severe or not - will be anytime after noon, with chances increasing through the afternoon and decreasing after dark as the activity moves east.

Then, as meteotrade said, the cold front will stall along the south coast of New England and might ruin a few picnics down there.

On Friday and Saturday the best weather will be in northwestern New England with greater chances for showers and clouds further south and east. Best chances for great weather will be in VT... best chances for lousy weather will be Cape Cod and the islands (including Long Island NY.) Meteotrade's forecast for stunning on the 4th does have good chances at the lake, but that stalled front makes me nervous. I don't like stalling fronts. They don't always stall where and when they're predicted to. When they stall, they sometimes serve as a storm track, as little waves of low pressure develop and scoot along them. Just pray Thursday's front goes way south and east of New England, into the ocean, before it stalls. That way if waves of low pressure start using it as a bowling lane, we'll be beyond the gutter.

On Sunday, high pressure moves in and acts as meteorological Ex-Lax, takes control of New England and gives us all a nice day.

Highs will be in the mid-80s Thursday with "sticky" humidity. Friday and Saturday we'll see temps in the mid-70s and less humidity.

I also post forecasts on the WeatherCenter site... in the upper right corner click on "local forecasts." Includes my weather notes, NWS forecast, and Weather Underground forecast.

Discussion from SPC for Thursday:

...OH VALLEY THROUGH NERN STATES...

SCATTERED THUNDERSTORMS MAY BE ONGOING IN VICINITY OF FRONT FROM SE
CANADA INTO THE LOWER GREAT LAKES AND NRN PARTS OF OH VALLEY. MOIST
AXIS WITH DEWPOINTS AROUND 60F WILL ADVECT NEWD INTO WARM SECTOR
IMMEDIATELY IN ADVANCE OF FRONT WHERE SOME BOUNDARY LAYER WARMING
MAY OCCUR OUTSIDE OF ONGOING CONVECTION. HOWEVER...POOR MID-LEVEL
LAPSE RATES WILL LIKELY LIMIT MLCAPE TO BELOW 1000 J/KG. FLOW IN THE
700-500 MB LAYER WILL LIKELY STRENGTHEN TO 40-50 KT OVER THE NERN
STATES AS SHORTWAVE TROUGH ADVANCES EWD AND TIGHTENS GRADIENT. A
SWLY 40+ KT LOW LEVEL JET IS ALSO FORECAST TO SHIFT NEWD THROUGH NE
U.S. WARM SECTOR. THIS WILL RESULT IN FAVORABLE UNIDIRECTIONAL WIND
PROFILE FOR ORGANIZED STORMS. POTENTIAL WILL EXIST FOR STORMS TO
INTENSIFY AS THEY DEVELOP ESEWD ALONG AND AHEAD OF THE FRONT DURING
THE DAY. THE KINEMATIC ENVIRONMENT WOULD SUPPORT THREAT FOR ISOLATED
DAMAGING WIND. HOWEVER...THE EXPECTED MARGINAL THERMODYNAMIC
ENVIRONMENT COULD SERVE AS A POTENTIAL LIMITING FACTOR SO WILL
MAINTAIN ONLY A LOW END 15% SLIGHT RISK AREA AT THIS TIME.

07-02-2008, 12:12 PM	#4
CanisLupusArctos Senior Member Join Date: Jan 2007 Location: Center Harbor Posts: 1,049 Thanks: 15 Thanked 472 Times in 107 Posts	A little of this, a little of that Actually meteotrade, severe t-storm potential is there for tomorrow, but looks only marginal. SPC has much of the northeast circled for slight risk (level 1 of 3, where 3 is cataclysmic.) Dewpoints are low now but they'll be back on the rise tomorrow as winds turn SW. The SPC sees us getting dewpoints near 60 tomorrow. Not incredibly high, but sticky. The limiting factor for severe potential tomorrow is the lapse rates (how quickly you would find the air cooling if you went straight up on a rocket.) The colder it is up there and the warmer/more humid it is down here (steep lapse rate) the better chance for severe weather. There are many other factors, but lapse rate is a biggie. Tomorrow's lapse rate, as SPC states in their discussion, looks only borderline for severe weather right now. Still, a thunderstorm doesn't have to be severe in order to be dangerous on the lake. Remember a severe thunderstorm is one that has damaging wind or damaging hail. All thunderstorms have lightning, which, as we all know, is not good to get hit by. Also, non-severe thunderstorms can still generate wind gusts enough to knock you around if you're on the open lake. Sometimes a non-severe thunderstorm can get its winds into the "severe" threshold while crossing the lake, simply because there's nothing to slow down the wind on the open lake. The NWS may not be able to warn you about that-- just another reason boaters should take all thunderstorms seriously. Tomorrow's thunderstorm threat - severe or not - will be anytime after noon, with chances increasing through the afternoon and decreasing after dark as the activity moves east. Then, as meteotrade said, the cold front will stall along the south coast of New England and might ruin a few picnics down there. On Friday and Saturday the best weather will be in northwestern New England with greater chances for showers and clouds further south and east. Best chances for great weather will be in VT... best chances for lousy weather will be Cape Cod and the islands (including Long Island NY.) Meteotrade's forecast for stunning on the 4th does have good chances at the lake, but that stalled front makes me nervous. I don't like stalling fronts. They don't always stall where and when they're predicted to. When they stall, they sometimes serve as a storm track, as little waves of low pressure develop and scoot along them. Just pray Thursday's front goes way south and east of New England, into the ocean, before it stalls. That way if waves of low pressure start using it as a bowling lane, we'll be beyond the gutter. On Sunday, high pressure moves in and acts as meteorological Ex-Lax, takes control of New England and gives us all a nice day. Highs will be in the mid-80s Thursday with "sticky" humidity. Friday and Saturday we'll see temps in the mid-70s and less humidity. I also post forecasts on the WeatherCenter site... in the upper right corner click on "local forecasts." Includes my weather notes, NWS forecast, and Weather Underground forecast. Discussion from SPC for Thursday: ...OH VALLEY THROUGH NERN STATES... SCATTERED THUNDERSTORMS MAY BE ONGOING IN VICINITY OF FRONT FROM SE CANADA INTO THE LOWER GREAT LAKES AND NRN PARTS OF OH VALLEY. MOIST AXIS WITH DEWPOINTS AROUND 60F WILL ADVECT NEWD INTO WARM SECTOR IMMEDIATELY IN ADVANCE OF FRONT WHERE SOME BOUNDARY LAYER WARMING MAY OCCUR OUTSIDE OF ONGOING CONVECTION. HOWEVER...POOR MID-LEVEL LAPSE RATES WILL LIKELY LIMIT MLCAPE TO BELOW 1000 J/KG. FLOW IN THE 700-500 MB LAYER WILL LIKELY STRENGTHEN TO 40-50 KT OVER THE NERN STATES AS SHORTWAVE TROUGH ADVANCES EWD AND TIGHTENS GRADIENT. A SWLY 40+ KT LOW LEVEL JET IS ALSO FORECAST TO SHIFT NEWD THROUGH NE U.S. WARM SECTOR. THIS WILL RESULT IN FAVORABLE UNIDIRECTIONAL WIND PROFILE FOR ORGANIZED STORMS. POTENTIAL WILL EXIST FOR STORMS TO INTENSIFY AS THEY DEVELOP ESEWD ALONG AND AHEAD OF THE FRONT DURING THE DAY. THE KINEMATIC ENVIRONMENT WOULD SUPPORT THREAT FOR ISOLATED DAMAGING WIND. HOWEVER...THE EXPECTED MARGINAL THERMODYNAMIC ENVIRONMENT COULD SERVE AS A POTENTIAL LIMITING FACTOR SO WILL MAINTAIN ONLY A LOW END 15% SLIGHT RISK AREA AT THIS TIME.