EWP Blog

Continued my first warning downstream.  Had a report called in for tree damage caused by this cell, and the wind signature on velocity is still warranting a warning.  Good signal on spectrum width of a wind shift colocated with the reflectivity gradient.  Lightning jump showed no changes in the data, as well as little in the way of CG strikes.

SPS for Litchfield county.  Saw this cell earlier get a CI blip of 60-70%.  Cell moving to the left of the mean flow.  Not overly tall yet, but growing faster than other parts as it merges into the line to its west.  Will have to watch to see if this one gets more organized.

Weak disturbance moving through the forecast area currently resulting in little more than cloud cover at this time. Behind that shortwave, skies are relatively cloudless across the western boundary waters in northwest Minnesota. This clearing has allowed temperatures to quickly jump into at least the upper 70s, lower 80s in some locations. A corridor of higher dewpoints were noted along eastern North Dakota with values commonly in the low 60s. The result is that SB CAPE values are >1500 J/KG, but a weak mid-level cap exists. Hi-res near term models indicate that this corridor of higher dewpoints will remain ahead of the front and push eastward into the CWA by 23Z. This will help fuel whatever convection does develop. To balance the moderate CAPE values, 50kts of deep 0-6km shear were noted. Freezing levels are about 12kft, so hail does seem plausible with stronger cells, but the inverted v shape to the soundings indicate that this may be more of a wind threat. SPC has a slight risk issued for the area including a 2% tornado area.

Agitated cu field beginning to develop along and ahead of the cold front nearing the Canadian/ND/MN border. While we don’t have access to the 1min super rapid scan, we have noted some expansion of the cu field over the last 45mins. The Convective Initiation Product returning a modest 10-27%, but even those numbers have started to increase over the last few scans. Looking at the total PW values sampled by the GOES-R LAP algorithm, values do seem consistent with the numbers from the SPC Mesoanalysis Webpage. However, the 18Z Total PW has shown a few bullseyes of values >1.4″ coincident with the aforementioned cu field.

Shasta/Wacha

CI product showing 58% chance of development at 1845Z in the western portion of our CWA

By the 1908 frame here on the box radar you can see that development has continued to occur in both areas that it showed the 50% and the over 70% to the SW of BOS CWA, here a new storm cell developed in front of the area. Here is the loop.

Not much lightning with this cell, and jump was not there.  Wind signature on radar above as well as refl. is bowing out indicated a need for a quick warning here.  ProbSevere not useful here, as line has been ongoing for awhile.  Line was over an area of higher CAPE as well as lowering LI, around -5.

A quick look at the environment shows a limited amount of instability based on LAP CAPE (up to 900 J/kg). LAP LI continues to drop (as low as -6) There is some clearing across our eastern counties which the CI product is expecting some development (50-60%). A line of storms is working into that area of clearing and wind velocities are starting to strengthen. Warnings will likely be issued soon.

-BT

At 17 UTC 9 June 2015 GOES-R LAP Alg 400-500 J/kg CAPE seems in line with SPC.  GOES-R LAP PW  1.4″ of PW highest in the NW part of our CWA.  GOES-R LI showing -1 to -3 with TT values in the upper 40s. KI are rather high around 34 for southern New England.  SPC mesoanalysis shows 30 kt of 0-6km effective bulk shear.

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SRSO vis showing development on eastern side of upper level trof through 1837 UTC and showed a hole in the clouds developing west of ALB and just behind the main convection.  Also shows cooling tops at the S edge of the line in ALYs area.

CI products showing some 40-60% with up to 79% in SW CT, so expecting cells to strengthen as the line moves in to ALY area then in to western part of BOX.

MrSnow/inthecards

Watching the southern half of the Albany CWA.  Line of scattered to numerous storms roughly bisecting this region. They are moving into a more moist airmass as they head east.  Latest visible satellite has a clear pocket ahead of these storms, so would expect them to maintain intensity.  Latest SPC mesoanalysis has a bullseye of higher bulk shear in this area, so will be watching for bowing segments and potential damaging wind gusts as these cells head northeast.  Surface-based CAPE not too impressive though, with readings around 1000 and DCAPEs are around 600.

CI showing some new development in the southeast.  Focus for now will be on the line of storms in the northern half of my area.

Overall with the pattern in place it seemed the DVIL and ProbSevere helped me to make warning decisions more than other products.  I used base velocity for a few of the SPS/warning decisions.  DVIL and clusters of total lightning helped focus on the stronger storms.  However there were several storms that we issued on with lower lightning data.  In particular the cell over Williamson county did not have a lot of lightning with it, but it did produce several reports of hail…and we later learned it had some wind damage as well.

We had some hiccups with the SRS satellite data not coming in.

Lightning time series data were not as difficult to work with as I anticipated.  I would expect a problem though if I had more than one storm to focus on.  Perhaps with experience that will get easier.  It was straight-forward to understand when cells falsely jumped in lightning data, but because of cell mergers.