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July 2020 General Discussions & Observations Thread


Rtd208
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No plans on new topics, yet.  Will post some rainfall verification in a couple of hours.  MARFC multi sensor analysis already complete. Multisensor-diminishes isolated extreme at the expense of spatial-areal coverage. Will add those to the original posts, hopefully by Noon. 

The future: after whatever happens Friday,  some sort of drops convection this weekend.  Monday afternoon is of interest to me for bigger storms-hail, because of ECMWF modeled 500MB temps near -12C, leftover moisture, modeled lightning, KI.  Will reevaluate Saturday, after we clear out the subtropical and kind of better know our soil moisture. 

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14 minutes ago, bluewave said:

This may be the first WAR retrograde so soon after a tropical or subtropical system crossing our area. The main question is whether we can reach 100 degrees once the heat eventually surges east. The last WAR retrograde in July when most stations reached 100 was back in 2013. But we have seen isolated 100 degree readings at LGA since then. Things should come into better focus once the trough lifts out in a few days.

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Chris, what day will be the peak of the heat and the best chances for us here in SW Nassau to hit 100?

 

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16 hours ago, donsutherland1 said:

Tomorrow will be steamy with readings near or above 90° in a large part of the region.  

Late in the week into the weekend, parts of the region could be impacted by tropical moisture. At that time, the region could see some rounds of heavy rain and thunderstorms. The potential for a swath of 2"-4" rainfall amounts with some locally higher figures exists. The guidance remains in disagreement over the location where the heaviest rain will fall.

With a high temperature of 92°, Washington, DC registered its 13th consecutive day on which the temperature reached 90° or above. That is Washington's longest heat wave since July 21-August 2, 2016 when the temperature also reached 90° or above on 13 consecutive days.

The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible Initially, extreme heat is unlikely, but that could change as July progresses, especially if the emerging drought continues to deepen. One or more heatwaves are likely in July across the region, including New York City.

The ENSO Region 1+2 anomaly was -1.1°C and the Region 3.4 anomaly was -0.1°C for the week centered around July 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.65°C and the ENSO Region 3.4 anomaly has averaged -0.32°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks.

The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below.

The SOI was +1.66.

Today, the preliminary Arctic Oscillation (AO) figure was -0.359.

On July 7, the MJO was in Phase 1 at an amplitude of 2.650 (RMM). That was the fourth highest amplitude in July when the MJO was in Phase 1. The July 6-adjusted amplitude was 2.605.

That was the 18th consecutive day the MJO was in Phase 1. The last time the MJO had at least as long a stretch in Phase 1 occurred during September 21-October 8, 2019 when the MJO was also in Phase 1 for 18 consecutive days. In addition, the MJO has been in either Phase 1 or Phase 2 for 38 consecutive days.

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.

Based on sensitivity analysis applied to the latest guidance, there is an implied 71% probability that New York City will have a warmer than normal July. July will likely finish with a mean temperature near 79.0°.

 

Don what do you think the chances are that July averages at or above 80 degrees and we (as in either NYC or JFK) have at least one 100 degree day?  Chances seem to be increasing.....

 

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1 minute ago, bluewave said:

Hard to tell the exact date since the Euro has been back and forth with the locations of the highs and fronts. But we would need to get into a westerly flow pattern for JFK to have a shot at 100. The models have been very changeable from run to run beyond 7 days. 

Yep, I'm envisioning us needing something like what we had last July when JFK reached 99 on back to back days with record high heat indices near 120.  We just need to get a tad bit hotter than that......

 

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1 hour ago, LibertyBell said:

Don what do you think the chances are that July averages at or above 80 degrees and we (as in either NYC or JFK) have at least one 100 degree day?  Chances seem to be increasing.....

 

A lot will depend on the duration and magnitude of the heat that develops next week. 80 will be a stretch, but it is possible.

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9 hours ago, SACRUS said:

 

77/74 here in Havana (I mean CNJ).  Low clouds burning off with a general S/SE flow.  Very warm airmass >18c (850 temps) should allow 90 degree readings in places that stay sunny away from the coast.  The storm that could be Fay will bring 2 - 4 swath of rains Fri PM into Sat AM PM.  Clear things out Sunday and begin the warmup as ridge builds over the Mid West and Mid Atalntic / Northeast 7/15 - D12 and beyond.  Western Atlantic ridge builds west and may hook with the MW ridge and enhance heights the week of the 7/19.  Perhaps the hottest airmass of the season and in a few years.  Could push triple digits in LGA, EWR, JFK, PHL, TTN.  Does look to include regular storms which should help keep things wetter.  Pushing a hot July and w'll see if we go more 2013 / 2017 like which was followed by a cooler / wetter August or do we continue the hot run like 2016,2012 and keep the wamrth into August,

Sounds a bit like 2011- remember that one?  Big heat in July around the time of the wx conference in Baltimore and then epic rains in August from a few different systems, including Irene.

 

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Tomorrow into Saturday, the region will be impacted by Tropical Storm Fay as it moves northward and passes near New York City into New England. Parts of Long Island and the south shore of Connecticut could experience an area of sustained winds near 50 mph.

The region will likely see periods of heavy rain and thunderstorms. A swath of 2"-4" rainfall amounts with some locally higher figures is likely.

The last time New York City received 1.00" or more rain in a single day was April 13, 2020 when 1.96" fell. The last time New York City picked up 2.00" or more daily rainfall was August 11, 2018 when 2.90" fell. The last time a storm brought 3.00" or more rain to New York City was April 15-16, 2018 when 3.29" was recorded.

With a high temperature of 91°, Washington, DC registered its 14th consecutive day on which the temperature reached 90° or above. That is Washington's longest heat wave since July 18-August 2, 2011 when the temperature reached 90° or above on 16 consecutive days.

The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City.

The ENSO Region 1+2 anomaly was -1.1°C and the Region 3.4 anomaly was -0.1°C for the week centered around July 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.65°C and the ENSO Region 3.4 anomaly has averaged -0.32°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks.

The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below.

The SOI was +12.37.

Today, the preliminary Arctic Oscillation (AO) figure was -0.694.

On July 8, the MJO was in Phase 1 at an amplitude of 2.601 (RMM). The July 7-adjusted amplitude was 2.647.

That was the 19th consecutive day the MJO was in Phase 1. That tied the record of 19 consecutive days in Phase 1, which was set during the July 6-24, 2004 period. In addition, the MJO has been in either Phase 1 or Phase 2 for 39 consecutive days.

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.

Based on sensitivity analysis applied to the latest guidance, there is an implied 76% probability that New York City will have a warmer than normal July. July will likely finish with a mean temperature near 79.2°.

 

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The next 8 days are averaging 84.5degs., or +6.5degs.

Rain from Fay: GFS,EURO about 2", CMC 3".

The next 17 days according to Hoyle, OOPS!  I mean the GFS is:  79/96 = 87.5 or +9.5.    Takes us to the 26th.

78* here(90%RH) (1013.0mb)at 6am, dark overcast.       79*(86%)(1011.7mb) at 9am, no rain yet.    Rain started about 9:30am.    77*(1009.9mb) at Noon.      76* (1006.0) at 3pm.            76*(1002.3mb) at 6pm.

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Not starting a thread today, for Saturday's SPC marginal risk (dealing w FAY today), nor the cold pool - 500mb trough potential hailers for Monday (event may occur too early in the day??). Think it's RAINFREE  after 8P Tue (14th) through 1159PM Wednesday (15th), before it possibly gets interesting again with Midwest eastward moving hot thrusts and weak fropa's providing interest one or two of Thursday-Saturday afternoons (much larger CAPE/KI potential). 

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77/73 as clouds have moved in from the SE to NW.  Rain to about Barnegat Lt House and moving north quickly.  Widespread 2 - 4 inches of rain from the cut off ULL that became Fay.  Well modeled on the Euro from last week.  Once we clear fay humid and steamy weekend and if enough sun more 90s and fuel for some storms sat and sun.  Mon - Tue we clear out the trough but still in a very warm airmass.  By 7/15 a very strong ridge will anchor into the Mid West and push heights and heat into the northeast. First push of heat peaks with upper 90s and some century mark r Thu - Sat  (7/16 - 7/18) ahead of a front by next Sun  (7/19).  Ridge looks to rebuild ad Western Atlantic Ridge builds west again in the 7/20 - 7/24 (way out there) period.  ECM and GFS have 850 temps >16 through 7/20, before brief cool down to 12c - 14c air, followed by high heat 7/21 and beyond the long range forecast.   Believe EWR, LGA, PHL, JFK will approach and perhaps exceed 100 a few times in the overall period, recent rains may hinder the park and other areas.  Flow looks solidly W / SW but still need to watch fairly consistent storms.  Night time lows could rack up some upper 70s and 80 degree minimums.  Have to see if we evolve for like 2013 / 2017 where heat fizzled by the second week of August or we follow more 2016/ 2012 where August continues hot.

 

 

 

 

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Not sure of surface wind direction when 100F in NYC CP-LGA... would think between 260-310 degrees?  I know there is talk of 100F in the forum... cant remember myself, the 100F day wind direction but am pretty sure isobars were west-east to northwest-southeast.  EWR I think can more easily reach 100 on a sfc wind backed to 230degrees.  Might be worth a check. I'd like to see 850T at least 20C, closer to 23C at 12z-18z of the proposed 100F day. 

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5 minutes ago, wdrag said:

Not sure of surface wind direction when 100F in NYC CP-LGA... would think between 260-310 degrees?  I know there is talk of 100F in the forum... cant remember myself, the 100F day wind direction but am pretty sure isobars were west-east to northwest-southeast.  EWR I think can more easily reach 100 on a sfc wind backed to 230degrees.  Might be worth a check. I'd like to see 850T at least 20C, closer to 23C at 12z-18z of the proposed 100F day. 

usually a west nw wind gives us our hottest temperatures...

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No new threads from myself, per ongoing FAY.  SPC continues Marginal risk Saturday per SPC D2 discussion. Has potential, wind, pwat etc. Reevaluating for a thread, Saturday morning. Monday: Potential hailers?  Need further look the day before (Sunday).  Next Thu-Sat (16-18th). One of those days could be a SVR day.  Pretty good heat nearby, as well bigger CAPE. Wind fields all the days listed offer marginal potential for wind damage, IF big convection develops. 

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