April 2019 General Discussions & Observations Thread

[SRRTA22]

@NycStormChaser What are your thoughts regarding late tonight? Looks kind of concerning for Eastern PA/WNJ northeast from there(atleast best chance of seeing a spin up)

[Rtd208]

Current temp 61/DP 58/RH 88%

[NycStormChaser]

1 hour ago, SRRTA22 said:

@NycStormChaser What are your thoughts regarding late tonight? Looks kind of concerning for Eastern PA/WNJ northeast from there(atleast best chance of seeing a spin up)

I personally think there will be a lot of straight line wind damage. The best chance of a spin up looks to be towards Southeast PA / Southwest NJ

[SnoSki14]

HRRR showing intense squall line near daybreak. Derecho maybe?

[Stormlover74]

Tornado watch for much of PA

[SRRTA22]

1 hour ago, NycStormChaser said:

I personally think there will be a lot of straight line wind damage. The best chance of a spin up looks to be towards Southeast PA / Southwest NJ

Thanks for the input. Greatly appreciated as you're one of the better voices regarding severe wx in our sub. Gonna be out there late night viewing the storms. 

[donsutherland1]

Through 4 pm, Chicago had picked up 4.8" snow. That set a new daily record snowfall amount for April 14. The previous record was 2.2", which was set back in 1980. This was only Chicago's second daily snowfall of 4" or above after April 10. The only other such daily snowfall occurred on April 16, 1961 when 5.4" accumulated (6.7" was the storm total from April 15-17, 1961). To date, Chicago has received 46.4" snow for the 2018-19 snowfall season, which ranks the current season as Chicago's 34th snowiest on record.

Tonight into tomorrow morning, a cold front associated with the storm responsible for Chicago's snowfall will bring periods of rain and thunderstorms. That system will likely bring a general 0.25"-0.75" rain to the New York City area with some locally higher amounts (especially to the north and west of New York City and Newark). The potential for strong to severe thunderstorms is somewhat elevated across southeastern New York State and more so south and westward.

Across central and Upstate New York, a widespread 1.00"-2.00" rainfall is likely with some locally higher amounts. As a result, flooding is possible in parts of that area, especially Upstate where above normal seasonal snowfall has occurred.

As the storm pulls away, the clouds will break. However, the wind could gust past 40 mph.

The ENSO Region 1+2 anomaly was 0.0°C and the Region 3.4 anomaly was +0.9°C for the week centered around April 3. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.27°C and the ENSO Region 3.4 anomaly has averaged +1.02°C. Conditions consistent with El Niño should persist through April in Region 3.4.

The SOI was -15.14 today.

Today's preliminary value of the Arctic Oscillation (AO) was +0.488. That ends the stretch of 10 consecutive days during which the AO was negative.

Over the next 5-6 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 58.0° for that period this year. The implied probability of a warmer than normal April has increased to 78%.

At this point in time, the EPS hints at a cooler than normal May. However, the CFSv2 favors warm anomalies in the region. Model skill from this point in time is generally poor, but current ENSO conditions suggest warm anomalies may be somewhat more likely than not.

On April 13, the MJO moved into Phase 1 after having spent 3 days at Phase 2. The MJO's amplitude was 0.375 (RMM). The amplitude was above the April 12-adjusted figure of 0.162. Within 3-7 days, the MJO could emerge into an amplitude of 1.000 or above, likely in Phase 2.

[Rtd208]

Pretty interesting discussions from Mt.Holly and Upton for late week/next weekend.

Mt.Holly:

 

 .LONG TERM /TUESDAY THROUGH SUNDAY/... 
  An unsettled period of weather is set for midweek as we have a warm  
  front draped across the region. The warm front lifts into the area  
  on Tuesday but starts to stall, leaving it draped across the region.  
  The front is likely to wobble a bit north and south before it  
  finally starts to move northward on Thursday. A strong cold front  
  will then approach from the west and cross the region as we  
  head into the weekend.  
   
  Tuesday looks to be the driest day of the period as the front starts  
  to develop to our west. As the front starts to push east and into  
  our area, we may see some showers develop later in the day, mainly  
  over the northwestern areas, before starting to spread across much  
  of eastern Pennsylvania and northern and central New Jersey. Even as  
  we head through Wednesday, best chances for rain will exist north  
  and west of the I-95 corridor as the front remains nearly stationary  
  and multiple shortwaves track along the boundary. The airmass  
  appears to remain fairly stable so no thunderstorms are expected at  
  this time. Areas across Delmarva and southern New Jersey are  
  expected to remain mostly dry through Tuesday and Wednesday as high  
  pressure to our south should be strong enough to continue to  
  influence their weather.  
   
  The front finally lifts to the north later Thursday into Friday as  
  low pressure over the midwest starts to move to the east. This low  
  will track up through the Great Lakes region and then into eastern  
  Canada by late Friday. The associated cold front will start to move  
  into our area on Friday. Showers and thunderstorms will be possible  
  ahead of the fronts arrival on Friday night, and then will continue  
  with the frontal passage into Saturday. The front looks to be strong  
  as it arrives just after peak heating and conditions are expected to  
  be fairly unstable. A very tight gradient will exist on Friday so  
  expect rather gusty southerly winds to occur through the day.  
   
  The cold front exits offshore on Saturday morning but a secondary  
  cold front follows behind along with the deep upper low/trough. This  
  may result in more showers and thunderstorms through Saturday. We  
  may not clear out that quickly on Sunday as the upper low/trough  
  moves through the area and then moves offshore Sunday night into  
  Monday. 
   
  && 

Upton:

 

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Upper flow briefly flattens out to start the period with an
upper low departing from the Canadian Maritimes. At the same
time, a trough moves into the desert southwest. Later in the
week, this feature will interact with northern branch energy,
sending a frontal system into the area for the end of the week
into the weekend. There is very good agreement with the 12Z
ECMWF and GFS with the extent of phasing of the two branches and
the progression of the aforementioned frontal system. The GGEM
is a bit more progressive, especially with the lead frontal band
precipitation Friday night into Saturday morning.

A consensus forecast approach brings high pressure into the
region Tuesday into Wednesday with a warm front approaching from
the southwest. Prior to that time, gusty W winds will follow on
the heels of deepening low pressure tracking northeast across
the Canadian Maritimes. There could be some gusts up 30 kt
through early Tuesday afternoon as winds gradually subside with
high pressure building in from the west.

There is a low chance of rain working in from the southwest
Tuesday night. However, unlike 24 hours ago, it appears
Wednesday will be dry as ridging builds in both aloft and at the
surface. The northward progress of the warm front will likely
be very slow due to an amplified ridge building along the
eastern seaboard as the upper trough amplifies across the mid
section of the country.

Warm frontal passage has trended faster in the global guidance,
lifting north of the region by daybreak Friday. A deep-layered
southerly flow develops along the east coast as the upper ridge
slowly translates east Thursday into Friday. A strong low-level
jet ahead of the approaching cold front supports moderate to
heavy warm conveyor belt rains with embedded thunderstorms late
Friday night into the first half of Saturday. There will likely
be timing changes through the week as the Pac jet energy has yet
to move onshore. Additionally, a strong onshore flow Friday
into Saturday will likely result in areas of stratus and fog,
especially east of the Hudson River. Dew points are forecast to
be in the 50s, but this may be conservative.

Scattered showers may linger into Sunday depending on how
quickly the upper trough/low passes through the area.

As for temperatures, daytime highs will be near seasonable
levels through Thursday before a warm frontal passage Friday
morning. Lows will be several degrees above normal due to
onshore flow and potential for stratus/fog. Following the warm
front, warmer, humid conditions are likely with areas away from
the coast getting into the 70s.

&&

 

[Rtd208]

Temp back on the rise here after falling back to 61 a few hours ago.

Current temp 66/DP 64/RH 89%

[weathermedic]

That squall line across central PA looks like it means business. Tornado watch up for Sullivan County NY. Hopefully the marine layer will weaken that line somewhat as it crosses the Hudson River.

[Rtd208]

Picked up 0.02" of rain for the day yesterday. 

Current temp 63/DP 61/RH 91%

[NycStormChaser]

 

 

[Rtd208]

15 minutes ago, NycStormChaser said:

 

 

 

[TriPol]

Tornado watch!

[Rtd208]

The temp has been fluctuating up and down. Back up to 67 here.

[SACRUS]

70 here storms are arriving now

[dWave]

Wow t storms woke me the hell up. Some window shaking thunder 

[CIK62]

Next 8 days averaging about 58degs., or about 5degs.  AN.

Month to date is  +3.2[53.5].    Should be about +3.6[54.9] by the 23rd.

[bluewave]

2nd day in a row for record warm minimums across the area. Very impressive subtropical moisture feed into our area for April . This lead to the intense convection this morning. It was my most frequent and intense display of CG lightning here on Long Island for the month of April.

https://mobile.twitter.com/iembot_okx/status/1117675844107939841

OKX issues Record Event Report (RER) at Apr 15, 2:26 AM EDT ...RECORD HIGH MINIMUM TEMPERATURE SET AT CENTRAL PARK NY...

 

 

 

 

[doncat]

15 minutes ago, bluewave said:

2nd day in a row for record warm minimums across the area. Very impressive subtropical moisture feed into our area for April . This lead to the intense convection this morning. It was my most frequent and intense display of CG lightning here on Long Island for the month of April.

https://mobile.twitter.com/iembot_okx/status/1117675844107939841

OKX issues Record Event Report (RER) at Apr 15, 2:26 AM EDT ...RECORD HIGH MINIMUM TEMPERATURE SET AT CENTRAL PARK NY...

 

 

 

 

59° and 56° Lows here  Sat and Sun. Normal is around 40°.

[Rtd208]

Picked up 0.82" of rain this morning, storm total 0.84"

[bluewave]

29 minutes ago, doncat said:

59° and 56° Lows here  Sat and Sun. Normal is around 40°.

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

[purduewx80]

Looks like another round of heavy showers and embedded thunderstorms w/ the cold front later this morning. There is also good support from a 500 vort max.

Forecast soundings support several hours of 50 MPH gusts across the city late this afternoon into the early evening as colder air returns to the area.

[Stormlover74]

26 minutes ago, purduewx80 said:

Looks like another round of heavy showers and embedded thunderstorms w/ the cold front later this morning. There is also good support from a 500 vort max.

Forecast soundings support several hours of 50 MPH gusts across the city late this afternoon into the early evening as colder air returns to the area.

Just getting some heavy rain at the moment. No thunder

[forkyfork]

i'm under that 50 dbz dot in rahway. no thunder either

[dWave]

I'm curious...what is this second batch of fog and rain? Wasn't it suppose to be clear behind the line of storms earlier than am. Wasnt that associated with a cold front?

[psv88]

3 hours ago, bluewave said:

2nd day in a row for record warm minimums across the area. Very impressive subtropical moisture feed into our area for April . This lead to the intense convection this morning. It was my most frequent and intense display of CG lightning here on Long Island for the month of April.

https://mobile.twitter.com/iembot_okx/status/1117675844107939841

OKX issues Record Event Report (RER) at Apr 15, 2:26 AM EDT ...RECORD HIGH MINIMUM TEMPERATURE SET AT CENTRAL PARK NY...

 

 

 

 

Very loud thunder last night

[purduewx80]

4 minutes ago, dWave said:

I'm curious...what is this second batch of fog and rain? Wasn't it suppose to be clear behind the line of storms earlier than am. Wasnt that associated with a cold front?

this is the cold front. the pre-dawn round wiped out the best instability, but there is a vort max w/ the upper trough accompanying the front, so the little bit of heating we had this morning allowed it to pop some showers. thunder risks will end up being a bit higher in southern new england where there will be a longer period of heating, resulting in over 500 j/kg of cape.

[Cfa]

62 and alternating between clouds and sunshine. 0.84” this morning, wasn’t expecting to see more rain today, but we could use it.

[LongBeachSurfFreak]

Nice little shelf cloud right now in wantagh. Pretty cool to have two lines in one day.

last nights MCS was extremely impressive for April right along the coast. It had some property’s of a derecho with the strongest winds occurring during the storm rather then with a gust front.