Jump to content

  • Member Statistics

    19,014
    Total Members
    49,013
    Most Online
    loganboehmewx
    Newest Member
    loganboehmewx
    Joined

Tropical connection NYC forum area Sun-Wed, 8/2-5/20- Tropical Storm Isaias

wdrag

By wdrag,
in New York City Metro

Recommended Posts

bluewave

bluewave

Posted
Posted
2 hours ago, PB-99 said:

Which leads me to believe it`s a ECMWF issue and just gets caught up in the coding. The snow ratio map issues crosses over even into Levi`s site and no one really uses them to forecast.

I would love to see a 10m wind gust chart from another algo from yesterday, pivotal etc and see how far off Ryan was with a 120 max gust S of LI. 

According to him he is just using the soundings. 

But Forky could be right, I just want to see how far off he was/ is. 

He needs to apply post processing to remove the ECMWF overestimation bias of the wind gusts. If he can’t, then he probably shouldn’t post those wind gust maps for the general public. It’s something that they have worked out in Europe.

https://www.ecmwf.int/sites/default/files/elibrary/2014/13777-improving-wind-gust-and-precipitation-form-forecasts-post-processing-ecmwf-data.pdf

ECMWF model overestimates wind gusts
Forecaster data is based on ECMWF model output => postprocessing removes or decreases the positive bias (NOTE: ECMWF data is a 3-hourly maximum wind gust)

Link to comment
Share on other sites
  • Replies 1.5k
  • Created
  • Last Reply
PB-99

PB-99

Posted
Posted
59 minutes ago, bluewave said:

He needs to apply post processing to remove the ECMWF overestimation bias of the wind gusts. If he can’t, then he probably shouldn’t post those wind gust maps for the general public. It’s something that they have worked out in Europe.

https://www.ecmwf.int/sites/default/files/elibrary/2014/13777-improving-wind-gust-and-precipitation-form-forecasts-post-processing-ecmwf-data.pdf

ECMWF model overestimates wind gusts
Forecaster data is based on ECMWF model output => postprocessing removes or decreases the positive bias (NOTE: ECMWF data is a 3-hourly maximum wind gust)

 

So it's model bias that he didn't correct.

He doesn't overestimate,  he just doesn't adjust for the error.

 

I bet the same can be said at 2m in the winter 

Link to comment
Share on other sites
bluewave

bluewave

Posted
Posted
20 minutes ago, PB-99 said:

 

So it's model bias that he didn't correct.

He doesn't overestimate,  he just doesn't adjust for the error.

 

I bet the same can be said at 2m in the winter 

Too bad those vendors don’t provide the ECMWF bias corrected MOS like they do in Europe.

https://www.dwd.de/EN/ourservices/met_application_mosmix/met_application_mosmix.html

https://www.europeandataportal.eu/data/datasets/de-dwd-mosmix-m552?locale=en

DWD’s fully automatic MOSMIX product optimizes and interprets the forecast calculations of the NWP models ICON (DWD) and IFS (ECMWF), combines these and calculates statistically optimized weather forecasts in terms of point forecasts (PFCs). Thus, statistically corrected, updated forecasts for the next ten days are calculated for about 5400 locations around the world. Most forecasting locations are spread over Germany and Europe. MOSMIX forecasts (PFCs) include nearly all common meteorological parameters measured by weather stations. For further information please refer to: [in German: https://www.dwd.de/DE/leistungen/met_verfahren_mosmix/met_verfahren_mosmix.html ] [in English: https://www.dwd.de/EN/ourservices/met_application_mosmix/met_application_mosmix.html ]

 

Link to comment
Share on other sites
jm1220

jm1220

Posted
Posted

Small differences mean a Matthew grazer track or one that goes inland along I-95 in FL. In a way we should hope for (for a less intense system up here) the 50 mile west track into FL. It being over water for 24 hours longer or more gives more time to strengthen before hitting NC and speeding up here. 

Link to comment
Share on other sites
Rtd208

Rtd208

Posted
Posted

SPC Day 2 

...Northeast...
   Moderate destabilization near and south of the surface warm front,
   combined with veering wind profiles with 35-50 kt of effective
   shear, will result in a conditionally favorable environment for
   supercells across much of central/eastern PA/NY and northern NJ by
   Sunday afternoon. However, substantial uncertainty remains regarding
   storm coverage across the region with the most favorable
   environment. Large-scale ascent associated with the departing
   shortwave trough is expected to primarily remain north of the
   international border, with a capping inversion around 700 mb
   potentially limiting deep convection across much of the warm sector.

   At least isolated thunderstorm development will be possible along an
   eastward-moving surface trough Sunday afternoon. All hazards would
   be possible with any sustained deep convection. A Slight Risk has
   been introduced from northeast PA into central NY, where confidence
   in storm coverage is somewhat greater due to potentially stronger
   heating and instability compared to areas further north and east.

day2otlk_0600.gif

Link to comment
Share on other sites
wdrag

wdrag

Posted
  • Author
Posted

Good Saturday morning everyone, Little change from what was posted yesterday and possibly my last post until Sunday morning.At that time, I may start a separate SVR topic for Sunday alone. Need more time to evaluate but SVR is likely for at least a few locations in our forum Sunday.

On SVR: big CAPE of 3000J, HI near 100 PHL feeding the storms, decent wind aloft with only worry a little drop of the KI during the afternoon. Nevertheless, this could be a 2 or 3 SVR episode day. The first, northeastward moving storms during the morning with WAA, the second in the afternoon (still northeast moving), and the third a final trough passage  line from west to east between 5 and 10PM. Eastern LI may be completely shut out of this. Primary threat region is far w CT-NYC all NJ se NYS and ne PA. Please follow local   office and SPC guidance discussions.                                                                                                                                                                                                                                                                                                  

Thereafter a PRE is possible ~ a DCA-POU axis Monday night followed by squally excessive rain producing Isaias Tuesday afternoon-night. 

More details on possible impacts below. This does not include power outages but will add concerns on that tomorrow if still possible (SVR Sunday and Isaias squalls Tuesday)

1) Potential killer Rip Currents Monday-Wednesday for anyone who ventures into the waters s of LI.  I'd be wary of swimming, especially non expert surfers/non expert swimmers. The significant undercurrent 1 feet 15 second swell may start arriving this weekend. These long period subtle swells surprise swimmers with their energy and are sneaky dangerous. The higher surf just preceding and following the storm (within 18 hours) usually scares off most swimmers.  

2) Rainfall as per multiple ensembles and WPC guidance. My impression is that between 1AM Sunday and 1AM Wednesday, a few locations will see ~5-7" rainfall, with isolated (1 location) 10" amount not impossible. My guess is heaviest is NJ, se NYS, w CT... presuming track continues as modeled through 06z/1. To the right of Isaias, squally and less rain, possibly less than 1" total extreme eastern LI if Isaias tracks west of Montauk. 

3) Per  NHC 5AM Saturday 8/1 track: surge and wind field risks on the western side of ISAIAS are minimal but if the track shifts to where a portion of our area is on the eastern side of the TC, then those risks would significantly increase.  I think eastern LI to the southeast New England coast are vulnerable for at least some of these stormier impacts. Preparation should continue for that...ie gusts 50 knot.   

4) PRE:  Composites posted yesterday.  Where this PRE occurs, IF it occurs, is unknown but my best guess now is on an axis from vicinity DCA-POU Monday night based on 00z/1 modeling. Still could end up further north, again if it occurs.  Not a CLASSIC PRE (need a little more se low level inflo than currently modeled) but hints are in the qpf modeling.  Need to look a lot closer at guidance details and surface wind shift axis on Monday.  Just too early to be sure of occurrence and if so, where. I'm thinking it will but I don't know where. These 6-12 hour events can be easy 4-8" producers in 6-12 hours. I'm looking for narrow slices of darker or even brightly colored heavier QPF in the modeling 12-24 hours in advance of Isaias in the GFS/EC/GGEM.  If we get to 36 hours and it's still possible, then we shift to the NAM and HRRR SPC HREF.  

636A/1

Link to comment
Share on other sites
Animal

Animal

Posted
Posted
1 hour ago, wdrag said:

Good Saturday morning everyone, Little change from what was posted yesterday and possibly my last post until Sunday morning.At that time, I may start a separate SVR topic for Sunday alone. Need more time to evaluate but SVR is likely for at least a few locations in our forum Sunday.

On SVR: big CAPE of 3000J, HI near 100 PHL feeding the storms, decent wind aloft with only worry a little drop of the KI during the afternoon. Nevertheless, this could be a 2 or 3 SVR episode day. The first, northeastward moving storms during the morning with WAA, the second in the afternoon (still northeast moving), and the third a final trough passage  line from west to east between 5 and 10PM. Eastern LI may be completely shut out of this. Primary threat region is far w CT-NYC all NJ se NYS and ne PA. Please follow local   office and SPC guidance discussions.                                                                                                                                                                                                                                                                                                  

Thereafter a PRE is possible ~ a DCA-POU axis Monday night followed by squally excessive rain producing Isaias Tuesday afternoon-night. 

More details on possible impacts below. This does not include power outages but will add concerns on that tomorrow if still possible (SVR Sunday and Isaias squalls Tuesday)

1) Potential killer Rip Currents Monday-Wednesday for anyone who ventures into the waters s of LI.  I'd be wary of swimming, especially non expert surfers/non expert swimmers. The significant undercurrent 1 feet 15 second swell may start arriving this weekend. These long period subtle swells surprise swimmers with their energy and are sneaky dangerous. The higher surf just preceding and following the storm (within 18 hours) usually scares off most swimmers.  

2) Rainfall as per multiple ensembles and WPC guidance. My impression is that between 1AM Sunday and 1AM Wednesday, a few locations will see ~5-7" rainfall, with isolated (1 location) 10" amount not impossible. My guess is heaviest is NJ, se NYS, w CT... presuming track continues as modeled through 06z/1. To the right of Isaias, squally and less rain, possibly less than 1" total extreme eastern LI if Isaias tracks west of Montauk. 

3) Per  NHC 5AM Saturday 8/1 track: surge and wind field risks on the western side of ISAIAS are minimal but if the track shifts to where a portion of our area is on the eastern side of the TC, then those risks would significantly increase.  I think eastern LI to the southeast New England coast are vulnerable for at least some of these stormier impacts. Preparation should continue for that...ie gusts 50 knot.   

4) PRE:  Composites posted yesterday.  Where this PRE occurs, IF it occurs, is unknown but my best guess now is on an axis from vicinity DCA-POU Monday night based on 00z/1 modeling. Still could end up further north, again if it occurs.  Not a CLASSIC PRE (need a little more se low level inflo than currently modeled) but hints are in the qpf modeling.  Need to look a lot closer at guidance details and surface wind shift axis on Monday.  Just too early to be sure of occurrence and if so, where. I'm thinking it will but I don't know where. These 6-12 hour events can be easy 4-8" producers in 6-12 hours. I'm looking for narrow slices of darker or even brightly colored heavier QPF in the modeling 12-24 hours in advance of Isaias in the GFS/EC/GGEM.  If we get to 36 hours and it's still possible, then we shift to the NAM and HRRR SPC HREF.  

636A/1

Sorta of alarming with your post regarding tomorrow.

Link to comment
Share on other sites
CIK62

CIK62

Posted
Posted

KWO-35 did not sound very scary about wind or rains here on Tues, in the this morning's broadcasts.

Aren't we in for up to 1" of rain not directly connected to storm?       Then maybe 3"-4" more by Wed. AM?.          Wind gusts at least 30 knots+?       EURO has a total of 5.3" by Wed AM.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...