91L no concern; more postcards from the AMS hurricane conference

By: Dr. Jeff Masters , 1:12 PM GMT on 四月 18, 2012

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I'm in Ponte Vedra Beach, Florida this week, where the world's hurricane experts are gathered to attend the 30th Conference on Hurricanes and Tropical Meteorology of the American Meteorological Society. Most of the Hurricane Specialists from the National Hurricane Center are here, and they are keeping an eye on the waters a few hundred miles east of Bermuda, where an extratropical storm has cut off from the jet stream and is slowly acquiring tropical characteristics. This system was designated Invest 91L last night by NHC. Ocean temperatures are around 20°C (68°F) in the region, which is well below the 26°C usually needed for a tropical storm to form. Wind shear is a high 20 - 30 knots. Nevertheless, 91L has managed to develop a small amount of heavy thunderstorm activity near its center, and may continue to show more organization as it moves slowly southeastward over the next day or two. I give 91L a close to 0% chance of becoming a named storm in the next two days, and NHC seems to have stopped issuing new products for the system. By the end of the week, 91L should get picked up by a trough of low pressure and move off to the northeast. The storm is not a threat to any land areas.


Figure 1. Morning satellite image of Invest 91L. The island of Bermuda is seen at the left side of the image.

Global tropical cyclones and climate: current signal
Now, I'll summarize a few of the excellent talks given at this week's AMS hurricane conference. Dr. Greg Holland of the National Center for Atmospheric Research talked about the impact of global warming on hurricane intensities. Using data beginning in 1975, the beginning of the satellite era, he showed that while the total number of hurricanes globally has decreased in recent years, the proportion of hurricanes that are of Category 4 - 5 intensity has increased by 40%. He showed that this change could be related to a 0.8°C increase in global temperature during the period. He concluded that when hurricanes form, they are finding that it is easier for them to reach higher intensities.

Sensitivity of the strongest hurricanes to ocean surface warmth
Dr. Jim Elsner of Florida State University showed that observations indicate a sensitivity of hurricane winds of 8.2 m/s +/- 1.19 per degree Centigrade of ocean warmth, using data in the Atlantic from 1981 - 2010 (for oceans areas warmer than 25°C.) Using a high resolution model (HiRAM) with 50 km resolution, a sensitivity of only 1.5 +/- .6 m/s was found, calling into question the usefulness of current models for assessing future hurricane activity.

How will climate change affect hurricane tracks?
Angela Colbert of the University of Miami used 17 global climate models, the BAM hurricane tracking model, and the Atlantic historical HURDAT data base to see how hurricane tracks might change in the future. She classified storms as either straight moving (which tend to hit the Caribbean or U.S. Gulf Coast), recurving landfalling (U.S. East Coast impacts), or recurving ocean storms that miss landfall. She projected a 6% increase in recurving ocean storms and an 8% decrease in straight-moving storms by the end of the century, due to climate change. A decrease of 1- 2 storms per decade is predicted for the Caribbean and Gulf of Mexico, and an increase of 1 - 2 storms per decade in the waters of the mid-Atlantic, and along the East Coast of Florida. This occurs primarily because of an increase in westerly winds over the Central Atlantic, and to a lesser degree, an eastward change in genesis location closer to the coast of Africa. Both of these factors would tend to increase the number of recurving storms.

Jeff Masters

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Quoting CybrTeddy:


No, I mean 2011.


Yeah, just saw that.. It was a bad squall line for me the day before that... I think this one means business though, concerning widespread reports all over the peninsula. Similar to March 29, 2001.
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350. Zappy
Looks like we'll be getting some much needed rain on Sunday through Monday. Can't wait until the next Drought Monitor.
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Florida may receive a Moderate Risk for severe storms..

Day 4-8 Severe Weather Outlook. A depicted severe weather area indicates a 30% or higher probability for severe thunderstorms within 25 miles of a point.

May be very dangerous for the Peninsula, especially when this could be a late night/overnight threat.
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Member Since: 八月 6, 2011 Posts: 4 Comments: 40845
I'm so happy it'll be raining almost all Sunday.We really need it.It was raining today to.And even though I was trying to avoid getting my hair wet I was still glad to see water falling out of the sky along with the smell of rain.
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Quoting reedzone:


You mean 2001??


No, I mean 2011.
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Member Since: 八月 6, 2011 Posts: 4 Comments: 40845
Quoting GTcooliebai:
If this pans out all I have to say is...I'll take it! :)

Your right on there..any rain at all is so welcome..gee its so dry
Member Since: 八月 6, 2011 Posts: 4 Comments: 40845
Quoting Some1Has2BtheRookie:


Should you look closely at the map, there is a small circle around presslord's house. The name given to this circle is ......... wait for it ............... The Carolinas!
Press will now destroy the universe the second he reads your post. you have done it.:)
Member Since: 九月 27, 2007 Posts: 1 Comments: 21734
342. DDR
Good evening
3 inches of rain with some localised flash flooding in parts of north Trinidad.
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Quoting GTcooliebai:
If this pans out all I have to say is...I'll take it! :)



Make sure some rain is leftover for Grothar...
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Quoting KoritheMan:


I thought Gustav shattered that record? Or maybe just for a hurricane...


highest official wind gust in Gustav was 211mph in Cuba, which is the highest in their history
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Quoting RitaEvac:
Presslord, we have a problem...


North Carolina-South Carolina State Line Redrawn


Should you look closely at the map, there is a small circle around presslord's house. The name given to this circle is ......... wait for it ............... The Carolinas!
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Special Statement

Statement as of 5:30 PM EDT on April 18, 2012

... A strong thunderstorm will move across Horry... Florence and Marion
counties through 630 PM EDT...

At 530 PM EDT... Doppler radar indicated a strong thunderstorm over
Hannah... or about 13 miles east of Lake City... moving east at 25 mph.

Some locations impacted include Conway... Marion... Mullins... Britton
Neck... Claussen... Evergreen... Friendfield... Galivants Ferry...
Gapway... Gresham... Hannah and Hickory Grove.

Hazards include...
half inch diameter size hail.
Gusty winds of 40 to 50 mph.

Heavy rainfall and minor flooding.

Thunderstorms can pose a variety of threats including gusty winds...
small hail... cloud to ground lightning... and localized flooding. It
is recommended that you remain indoors until the storms pass.


Lat... Lon 3415 7970 3425 7912 3382 7901 3378 7932
3380 7933 3382 7938 3380 7940 3378 7949
3381 7962 3382 7964 3381 7965
time... Mot... loc 2130z 253deg 21kt 3388 7952


Weiss


Member Since: 二月 13, 2012 Posts: 11 Comments: 3819
If this pans out all I have to say is...I'll take it! :)

Member Since: 八月 31, 2009 Posts: 0 Comments: 5628
Quoting KoritheMan:


It happened with Wilma:



Interesting.. didn't know that.
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Quoting reedzone:
Would be amazing to see a MODERATE RISK for storms in the Peninsula of Florida. I don't think I've seen that before... Day 4 outlook shows me that it's possible.


It happened with Wilma:

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Quoting NCHurricane2009:
I posted another tropical update last evening on my blog...I'll be posting another one this evening.

This is a new kind of blog I am planning to post daily during this upcoming season...so any feedback on how to make it better...etc...would be good.


I like it, but I feel you should add a "special features" section or something along those lines when discussing tropical entities, like the NHC does. Would make it much more user friendly.
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To answer Rita's question this is what I found, not sure it helps.

Vorticity looks good


Rainfall Amounts for Sat. morning looks like a half inch
Member Since: 八月 31, 2009 Posts: 0 Comments: 5628
Quoting Levi32:


Hey Nigel. As far as I know, in 2010 the WMO made the 253mph gust from TC Olivia on Barrow Island, Australia in 1996 official, making it the highest official gust over the previous record-holder of 231mph at Mount Washington in 1931.



I thought Gustav shattered that record? Or maybe just for a hurricane...
Member Since: Posts: Comments:
I posted another tropical update last evening on my blog...I'll be posting another one this evening.

This is a new kind of blog I am planning to post daily during this upcoming season...so any feedback on how to make it better...etc...would be good.
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Quoting KEEPEROFTHEGATE:
Reverse the lines, and it would look like August or September..:)
Member Since: 九月 27, 2007 Posts: 1 Comments: 21734
329. skook
For one to make a post, please type in da box below, to contribute to the blog.
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Quoting 1911maker:


What is the problem, its just the Carolinas Link after all. Just one place, no problems...........

Just like it is the Dakotas............. (were I live)

Press, I feel your pain......... :)
o my holy God...First R.E., now 1911...everyone brace yourselves when Press sees this....I mean really...
Member Since: 九月 27, 2007 Posts: 1 Comments: 21734
Quoting:-307. 1911maker

"Most Americans believe that global warming has played a role in a series of unusual weather events during the past year."

What are the possibilities of convincing the unbelievers that they are being misled?
I don't want to instigate a global warming fight on a Wednesday night but if Americans belive in things just because the localised evidence points to it? Then what chance have the statisticians got of convincing them that they are being misled? NOW?

Wait it out! but at the end of the day as that Lincoln Chappy said you can fool all of the people some of the time and some of the people all of the time but you can't fool all of the people, all of the time?
I might not remember that totally correctly but I'm sure Grother will!
Member Since: 一月 21, 2011 Posts: 0 Comments: 2093
Would be amazing to see a MODERATE RISK for storms in the Peninsula of Florida. I don't think I've seen that before... Day 4 outlook shows me that it's possible.
Member Since: Posts: Comments:
Time Out.......Before anything happens for Florida, is TX gonna get a weak squall line with the front BEFORE the low in the GOM starts cranking up....our rain chances have been creeping up lately.






Member Since: 七月 14, 2008 Posts: 1 Comments: 9645
Quoting xcool:
Effective on or about Tuesday, May 22, 2012, beginning with the 1200 Coordinated Universal Time (UTC) run, the National Centers for Environmental Prediction (NCEP) will upgrade the GFS model and its associated data assimilation system (GDAS). The primary changes will be to the analysis system. There will be no major changes to the GFS model itself, but there will be a few modifications to the output products available from the GFS.

The major component of the analysis change will be the incorporating a hybrid variational/ensemble assimilation system. In this system, the background error used to project the information in the observations into the analysis is created by a combination of a static background error (as in the prior system) and a new background error produced from a lower resolution (T254) Ensemble Kalman Filter. The development of this system was done in collaboration with PSD at ESRL. Including this change and the other smaller changes listed below produce significant positive impact on forecasts in both the northern and southern hemispheres and in the tropics. In almost all measures, a positive impact is noted; however, during the summer (convective precipitation) season, a small consistent degradation of the rain/no rain line and an increase in the bias was noted. This problem will be addressed through modifications to the convective parameterization in the next global implementation.



Additional changes in this upgrade include:

Analysis Changes:

- Use GPS RO bending angle rather than refractivity

- Include compressibility factors for atmosphere

- Retune SBUV ob errors, fix bug at top

- Update radiance usage flags

- Prepare for monitoring NPP and Metop-B satellite data

- Add NPP ATMS satellite data

- Add GOES-13/15 radiance data

- Add SEVERI CSBT radiance product

- Include satellite monitoring statistics code in operations

- Add new satellite wind data and quality control

- Update to current version of analysis trunk for optimization

and preparation for future updates


http://www.nws.noaa.gov/os/notification ... hybrid.htm
Hey long time no see, how are you doing xcool?
Member Since: 八月 31, 2009 Posts: 0 Comments: 5628
March 29, 2001 .. Major outbreak of Severe Storms MSC/Squall line.

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Afternoon. Been swamped at work so a late comment on Dr. Master's the latest Blog; the proportion of hurricanes that are of Category 4 - 5 intensity has increased by 40%. He showed that this change could be related to a 0.8°C increase in global temperature during the period. He concluded that when hurricanes form, they are finding that it is easier for them to reach higher intensities.....Warmer temps (even to such a minute degree) = more potential for majors.


She projected a 6% increase in recurving ocean storms and an 8% decrease in straight-moving storms by the end of the century, due to climate change. A decrease of 1- 2 storms per decade is predicted for the Caribbean and Gulf of Mexico, and an increase of 1 - 2 storms per decade in the waters of the mid-Atlantic, and along the East Coast of Florida.
....Stronger fish storms we can all watch at in amazement in the mid-Atlantic vs. a higher chance for Florida to get whacked by a Major.

That last one is a mixed blessing.
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Quoting CybrTeddy:


Bring it on. I wonder if it will be anything like what effected us on March 31st, 2011.


You mean 2001??
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320. xcool
Effective on or about Tuesday, May 22, 2012, beginning with the 1200 Coordinated Universal Time (UTC) run, the National Centers for Environmental Prediction (NCEP) will upgrade the GFS model and its associated data assimilation system (GDAS). The primary changes will be to the analysis system. There will be no major changes to the GFS model itself, but there will be a few modifications to the output products available from the GFS.

The major component of the analysis change will be the incorporating a hybrid variational/ensemble assimilation system. In this system, the background error used to project the information in the observations into the analysis is created by a combination of a static background error (as in the prior system) and a new background error produced from a lower resolution (T254) Ensemble Kalman Filter. The development of this system was done in collaboration with PSD at ESRL. Including this change and the other smaller changes listed below produce significant positive impact on forecasts in both the northern and southern hemispheres and in the tropics. In almost all measures, a positive impact is noted; however, during the summer (convective precipitation) season, a small consistent degradation of the rain/no rain line and an increase in the bias was noted. This problem will be addressed through modifications to the convective parameterization in the next global implementation.



Additional changes in this upgrade include:

Analysis Changes:

- Use GPS RO bending angle rather than refractivity

- Include compressibility factors for atmosphere

- Retune SBUV ob errors, fix bug at top

- Update radiance usage flags

- Prepare for monitoring NPP and Metop-B satellite data

- Add NPP ATMS satellite data

- Add GOES-13/15 radiance data

- Add SEVERI CSBT radiance product

- Include satellite monitoring statistics code in operations

- Add new satellite wind data and quality control

- Update to current version of analysis trunk for optimization

and preparation for future updates


http://www.nws.noaa.gov/os/notification ... hybrid.htm
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Quoting TropicalAnalystwx13:

Well of course, a handful of tornadoes will be possible along the leading edge of the MCS/Squall line. My main point that I've been trying to tell everybody is that this will not be a tornado outbreak like a certain blogger said the other night.


Ok I agree there I thought you meant there wouldn't be any tornadoes just wind event. Most of our tornadoes are small in nature and usually occur from situations like this. Have a great evening man!
Member Since: 十月 26, 2011 Posts: 0 Comments: 2651
Quoting StormTracker2K:


What you are forgeting is that Gulf Lows are notorious for tornadoes. Lived here all my life and I can tell you first hand that when these lows come out of the gulf like this we tend to some some small spin ups not large tornadoes but usually EF-1 maybe EF-2. The NWS offices are concerned about this here as this could occur Saturday night. They have been having meetings all afternoon if you want I can send you the e-mails that I received from them earlier.

Well of course, a handful of tornadoes will be possible along the leading edge of the MCS/Squall line. My main point that I've been trying to tell everybody is that this will not be a tornado outbreak like a certain blogger said the other night.
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Quoting hydrus:
Where, and for how long? If its o.k. to ask.


Yes, the weekend pattern looks very interesting and quite unusual for April. We'll be providing early briefings to the emergency managers and skywarn coordinators later today.

Scott

Member Since: 十月 26, 2011 Posts: 0 Comments: 2651
Member Since: 七月 15, 2006 Posts: 175 Comments: 54827
With so much shear in place I would expect tornado watches Saturday afternoon.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
154 PM EDT WED APR 18 2012

.LONG TERM (FRIDAY NIGHT-TUESDAY)...
MODELS REMAIN SIMILAR THROUGH THE LONG TERM PERIOD WITH THE
DEEPENING TROUGH FORECAST TO CUTOFF AS IT MOVES ACROSS THE DEEP
SOUTH OVER THE WEEKEND THEN OPENING UP AND LIFTING OUT ON MONDAY.
MEANWHILE AT THE SURFACE...AN AREA OF LOW PRESSURE IS EXPECTED TO
DEVELOP OVER THE LOWER MISSISSIPPI VALLEY SATURDAY AND TRACK EAST
ACROSS THE DEEP SOUTH DURING SUNDAY AND THEN NORTHEAST UP INTO THE
CAROLINAS ON MONDAY. THIS SCENARIO WILL BRING ABUNDANT MOISTURE
NORTHWARD INTO THE REGION ON BREEZY SOUTH TO SOUTHWEST WINDS AHEAD
OF A COOL FRONT LEADING TO THE BEST RAIN CHANCES WE HAVE SEEN IN
MANY WEEKS AND LATER FORECASTS WILL LIKELY NEED TO RAISE POPS EVEN
HIGHER AS TIMING AND LOCATION OF THE SYSTEM BECOMES MORE CERTAIN.
STILL LOOKS LIKE THE THREAT FOR SOME STRONG TO POSSIBLY SEVERE
STORMS WILL EXIST SATURDAY NIGHT INTO SUNDAY AS DECENT SHEAR AND
STRENGTHENING WIND FIELDS SETUP ACROSS THE REGION
. BY EARLY NEXT
WEEK THE SYSTEM WILL BE SHIFTING NORTHEAST AWAY FROM THE AREA WITH
HIGH PRESSURE BUILDING IN BRINGING SOME DRIER AND SLIGHTLY COOLER
AIR INTO THE REGION.

Member Since: 十月 26, 2011 Posts: 0 Comments: 2651
Quoting StormTracker2K:


What you are forgeting is that Gulf Lows are notorious for tornadoes. Lived here all my life and I can tell you first hand that when these lows come out of the gulf like this we tend to some some small spin ups not large tornadoes but usually EF-1 maybe EF-2. The NWS offices are concerned about this here as this could occur Saturday night. They have been having meetings all afternoon if you want I can send you the e-mails that I received from them earlier.
Where, and for how long? If its o.k. to ask.
Member Since: 九月 27, 2007 Posts: 1 Comments: 21734
Quoting hydrus:
You are really stirring the pot this time R.E.


What is the problem, its just the Carolinas Link after all. Just one place, no problems...........

Just like it is the Dakotas............. (were I live)

Press, I feel your pain......... :)
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Quoting TropicalAnalystwx13:
Looks like the state of Florida will be affected by a Severe Weather outbreak (NOT tornado) over the weekend. With a likely squall line moving across the state, damaging winds look like a very high threat.



What you are forgeting is that Gulf Lows are notorious for tornadoes. Lived here all my life and I can tell you first hand that when these lows come out of the gulf like this we tend to some some small spin ups not large tornadoes but usually EF-1 maybe EF-2. The NWS offices are concerned about this here as this could occur Saturday night. They have been having meetings all afternoon if you want I can send you the e-mails that I received from them earlier.
Member Since: 十月 26, 2011 Posts: 0 Comments: 2651
Looks like some MCS and bowing segments for this weekend for most of Florida.

More than likely, the tornado threat will be limited.
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Quoting aspectre:
Wanna know how to tell when you're located amidst a buncha weather weenies?
Ya can go for years and years there without hearing anyone wishing for an exotic sports car.

313 hydrus: It is hard for me to imagine a wind gust of 253 mph.
393 aspectre: Try roof-surfing on a BugattiVeyron running at top speed.
72 jeffs713: I'll just take the Bugatti.
75 hydrus: I was going to say, I wish I had one... :)

But just mention that roof-surfing on one is like experiencing 250mph hurricane winds...
...and suddenly everyone wants one.
I wanted one before the wind surfing post..I dig cars as much as I do science and weather.:)
Member Since: 九月 27, 2007 Posts: 1 Comments: 21734
Quoting TropicalAnalystwx13:
All I can say is that it is a good thing this is not winter...

Looks like it will be for some.
Member Since: 九月 27, 2007 Posts: 1 Comments: 21734
Quoting RitaEvac:
Presslord, we have a problem...


North Carolina-South Carolina State Line Redrawn
You are really stirring the pot this time R.E.
Member Since: 九月 27, 2007 Posts: 1 Comments: 21734
I see you druggies need some politics for balance today..........


http://www.npr.org/blogs/thetwo-way/2012/04/18/15 0895328/organizations-cant-be-sued-for-torture-hig h-court-rules
Link

"No one, we hazard to guess, refers in normal parlance to an organization as an 'individual,'" Sotomayor said, and there was no indication that Congress intended otherwise.

Citizens United aside.............

http://www.npr.org/blogs/thetwo-way/2012/04/18/15 0886905/poll-most-americans-link-climate-change-to -unusual-weather-events
Link

Most Americans believe that global warming has played a role in a series of unusual weather events during the past year.
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Quoting CybrTeddy:


Bring it on. I wonder if it will be anything like what effected us on March 31st, 2011.

This?

It'll probably be worse than that.

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All I can say is that it is a good thing this is not winter...

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Quoting TropicalAnalystwx13:
Looks like the state of Florida will be affected by a Severe Weather outbreak (NOT tornado) over the weekend. With a likely squall line moving across the state, damaging winds look like a very high threat.



Bring it on. I wonder if it will be anything like what effected us on March 31st, 2011.
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Looks like the state of Florida will be affected by a Severe Weather outbreak (NOT tornado) over the weekend. With a likely squall line moving across the state, damaging winds look like a very high threat.

Member Since: Posts: Comments:
Wanna know how to tell when you're located amidst a buncha weather weenies?
You can go for years and years there without hearing anyone wishing for an exotic sports car.

313 hydrus: It is hard for me to imagine a wind gust of 253 mph.
393 aspectre: Try roof-surfing on a BugattiVeyron running at top speed.
72 jeffs713: I'll just take the Bugatti.
75 hydrus: I was going to say, I wish I had one... :)

But just mention that roof-surfing on one is like experiencing 250mph hurricane winds...
...and suddenly everybody wants one.
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301. HurrikanEB
8:55 PM GMT on 四月 18, 2012
Quoting StormTracker2K:
CPC seems to think that some areas of C & N FL up to Maine could get locally 4" to 6" of rain with some amounts not out of the question nearing 10". Crazy because even with 4" here in C FL we would get lots of run off as the ground is hard as a rock due to 6 months of almost no rain.



Albany, New York:
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MUCH NEEDED RAINFALL EXPECTED THIS WEEKEND.... QPF AMOUNTS ARE HIGHLY IN QUESTION. AT THIS TIME...LOOKING AT SIGNIFICANT MULTI-DAY RAINFALL EVENT WITH
POTENTIALLY UP TO 5 INCHES OCCURRING.
PRECIPITATION SO FAR THIS YEAR
IS ABOUT HALF OF WHAT IT SHOULD BE. PRECIPITATION ACROSS THE AREA IS
RUNNING AROUND 5 TO 6 INCHES BELOW NORMAL.

Should be enough to just about end this drought in the northeast.
Member Since: 五月 2, 2008 Posts: 12 Comments: 1342

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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.