Wednesday, June 13, 2012

MAF – close to 1st warning for storm north of Davis Mtns

Forecaster comments from EWP blog...

The Cloud Top Cooling product has picked up on the cell north of the Davis Mountains.  The CTC rate was modest at -12.5 degrees/15 minutes near the apex of northern Jeff Davis County at 2030z.

ABQ-N: CTC FAR/POD Mini-Mini-Study

Forecaster comments from EWP blog...

While waiting for deep convection to fire, I decided to study each CTC detection < -10C/15min beginning with data from 1815 UTC, about when shallow convection was developing over the Nrn NM front range.
Between 1815 and 2045 UTC, I logged 8 CTC detections < -10C/15min. The first 4, between 1830 and 1915 UTC had no reflectivity > 35 dBZ develop within 90 minutes of the detection. The fifth detection at 1930 UTC over NW Colfax had a -18C/15min value and 5-10 minutes later showed composite reflectivity around 40 dBZ but never intensified further.  Still awaiting the 90 minute window for any reflectivity or MESH > 1″ to develop near the detection.

Caveats to any conclusion is that this mini-mini-study is soley dependent on the environment today over northeast NM. The CTC algorithm may work better in more favorable environments for deep convection.

ABQ-S – Great start for WRF Simulated imagery in Lincoln Co

Forecaster comments from EWP blog...

The simulated IR imagery for the ABQ CWA has initiated well with convection over Lincoln Co developing between 19-20z and the overall cirrus shield over the sw US.

Fcst valid at 13 Jun 20z:
GOES IR 13 Jun1959z:
FDX 0.5 Z 13 Jun 2003z:
Will be watching for new convection in eastern Torrence Co and western Guadalupe co by 2100z.

Sim IR valid at 2100z:

MAF – Waiting for Storm Initiation near Alpine

Forecaster comments from the EWP blog...

Forecast models are pointing toward the Davis Mountains region for convective initiation. The latest OUN WRF is again early with convective initiation east of Fort Davis around 20z.
HRRR model shows the same location but just a bit later, between 20 and 21z.
Visible satellite image at 1930z shows quite a bit of mid-level clouds but there was an isolated higher strength of signal for convective initiation south of Alpine.  Higher moisture was located just east of the Davis Mountains with lower to mid 60s dewpoint temperatures west of the Pecos River.

ABQ South — 1st severe storm of the day??????

Forecaster comments from EWP blog...

Will need to watch the storm over Lincoln County. CTC product shows -31c/15min with the storm and it is moving into very stout instability as it moves off the terrain. Will probably warn if we start to see better radar returns aloft.

ABQ North: OUN WRF Initialzing Well Today

Forecaster comments from EWP blog...

First echoes on the KABX radar is matching up well with the 18z run of the OUN WRF. Timing and placement are very close to reality.
The KABX radar at the same time:
CI and Cloud top cooling products are showing strong returns on the elevation. We’ll see if they pan out.
Unfortunately, if the OUN WRF is correct, only a few storms will develop and move east this afternoon/evening.

EWP daily debrief 6/13

We had a good severe weather day yesterday and was able to capture some feedback today on how things went...

SATCAST / UW Cloud-top Cooling
- "The stuff over the mountains had a lot of false alarms in both CI products."
- "We were seeing the occurrence of 35 DBZ at mid levels about 30 minutes after we saw cooling rates of -20 C / 15 mins or higher."
- "The survey questions for the CTC were implying that I should be using it for warning decision making, but it became problematic once storms became mature and there was increased cloud cover."
- "If the CTC got over -20 C / 15 mins anywhere other than over the terrain yesterday, there were really no false alarms...  I did do one warning solely on the CTC, but it was on the terrain and never really did anything."
- "There was one supercell going to the Clovis radar late in the day yesterday, at one point the CTC peaked a bit at -16 C / 15 min... within 30 minutes that thing had MESH of 3.5"... then it turned right and had some big hail stones... that was a very interesting case where it identified some additional strengthening of storms."
- "We were halfway through making the polygon and we saw a new CTC signal and that pretty much made us continue to issue the warning."
- "You have to weigh the environment too."
- "That product (CTC) can certainly help raise your awareness of strengthening storms."
- "I noticed that there was no CTC signals and then there was one where it got way up there at -31 C / 15 mins and then it went away again... it did turn out to be a very severe storm, but I would have liked to see some sort of continuity to increase my confidence."
- "It seemed that there was a 15-20 minute lead time on seeing the CTC and the storm really intensifying."
- "It seems like you could remove the lower strength of signal in the SATCAST... it gets a bit noisy... maybe anything below 40."
- "Once the storms got off the terrain, the SATCAST strength of signals above 70 would definitely initiate."

Nearcast
- "We saw in both the CAPE and theta-e difference that the values would just blank out with time... we were on the edge of both the GOES-E and GOES-W boundaries."
- There was some discussion about the need to preserve information from both GOES-W and GOES-E, especially over these boundaries in the mountains and high plains.  The forecasters agreed that a merged GOES-W and GOES-E product would be very beneficial.

Overall
- "From an aviation perspective, if I can know an hour or two hours in advance where and when CI will occur, that is incredibly important.  If I can have some strong confidence in that, it would be huge."
- "Having something between watch issuance time and warning time would be incredibly useful in being able to narrow down which areas will go first."

Tuesday, June 12, 2012

Time To Update Guadalupe DeBaca Storm Warning…OUNWRF Considerations…0045Z ABQ Update

Forecaster comments from EWP blog...
Time to update our SVR for the storm moving southeast out of Guadalupe County.  Latest OUNWRF showing a more southeastward progression with this storm (not suggesting a split)…so we are issuing d new SVR to the southeast for the next hour.  Also, CTC rates are showing a -15.5C/15 min to the east.

Watching New Development in San Miguel and Western Guadalupe Counties for Possible Warnings…0021Z ABQ Update

Forecaster comments from EWP blog...
New towers going up western Guadalupe and San Miguel Counties being watched closely for cooling cloud tops around -15C/15min.  If growth rate increases slightly, may need additional SVRs for this area shortly.

LUB – We’re BACK!

Forecaster comments from EWP blog...

Strong convection has finally initiated over southeastern New Mexico. Storms are exhibiting splitting characteristics as they move toward the South Plains. Again, the latest OUN WRF seems to have a good handle on location as storms move into the southwest part of the CWA.
The Cloud Top Cooling was rather impressive with the cells that increased in severity over Lea County NM. Cloud top cooling rate was above 30 degrees C/15 min in northern Lea County. Close to issuing severe thunderstorm warning for Yoakum County but left movement of storm causing some hesitation at the moment.