Pattern Shift?

[Andrew Pritchard]

Well, it appears y'all are going to be toasting down in the southern plains. The 168 hr GFS from 0Z is showing temps into the 100s down there. Enjoy!

 

[Anthony Silver]

EWWW :?

 

[Aric Cylkowski]

Well, considering the last few years have been rather active for Michigan, we were probably due for a severe weather 'dryspell' of sorts. It doesn't help that all the storm systems are effectively stalling out towards the coast so the next storm has barely anything in the way of instability to work with.

I'm going to dub 2005 the "Year Without a Summer" for SE Michigan if the temperatures keep up this trend. It gets reasonably warm for this time of year, then it plunges back to the upper 50s for long stretches with rain. This would follow another "Year Without a Summer", 2004, which didn't break 90 for longer than one day and I was wearing a sweater at noon in mid to late July (but had great severe weather before then).

 

[Mickey Ptak]

The first week or so of June could be the time for the SP's. It is truly a welcome sight to get rid of this NW flow and return to some storm brewing SW flow. Still several days out but the GFS has been somewhat persistent with the overall upper air pattern. I am personally keeping my fingers crossed for at least one more round of severe wx before a permanent summer time ridge sets itself over the SP's. I could use at least one more 5/12/05 (less the hail) before it's all over.

http://weather.cod.edu/forecast/AVN/avn_us...0_avort_240.gif

Mick

 

[Dan Robinson]

http://www.cpc.ncep.noaa.gov/products/pred...ts/threats.html

Updated just now.

 

[Peter Wharton]

Pattern Shift

Looks promising! I'm there from May 28th - perhaps this will be the year that I hit it right!

 

[Anthony Silver]

Looks like tha active pattern is waiting off later this year. Maybe some light showing at the end of the tunnel.

 

[Jason McKittrick]

The GFS forecast from 00z 25th looks encouraging. Its almost as if mother nature wanted to give everyone a quiet opportunity to enjoy all the picnics and gatherings before starting the season. If the general idea of the GFS is to be believed we have about 7 days of crummy NW flow left to endure. Then the Appalachian Rex block shifts west to the Great Divide. The GFS and the ECMWF have been consistant for several days now in forecasting this shift. Therefor IMO there is good reason to believe the general pattern change will occur. As for the specifics, i.e. dew points, frontal positions, and magnitude of shear,we will have to wait and see exactly how things play out. While that is still not an ideal pattern, it is bound to be a little more exciting as it should allow for more Gulf air to return to the plains while at the same time providing a decent shear environment atleast over the central and northern plains.
I missed one of the best chase days of the year while I attended my great grandmother funeral, God bless her soul. I am hoping that that was not the entire season. I have not been able to excited about upper 50 dewpoints at the end of May, especially with 800mb temps of +22. Its just not happening.

 

[Dan Robinson]

[Broken External Image]:http://wvlightning.com/chase2005/photos/may25gfs.jpg

I'm interested in what that low pressure center is sitting off the California coast showing up at 72-180 hours. Later frames show it deepening and staying pretty well in the same spot. It shows up from 850mb through 250mb. Is this a cutoff low or a tropical system?

BTW, I have to offer the standard 'long range model' disclaimer - I know that this is a guesscast this far out, just curious what this would mean if it verified at all.

 

[Kurt Hulst]

Dan what was the model run on that? Was it from the 12z becasue i know the 00z GFS isnt out yet and Amos posted on his Blog

Earlier today I wrote this:

\"The large Canadian low that forms from the merger of the east coast and Hudson Bay troughs still gets pushed out to sea, as I mentioned in the earlier outlook, but on this morning's 12z GFS it is quickly replaced by ANOTHER large upper level low that drops in from the polar regions.\"

Two hours later, the Hydrometeorological Prediction Center wrote this:

\"THE GFS AND GFSP HAVE NO SUPPORT FROM THEIR ENSMEAN W/THEIR DESCENDING VORTEX IN ERN CAN...SO THEIR PATTERN IN THE EAST IS SUSPECT.\"

Here's their full discussion. So we have official sanction for blowing off this morning's crazy ass GFS and continuing to expect a gradual ridge breakdown and all the good things that flow from that.

And that Low looks like a closed low thats why the models have it floating around over the pacific so long but i may be wrong in that sense as well could be a tropical system brewing.

 

[Jeff Wear]

The low off the southern CA coast that tonight's run of the GFS is putting there May 31-June 2 is a cut off - no way the waters down there would support anything tropical.

 

[Gabe Garfield]

Originally posted by Dan Robinson
Is this a cutoff low or a tropical system?

A quick way of checking would be to check out the 500 mb temps. If they decrease toward the center, it is a cutoff low (cold core); if they increase toward the center, it is a tropical system (warm core).

Gabe

 

[Dan Robinson]

Earlier today I wrote this:

\"The large Canadian low that forms from the merger of the east coast and Hudson Bay troughs still gets pushed out to sea, as I mentioned in the earlier outlook, but on this morning's 12z GFS it is quickly replaced by ANOTHER large upper level low that drops in from the polar regions.\"

Two hours later, the Hydrometeorological Prediction Center wrote this:

\"THE GFS AND GFSP HAVE NO SUPPORT FROM THEIR ENSMEAN W/THEIR DESCENDING VORTEX IN ERN CAN...SO THEIR PATTERN IN THE EAST IS SUSPECT.\"

Yeah, this is pretty agonizing. Such is planning a long-distance chase from the eastern USA. I know that some are probably tiring of all this talk about models. But when you have thousands of dollars of gas/hotel money on the line - along with friends, family and employers patiently enduring our constantly changing plans - relying on this love-hate relationship with models is the only way to get an idea of what's going on.

We've planned for a re-departure on Friday based on indications that NW flow would be on its way out. Looks like this will be another last-minute decision on whether to postpone for another week. As long as I get some indication that those last runs are indeed way off OR that supposed cutoff low slides east, I'll be happy.

Jeff and Gabe, thanks for the info. A closed low was my guess but I wasn't sure.

 

[Amos Magliocco]

The ETA tonight has joined the chorus line of singals that the ridge will get cut apart. In fact, it even sort of looks like a sheared off turkey tower on the 84 hour 500mb map, snapped in two and replaced with zonal flow. This is the first step in reorganizing our pattern.

What happened on this morning's GFS made me want to spew. I was happy to hear HPC felt the same way, and there is little evidence for it in other guidance products.

 

[Joe Zemek]

The pattern needs to go away. Today, I was amazed to see a tall thunderstorm with a backsheared anvil near Tucson. I knew the southern high was impersonating our monsoonal flow pattern; we've had Tds of 45-50 in Phoenix this week. But to actually see resulting storms... if you ask me to pick a month guaranteed to be storm-free in AZ, May is that month! As much as I'm looking forward to the crack of thunder on my chase trip it felt unnatural to see those storms there.

As Sideshow Bob would put it: Die, Pattern; Die.