The Ridge

[southerngale]

Could someone more knowledgeable than me (probably most of y'all ) please explain where the ridge is now and what it's expected to do over the next several days? I see that 91L is expected to move into Mexico so I assume the ridge is in place over the northern Gulf states. It's been raining her all day though...not sure if that means anything. Anyway, I stare at water vapor loops until I think ghosts have taken over my computer and I start to hear They're heeeeeeeeere! but I still can't figure out exactly where the ridge is.

When Emily was approaching and people were talking about the ridge building west (or that it being in place) was obvious on water vapor loops, I could never see it. I think it's the dark areas but they're all over the place and were even in the spot Emily was headed. If anyone wants to use maps to show this Ridging for Dummies pupil how to spot it, that'd be great too.

[Cookiely]

I second the motion. Can someone show us on an image the ridge in question?

[Ivanhater]

haaa the illusive ridge

[Brent]

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_000l.gif

See the H in the middle of the Gulf? There's also another one over the Southern U.S., these storms are storms that form this time of year are from the heat and humidity... we just had one here that turned severe over me(nothing severe here though).

[Wacahootaman]

I watch this for steering currents although I dont know how to precisely interpet it. I do know just yesterday Franklin had a high pressure dome just to its east and that seems to be gone now.

http://cimss.ssec.wisc.edu/tropic/real- ... g8dlm4.GIF

[wayoutfront]

I think this is it at 500mb ???????

[rockyman]

Try this website:

http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8dlm1.html

This is "real time" (updated every 3 hours)...showing the placement of various highs, lows, and troughs at different layers of the atmosphere...you can change the steering layer (depending on the strength of the system you are monitoring) and can go back in time in 3 hour increments to see how the features are moving and developing.

Based on the "shallow" (weakest) map, the steering flow for now will move 91L toward Mexico...and the "steering high" is located over the south central states (MO/KS).

By the way...it is extremely difficult (IMHO) to pick out the steering mechanisms on satellite loops...you might see an upper level low (such as the one going inland over Mexico) but that ULL might not have a thing to do with steering this particular system.

Hope this helps a little.

[artist]

here is one that i use http://www.nhc.noaa.gov/tafb_latest/atl24_latestBW.gif

you can find different items to help you on this page -

http://www.nhc.noaa.gov/tafb-atl.shtml

[southerngale]

Ok, thanks for all the input and I'm gonna check out the links a little better. Is the ridge supposed to stay put for a while?

[deltadog03]

actually the ridge is forecasted to push EASTWARD in the next couple of days....

[NEXRAD]

This evening, the low level ridge influencing the Gulf of Mexico is situated near the Missouri-Oklahoma border. A deeper, mid-level ridge is centered over northeast Colorado. Combined, this broad, deep-layer, ridging is providing an easterly flow across most of the Gulf. During the weekend, the high pressure now in Colorado is forecast to slide southeast as the trough over the Eastern US deepens and another trough moves onshore the US Pacific Coast. This will maintain a strong easterly steering pattern over the Gulf of Mexico at least into early next week. On late Monday and Tuesday, some guidance suggests that there may be weakness over the far western Gulf with the backside of the low-level ridging.

I can see where the water vapor is giving trouble with the various storms over Eastern Texas tonight. Try the RUC/2 data from NCEP. I find the RUC model's initial synopsis to be good for quick discernment of various features. Here's the output for the 850mb level, showing low-level steering influences over the United States and environs.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/ruc/hr4/images/ruc_850_000l.gif

Here's the main NCEP model page. The RUC is updated here every 6-hours at the bottom of the page. I always select the "fine" resolution.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/

- Jay
KSC FL

[deltadog03]

thanks for the input, also FWD said something about that ULL is forecasted to push or is pushing SSWd....that might be something to watch...

[Scott_inVA]

Jay has excellent points regarding using the RUC.

For a broader scenario, I'll use the 500mb 18Z NAM as a backdrop.

Here's the "heat" ridge over central CONUS (that's a 594 line...outrageous heat):
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_000l.gif
note how winds at 500MB are progged to shift from SE to NE around the bottom of the ridge...near the Invest.

At 24 HRS (18Z SA) the NAM shows the Ridge over CONUS has elongated...actually splitting in two). BTW inside the eastward progressing 594 line, temps will soar:
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_024l.gif
Over WGOM you'll see the NAM depicts winds begin to straighten out of the SE...again in response to the Ridge moving east.

At 48 HRS there's 2 ridges with the dominant eastern Ridge now centered over the lower TN Valley.
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_048l.gif
check the mid-level winds over WGOM again shift.

Lastly at 72 HRS this ridge is centered over SE US (still with hideous heat)
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_072l.gif
winds over the Invest again shift as the ridge moves.

NAM isn't going to be perfect and 500MB certainly isn't the only consideration but it shows where high pressure over the US will move and what to expect in the mid-levels as the Invest enters the WGOM.

hope it helps.

Scott

[jasons2k]

Jay has excellent points regarding using the RUC.

For a broader scenario, I'll use the 500mb 18Z NAM as a backdrop.

Here's the "heat" ridge over central CONUS (that's a 594 line...outrageous heat):
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_000l.gif
note how winds at 500MB are progged to shift from SE to NE around the bottom of the ridge...near the Invest.

At 24 HRS (18Z SA) the NAM shows the Ridge over CONUS has elongated...actually splitting in two). BTW inside the eastward progressing 594 line, temps will soar:
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_024l.gif
Over WGOM you'll see the NAM depicts winds begin to straighten out of the SE...again in response to the Ridge moving east.

At 48 HRS there's 2 ridges with the dominant eastern Ridge now centered over the lower TN Valley.
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_048l.gif
check the mid-level winds over WGOM again shift.

Lastly at 72 HRS this ridge is centered over SE US (still with hideous heat)
http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_072l.gif
winds over the Invest again shift as the ridge moves.

NAM isn't going to be perfect and 500MB certainly isn't the only consideration but it shows where high pressure over the US will move and what to expect in the mid-levels as the Invest enters the WGOM.

hope it helps.

Scott

Scott, excellent post!

[southerngale]

Thanks for your posts, Jay and Scott. Very interesting and informative. I actually understand the ridge and its (their) position better.

Btw, welcome to storm2k Jay!