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Rtd208

August 2020 General Discussions & Observations Thread

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Too much uncertainty.  Looks nasty except no 12z UK yet, and the EC has very little going.  For now,  I think 700MB FGEN is driving showers in southern PA and it looks to me like a decent event is coming I80-LI southward BUT with lots of uncertainty.  The differences in the modeling has to be related to initialization-sensitivity but I'm not the one to know for sure.  I do think this is highly unusual to have so vast a difference in the 24 hour time frame. NOT good for the science.  Take a compromise.  Not posting a topic, as yet. 219P/15

 

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Looking at reality vs modeling: Someone tell me that this will fade to the EC/UK dry solutions. VERY difficult to believe.  

In the end I think I'll work some sort of 12z-18 NAM HRDPS mix to this. Looks impressive to me...moderate rain into southern PA at 1830z.    Will check 18z NAM and then try to figure it out different than already posted earlier this afternoon. I do see the UK/EC doing so well with this system, certainly not off to a very good start. 

313P/15

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42 minutes ago, SI Mailman said:

Looks like a storm popped up over the north shore of Staten Island. Very cloudy with a breeze by me on the south shore.

Yeah had a quick 0.33" in castleton corners section.

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NAM is looking increasingly lonely on the 18z runs in calling for higher rain amounts for tomorrow for the majority of the metro area.  The GFS and RDPS would bring heavier amounts to LI and parts of the city however most other model runs have negligible amounts except for central NJ and points south.

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Under partly sunny skies, temperatures reached the upper 70s and lower 80s in much of the region. Coastal areas saw a stiff northeast breeze.

Out west, extreme heat prevailed in the Southwest. Select high temperatures included:

Death Valley, CA: 125° (old record: 124°, 2002)
Kingman, AZ: 111° (old record: 106°, 1933) ***Tied August Record***
Lake Havasu City, AZ: 120° (old record: 118°, 1994)
Las Vegas: 113° (old record: 111°, 1939, 1994 and 2002)
Mesa, AZ: 112° (tied daily record set in 2019)
Needles, CA: 123° (old record: 118°, 2019) ***New August Record***
Phoenix: 114°
Tucson: 109°
Yuma, AZ: 111°

Final figures will be available for Death Valley and Lake Havasu City tomorrow.

More intense heat is likely in that region through midweek next week.

Tomorrow could see some showers and perhaps periods of rain with readings mainly in the 70s. From southern New Jersey southward to Virginia, a soaking rain is in store. There, widespread 1"-2" with locally higher amounts is likely. A moderate rainfall of 0.50"-1.00" is possible on portions of Long Island.

Nevertheless, the current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible.  

The ENSO Region 1+2 anomaly was -1.2°C and the Region 3.4 anomaly was -0.6°C for the week centered around August 5. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.15°C and the ENSO Region 3.4 anomaly has averaged -0.37°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions will likely develop.

The SOI was +5.46.

Today, the preliminary Arctic Oscillation (AO) figure was -0.097.

On August 14, the MJO was in Phase 8 at an amplitude of 0.836 (RMM). The August 13-adjusted amplitude was 0.617.

The MJO's recent passage through Phase 4 at an amplitude of 1.500 or above has been uncommon during the first half of August. During the 1981-2019 period only 1983 and 2019 saw the MJO move through Phase 4 with an amplitude of 1.500 or above during the first half of August. August 1983 had the longest such stretch. Both cases saw the second half of August average generally warmer than normal in the Middle Atlantic region. Both cases also featured a warmer than normal September.

Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period.

Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period.

Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September.

Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO.   

Based on sensitivity analysis applied to the latest guidance, there is an implied 73% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 77.0°.

 

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8/15

EWR: 85
JFK: 85
LGA: 85
TEB: 85
NYC: 84
New Brnswck: 84
TTN: 83
PHL: 82
BLM: 81
ISP: 81
ACY: 79

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Whether the heavier rain tracks north once developing or not, this may be a typical faster than guidance storm and we clear out for a bit of the later afternoon.  Already saw the clouds deck clear into OH before the visible went into IR mode.  Following the trend Thu below guidance/ Fri warmer / today more cloudy / perhaps tomorrow later PM highs if we get into the sun.

 

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Good Sunday morning all,

Looking beyond the topic'd developing nor'easter for our I84 area southeastward,  SPC continues D2 marginal risk for severe for our area. No topic til late afternoon since we're on-going with one event and small timing issues are developing for later Monday-Monday night. 

I am now having to think two bands of scattered gusty showers-thunderstorms...one mid Monday afternoon and the other around midnight to 3 am Tuesday.  The afternoon would probably be more likely to produce a few severe, but I think the one overnight might surprise as it has quite a bit of KI/cooling 500MB temps and leftover CAPE to work with, along with a pretty decent 500mb jet/vort max coming through. 

The 22nd-24th (yesterdays's 23rd), looks interesting for a couple bands of heavy showers/thunderstorms. 649A/16

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The next 8 days are averaging 78degs., or 2.5degs. AN.

Month to date is  +2.7[78.7].        Should be about  +2.7[78.4] by the 24th.

69*!!!(83%RH) here at 6am and 7am, overcast, drizzle.

All models are about 0.5in. rain the next 2 days.

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The NWS did an extensive post about  the leaf burn on the south sides of the trees following Isaias.

We at the office have noticed an interesting phenomenon in the wake of Tropical Storm Isaias here on Long Island... 
A lot of the south side of exposed vegetation is withering while the north side of the same vegetation seems fine.

This picture is taken by one of our meteorologists on the south shore of Long Island today (August 15th, 2020), about 11 days after Tropical Storm Isaias swept through the area. The picture is taken looking to the north.

You can very clearly see that much of the south side of the vegetation looks as if it has progressed into late autumn with much of it turning brown. However, the north side of the trees and the bushes are still green! How and why is this happening??

We believe that the cause of this weird occurrence has to do with the blowing of ocean spray (and thus sea salt) onto the south side of exposed vegetation by strong winds. Tropical Storm Isaias had strong winds associated with it on Long Island, but not much rainfall.

Strong southerly winds (with gusts up to and exceeding 70 mph) off of the ocean picked up sea salt off the ocean surface and battered the south sides of just about everything.

With little to no rain to wash the salt off of trees and bushes in the wake of these strong winds, the south sides of the vegetation that experienced the brunt of the winds (and thus most exposure to the sea salt) seems to have begun to wither and wilt.

Additionally, much of Long Island is currently in a moderate drought with Islip, NY (KISP) a little more than 6" of precipitation below average for the calendar year so far. This may at least partially enhance these withering effects.

There is anecdotal evidence of this phenomenon occurring from tropical events in the past, like Hurricane Sandy in 2012 and the "Long Island Express" Hurricane in 1938, though both of these prior events occurred later in the year than Tropical Storm Isaias.

With all that being said, have you noticed this weird occurrence in your area? We at the office would be very interested to hear (and see) from you if you've noticed this happening near you!

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Morning thoughts...

At 8 am, moderate rainfall was moving through area that included parts of Virginia, Maryland, Delaware, Pennsylvania and New Jersey. Another smaller area of moderate rainfall was moving through parts of the Hudson Valley. In New York City, light rain was falling with a temperature of 67 degrees.

A moderate to heavy rainfall remains likely parts of the Middle Atlantic region. Virginia, Maryland, Delaware, Pennsylvania and southern New Jersey could be in line for 1”-2” rain with locally higher amounts. Parts of Long Island could see 0.50”-1.00” rain. New York City will likely see less than 0.50”. 

Out west, intense heat will again sear parts of California, Arizona and Nevada. Death Valley is poised to challenge the August heat record. Yesterday’s high temperature there was 126 degrees, which beat the daily record of 124 degrees from 2002. Yesterday’s high temperature was just below the monthly record of 127 degrees, which was set on August 12, 1933 and tied on August 1, 2017. 

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With all the clouds and rain, White Plains has a chance to break its record 75° high temperature streak. It’s currently tied for 1st place with 2006 at 60 days. But it looks like the record 60° minimum streak  will continue.

Number of Consecutive Days Max Temperature >= 75 
for WESTCHESTER CO AP, NY
Click column heading to sort ascending, click again to sort descending.
Rank
Run Length
Ending Date
1 60 2020-08-15
- 60 2006-08-24
2 57 1966-08-09
3 55 2016-09-02
- 55 2010-08-11
4 52 2015-09-13
5 51 2003-08-30

 

Number of Consecutive Days Min Temperature >= 60 
for WESTCHESTER CO AP, NY
Click column heading to sort ascending, click again to sort descending.
Rank
Run Length
Ending Date
1 57 2020-08-15
2 53 2012-08-18
3 51 2008-08-15
- 51 1970-08-19
4 49 2016-08-21
5 45 1988-08-18
44 2019-08-07
- 44 2018-08-22
- 44 2005-08-17
7 42 2013-08-03

 

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Light rain and 68 (!) degrees. Grown unaccustomed to anything not hot b/c it feels very chilly to me. 

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67 and 0.17 of rain so far.  Coolest day overall since Fay (7/10) likely daytime highs below 70?  Sun is about 100 miles west into C- PA.  Rockies heat dome locked and loaded the next 7 - 10 days.  Overall near to slightly above normal around these parts once past today for this coming week 8/17 - 8/21 with lots of low - mid 80s. Storms possible Mon and Wed PM but the week looks good overall.  Pending on any storms next weekend (8/22 - 23) offers the next opportunity to reach 90, especially in the warmer spots before trough pushes into the east.

 Beyond next weekend and into the final week of August 8/24,  Rockies ridge nudging into the plains and piece of that heat is heading east should allow for much warmer close to the month with chance of 90s and perhaps a piece of the stronger heat gets here for a 2 day window.  Beyond there have to watch for Plains ridge to establish and WAR pushing west.

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3 hours ago, bluewave said:

The NWS did an extensive post about  the leaf burn on the south sides of the trees following Isaias.

We at the office have noticed an interesting phenomenon in the wake of Tropical Storm Isaias here on Long Island... 
A lot of the south side of exposed vegetation is withering while the north side of the same vegetation seems fine.

This picture is taken by one of our meteorologists on the south shore of Long Island today (August 15th, 2020), about 11 days after Tropical Storm Isaias swept through the area. The picture is taken looking to the north.

You can very clearly see that much of the south side of the vegetation looks as if it has progressed into late autumn with much of it turning brown. However, the north side of the trees and the bushes are still green! How and why is this happening??

We believe that the cause of this weird occurrence has to do with the blowing of ocean spray (and thus sea salt) onto the south side of exposed vegetation by strong winds. Tropical Storm Isaias had strong winds associated with it on Long Island, but not much rainfall.

Strong southerly winds (with gusts up to and exceeding 70 mph) off of the ocean picked up sea salt off the ocean surface and battered the south sides of just about everything.

With little to no rain to wash the salt off of trees and bushes in the wake of these strong winds, the south sides of the vegetation that experienced the brunt of the winds (and thus most exposure to the sea salt) seems to have begun to wither and wilt.

Additionally, much of Long Island is currently in a moderate drought with Islip, NY (KISP) a little more than 6" of precipitation below average for the calendar year so far. This may at least partially enhance these withering effects.

There is anecdotal evidence of this phenomenon occurring from tropical events in the past, like Hurricane Sandy in 2012 and the "Long Island Express" Hurricane in 1938, though both of these prior events occurred later in the year than Tropical Storm Isaias.

With all that being said, have you noticed this weird occurrence in your area? We at the office would be very interested to hear (and see) from you if you've noticed this happening near you!

I was in guilford ct the last few days, right on the sound, and noticed the same phenomena.

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At 12 pm, the temperature at LaGuardia Airport was 69°. That ended LaGuardia's record-breaking 44-day streak (July 3 through August 15) during which the temperature remained at or above 70°. The previous record was 34 days, which was set July 8 through August 10, 2006.

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32 minutes ago, donsutherland1 said:

At 12 pm, the temperature at LaGuardia Airport was 69°. That ended LaGuardia's record-breaking 44-day streak (July 3 through August 15) during which the temperature remained at or above 70°. The previous record was 34 days, which was set July 8 through August 10, 2006.

This will be probably be broken again in the next 5 years

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1 hour ago, donsutherland1 said:

At 12 pm, the temperature at LaGuardia Airport was 69°. That ended LaGuardia's record-breaking 44-day streak (July 3 through August 15) during which the temperature remained at or above 70°. The previous record was 34 days, which was set July 8 through August 10, 2006.

MPO is the higher elevation interior version of the streak.

Number of Consecutive Days Min Temperature >= 55 
for Mount Pocono Area, PA (ThreadEx)
Click column heading to sort ascending, click again to sort descending.
Rank
Run Length
Ending Date
1 49 2020-08-15
2 32 1938-08-18
- 32 1919-06-27
3 31 2013-07-23
4 24 2004-08-04
- 24 1947-08-31
5 23 1917-08-03
- 23 1916-07-28

 

Number of Consecutive Days Min Temperature >= 70 
for LAGUARDIA AIRPORT, NY
Click column heading to sort ascending, click again to sort descending.
Rank
Run Length
Ending Date
1 44 2020-08-15
2 34 2006-08-10
3 32 1980-08-15
4 29 2018-08-19
5 28 2010-07-30

 

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