Thoughts on first few weeks in May

[Cstok]

Well the long term models are now coming out for the first part of May. I generally check:

http://wxcaster.com/animate/gfs2p5_loops.p..._500_GPHTMPVORT
http://www.nco.ncep.noaa.gov/pmb/nwprod/an...0348384_l.shtml
http://www.nco.ncep.noaa.gov/pmb/nwprod/an...8/fp0_384.shtml

What is your opinion / view on the broader weather regime / long wave pattern, during the first part of May? I am a novice, but I do not see a trough east ridge west block, nor the Hudson Bay vortex pattern, so I think the broader long wave pattern looks favorable.

Let the brick bath begin (ducks under desk).

 

[Joerg Kachelmann]

I think it's sometimes impossible to look beyond the normal range of a few days, and it's especially true this time. When you look at the spaghetti for the capitals in there area

Ensembles

you can notíce a largely spread pattern even for the temperatures (of which the perturbations have been very consistent in the past weeks), even if you choose OKC or the TX capital.

So IMHO one can say that you can't say anything for the first week of May but that all options are in the game and there are nor significantly higer probs neither for the kiss of the killer ridge nor for stalled dryline in the western TX panhandle.

 

[Eddie Natenberg]

Well Im sure this will be my first post of many updates since the art of wishcasting tends to offset my of SDS.

The only site i found that runs the GFS out to 360? hours is ncep so I'm going to go on what I see there. If anyone has any other good links please pm me or reply.

Well first off it looks like today we are going to do some spring cleaning and clean out all of this moisture rich air and send it back to the gulf on a backdoor coldfront comming south out of the northern plains. This doesn't only happen once but twice (probably this Sunday too)! I see this as a consequence of the 250 polar jet becoming amplifed along the western coast as a ridge moving warmer temps east (onto the west coast of Canada) colapsing and bringing in strong AVA southward into the Northern great plains(V72 hrs). The bad news is this nearly kills all our severe weather chances up till finals week. The good news is that because of all this cold air advection the ridge to our west builds and strethens an intese low off the south coast of Alaska. Given time and patients the baroclinc zone assocated with area of cyclogensis will help intesify the zonal winds and cause extreme baroclinic instability to SLOWLY move eastward towards the US coast starting around V168 or the first week of May. As the flow evolves into a wave train pattern we could see not only a first round of storm on may 9th(ish) but, several more rounds the week after (assuming the flow does not amply any more).

I have been watching the GFS the last couple of runs, and although the ageostrophic solution is rapidly changing, the geostophic levels and patterns seem to be consistant and in some agreement. What I am concerned about is the amout of meridional absolute vorticity advection just west of the cyclone south of Alaska at V168 hours (which could allow the trough to retrograde) and the amout of warm air advection (meridionally) east of the trough which could stall it (building a ridge and hopefully not give us another back door cold front).


Im glad I kept May open this year, but thats based on my wishcast :unsure: .

Eddie

 

[David Wolfson]

Yeah. Good analysis, Eddie! NCEP is where I look too.

Our decision point is Thursday night after the 00Z for postponing the next two week's venture. Unless more STJ action manages to sneak in from the weeds it's looking like an A-1 bustola. Can't make it for the end of May, either, which could redeem itself, like you say.

 

[Mike Johnson]

The NCEP ensemble still looks like a bust for the first week of May with the first chance of any sig. svr.
beginning abound the 8-9th.

Stay tuned!

Mike

 

[Marc Austin]

Well we've planned our trip for the last two weeks of May beginning on May 14 and ending May 28. Anyone have any thoughts on the END of May? I know that statistically, this is a good time, but noting recent weather oddities, it seems that words like "average" and "statistically" are going out the window quickly. Anyway, I know that models don't go out far enough to even have an inkling into what will happen at the end of May, but I thought some of you might have some ideas. I was thinking we would have to be chasing up in NE/SD/NRN KS, but we'll just have to see... seems like a lot of severe in the south right now.

 

[Chris Wilburn]

Marc,

No idea on the last two weeks of May. Maybe you can get lucky and it will be like 2004 when we had some awesome days. Oh ya are you going to come to Miami and eat at the Ku-Ku? lol How many of you are coming and where are you going to base out of?

 

[Dave Nelson]

hi guys,
hopefully your predictions are close to true. As during the 1st week of may we land in the USA
and make our way nth to Portland OR and across to NE and down into OK area by ~ 6th or 7th of May.
We will base ourselves in the OK - KS area for 3 weeks of chasing. then heading to Los Angeles via TX,
NM, AZ and NV and flying home to Australia.

looking forward to maybe seeing some of you on the road as we tour 'Tornado Alley'
the info and predictions that are made on the forums are always much appreciated
Thankyou

cheers
Dave and Cindy Nelson
Sydney
Australia

 

[Robert Edmonds]

Any thoughts on the last half of may? Sorry I had to ask...

edit: I had to ask because I don't have the ability to chase till after the 18th....

 

[rdale]

I have a thought - wait until we make it a bit into May before we guess how it might end...

 

[Mike Hollingshead]

I bet the second half won't be any worse than the first half.

 

[Mike Johnson]

Here is an interesting discussion from DDC regarding the next 8-10 days. The main models including NCEP
seem to agree at this point. Caution... there will be NW flow during the period -- much like the late season svr wx pattern, so watch out!

Mike

DAYS 3-7...

PUNCH LINE IS I WOULD EXPECT THE JET ACROSS THE NORTH
PACIFIC TO BECOME MORE ACTIVE WITH ENHANCED BAROCLINIC DEVELOPMENT
AT ITS LEADING EDGE (KEEPING IN MIND THE SEASONAL CYCLE). HOWEVER,
GIVEN THE ANOMALOUS ZONAL MEAN EASTERLY FLOW STILL PRESENT ACROSS
THE NORTHERN MIDLATITUDES PARTICULARLY ACROSS THE PACIFIC (LINKED TO
THE LA NINA), I WOULD EXPECT THIS JET TO BE DISPLACED NORTH OF
CLIMATOLOGY. A DOWNSTREAM RIDGE (PROBABLY NORTHEAST-SOUTHWEST
ORIENTED) WOULD BE EXPECTED OFF THE USA WEST COAST ALLOWING SOME
DEGREE OF A TROUGH ACROSS THE ROCKIES. I WOULD NOT EXPECT THIS
TROUGH TO BE A "BIG DEAL"; HOWEVER, THE DETAILS OF JUST HOW THIS
SYSTEM DEVELOPS MAKES A HUGE IMPACT ON THE WEATHER FOR MY CWA NEXT
WEEK.

CLICK HERE to read the rest of DDCs discussion.
MOD: Added non-changing / static link to the AFD.

 

[Stan Rose]

Looks like the front that blows through thursday night will wipe out moisture for at least a couple days. im skeptical it will return by sunday (which the last two gfs runs have) but still holding out hope that ill be able to chase somewhere in TX. ABout all i can say with confidence is that there WILL be a major outbreak the day i have to return to work--May 14. :blink:

 

[nickgrillo]

The first week of May doesn't appears to look as bad now... The latest NAM and GFS support a decent threat for supercells across the central plains on both TUE and WED (and even tomorrow -- except a bit further east) with strong instability developing as a result of moist advection (e.g. >2500 j/kg sbCAPE on both TUE and WED afternoon) with 60-65 tds progged to be spread across the moist sector. Additionally, deep tropospheric veering -- with sufficient northwest flow aloft to backing surface flow -- will poise for highly favorable shear profiles to yield a supercell threat (and possible tornadoes) on both days (quite possibley KS being the best shot on TUE and then northern OK on WED). Deep, moist convective initiation seems to be a bit less harder to accomplish on WED (the NAM shows strong sbCINH for boundary layer ascent across a lot of the broad moist sector on TUE)... I may very well leave tomorrow afternoon for KS... Bring on thee May!

 

[Dick McGowan]

I have a thought - wait until we make it a bit into May before we guess how it might end...
[/b]

I'm willing to bet Michigan isn't going to have a very active May. :lol: Just a thought.

My bet is the second half will be quite active for the Plains. Of course I'm always optimistic......