Flagstaff Warning

Issued a severe thunderstorm warning for a storm across the western portion of the CWA. The cloud tops on the 1 min Clean IR imagery showed cooling to near -80C which remained relatively constant. This matched up well with reflectivity in the upper 60s well above the -20C. PROBSevere gradually increased to over 50%. ProbHail increased to almost 80% well after the warning was issued. Lightning was there, but was not useful in helping to determine whether or not to warn.

Warning Decision -Storm East of Pauldon AZ

At 2146 UTC, made decision to warn on cell to the east of Pauldon. Reflectivity wise, storm had lots of indication of large hail with 50 dbz echoes reaching to around 40 kft AGL and ZDR values approaching 0 in lowest scans. IR data indicated cloud top temperatures around -73 C that stayed consistent for several scans.  Lightning data however, did not show much of an increase and was in the 30-50 flashes per 5 minutes range which was slightly higher than surrounding storms. Probsevere increased to around 50% just after warning issuance.

GRB satellite trends.

The Sandwich display (Vis with transparent IR overlay) depicts a quick increase in convection and cooling cloud tops across southwestern GRB's area

This is along an advancing boundary associated with a shortwave trough noted in all 4 water vapor images approaching western WI.

The interpolated 8km GLM data depicts an increase in this activity well, and seems a little more intuitive than the grid box/flash display.

-64BoggsLites

NUCAPS for OAX area

NUCAPS sounding from 19z near the aforementioned storm shows a very substantial cap....

, and Experimental NUCAPS also showed a substantial CAP (although not as strong likely given the use of surface obs.

Unfortunately gridded data is not available, but the experimental NUCAPS sounding seems more realistic, likely based on the use of surface obs. In this case the boundary layer mixing seemed a little more reasonable than what was observed yesterday.

-64BoggsLites

21z post for omaha

The agitated cu field did allow one cell to glaciate, which shows up well in day cloud rgb, but can be difficult to discern in the vis imagery...an advantage of using the day cloud rgb to monitor initiation.

GLM picked up on one flash (not shown) and KOAX shows this cell. Unfortunately this cell quickly died by 2100z.

-64BoggsLites

Rapidly Stregthening Storm - Flagstaff Area north of Seligman

With numerous weaker updrafts in area, this storm began to stand out based on 1 minute IR signature.  A brief increase in reflectivity aloft with storm was noted with 50 dbz heights. Saw an increase in the lightning rate as well per ProbSevere data, but GLM flash count did not show much of an increase at all. While IR data did help highlight a rapidly developing storm, trends after this point suggested another pulse storm and decision not to issue warning was made, which was supported by ProbSevere maxing out around 20%.


-JRM

DMW with 4 panel Water Vapor

I was looking at the GOES-16 derived motion winds alongside a 4 panel of the 3 water vapor channels and the simple water vapor RGB with another forecaster. A few thoughts: First, for the most part, the winds seem to match up pretty well with the motions observed on the three different water vapor channels. Looking over north central Missouri, we notice the anticyclonic motion in the mid and upper level water vapor channels. Looking closer at the low-level water vapor loop there is evidence of some more cyclonic motion due to a remnant MCV from morning convection. The winds pick up pretty well on these differential motions. Some thoughts for improvement from me and the forecasters here at the experiment are that it would be nice to first see the winds time matched to each other at the same time. Some levels of winds show up at different times than winds at other levels and makes looking at a loop of winds very difficult. Also it would be good if the winds stay on the screen the entire time until a new update comes in. Just keep the previous barb up until a new update instead of the winds just flashing on and off as the loop rolls. Lastly, it would be more helpful to see the wind barbs color coded by level instead of speed. The barb already has the speed on it and when multiple levels are loaded it is tedious and difficult to tell what level you are sampling.

-Michael

Flagstaff PROBSevere

Two cells across our western CWA show the coolest cloud tops of about -67C on IR via the 1 minute imagery. Radar reflectivity from FSX shows over 60DBz above 21000ft. However, PROBSevere is only showing about a 3% prob of severe hail. Lapse rates are also near 7 C/Km. Nearby radars also show high Z well over 2000ft.

Storm North of Forest Lake

Saw an intensifying storm to the north of Forest Lakes. At one point TBSS signature was noted on the 1948 and 1954 UTC 6.4 degree scan.  A coinciding decrease in cloud top temperatures and slight increase in lighting flashes noted as well. Low levels of storm would suggest lots of melting taking place as there was not much in the way of hail signature. Probsevere did increase to around 28% for hail as well.

However, given low level ZDR profile of storm and 1 minute IR/lightning data indicating a weakening trend immediately after 1954 UTC a decision not to issue a warning was made as storm looked to be rather pulse like and not a persistent sustained updraft.  May have issued a SWA for smaller hail, but trends in IR/Lightning as well as lower ProbSevere data gave confidence to hold off.

-JRM

omaha overnight precip

The overnight MCS which is currently dissipating across northern MO brought several inches of rain to portions of south central NE overnight, as noted in MRMS 24hour precip analysis.

What was rather interesting was the 20z visible imagery, which depicted a little more agitation in the cu field in south central NE, then a noted linear break just to the north of this field, followed by a less agitated and dissipating CU field to the north. This is also shown in the day cloud phase RGB, which depicts an increase in yellow to the south of this line.

It would seem this area to the south may be where boundary layer moisture from overnight heavy rainfall is burning off with daytime heating. Just an observation. Waiting for NUCAPS data to arrive, so we can take a look at the vertical profile of the atmosphere in this area.

-64BoggsLites