irishbri74 Posted September 1, 2021 Report Share Posted September 1, 2021 Post all obs for Ida in here. Good luck everyone, stay safe! Quote Link to comment Share on other sites More sharing options...
ezweather Posted September 1, 2021 Report Share Posted September 1, 2021 Welp, here we go. SPC expanding that enhanced risk across most of the area. Looks like they just updated the outlook for the area late tonight. Even the DC area already under the gun for tornadoes.. They even have a tornado watch till 8am. https://www.spc.noaa.gov/products/outlook/archive/2021/day1otlk_20210901_1200.html Going to be a long and nerve racking day with this tornado threat. I can't recall seeing a 10% for are area, which is pretty high. Time for bed. No doubt, we'll all be watching how things go tomorrow. Definitely be safe out there.. Quote Link to comment Share on other sites More sharing options...
susqushawn Posted September 1, 2021 Report Share Posted September 1, 2021 Dayum...993 LP? Where did that come from? Quote Link to comment Share on other sites More sharing options...
susqushawn Posted September 1, 2021 Report Share Posted September 1, 2021 Quote Link to comment Share on other sites More sharing options...
susqushawn Posted September 1, 2021 Report Share Posted September 1, 2021 Cape is meager but look at that curved hodograph: Quote Link to comment Share on other sites More sharing options...
susqushawn Posted September 1, 2021 Report Share Posted September 1, 2021 The remnants of Ida will be affecting the region today and tonight, with significant impacts expected for the area. Model trends early this morning continued a slight northward nudge of the highest QPF axis, with the GFS/NAM/ECMWF in good agreement that 3+ inches of rainfall will occur near/northwest of the Fall Line (with embedded totals 6+ inches somewhere in the southern Poconos and/or Lehigh Valley and vicinity). The CMC remains farther south (almost to outlier status), with the main axis generally between I-76 and I-80. The convection-allowing models (CAMs) are in between, and these are generally in line with our current thinking this morning. There are a few reasons for favoring a slightly farther south solution to the main QPF axis. For one thing, models tend to shunt warm sectors too far northward in advance of these systems, particularly ones that are in the process of intensifying via large- scale baroclinic processes. Additionally, models tend to bias convective precipitation too far north, in association with the synoptic forcing, rather than with the ambient/pooling instability (which tends to win out with convectively-enhanced events like these). Finally, suspect upslope contributions to precipitation are being underrepresented farther southeast near the Fall Line to the I- 95 corridor. For these reasons, our latest QPF forecast did not adjust totals as far north as the consensus of the coarser NWP models. However, these discrepancies do lead to higher uncertainty with forecast totals along the I-95 corridor. For example, Philadelphia may end up anywhere between 1 and 5 inches of rain based on the array of guidance available. However, the risk of flash flooding is not only tied to total rainfall but also duration, and the CAM solutions would suggest that much of the rainfall south of the high-QPF axis will be occurring in a relatively short period of time. Excessive rainfall rates (via PWs well north of 2 inches) are likely with the main convective show late this afternoon into the early overnight hours, and will likely lead to several instances of flash flooding near the urban corridor. Therefore, despite somewhat lowered QPF for the I-95 corridor southeastward, the risk of flash flooding remains quite elevated because of the rainfall rates. The HREF guidance provides some insight here, with the 00z ensembles indicating probabilities of 1-h rainfall accumulations exceeding flash flood guidance (FFG) above 50 percent in virtually all areas northwest of I-95 in our CWA during the evening hours, despite a range of 3-5 inches in total QPF. Notably, the probabilities of 6-h rainfall accumulations exceeding FFG are above 90 percent in much of the same area, which conveys the seriousness of the flooding threat for our area quite well. Of course, that is not all. With the warm sector expected to shift northward into at least the southern half of the CWA, the ambient preconvective environment will be quite favorable for severe weather. Model soundings indicate MLCAPE 1000-2000 J/kg (closer to 500-1000 J/kg near the warm front), 0-6 km bulk shear nearing 40 kt, and SRH > 200 J/kg in the late afternoon and early evening hours. This is an environment supportive of rotating storms, with CAM simulations suggesting a mixed mode of short line segments and cellular storms. Damaging wind gusts and tornadoes are the main threats, and the SPC has nudged the enhanced risk slightly farther north given model trends this morning. Given the coverage of convection expected, the favorable environment is quite concerning, with the severe potential continuing to look more and more impressive. The main time window for severe weather is likely in the 20z to 06z time frame from west to east. Individual cells will likely move quickly north-northeast, but the overall system will move only slowly eastward, so training convection poses a flash flood risk in the southern half of the CWA. Quote Link to comment Share on other sites More sharing options...
Chubbs Posted September 1, 2021 Report Share Posted September 1, 2021 0.22" 70F/70DP - heavy rain with a few rumbles of thunder Quote Link to comment Share on other sites More sharing options...
Chubbs Posted September 1, 2021 Report Share Posted September 1, 2021 Heavy cell rolling through, frequent lightning Quote Link to comment Share on other sites More sharing options...
irishbri74 Posted September 1, 2021 Author Report Share Posted September 1, 2021 Terrible start to the day .. Quote Link to comment Share on other sites More sharing options...
Parsley Posted September 1, 2021 Report Share Posted September 1, 2021 Models clearly struggling (not robust enough) already with the scope of the early morning rain and thunderstorms over NE MD, N. DE and SE PA. I believe this is the activity that rocked central VA overnight. HRDPS showed this scenario best at 0z. If we are to run with that model it paints a brutal picture later today for most of us. Quote Link to comment Share on other sites More sharing options...
SalemCountyNJ Posted September 1, 2021 Report Share Posted September 1, 2021 19 minutes ago, irishbri74 said: Terrible start to the day .. I had the joy of driving from Pennsville, NJ to Newark DE. I encountered heavy downpours from I95 to 896 to 279. Wasn't expecting such a miserable drive to work today, thought it would only be going home. As usual, I was incorrect. Quote Link to comment Share on other sites More sharing options...
irishbri74 Posted September 1, 2021 Author Report Share Posted September 1, 2021 Awesome… radar outrages/info outtages? Quote Link to comment Share on other sites More sharing options...
eastonwx Posted September 1, 2021 Report Share Posted September 1, 2021 .29” at 7 AM 1 Quote Link to comment Share on other sites More sharing options...
mshaffer526 Posted September 1, 2021 Report Share Posted September 1, 2021 .28" so far Quote Link to comment Share on other sites More sharing options...
susqushawn Posted September 1, 2021 Report Share Posted September 1, 2021 4 minutes ago, mshaffer526 said: .28" so far Same 1 Quote Link to comment Share on other sites More sharing options...
Chubbs Posted September 1, 2021 Report Share Posted September 1, 2021 0.67", fortunately the heaviest with this first batch stayed to our south. Quote Link to comment Share on other sites More sharing options...
cbelke Posted September 1, 2021 Report Share Posted September 1, 2021 26 minutes ago, irishbri74 said: Awesome… radar outrages/info outtages? They are doing maintenance on Radarscope. Great timing huh? Use the Base modes from 5:30 AM CT - 6 AM CT. After that it should be back up and running on Super-res. Additional - Everything is down. Switch to NOAA for the data provider. Sorry for the bad info. 😬 1 Quote Link to comment Share on other sites More sharing options...
Mitchnick Posted September 1, 2021 Report Share Posted September 1, 2021 Nws reporting station 13 miles away from my location in Hanover shows about .5" so far. But I checked my old digs at Bwi and they had a thunderstorm between 4-5am that dropped 1.98"! Now that's some heavy rain. https://w1.weather.gov/data/obhistory/KBWI.html Edit: Here's that storm on radar. Time sensitive. It was a quick mover to drop that much rain. https://weather.cod.edu/satrad/nexrad/?parms=LWX-N0Q-1-200-100-usa-rad 2 Quote Link to comment Share on other sites More sharing options...
Robnj88 Posted September 1, 2021 Report Share Posted September 1, 2021 Torrential rain and some thunder in West Deptford this morning. Thought I’d be ok leaving for work and wet coming home later. Looks like we should catch a break after these initial cells roll through. Then we wait to see what this afternoon/ evening brings with severe weather. Quote Link to comment Share on other sites More sharing options...
november2003 Posted September 1, 2021 Report Share Posted September 1, 2021 Had some heavy rain a few minutes ago. Up to .63 1 Quote Link to comment Share on other sites More sharing options...
frankdp23 Posted September 1, 2021 Report Share Posted September 1, 2021 .20" so far Quote Link to comment Share on other sites More sharing options...
Qtown Snow Posted September 1, 2021 Report Share Posted September 1, 2021 Quote Link to comment Share on other sites More sharing options...
cbelke Posted September 1, 2021 Report Share Posted September 1, 2021 Nice heavy downpour got me over the 1/2" mark for the morning. More to come I'm sure. Quote Link to comment Share on other sites More sharing options...
eastonwx Posted September 1, 2021 Report Share Posted September 1, 2021 a few heavier downpours so far, up to .80" (Davis Vue) Quote Link to comment Share on other sites More sharing options...
Parsley Posted September 1, 2021 Report Share Posted September 1, 2021 Schools dismissing early here. Should have just had a virtual day set up instead of running buses 2x this morning. 0.30" so far. 1 Quote Link to comment Share on other sites More sharing options...
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