3-4 day heat wave through Aug 13-14, with small pockets 6" rainfall by the 15th

[wdrag]

Left the botched Title here Wed morning 440AM:  Longest heat wave of the season so far, "possible" Sun Aug 8 to possibly Wed Aug 18.

 

Heat:  00z/4 EPS continues 19C Mon-Thu before slight cooling thereafter, but that may be in part climo? 00z/4 GFS has made an abrupt change on backdooring and now has potential 90F heat NON-marine influenced I95 corridor for many days. There could be interruptions due to convection-sea breezes but by and large a lengthy hot spell seems to be increasingly modeled.  NAEFS suggests that the above normal temps may continue through the 18th, possibly longer.

Heat indices may rise to 100-105F in the I95 corridor (non marine), for two days next work week.  This is a time of lush vegetation that contributes to high dew points and it appears dewpoints should rise into the low-mid 70s, as modeled,  at times next week.   The first hottest HI day should be next Tuesday or Wednesday (10th-11th).

The 00z/ 4 GGEM is not favoring a big heat wave and WPC Day 6-7 for next Tue-Wed MAX HI is generally mid 90s... so there is uncertainty although I sense NCEP NDFD blend may be muting the potential heat.  We will know more in a week.  

The reason for this thread: This pattern gives appearance of providing non marine areas with their longest spell of summery 90+ heat. EWR current max stretch is I believe 5 days.  This doesn't mean historic numbers but does suggest precautions will need to be taken each afternoon-night in the interior urban centers. 

QPF: in addition to the 1-2" of rain that at least eastern LI should receive later today-Thursday morning,  there could be sea breeze induced thunderstorms in the high CAPE over a portion of the LI  shores next week, that could drive up iso max rainfall there to 6".  The pattern also suggests, with waves of PWAT near 2" next week and KI in the mid 30s, that there may be small pockets of brief excessive rainfall and wet microbursts in an otherwise light westerly steering flow (generally less than 25 knots next week) I95 corridor northwestward.  Where, when or IF?

It doesn't look like it gets too warm aloft at upper levels (500MB) to stifle thunderstorm growth, until next weekend at the earliest (14th).

fwiw: Marginal 90F appears possible this Fri-Sat (6-7), but the heat portion the thread concentrates from the 8th-possibly as long as the 18th with the initial primary focus next Mon-Fri (9-13)

[wdrag]

Update: No sig changes to the outlook... more complicated than I thought it would be using the 00z/4 guidance...  but the overall suggested outcome I think could still occur.  It may be that there is an interruption of 90 degree days this Sunday but haven't studied enough to be sure. It does look like big heat I anticipated Tuesday may be delayed a day or two but it's only Thursday the 5th.   Still 5 days til the 10th. 

Storms: mid week next week with PW 2" and KI mid-upper 30s.  Will rereview this on the weekend.

Next weekend and beyond:?  IF it doesn't rain during the day during next weekend, pretty good chance 90 or higher, at least interior and model guidance while showing more significant troughing just to our west,  unsure how fast the cold front can pass through. 

So the future value of this thread:  May be a little overdone but the potential exists for reasonably accurate outcomes.  We do know 90-95F heat is coming to the interior...just can we string together 6 or more consecutive for the longest of the season so far and can we surpass 100HI?  Some of the guidance has even bigger heat to our north near the Canadian border.  AND....  the last few days have been dry so the ground is drying out... a little better chance to warm up.   Already max'd 83-85 today the 5th, at EWR-POU. 

YESTERDAY: I am beginning to get a feeling that the NAM can still get tooooo energized even 24 hours in advance of what was a light to moderate shower event for parts of LI... a far cry from the modeled 2".  No question the GFS was best on this and the EC op was smashed when compared to the GFS in the many days advance guidance.  EC OP even within 48 hours was too far west.  

Gives me even more pause to hang my hat on the EC OP.  

 

Finally' Atlantic Basin may be seeing a couple of storms within the next 5 days. The one NHC has at 2pm today, a 70% chance off of Cape Verde.  70% means 30% chance it won't grow into a TC within the next 5 days.  Also monitoring any potential TC formation response to the unusual cold outbreak in S America-that is a very long shot. 

Walt 521P/5

 

 

 

[Rtd208]

Temp overperformed a bit here.

High for the day was 87

Current temp 71/DP 67/RH 87%

[wdrag]

QUICK 00/6 review of ens and op runs exclusively GFS/EC related and the NAEFS.  I think we're ok as written. Sunday 90F in doubt but depends on newd qpf trajectory and isobars-resultant sfc wind.   00z/6 GFS MOS seems a bit cool for ens temps.  I did not check NDFD nor WPC HI...  but I'm prepared for a hot Tue-Fri with indications that it will remain above normal into the third week of August.  Also TC may become of interest here around the 18th-19th but no thread until I see much more toughing near 80-85W (EC is more westerly flow here by that time at 500MB). Noting 00z/6 EC HI is coming back to the hotter original outlooks 2-3 days ago...possibly 1 day later.  

Have a good day.

[Rtd208]

High for the day was 91 here.

 

[LibertyBell]

On 8/6/2021 at 5:48 AM, wdrag said:

QUICK 00/6 review of ens and op runs exclusively GFS/EC related and the NAEFS.  I think we're ok as written. Sunday 90F in doubt but depends on newd qpf trajectory and isobars-resultant sfc wind.   00z/6 GFS MOS seems a bit cool for ens temps.  I did not check NDFD nor WPC HI...  but I'm prepared for a hot Tue-Fri with indications that it will remain above normal into the third week of August.  Also TC may become of interest here around the 18th-19th but no thread until I see much more toughing near 80-85W (EC is more westerly flow here by that time at 500MB). Noting 00z/6 EC HI is coming back to the hotter original outlooks 2-3 days ago...possibly 1 day later.  

Have a good day.

Cap of the heat around 95, Walt? and will the peak of the heat end by Saturday the 14th?

 

[wdrag]

Probably but await possible 5H trof delay and sharpening oh valley unlikely but?  

[Damage In Tolland]

6 hours ago, wdrag said:

Probably but await possible 5H trof delay and sharpening oh valley unlikely but?  

What are your thoughts next weekend and beyond? Seems a possible fake mild down next weekend 

[wdrag]

OK:  Lots to think about. NWS local offices now have Hazardous wx outlook mention of HI low 100's Tue-Thu and I can easily see Friday as the worst day.  EC is gravitating back to its original projections through Fri.   If the wind direction at EWR is north on Monday instead of se, the Heat wave begins Monday there and possibly POU as well and lasts through Fri.  I can even see EWR contg dry n wind 90F Saturday and sporadically occurring the following week.  This per EPS ens heating up to 19C Wed-Fri and only slowly cooling thereafter.  Some minor suggestion that the 5H trough trying to dig into the Great Lakes, splits, with a short wave piece lifting ENE through the St Lawrence Valley Fri-Sat and another digging  back into OHIO Sun-Mon.  We'll see if the warmth continues beyond Fri... I can't rule it out.

 

In the meantime...I'll be tracking HI this week. Little question in my mind that persistent 95-102 HI will occur in NJ and probably Hud Valley Tue-Fri and may b  surprisingly near 95 on Monday there.  LI and the city... I won't debate the ocean breeze nuances but it's going to be close for the city to see an HI of 100.

Max T...these thicknesses suggest to me EWR max T 97 later this coming week.   Also, I think 12z/7 MOS max T is running too cool at EWR.

Already EWR and NNJ near I95 were 90-92F today and yesterday.  Sunday a break in the 90F and then we'll see if we resume 90+ heat Monday. I think there is a chance for EWR.

QPF: I stand by the iso 6+ and now,  by Saturday eve the 14th.  Could be a fairly wide SVR event late Friday?? Timing dependent as wind fields aloft increase.  Plenty of CAPE Tue-Fri with SSEWD drifting late day storms Tue-Wed, [maybe even Monday along an inverted trough CATSKILLS-to ne NJ?]; then E or ESEWD moving storms this Thu-Fri. PWAT frequently near 2" Tue-Fri... and generally slow moving storms til Fri.  Isolated wet microbursts possible Tue-Thu then the more general SVR threat Fri.

I do see the TC for the 18th-19th part way up the east coast but no separate thread for a few days. 

 

 

[wdrag]

4 minutes ago, Damage In Tolland said:

What are your thoughts next weekend and beyond? Seems a possible fake mild down next weekend 

I have to wait  out the modeling but the  troughing may be too consolidated and maybe slightly too strong near the Canadian border. 

[hudsonvalley21]

It was a nice day today heat wise here near KSWF with a high of 81 and a dewpt. in the mid to upper 60’s under mostly cloudy to cloudy skies to what’s coming in the next days. The water and electric meters will be getting a definite workout. Planning on going to Sandy Hook Tuesday, I think it’s a good call to catch a sea breeze there.

OKX’s extended AFD below,

.LONG TERM /TUESDAY THROUGH SATURDAY/... High pressure over the western Atlantic will result in a typical summertime airmass with increasingly hot and humid conditions. This comes from a continuous south to southwest flow that will be in place as a result of the region being on the western periphery of surface high pressure that will be anchored out in the Western Atlantic. With respect to temperatures, which will be the main highlight for the week, continued to run with the, NBM 50th percentile which continued to be slightly warmer than other guidance sources. Models are showing a consensus of warming 850mb temperatures to 16 to 18 degrees C Tuesday through Thursday. With temperatures rising well into the 80s and low to mid 90s, coupled with dew points in the upper 60s and lower 70s, heat indices should warm into the mid 90s to lower 100s, with the warmest day on Thursday. For now, Friday should be slightly cooler, but still warm with heat index values in the 90s. As we typically see here in our area, the highest temperatures and heat indices will occur in the NYC Metro, urban Northeast NJ corridor extending into Nassau and southern parts of Lower Hudson Valley into SW CT. For now, it appears the best days for any potential heat advisory criteria to be met would be Tuesday through Thursday, and potentially Friday. There will be a chance each afternoon for showers and thunderstorms each afternoon as daytime surface troughs development. Chances each afternoon will gradually increase through the week. A cold front approaches late in the work week into the first half of the weekend.

[wdrag]

Sunday morning update:  745A:  Staying the course on this outlook. Still undecided whether heat wave will be 4-6 days (Mon or Tue-Fri, or Mon or Tue-Sat?).  I think heat is going to return quickly, certainly 85 here in nw NJ today and 85-90 EWR Monday.  HI 95-100 Tue and 100-105 Wed-Fri.  

Next weekend:  'probably' drier and cooler but not sure how cool??  Warm thicknesses continue. 500MB pattern still showing signs of a split of the big Canadian trough so weekend uncertain on whether front hangs up around here.

QPF outlook no change.

fwiw... see attached, extreme southern part of out forum had 3-5.5" today, unexpected from the original thread but the idea... this is a potent pattern for pockets of very heavy qpf. 

TC 18th-19th?  Still a small chance. Long ways off... no thread on anything beyond the 17th.  

 

 

I'll look at everything much more carefully this evening.

[LibertyBell]

Looks like peak 90 degree heat will be Wednesday through Friday with some cooling in time for next weekend.

[LibertyBell]

6 hours ago, wdrag said:

Sunday morning update:  745A:  Staying the course on this outlook. Still undecided whether heat wave will be 4-6 days (Mon or Tue-Fri, or Mon or Tue-Sat?).  I think heat is going to return quickly, certainly 85 here in nw NJ today and 85-90 EWR Monday.  HI 95-100 Tue and 100-105 Wed-Fri.  

Next weekend:  'probably' drier and cooler but not sure how cool??  Warm thicknesses continue. 500MB pattern still showing signs of a split of the big Canadian trough so weekend uncertain on whether front hangs up around here.

QPF outlook no change.

fwiw... see attached, extreme southern part of out forum had 3-5.5" today, unexpected from the original thread but the idea... this is a potent pattern for pockets of very heavy qpf. 

TC 18th-19th?  Still a small chance. Long ways off... no thread on anything beyond the 17th.  

 

 

I'll look at everything much more carefully this evening.

Walt, do you have a rainfall map for Long Island?  It's actually raining here again and windy.

 

[wdrag]

39 minutes ago, LibertyBell said:

Walt, do you have a rainfall map for Long Island?  It's actually raining here again and windy.

 

Later in the day.   I can see then ice sse feed on radar.  

[doncat]

1 hour ago, LibertyBell said:

Walt, do you have a rainfall map for Long Island?  It's actually raining here again and windy.

 

https://www.wunderground.com/wundermap

[wdrag]

12z/8 EC OP delays CFP til Sat.  

 

MOS still looks too cold at EWR this week but now has mid 90s... during mid week and several days of ~100 HI.  Going to be toasty.  Even Tue near I95 (KEWR) should reach Hi of 95-100. 

 

More late tonight if I have time...  Heat starting today and possibly tomorrow was probably wrong in the original thread. Everything else looks reasonable to me

 

Beyond the 17th...NAEFS and modeling trying to warm it up above normal. 

 

[wdrag]

Challenging days ahead:  This unexpected rain conundrum (Wednesday Aug 4 thread start) has delayed the interior heat wave 2 days, but it's also becoming evident that it can last til Saturday.

Wed-FRI afternoon looks good for HI 100-105.  Heat wave should begin EWR Tuesday, but not a guarantee. Could be hotter in Morristown-Somerville-Poughkeepsi than EWR on Tue.

HEAVY QPF: I'll be adding numbers as I get a chance, but not til this eve. A possibility of some heavy showers between midnight and 10A Tuesday, especially NJ/se NYS.

Then late day scattered heavy thunderstorms Tue-Fri with potential for a few wet microbursts....especially NJ-NYS-PA. Even Saturday there could be lingering heavy showers, especially I80 south. 

SVR threat as above and will look at details day by day., 

TC: who knows, but no separate thread till a TC actually forms and we get 24 hours of tracking. The small risk is there for the 18th-19th but no action on my part. 

Have a good Monday,  Walt

[wdrag]

Think we're on our way to  a 4-5 day heat wave EWR (interior NJ) and 3-4 day POU-NYC with some nice toasty #s coming. 89 nw NJ this afternoon, 90-93 e PA so not far away and the heretofore unexpected rainy low of 1-5" for NJ and 1-2.5" LI resulted in a cooler than normal daytime there Sun-Mon and therefore cannot do longest of the summer so far (8th-9th nixed by coastal low)

The tropics has a depression going but that is beyond this thread. 

Not much else I can say on potency...it's now redeveloping.  Could her some quite heavy storms early Tue in NJ... modeling has trended south today so tough for me to say where.

I should have more time to delve into the coming numbers.  

[wdrag]

Should be about to roll on a 4-5 day heat wave EWR, 3-4D POU-NYC ending later Sat.  HI projections 100-105 Wed-Fri and maybe near 100 Sat.    Max T with 850T 20-21C should make 97 in EWR, maybe a touch higher dependent on heavy rainfall. EWR could begin Heat wave today tho marginal... it will probably get to 90 just a couple of miles west of EWR today. 

This mornings heavy showers on radar threatens to make to NYC, tho modeling has most of it I78 south.

SVR: SPC has us in marginal risk Thu and the D4 rarity this time of year, SLIGHT RISK already into NE PA.  TT modeled by op EC into the lower 50s Thu-FRI parts of the area. Presuming a trigger, should be some  hailers (heat may melt the big stuff down to dime or less), and of course wet microbursts, despite wind fields below 30KTS, below 500MB.  Possibly the best days of SVR are Frir or Sat. The usual big qpf amounts in pockets.  Not only SVR potential, but a few pockets of FF, especially NJ/se NYS.  ISO 6+ by Saturday night in a couple spots, inclusive of the past couple of days, esp NJ. BIG CAPE is the feed for FF.

Regarding our next TC: It threatens big PWAT - moisture contribution 18th-20th, especially s of I80, even if worn and torn coming up into the eastern USA.  Depends on the ridging lifting northward to the north of the Great Lakes. The more it lifts, the further north remnants move.  Finally, it should be shredded eastward. No thread till have time to be sure.

Am offline most of the rest of today. Have a good one.  Walt

[Rtd208]

High for the day was 90 here.

Picked up 0.89" of rain for the day.

[wdrag]

Edited-winnowed my botched Aug 4 thread title window down to the probable reality at 440AM. My botch on Aug 8-10 due to unanticipated impact of the coastal low. Longer range NWS NDFD-MOS was better on lower HI for Mon-Tue.

This morning: Modeling doesn't seem to have much clue on what's going on. Apparently a decent trigger for heavy showers continues across the subforum.  Looks to me like CoCoRahs should have a couple of 5+ amounts for the entire thread period of Aug 4-11, by the time of Thursdays reports.

My guess is we'll see some heavy convection late today-this eve across ne PA-nNJ-se NYS in the hot air with potential for wet microburst wind damage and iso 2" rain in an hours time. 

Thu-Fri: My guess is that these two days will rival the heat and HI of late June (29th-30th). I can see a max T NYC of 95-98, and EWR 98-100.  HI pushing 105 both days. SPC has marginal risk Thu-Fri and so the wet microburst SVR looms for parts of the area. CAPE looks possibly the largest of the summer late Fri?

Modeling still debating Saturday: but EC has heat wave continuing parts of the area and PW 2+" lingering into Sat morning. 

After that??  The Canadian trough is not poking south so much any more.  Cools later Saturday...

FRED, might be a problem  for NJ-LI with moisture here 18th-19th and even a big swell if it gets stuck off the Delmarva with gale gusts just to our south.  Worthy of monitoring but no thread from myself, at least not yet. 

5A/11.

 

[wdrag]

Decent rainfall of 1/4"+ past half hour nw NJ.  

[gravitylover]

.04 so far this am and another line is about to pass through. Very unpleasant with 70/69 - 98%RH right now.

edit: The second line was a dude, just a bit of drizzle that didn't register. Good thing those few hundredths soaked things, the garden looks very happy but, it's unpleasantly muggy now.

[wdrag]

0.22 Wantage. No watering this

morning and no lightning so our dog didn’t bark.  Sun coming out now. Big furnace for 3 days. Good luck NYC and urban centers non marine areas. 

[gravitylover]

Yup sun is out and it's heating up and drying out. 

[wdrag]

Some of the numbers from the 12z/11 NAM BL temp suggest 98-100F at EWR Thu-Fri. 

[hudsonvalley21]

3 hours ago, wdrag said:

0.22 Wantage. No watering this

morning and no lightning so our dog didn’t bark.  Sun coming out now. Big furnace for 3 days. Good luck NYC and urban centers non marine areas. 

0.13 here, had to give the plants a little water. 82/75 currently with mostly sunny skies.

[hudsonvalley21]

4 hours ago, wdrag said:

Decent rainfall of 1/4"+ past half hour nw NJ.  

Driving back from Sandy Hook yesterday around 6pm ran into the thunderstorm around the South Amboy area. Nice shelf cloud and torrential rains with some cloud to ground lightning.

[wdrag]

Monitor the W PA convection: Looks like a little self generating convective complex with a cool pool aft,  SPC added SVR potential in eastern PA and I could see a few SVR in our area, esp NJ between 5P-midnight.  Stripe of mid 70s dew point is a feed near I95.  HI in the upper 90s to near 100 in NJ at 1P. Modeling doesn't look too good on this complex.

 

Walt