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November Discussion


DaculaWeather

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The poor folks in west Alabama are going to get bombarded again by severe weather... The shear is a good 40 knots and Storm Relative shear is up over 300... These storms have already produced damage across Mississippi and Louisiana and continue to march to the northeast, closer to the better shear environment... Let's hope it doesn't get too bad for them out there!

I've been watching the trends here locally and I'm getting a little concerned about the possibility of a tornado or two for East Alabama/West Georgia. Only reason I'm concerned is because we could see enough clearing in the clouds to bump temperatures into the low to mid 80s. That would be ample enough to fire off a few strong storms! Our only saving grace is the surface low isn't forecast to strengthen all that much... Never the less, a few severe thunderstorms are likely and winds up to 70 mph will be experienced by some...

Those in the eastern Carolinas better watch the sky VERY carefully this evening... As I could see a few tornadoes spin up with the STP elevated some and enough heating, highs will get into the mid to upper 70s.

It'll be interesting to see the radar trends as we go into the early afternoon hours.

Somewhat skeptical yesterday I am starting to grow concerned that this may be worse than originally thought... Updated day 1 disco is out from the SPC and the slgt hatch has once again been broadened on both the north and south sides. SVR reports were min out of TX but picked up early this morning with 5 possible touchdowns in LA & AL, and a new MD that just went up.

day1otlk_1300.gif

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0700 AM CST WED NOV 16 2011

VALID 161300Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LWR MS VLY/ERN GULF

CST INTO THE CAROLINAS/MID ATLANTIC...

...SYNOPSIS...

BROAD CYCLONIC FLOW OVER THE CONUS IN RECENT DAYS WILL AMPLIFY THIS

PERIOD AS JET STREAKS NOW OVER AB...MT...AND WY SWEEP RAPIDLY

SEWD...RESULTING IN A DEEP BUT PROGRESSIVE TROUGH OVER THE LWR OH

VLY BY 12Z THU. IN THE MEANTIME...UPR IMPULSE THAT CROSSED E TX

YESTERDAY WILL CONTINUE TO BECOME ABSORBED WITHIN STRONG AND FURTHER

STRENGTHENING SW FLOW OVER THE SERN STATES. THE MAIN PART OF THAT

DISTURBANCE IS OVER MS ATTM...AND SHOULD REACH PIEDMONT NC BY EARLY

EVE AS A HIGH LVL JET ENTRANCE REGION DEVELOPS OVER THE MID ATLANTIC

IN RESPONSE TO AMPLIFICATION OF LARGER SCALE TROUGH.

AT THE SFC...SEASONABLY RICH MOISTURE /WITH SFC DEWPOINTS IN THE MID

60S F AND PW AROUND 1.50 INCHES/...WILL CONTINUE TO STREAM NEWD

ACROSS GA AND THE CAROLINAS TO VICINITY OF STNRY FRONT OVER VA. SFC

WAVE NOW OVER NRN MS/AL SHOULD REDEVELOP ENE ALONG THE FRONT INTO

CNTRL VA LATER TODAY. ADDITIONAL WEAK WAVES LIKELY WILL DEVELOP

ALONG THE BOUNDARY UNTIL IT FINALLY CLEARS THE CAROLINA CST AS A

COLD FRONT LATER THU MORNING.

...LWR MS VLY/ERN GULF CST INTO CAROLINAS/MID-ATLANTIC...

BAND OF SCTD SUPERCELLS ALONG LOW LVL CONFLUENCE AXIS OVER SE LA/ERN

MS AND WRN AL LIKELY WILL PERSIST FOR AT LEAST A WHILE LONGER THIS

MORNING AS THE AXIS EDGES SLOWLY EWD IN RESPONSE TO EJECTING UPR

IMPULSE. COMBINATION OF RICH MOISTURE INFLOW AND STRONG LOW LVL

SHEAR MAY CONTINUE TO FOSTER LOW LVL ROTATION/ISOLD TORNADOES AS THE

FEATURES CROSSES AL /REF WWS 887 888/.

WITH TIME...MODEST DIURNAL HEATING MAY FOSTER REJUVENATION OF THE

CONFLUENCE AXIS STORMS. MORE LIKELY...HOWEVER...HEATING WILL

SUPPORT EVENTUAL ADDITIONAL DEVELOPMENT EAST OF THE CONFLUENCE AXIS

OVER PARTS OF GA AND THE CAROLINAS...S AND E OF SHALLOW

RAIN-REINFORCED BOUNDARY ALONG THE SRN SLOPES OF THE APPALACHIANS.

WEAKENING OF UPR IMPULSE IN CONFLUENT FLOW ALOFT SUGGESTS THAT LARGE

SCALE FORCING FOR ASCENT WILL BE WEAK. BUT COMBINATION OF EVEN WEAK

DESTABILIZATION /SBCAPE TO 1000 J PER KG/ WITH STRONG VEERING WIND

PROFILES /40 KT SW 850 MB FLOW BENEATH 60-70 KT WSW FLOW AT 500 MB/

LIKELY WILL SUPPORT SUSTAINED STORMS/SUPERCELLS. THESE MAY ORGANIZE

INTO BROKEN BANDS THAT WILL POSE A RISK FOR BOTH TORNADOES AND

NARROW SWATHS OF DMGG WIND...ESPECIALLY ACROSS APPALACHIAN

FOOTHILLS/PIEDMONT OF GA AND THE CAROLINAS/VA. ADDITIONAL CLUSTERS

OF STORMS MAY FORM TNGT THROUGH EARLY THU CLOSER TO THE CST AS LARGE

SCALE ASCENT INCREASES WITH THE DEVELOPMENT OF AFOREMENTIONED UPR

LVL JET ENTRANCE REGION.

FARTHER NW...OTHER TSTMS MAY PERSIST THROUGH THE PERIOD ALONG

MERGING COLD FRONTS OVER THE TN VLY...BUT THIS ACTIVITY SHOULD

REMAIN MARGINAL DUE TO WEAKER INSTABILITY.

..CORFIDI/ROGERS.. 11/16/2011

I went through the CIPS analog guidance based on the 11/15 12z GFS t-stepped at 36 hrs and these are the svr reports based on the top 15 analogs. Keep in mind most of the analogs had 0 svr reports, and more than half occurred in a month other than Nov; 6 in Dec, 6 in Nov & 3 in Oct.

SVR15gfs212F036.png

The best match I could find is 11/5/1992, it is the #3 analog overall, and #1 in terms of PMSL, 2mTMP and 2mDWP (all by a good margin). The only issue I see is the H3 match, where it falls in at #9. In 1992 the 300mb jet was more potent running up through the MS Valley into northern New England. Here are the svr reports for this analog, and I feel that given some clearing E NC may see something slightly more subdued than this tonight.

1992110518_024_ptsvr.png

The 15z SREF from yesterday was picking up on some enhanced supercell potential for GA, SC and NC. The 3z run has come in much more bullish showing composite parameters >9, as a mean, for the northern half of GA, almost all of SC, and NC bounded by I-77&95. This run even hatches a 12 right over CLT at 6pm tonight which is impressive!

SREF_SCCP_MEDIAN_MXMN__f021.gif

Moving east into the Coastal Plain of NC tonight, the potential for tornados is the greatest. While we are starting the day with OVC conditions, most of the guidance has areas along and east of 95 clearing out with 25-35% cloud cover after 12pm. That is going to be the determining factor, and really impossible to predict until it actually happens as often times the clearing does not happen, and the event does not materialize as a result. However, if we do clear out, folks need to keep the wx radios close tonight because all one has to do is go back to the Kenly event in 2008 to see that even these low end EF0-EF2 touchdowns can take lives. That being said, this is the sig tornado parameter based on the 3z SREF for ENC tonight, solid hatch of 4 showing up around midnight, 3 hrs prior it is even over Florence.

SREF_SIGTOR_MEDIAN_MXMN__f027.gif

When looking at the mean sig tor param, 50% of the members have E NC as a 5 or better, the highest value used on the SPC site.

SREF_prob_sigtor_5__f027.gif

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From well-respected severe weather met out of Alabama...

"Instability is increasing across the region (in Alabama), but the shear is starting to rapidly decrease. For the most part, this is going as expected. Still, a couple of isolated, weak, short-lived tornadoes remain possible for at least a few more hours, before transitioning to predominantly a damaging wind threat. Still think the main threat east of I-75 into the Carolinas will be damaging straight-line winds."

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From well-respected severe weather met out of Alabama...

"Instability is increasing across the region (in Alabama), but the shear is starting to rapidly decrease. For the most part, this is going as expected. Still, a couple of isolated, weak, short-lived tornadoes remain possible for at least a few more hours, before transitioning to predominantly a damaging wind threat. Still think the main threat east of I-75 into the Carolinas will be damaging straight-line winds."

Do you mean Highway 75 here in union county?

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Some hope starting to appear more often on the 6Z GFS...

Maybe that storm can help begin to change our pattern, otherwise it's more of the same with healthy doses of rain and warm, followed by a quick, but sharp cold snap.

Looking at other maps clearly shows a -PNA, +NAO, and the firehose still turned on in the Pacific. I am thinking it may well be mid December before this flips, which is ok with me. Doing outside stuff in November and early to mid December is a plus in my book.

This year may very well have more variability, meaning less sustained cold, but I think the chances of bigger storm systems goes up as well. Patience grasshoppers.

Hoping for minimal damage today for our brothers and sisters to my south having to face severe weather today and tonight.

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Tornado Watch just went up for parts of Georgia, including my location.

Tornado Watch

TORNADO WATCH OUTLINE UPDATE FOR WT 889 NWS STORM PREDICTION CENTER NORMAN OK 945 AM CST WED NOV 16 2011 TORNADO WATCH 889 IS IN EFFECT UNTIL 600 PM CST FOR THE FOLLOWING LOCATIONS GAC015-045-047-053-055-057-063-067-077-083-085-089-097-111-113- 115-117-121-123-129-135-139-143-145-149-151-187-199-213-215-223- 227-231-233-247-255-259-263-281-285-291-295-311-313-170000- /O.NEW.KWNS.TO.A.0889.111116T1545Z-111117T0000Z/ GA . GEORGIA COUNTIES INCLUDED ARE BARTOW CARROLL CATOOSA CHATTAHOOCHEE CHATTOOGA CHEROKEE CLAYTON COBB COWETA DADE DAWSON DEKALB DOUGLAS FANNIN FAYETTE FLOYD FORSYTH FULTON GILMER GORDON GWINNETT HALL HARALSON HARRIS HEARD HENRY LUMPKIN MERIWETHER MURRAY MUSCOGEE PAULDING PICKENS PIKE POLK ROCKDALE SPALDING STEWART TALBOT TOWNS TROUP UNION WALKER WHITE WHITFIELD $

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I've gotten a half inch so far. I wasn't expecting that much before the front came through, so I'm ahead. I my own mind, anyway. The bad news is the sun is out, and it has been near 80 the past few days in mid Nov...and a squall line is approaching :) Oh, well, maybe CandyMan gets to see some hail, finally. T

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It's quickly becoming an active afternoon! There are a few tornado warnings up and a few reports of damage coming in from them too....

The southern end of this line is coalescing and becoming linear in fashion. This also means it's starting to bow in sections.... That bow is heading right for Montgomery. It will also head for my area, so HOPEFULLY I don't have to worry about tornado warnings... But you never know with the temps already well into the 70s and DPs near 70. The northern half of this line is becoming more discreet and will REALLY need to be watched for tornadoes, albeit smaller ones than the spring ones, in NW Georgia and into the Carolinas...

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It's quickly becoming an active afternoon! There are a few tornado warnings up and a few reports of damage coming in from them too....

The southern end of this line is coalescing and becoming linear in fashion. This also means it's starting to bow in sections.... That bow is heading right for Montgomery. It will also head for my area, so HOPEFULLY I don't have to worry about tornado warnings... But you never know with the temps already well into the 70s and DPs near 70. The northern half of this line is becoming more discreet and will REALLY need to be watched for tornadoes, albeit smaller ones than the spring ones, in NW Georgia and into the Carolinas...

Here's the picture for most of the SE. Dynamics look poised to explode...

ttd_sf.gif?1321461494102

ttd_sf.gif?1321461683480

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Sun is out and heating underway as of 11am, about an hour ahead of schedule, with PC skies currently... Eastern US 1km vis valid 11:15am EST shows a couple pockets of clearing that may work into the upstate of SC and over towards Charlotte during the afternoon. Just looked at some of the experimental rapid-refresh products from NCEP and most take a robust segment (linear in nature) through RDU later tonight and up into SE VA.

post-382-0-80796300-1321462013.jpg

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