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bluewave

April 2019 General Discussions & Observations Thread

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10 hours ago, bluewave said:

Looks like our next subtropical moisture connection with the storm Friday into Saturday. 

CEED0BEC-B600-4D16-B037-FD6202F168F7.png.cde4a93d5a85eedb370f4871575490e0.png

while we'll still probably get 1"+ the best totals are west of us on both the euro and gfs

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Glad the mean trough axis is going to be in the East going into next week. Headed to California where the weather has been wet and wild in recent months, however a nice dry stretch appears to be on tap for the extent of my stay with temps mostly in the mid to upper 60’s.

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11 hours ago, bluewave said:

Looks like our next subtropical moisture connection with the storm Friday into Saturday. 

CEED0BEC-B600-4D16-B037-FD6202F168F7.png.cde4a93d5a85eedb370f4871575490e0.png

Models have the storm stacking and starting to dissipate west of us, so here it's just showery but west where the low is still strengthening has more organized heavy rain. 

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The final snowfall in Chicago on Sunday was 5.4". That tied the record set on April 16, 1961 for the greatest daily snowfall after April 10.

The ENSO Region 1+2 anomaly was 0.1°C and the Region 3.4 anomaly was +0.9°C for the week centered around April 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.20°C and the ENSO Region 3.4 anomaly has averaged +0.98°C. Conditions consistent with El Niño should persist through April in Region 3.4.

The SOI was -4.04 today.

Today's preliminary value of the Arctic Oscillation (AO) was -0.066.

Over the next 4-5 days, variable temperatures can be expected. Several days of generally cooler than normal readings are possible, along with several warmer days. The closing 7-10 days of the month could be warmer than normal with perhaps a turn toward normal as the month comes to a close. There remains uncertainty concerning the risk of a possible turn to near normal readings near the end of the month.

Since 1950, there have been 6 cases where the AO dropped to -2.500 or below during the April 1-10 period, as happened on April 7. The mean April 16-30 temperature was 56.3° with a standard deviation of 2.3°. The latest guidance shows an estimated mean temperature of 57.6° for that period this year. The implied probability of a warmer than normal April is currently 78%.

On April 14, the MJO was in Phase 1 at an amplitude of 0.444 (RMM). The amplitude was above the April 13-adjusted figure of 0.377. The MJO has now had an amplitude below 1.000 for 32 consecutive days. That's the longest such stretch since the MJO was at a low amplitude for 39 consecutive days from April 21, 2015 through May 29, 2015.

Within 2-6 days, the MJO could emerge into an amplitude of 1.000 or above, likely in Phase 2.

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2 hours ago, jm1220 said:

Models have the storm stacking and starting to dissipate west of us, so here it's just showery but west where the low is still strengthening has more organized heavy rain. 

I think Friday has the potential to be another severe day on the east coast. Certainly have to keep an eye on it. Last night into this morning there was 15 confirmed tornadoes along the east coast. 5 in GA, 5 in PA, 2 in OH, 1 each in SC, NC and DE.  

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5 hours ago, donsutherland1 said:

The final snowfall in Chicago on Sunday was 5.4". That tied the record set on April 16, 1961 for the greatest daily snowfall after April 10.

The ENSO Region 1+2 anomaly was 0.1°C and the Region 3.4 anomaly was +0.9°C for the week centered around April 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.20°C and the ENSO Region 3.4 anomaly has averaged +0.98°C. Conditions consistent with El Niño should persist through April in Region 3.4.

The SOI was -4.04 today.

Today's preliminary value of the Arctic Oscillation (AO) was -0.066.

Over the next 4-5 days, variable temperatures can be expected. Several days of generally cooler than normal readings are possible, along with several warmer days. The closing 7-10 days of the month could be warmer than normal with perhaps a turn toward normal as the month comes to a close. There remains uncertainty concerning the risk of a possible turn to near normal readings near the end of the month.

Since 1950, there have been 6 cases where the AO dropped to -2.500 or below during the April 1-10 period, as happened on April 7. The mean April 16-30 temperature was 56.3° with a standard deviation of 2.3°. The latest guidance shows an estimated mean temperature of 57.6° for that period this year. The implied probability of a warmer than normal April is currently 78%.

On April 14, the MJO was in Phase 1 at an amplitude of 0.444 (RMM). The amplitude was above the April 13-adjusted figure of 0.377. The MJO has now had an amplitude below 1.000 for 32 consecutive days. That's the longest such stretch since the MJO was at a low amplitude for 39 consecutive days from April 21, 2015 through May 29, 2015.

Within 2-6 days, the MJO could emerge into an amplitude of 1.000 or above, likely in Phase 2.

Don do you think we make it through April without the city hitting 80?

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Next 8 days averaging 59degs., or about 5degs. AN.

Month to date is  +3.1[53.6].      Should be +3.8[55.5] by the 23rd.

EURO WEEKLIES are AN for next two weeks, then take on a useless, mottled appearance, for May.   I guess this boils down to near Normal for May.    The RRWT agrees for May.

On a more certain note, it was 43* with a bright clear sky at 6am. here.    Up 10 degrees to 53* by 11am.   55* by Noon.

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5 hours ago, LibertyBell said:

Don do you think we make it through April without the city hitting 80?

I still think it is more likely than not that the temperature will reach 80° in Central Park this month. The most likely timing could be early next week.

Since 2000, only April 2000 and 2014 had no 80° days.

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This April is continuing the 2010’s temperature departure reversal theme from March. NYC is on track for 7 out of the last 10 Aprils finishing with a positive temperature departure. March was the complete opposite with 7 out of 10 colder years.

NYC

Apr

2019....+3.1 so far

2018....-3.5

2017...+4.2

2016...+0.3

2015...+1.3

2014...-0.7

2013....0.0

2012...+1.8

2011...+1.3

2010..+4.9

Mar

2019...-0.8

2018...-2.4

2017....-3.3

2016...+6.4

2015...-4.4

2014...-4.8

2013...-2.4

2012...+8.4

2011....-0.2

2010...+5.7

 

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A strong storm will likely bring 1.00" or more rain across parts of the Gulf Region Thursday into Saturday. The heaviest amounts could be focused on northern Mississippi, northern Alabama, Tennessee, Kentucky, and parts of North Carolina. That region could also see severe thunderstorms. Excessive rainfall figures of 2.00" or more are likely along the Appalachians. Afterward, a general 0.50"-1.00" rain is likely in the New York City area.

The ENSO Region 1+2 anomaly was 0.1°C and the Region 3.4 anomaly was +0.9°C for the week centered around April 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.20°C and the ENSO Region 3.4 anomaly has averaged +0.98°C. Conditions consistent with El Niño should persist through April in Region 3.4.

The SOI was -7.14 today.

Today's preliminary value of the Arctic Oscillation (AO) was -0.655.

Over the next 3-4 days, variable temperatures can be expected. Several days of generally cooler than normal readings are possible, along with several warmer days. The closing 7-10 days of the month could be warmer than normal with perhaps a turn toward normal as the month comes to a close. There remains uncertainty concerning the risk of a possible turn to near normal readings near the end of the month.

Since 1950, there have been 6 cases where the AO dropped to -2.500 or below during the April 1-10 period, as happened on April 7. The mean April 16-30 temperature was 56.3° with a standard deviation of 2.3°. The latest guidance shows an estimated mean temperature of 58.2° for that period this year. The implied probability of a warmer than normal April is currently 82%.

On April 15, the MJO moved into Phase 2 at an amplitude of 0.553 (RMM). The amplitude was above the April 14-adjusted figure of 0.444. The MJO has now had an amplitude below 1.000 for 33 consecutive days. That's the longest such stretch since the MJO was at a low amplitude for 39 consecutive days from April 21, 2015 through May 29, 2015.

Within 1-5 days, the MJO could emerge into an amplitude of 1.000 or above, likely in Phase 2. Historic data with the very long duration periods of low amplitude favors a return to higher amplitude at Phases 8, 1, or 2 (Phase 2 accounts for 6/14 or 43% cases). Typically, additional days at low amplitude then follow during the subsequent 30 days.

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18 hours ago, donsutherland1 said:

I still think it is more likely than not that the temperature will reach 80° in Central Park this month. The most likely timing could be early next week.

Since 2000, only April 2000 and 2014 had no 80° days.

Models show temps could be well in the 80s for early next week as massive ridge dominates the CONUS. 

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Mt.Holly and Upton ref: severe/heavy rain potential Friday/Saturday.

Mt.Holly:

 

 Active weather begins to take shape Friday as the aforementioned mid- 
  level trough strings out across the mid-Mississippi Valley. The  
  parent surface low looks to slide out of the Great Lakes into  
  Southeastern Canada, trailing a cold front toward the Northeast.  
  Another wave of low pressure looks to develop along the front  
  somewhere over the Ohio Valley Friday, translating northeastward  
  along the front. By Friday evening, another stronger surface low  
  pressure center should develop across the southern Appalachians, and  
  begin shifting northeast toward our area. This looks to pull  
  relatively deep moisture across the area, thus leading to  
  potentially heavy rainfall. PWAT values from 1-2 inches is  
  forecast as well. The NAM suggests some instability could creep  
  into the region, especially over portions of Delmarva, thus  
  thunderstorms are also possible. The severe potential exists,  
  but will ultimately depend on the amount of instability that  
  develops. Shear looks a little more certain however, given the  
  structure of the system and 850 mb southerly flow ahead of the  
  parent trough. Deep vertical mixing should develop as WAA takes  
  shape across the area, thus it will likely be windy Friday with  
  gusts of 30-40 mph possible. Mild Friday as the warm front  
  clears the area, thus widespread 70s are likely every where,  
  with the exception of the southern Poconos, where upper 60s will 
  be found. 
   
  Scattered showers are likely through the weekend as the main surface  
  low slowly works its way northeastward across the region. Some  
  breaks in the rain will occur, thus it does not look to be a  
  complete washout. Highs in near 70 Saturday and the mid 60s Sunday.  
   
  Weak high pressure builds into the area Monday, leading to a  
  seasonable and dry day. A weak cold front tries to slide southward  
  out of the Great Lakes into Monday night, thus scattered  
  showers are possible Monday night into Tuesday. Highs look to  
  sit in the low 70s across the area both Monday and Tuesday, with 
  upper 60s across the higher terrain to the north.  
   
  && 

Upton:

 

Rain chances will then increase again on Friday when the cold front
approaches from the west. Precipitable water values will range
between 1 to 2 inches as tropical moisture is advected into the
region. This will lead to a period of moderate and possibly even
heavy rain late Friday night into Saturday. There is also a
threat of localized flooding which will need to be watched.

Models showing a dry slot will cut off rain Saturday afternoon,
however, with the upper low remaining in the vicinity, have kept
PoPs in the forecast through Sunday.

High pressure looks to make a brief return on Monday with the next
cold front arriving as early as Monday night into Tuesday.

Temperatures will remain above normal through the period.

&&

.HYDROLOGY...
No hydrologic impacts are expected through Thursday night.

A slow moving frontal system will bring the potential for hydrologic
impacts Friday into Saturday. Widespread minor urban and poor
drainage flooding is possible, with a chance of flash flooding,
especially in any heavier bands of rain. Uncertainty still remains
with the exact location and timing of the heaviest rain.

Minor flooding is expected on the Lower CT River by
tonight/Wednesday due to runoff from recent rainfall events and from
upstream snow melt in VT and NH. This flooding could continue
through late week.

&&

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Next 8 days are averaging 61degs., or about 7degs. AN     (The Mins. appear to be +10)

Month to date is +3.1[53.7].      Should be +4.4[55.9], by the 25th.

Seems to me, if we finish with a flurry(not from the sky of course) of AN, we could have the warmest April ever.      Mean > 53.0    Warmest Ever > 57.9, or +4.9

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8 hours ago, Rtd208 said:

Mt.Holly and Upton ref: severe/heavy rain potential Friday/Saturday.

 

It's funny how much they differ in the medium range. It was like that this past sunday night into monday morning. Mt Holly discussed the threat of storms 3 days before while upton brushed it off until the day of. Not knocking them but its interesting to see. Models are in more agreement that parts of the East Coast will experience severe weather on friday. Right now the SPC is eyeballing the carolinas but I think the outlook will be expanded north over the next 24 hours. I can see a setup similar to what we had a few days ago but with more flash flooding and PWAT values are really high.  

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A strong storm will likely bring 1.00" or more rain across parts of the Gulf Region tomorrow into Saturday. The heaviest amounts could be focused on northern Mississippi, northern Alabama, Tennessee, Kentucky, and parts of North Carolina. That region could also see severe thunderstorms. Excessive rainfall figures of 2.00" or more are likely along the Appalachians. Afterward, a general 0.50"-1.50" rain is likely in the New York City area.

The ENSO Region 1+2 anomaly was 0.1°C and the Region 3.4 anomaly was +0.9°C for the week centered around April 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.20°C and the ENSO Region 3.4 anomaly has averaged +0.98°C. Conditions consistent with El Niño should persist through April in Region 3.4.

The SOI was -11.03 today.

Today's preliminary value of the Arctic Oscillation (AO) was -0.700.

The closing 7-10 days of the month will likely be generally warmer than normal. Since 1950, there have been 6 cases where the AO dropped to -2.500 or below during the April 1-10 period, as happened on April 7. The mean April 16-30 temperature was 56.3° with a standard deviation of 2.3°. The latest guidance shows an estimated mean temperature of 59.1° for that period this year. The implied probability of a warmer than normal April is currently 88%.

On April 16, the MJO was in Phase 2 at an amplitude of 0.666 (RMM). The amplitude was above the April 15-adjusted figure of 0.540. The MJO has now had an amplitude below 1.000 for 34 consecutive days. That's the longest such stretch since the MJO was at a low amplitude for 39 consecutive days from April 21, 2015 through May 29, 2015.

Within the next 4 days, the MJO could emerge into an amplitude of 1.000 or above, likely in Phase 2. Historic data with the very long duration periods of low amplitude favors a return to higher amplitude at Phases 8, 1, or 2 (Phase 2 accounts for 6/14 or 43% cases). Typically, additional days at low amplitude then follow during the subsequent 30 days.

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Next 8 days are averaging 62degs., or 8degs. AN.

Month to date is +3.0[53.8].     Should be +4.6[56.4], by the 26th.

Mean = 53.0.   Warmest  = 57.9.  +4.9

Is this going to be the warmest April ever---  W/O an 80 degree day, yet?    The low temps. are ridiculous.    With the 12 warmest days of the month yet to go, we have already exceeded the normal low of the whole month.

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