From the Lee Side: Penn State's Lee Grenci now a featured wunderblogger

By: Dr. Jeff Masters , 6:24 PM GMT on December 12, 2012

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"From the Lee Side" is the blog of wunderground's newest featured blogger--Lee Grenci. Lee put up his first post today, an educational piece on "Arctic Air Masses." He did an earlier guest post in Angela's blog, "The science of Sandy's transition", on whether or not Sandy was a hurricane at landfall (it wasn't.) Lee resides in Pennsylvania, and just retired as senior lecturer in Meteorology at Penn State University, where he was the lead faculty member for their online certificate in weather forecasting. I've been enjoying Lee's writings for many years in Weatherwise magazine, where he is a frequent contributor. Welcome, Lee!

While I'm on the subject of featured bloggers, I want to draw attention to the latest post by TWC's Stu Ostro, "Reflections on a surreal superstorm and the 2012 hurricane season". He discusses NHC's decision not to issue Hurricane Warnings for Sandy, as well as how climate change may have influenced the storm. TWC's Bryan Norcross has also posted his take on NHC's decision not to post hurricane warnings for Sandy.

Jeff Masters

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Hello Jeff,

Thanks for the warm welcome and the opportunity to share my thoughts on weather and atmospheric science at Weather Underground. Everybody, including readers, have been so generous. I am very grateful.
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I am so glad I am not in Samoa right now. Reports of 2 people killed so far Link

TC Evan is just sitting over Samoa continually pounding them with 65kt winds and 80kt gusts also driving rains.





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Rain coming!:)
Member Since: May 23, 2012 Posts: 0 Comments: 4460
Quoting aislinnpaps:
Morning, everyone, evening Aussie. This should be our last cold morning again for a little bit. Warms back up into the 50s tomorrow morning.

Mornin'

Quoting indianrivguy:
Mornin' Doug!

Evening Aussie!


Mornin' Mate

Quoting HadesGodWyvern:
Fiji Meteorological Services
Tropical Cyclone Advisory #10
SEVERE TROPICAL CYCLONE EVAN, CATEGORY THREE (04F)
18:00 PM FST December 13 2012
===================================

A TROPICAL CYCLONE ALERT IS NOW IN FORCE FOR NIUATOPUTAPU AND NIUAFO'OU IN TONGA

At 6:00 AM UTC, Severe Tropical Cyclone Evan (975 hPa) located at 14.0S 171.2W has 10 minute sustained winds of 65 knots. The cyclone is reported as moving east at 3 knots. Position good based on hourly GMS infrared imagery and peripheral surface reports.

Hurricane Force Winds
========================
20 NM from the center

Storm Force Winds
====================
35 NM from the center

Gale Force Winds
================
60 NM from the center

Deep convection persistent past 12 hours. Cyclone intensifying over the last 12 hours. EVAN lies under an upper diffluent region. Outflow good to the south. System lies in a low sheared environment. Sea surface temperature is around 30C. Dvorak analysis based on embedded center LG surround yielding DT=4.5, MET=4.0, PT=4.5. Final T number based on DT.

Dvorak Intensity: T4.5/4.5/D1.0/24 HRS

Forecast and Intensity
=====================
12 HRS: 14.0S 171.1W - 70 knots (CAT 3/Severe Tropical Cyclone)
24 HRS: 14.1S 171.7W - 75 knots (CAT 3/Severe Tropical Cyclone)
48 HRS: 14.9S 174.9W - 85 knots (CAT 3/Severe Tropical Cyclone)


A TROPICAL CYCLONE ALERT IS NOW IN FORCE FOR NIUATOPUTAPU AND NIUAFO'OU IN TONGA
Can anyone explain why Tonga is under a TC alert. Tonga is 560 miles SW of Samoa and TC Evan is going to turn back west and head towards Fiji.


Tonga is the lower part of the group of Islands SW of TC Evan's current location.
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Good morning, afternoon or evening as the case may be.
Here in Fort Myers we finally received some much needed rain. My three day total came to 2.25 inches.
Oh happy days
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Quoting Xyrus2000:


What nymore isn't telling you, and would absolutely hate for you to do, is actually read the whole thing because it doesn't say nearly what he wants it to say. The link to the full thing is here: Link.

Also, this is examining surface station data over land ONLY. It does not include satellite measurements, SST's, or any other data. You can jump down to the summary section if you want to skip most of the gory details.


You are exactly right. I don't want anyone to read the article. That is why I posted where to find it.

Remember folks if you see a study or data based on surface station data over land it is worthless.
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Quoting indianrivguy:
Mornin' Doug!

Evening Aussie!


Back at cha!
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Morning, everyone, evening Aussie. This should be our last cold morning again for a little bit. Warms back up into the 50s tomorrow morning.
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looks like the whole gulf coast is dry today...
Member Since: August 6, 2011 Posts: 4 Comments: 37950
Member Since: August 6, 2011 Posts: 4 Comments: 37950
Member Since: August 6, 2011 Posts: 4 Comments: 37950
Member Since: August 6, 2011 Posts: 4 Comments: 37950
Good Morning folks!..rain is gone i guess,have a great day...
Member Since: August 6, 2011 Posts: 4 Comments: 37950
Quoting Astrometeor:


Concert is amazing. And I don't live up there, I'm down in the south, but this is a great, and well done concert so far, and it is even better how many great artists have come together. Even from different generations and different venues of music, and the way the audience receives them (I'm listening over the radio), is truly spectacular.

That being said, I wish I could donate, since I would have donated several times over.
wow that 121212 concert was simply AWESOME..i grew up there and the scenes of the flooding and destruction and the misery real hit home for me..living in florida now we take these hurricanes as they come each year but..up there they arent used to that..geez..awesome concert last night for sure...
Member Since: August 6, 2011 Posts: 4 Comments: 37950
Mornin' Doug!

Evening Aussie!
Member Since: September 23, 2006 Posts: 1 Comments: 2535
That's a goofy argument you guys are having.

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322. HadesGodWyvern (Mod)
Fiji Meteorological Services
Tropical Cyclone Advisory #10
SEVERE TROPICAL CYCLONE EVAN, CATEGORY THREE (04F)
18:00 PM FST December 13 2012
===================================

A TROPICAL CYCLONE ALERT IS NOW IN FORCE FOR NIUATOPUTAPU AND NIUAFO'OU IN TONGA

At 6:00 AM UTC, Severe Tropical Cyclone Evan (975 hPa) located at 14.0S 171.2W has 10 minute sustained winds of 65 knots. The cyclone is reported as moving east at 3 knots. Position good based on hourly GMS infrared imagery and peripheral surface reports.

Hurricane Force Winds
========================
20 NM from the center

Storm Force Winds
====================
35 NM from the center

Gale Force Winds
================
60 NM from the center

Deep convection persistent past 12 hours. Cyclone intensifying over the last 12 hours. EVAN lies under an upper diffluent region. Outflow good to the south. System lies in a low sheared environment. Sea surface temperature is around 30C. Dvorak analysis based on embedded center LG surround yielding DT=4.5, MET=4.0, PT=4.5. Final T number based on DT.

Dvorak Intensity: T4.5/4.5/D1.0/24 HRS

Forecast and Intensity
=====================
12 HRS: 14.0S 171.1W - 70 knots (CAT 3/Severe Tropical Cyclone)
24 HRS: 14.1S 171.7W - 75 knots (CAT 3/Severe Tropical Cyclone)
48 HRS: 14.9S 174.9W - 85 knots (CAT 3/Severe Tropical Cyclone)
Member Since: May 24, 2006 Posts: 50 Comments: 45214
321. HadesGodWyvern (Mod)
Mauritius Meteorological Services
Tropical Cyclone Advisory #29
DEPRESSION EXTRATROPICALE CLAUDIA (04-20122013)
10:30 AM RET December 13 2012
======================================

At 6:00 AM UTC, Extratropical Cyclone, Former Claudia (995 hPa) located at 28.6S 76.8E has 10 minute sustained winds of 35 knots with gusts of 50 knots. The cyclone is reported as moving southeast at 15 knots.

Dvorak Intensity: NIL

Gale Force Winds
================
100 NM in the eastern semi-circle

Near Gale Force Winds
=====================
45 NM radius from the center, extending up to 60 NM in the southwestern quadrant, up to 175 NM in the northeastern quadrant and up to 215 NM in the southeastern quadrant

Forecast and Intensity
======================
24 HRS: 31.4S 79.2E - Depression Extratropicale
48 HRS: 34.3S 83.4E - Depression Extratropicale
72 HRS: 38.5S 94.4E - Depression Extratropicale

Additional Information
=====================
Last OSCAT pass at 1856 PM UTC shows a very asymmetrical winds, with the strongest winds far from the center in the eastern semi-circle, due to the gradient with the high pressures in the east.

Global philosophy remains the same: gradual speed up in a southeastwards track and then, Saturday, over the southern edge of the subtropical ridge, an eastwards motion at a slower rate.

Winds might remain strong until Friday in the eastern then northern sectors by gradient effect with the subtropical high pressures.

Last warning about this system, unless re-intensification, it will be closely monitored until final dissipation into FQIO21 FMEE warning.
Member Since: May 24, 2006 Posts: 50 Comments: 45214
Quoting KoritheMan:


I didn't say they were sustained. Hell, the very post you quoted specifically mentioned gusts.

Seriously though, I know how ****ed I'd be if I were in a more open area. I was standing in my dad's protected street during Gustav and Isaac.


that does not prove my fact wrong...you lost
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Quoting Xyrus2000:


Yes, but were standing in an open field with no obstructions? Were you on a hill or in a local depression?

Sorry but 90 mph sustained is really pushing it when it comes to remaining standing. At that wind speed even leaning into the wind creates enough lift over the body to pick the average sized person up off the ground. Not to mention the fact that someone should get an honorable mention in the Darwin Awards for being outside in winds like that.


I didn't say they were sustained. Hell, the very post you quoted specifically mentioned gusts.

Seriously though, I know how ****ed I'd be if I were in a more open area. I was standing in my dad's protected street during Gustav and Isaac.
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Quoting Xyrus2000:


Yes, but were standing in an open field with no obstructions? Were you on a hill or in a local depression?

Sorry but 90 mph sustained is really pushing it when it comes to remaining standing. At that wind speed even leaning into the wind creates enough lift over the body to pick the average sized person up off the ground. Not to mention the fact that someone should get an honorable mention in the Darwin Awards for being outside in winds like that.


thank you very much... plus1000000000!!!

someone knows what Im talking about
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Quoting KoritheMan:


Yet 20 mph above that didn't knock me down. Maybe I'm just too sexy?

btw, the surface observations for Baton Rouge do actually show a 91 mph gust on September 1, and since I live near there...


anyway... sexy?????
you guys, I just checked the forecast for Pago Pago in NWS site...bad stuff
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Quoting KoritheMan:


Yet 20 mph above that didn't knock me down. Maybe I'm just too sexy?

btw, the surface observations for Baton Rouge do actually show a 91 mph gust on September 1, and since I live near there...


Yes, but were standing in an open field with no obstructions? Were you on a hill or in a local depression?

Sorry but 90 mph sustained is really pushing it when it comes to remaining standing. At that wind speed even leaning into the wind creates enough lift over the body to pick the average sized person up off the ground. Not to mention the fact that someone should get an honorable mention in the Darwin Awards for being outside in winds like that.
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TXPS26 KNES 130024
TCSWSP

A. 04P (EVAN)

B. 12/2330Z

C. 14.1S

D. 171.5W

E. THREE/MTSAT

F. T4.5/4.5/D2.0/24HRS

G. IR/EIR/AMSU

H. REMARKS...SYSTEM CONTINUES TO DEVELOP RAPIDLY WITH DT=4.5 BASED
ON 13/10 WHITE BANDING. MET=4.0 AND PAT=4.5. FT IS BASED ON RAPID
INTENSIFICATION.

I. ADDL POSITIONS

12/2107Z 14.2S 171.7W AMSU


...SWANSON

JTWC has Evan at 65.0kts
Nadi has Evan at 69.8kts

Forecast 24hr Rainfall
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HURRICANE WARNING 025 ISSUED FROM RSMC NADI Dec 13/0129 UTC 2012 UTC.

TROPICAL CYCLONE FORECAST TRACK MAP


TROPICAL CYCLONE EVAN CENTRE 975HPA CATEGORY 2 WAS LOCATED NEAR 14.0 SOUTH 171.5
WEST AT 130000 UTC.
POSITION FAIR.
REPEAT POSITION 14.0S 171.5W at 130000 UTC.
CYCLONE MOVING EAST AT 6 KNOTS. CYCLONE INTENSIFYING.
EXPECT SUSTAINED WINDS OF 60 KNOTS CLOSE TO THE CENTRE, INCREASING TO 65 KNOTS
BY 140000.
EXPECT SUSTAINED WINDS OVER 47 KNOTS WITHIN 25 NAUTICAL MILES OF CENTRE
EXPECT WINDS OVER 33 KNOTS WITHIN 45 NAUTICAL MILES IN NE QUADRANT
AND WITHIN 40 NAUTICAL MILES IN SE QUADRANT
AND WITHIN 45 NAUTICAL MILES IN SW QUADRANT
AND WITHIN 60 NAUTICAL MILES IN NW QUADRANT

FORECAST POSITION NEAR 13.9S 170.9W AT 131200 UTC
AND NEAR 14.0S 171.2W AT 140000 UTC.

ALL VESSELS WITHIN 300 NAUTICAL MILES OF CENTRE ARE REQUESTED TO SEND REPORTS
EVERY THREE HOURS TO RSMC NADI. VOS REPORTING SHIPS USE NORMAL CHANNELS. OTHER
VESSELS FAX PLUS 679 6720190 OR EMAIL NADITCC AT MET DOT GOV DOT FJ

TROPICAL CYCLONE THREAT TRACK MAP

Tropical Cyclone EVAN Category 2
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Quoting bappit:

The guy who wrote this study sounds like a stray data point. How did you get hold of this?


What nymore isn't telling you, and would absolutely hate for you to do, is actually read the whole thing because it doesn't say nearly what he wants it to say. The link to the full thing is here: Link.

Also, this is examining surface station data over land ONLY. It does not include satellite measurements, SST's, or any other data. You can jump down to the summary section if you want to skip most of the gory details.
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Quoting trHUrrIXC5MMX:


yes I did. even 70 mph can knock down people


Yet 20 mph above that didn't knock me down. Maybe I'm just too sexy?

btw, the surface observations for Baton Rouge do actually show a 91 mph gust on September 1, and since I live near there...
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Quoting KoritheMan:


Irrelevant. You said there was no physical way a person could take 90 mph winds. Doesn't my claim contradict that?


yes I did. even 70 mph can knock down people
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Quoting trHUrrIXC5MMX:


really??

You went out to the street to say hi


Irrelevant. You said there was no physical way a person could take 90 mph winds. Doesn't my claim contradict that?
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Quoting KoritheMan:


Really? Then why did I take them head on during Gustav? Hmm?


really??

You went out to the street to say hi
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Quoting trHUrrIXC5MMX:


Im pretty sure 90 mph are somewhat destructive...

FACT... you won't be able to take 90 mph winds!


Really? Then why did I take it head on during Gustav? Hmm?
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I find it interesting that the Tallahassee NWS weather discussion this evening mentions that parts of the area experienced graupel and small hail this afternoon as the shortwave passed through. Especially considering temperatures were 48F-54F during this time at the reporting stations I checked and none of these officially reported any frozen precipitation in the hourly observations.

Pretty fascinating as this frozen precipitation was clearly caused by freezing temperatures relatively near the surface, rather than processes which create thunderstorm-related hail (which can and usually does occur when surface temps are fairly warm).

So, my point is-frozen precipitation is fairly uncommon and noteworthy anywhere in Florida (not that rare in the FL Panhandle though). I feel that with the ever-increasing population, present and observing weather in more areas, localized events such as this which have tended to be considered "rare", will be discovered to not be that rare.
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Quoting Xyrus2000:


Linear equations will kill you. Non-linear equations will kill you, resurrect you, torture, and kill you again in very ingenious ways. XD


that's linear...wait for parabolas, sice, cosine, tangents etc..you are just smelling the honey
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G'evening all, late 12-12-12 flyby!

Gorgeous chilly December night in SE LA, under clear skies, 37F with frost forming...
Concert is awesome!
But also was outside enjoying the view - Geminid meteors to peak tomorrow night, but in around a 10 min period before 11 PM, quickly saw 5, with another 4 faint "maybes" in the peripheral realm of possibility.
Thought I'd mention, might be worth a gander if inclined... ;)

Back outside to test if it was just dumb luck, lol.
Later!

EDIT / ADD 11:35PM:
Okay, just saw another as counted to 78 secs... Best view I'm having is looking up, facing west... meteors all traveling generally E-W (SE-NW to ENE-WSW)...

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Quoting Civicane49:
Tropical Cyclone Evan continues to bring heavy rains and strong winds to Samoa and would continue to affect that region in the next couple of days, due to its slow movement. Currently, there are no casualties reported, but some damage was already reported.

With favorable environmental conditions, the cyclone is expected to further strengthen during the next few days, possibly reaching Category 4 intensity. It is forecast to meander around Samoa before moving towards west-southwest. Evan would threaten Fiji by the coming weekend; however, it is expected to weaken by the time it reaches there.



Im pretty sure 90 mph are somewhat destructive...

FACT... you won't be able to take 90 mph winds!
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Tropical Cyclone Evan continues to bring heavy rains and strong winds to Samoa and would continue to affect that region in the next couple of days, due to its slow movement. Currently, there are no casualties reported, but some damage was already reported.

With favorable environmental conditions, the cyclone is expected to further strengthen during the next few days, possibly reaching Category 4 intensity. It is forecast to meander around Samoa before moving towards west-southwest. Evan would threaten Fiji by the coming weekend; however, it is expected to weaken by the time it reaches there.

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Quoting BtnTx:
The Who completely blew me away as they played my favorites as well as Pink Floyd! I have already pre-purchased the sound track on iTunes!
I forgot to mention Floyd..They were fabulous and one of my favorites.
Member Since: September 27, 2007 Posts: 1 Comments: 20935
Quoting thunderbug91:

really? Linear equations killed me this semester!!!


Linear equations will kill you. Non-linear equations will kill you, resurrect you, torture, and kill you again in very ingenious ways. XD
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Quoting bappit:

You read GRL regularly?
Actually found it a couple of years ago while looking into a study showing deep warm water jets along the equator west of the African coast
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Quoting KoritheMan:


Misspelled is one word.


This coming from the guy who uses "it's" when using it in the context of possession.

;)

JTWC is thinking Evan will be a category 4 by Friday:
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Quoting KoritheMan:


It's not if I say it's not.
*roll eyes*
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Quoting KoritheMan:


It's not if I say it's not.

Whatever Kori says goes eh?

Goodnight everyone.
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Quoting allancalderini:
its Allen. I am really thinking of changing my name.


It's not if I say it's not.
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Quoting KoritheMan:


Misspelled is one word.

Grrrrrrrrrrrrrr.

Like you haven't made any spelling mistakes.
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Quoting KoritheMan:


Hurricane Allan.
its Allen. I am really thinking of changing my name.
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290. BtnTx
Quoting hydrus:
Excellent concert so far. Impressed with how well The Who, Clapton and " The Boss " are doin after all these years.
The Who completely blew me away as they played my favorites as well as Pink Floyd! I have already pre-purchased the sound track on iTunes!
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.