2015 Severe Weather Thread

[downeastnc]

A whole lot of "if's" in the AFD...

 

AS OF 240 PM WEDNESDAY...

THERE IS STILL A MARGINAL RISK OF SEVERE THUNDERSTORMS THURSDAY

AFTERNOON AND EVENING... MAINLY ACROSS THE SANDHILLS AND COASTAL

PLAIN.

PROBLEMS OF THE DAY WILL BE THE DEVELOPMENT AND STRENGTH OF THE WARM

SECTOR IN THE EAST... AND HOW FAR NW IT CAN PENETRATE INLAND.

RAIN AND POSSIBLY AN ELEVATED THUNDERSTORM OR TWO WILL BE ONGOING

OVER THE WESTERN THIRD OF CENTRAL NC THURSDAY MORNING AS THE WARM

FRONT APPROACHES FROM THE SOUTH. DEPENDING ON THE POTENTIAL FOR A

WAVE ALONG THE COAST (IF IT DEVELOPS THEN THE WARM SECTOR MAY BE

DISRUPTED OR VERY LIMITED/CONFINED TO THE COASTAL AREA) THURSDAY

AFTERNOON. REGARDLESS... HYBRID COLD AIR DAMMING WITH STRONG SURFACE

BASED STABILITY WILL BECOME ENTRENCHED OVER THE NW PIEDMONT AND

POTENTIALLY DEEP INTO THE PIEDMONT AS WAVES OF RAIN AID EVAPORATIVE

COOLING AND DIABATIC PROCESSES THROUGHOUT THE DAY. TEMPERATURES

SHOULD START AROUND 50 IN THE NW ZONES... AND MAY HOLD IN THE LOWER

TO MID 50S ALL DAY.

THE EASTWARD EXTENT OF THIS CAD IS PROBLEMATIC AS THE LATEST 12Z/GFS

INDICATES THAT EVEN RALEIGH AND SOUTHERN PINES WILL BE ON THE COOL

STABLE SIDE OF FRONT EVEN LATE DAY... WITH THE UNSTABLE AIR LIMITED

TO THE SE COASTAL PLAIN FROM FAY TO GSB AND LATE IN THE DAY INTO THE

EVENING. THERE SHOULD BE A STRONG GRADIENT IN TEMPERATURES BY LATE

AFTERNOON AND EARLY EVENING... WITH 50-55 NW TO NEAR 75 AROUND

LUMBERTON. JUST HOW FAR NORTH AND WEST THE GENUINE WARM SECTOR GETS

REMAINS IN FLUX WITH EACH RUN OF THE MODELS.

FOR NOW IT MAY BE BEST TO STICK WITH THE CURRENT FORECAST WORDING IN

THE HAZARDOUS WEATHER OUTLOOK WHICH TO ADVERTISES THE SOUTHERN AND

EASTERN ZONES IN A MARGINAL RISK OF SEVERE THUNDERSTORMS. DAMAGING

WIND (AND A LOW END TORNADO RISK) THE MAJOR CONCERNS. KEEP IN MIND

THE EXTENT OR LACK THEREOF THE WARM SECTOR WILL PROBABLY NOT BE

DETERMINED UNTIL DURING THE DAY THURSDAY (BASED ON HOW FAR SOUTH AND

EAST THE RAIN COOLED AIR/STABILITY IN THE WEST ADVANCE... THE

PLACEMENT OF THE MAIN LOW PRESSURE WAVE LATER IN THE DAY AND

THURSDAY EVENING (CENTRAL OR COASTAL NC)... AND TIMING OF THE COLD

FRONT THURSDAY NIGHT. EVEN THE WEAK COASTAL WAVE LATER TONIGHT AND

EARLY THURSDAY WILL HAVE AN IMPACT AS TO THE PLACEMENT OF THE LOW

LEVEL JET AND WARM SECTOR TIMING DURING THE EVENT THURSDAY.

REGARDLESS... THE APPROACHING MID/UPPER TROUGH IS STRONG AND THE SW

FLOW ALOFT WILL INCREASE ESPECIALLY LATER IN THE DAY WITH THE

APPROACHING MID LEVEL TROUGH AND THE HEIGHT FALLS WILL ENSUE. STRONG

KINEMATIC FIELDS WILL DEVELOP OVER THE REGION... LEAVING THE KEY TO

THE SEVERE POTENTIAL TO THE AFOREMENTIONED LOW LEVEL FEATURES.

RAIN WILL PREDOMINATE NW WITH SHOWERS SE... AND ISO THUNDERSTORMS SE

LATE AFTERNOON AND EVENING. STEADY RAIN WILL END THURSDAY NIGHT WITH

LINGERING LOW CLOUDS... DRIZZLE... AND FOG (POSSIBLY A DENSE FOG

EVENT AGAIN THUR NIGHT AND EARLY FRIDAY).

THIS IS A FLUID SITUATION AND ONE THAT BEARS CLOSE WATCHING. SURFACE

LOW TRACKS ALONG THERMAL MOISTURE BOUNDARIES (TMB) ON THE SOUTH AND

EAST SIDE OF PIEDMONT COLD AIR DAMMING (CAD) RESUMES OFTEN BRING

SEVERE STORMS AND TORNADOES IN THE FALL AND SPRING SEVERE WEATHER

SEASONS. JUST BECAUSE IT IS DECEMBER... WE CAN NOT TAKE OUR GUARD

DOWN ESPECIALLY IN THE CLIMATOLOGICALLY FAVORED SE ZONES THIS TIME

OUT.

&&

 

The bolded part is spot on, setups like this almost always produce tornados IF the storms form.....any updrafts tomorrow along that boundry will spin up ...could be interesting either way 50-55 knt LLJ is pretty stout and any mixing will get that to the surface so even "strong" storms could pack a punch.

 

 

MHX had this to say.....

 

CONTINUED MENTION OF THUNDERSTORMS THURSDAY AS MODEST INSTABILITY

WITH SLIGHTLY BACKED SURFACE WINDS WILL BE PRESENT. THIS EVENT

WILL BE A MARGINAL HIGH-SHEAR/LOW-CAPE SCENARIO AS 850 MB/LOW

LEVEL JET INCREASES TO 50-55 KNOTS THURSDAY EVENING AHEAD OF THE

FRONT WITH MOST UNSTABLE CAPE VALUES AROUND 500 J/KG OR LESS.

LATEST SHERBS3 PARAMETER FROM HIGH-RESOLUTION GUIDANCE INCREASES

TO AROUND 0.9 NEAR 00Z FRIDAY FOR THE COASTAL PLAINS COUNTIES,

THOUGH BEST UPPER SUPPORT REMAINS WELL NORTHWEST OF THE REGION.

TEMPS WILL REMAIN VERY WARM AHEAD OF FRONT AND DESPITE THE CLOUDS

AND RAIN WITH HIGHS THURSDAY IN THE 70S PER MODEL THICKNESSES

1385-1395 METERS.

 

[Solak]

GSP...

ON THURSDAY...THE OPERATIONAL MODELS SHOW A SURFACE WAVE (OR WAVES)LIFTING NE ALONG THE EWD MOVING COLD FRONT...WITH THE PRIMARY LOWMOVING E OF THE MTNS. THIS BRINGS TO MIND A NUMBER OF POTENTIALPROBLEMS. A LOW LEVEL JET WILL STRENGTHEN FROM THE SW DURING THE DAYE OF THE MTNS. THE ORIENTATION NOT-QUITE NORMAL TO THE BLUE RIDGEMIGHT CUT DOWN ON SOME PRECIP POTENTIAL. THE QPF...TAKEN FROM WPC...LOOKS DECENT...BUT SHOULD NOT BE QUITE ENOUGH TO CAUSE SIGNIFICANTFLOODING NOW THAT STREAM FLOWS HAVE RETURNED CLOSE TO NORMAL AND FFGHAS ALSO IMPROVED. A FLOOD WATCH WILL NOT BE ISSUED AT THIS TIME.THE MODELS DO NOT INDICATE THE WEAK HIGH TO THE NE AS BEING STRONGENOUGH TO MAINTAIN ANY COOL POOL E OF THE MTNS OUTSIDE OF PERHAPSTHE NRN FOOTHILLS. THE SURFACE BOUNDARY LIFTS WELL INTO THE WESTERNCAROLINAS IN THE AFTERNON...AT LEAST TO I-85 OR SO...MEANING WE MAYBE ABLE TO DESTABILIZE SUFFICIENTLY TO CONSIDER THUNDERSTORMS. THEENVIRONMENT WILL HAVE CONSIDERABLE SHEAR WHICH WILL HELP TO ORGANIZESTORMS. THE TREND IN THE NAM IS FOR GREATER BUOYANCY...UPWARDS OF500 J/KG REACHING THE SE FRINGE...MORE THAN ENOUGH TO WORRY ABOUTCONVECTIVE LINES THAT WOULD PRODUCE WIND DAMAGE AND/OR BRIEF WEAKTORNADOES. MEANWHILE...THE GFS HAS ALMOST NO BUOYANCY. HOWEVER...THELIMITING FACTOR MIGHT BE THAT WE LACK A STRONG ADVECTIVE VORT CENTERAND STRONG MID-LEVEL DRYING AS HAS BEEN NOTED IN OTHER SIMILARSITUATIONS THAT PRODUCED SEVERE WEATHER. THE DAY2 OUTLOOK FEATURESA MARGINAL RISK PLACED TO THE SE...WHICH LOOKS GOOD FOR THE TIMEBEING. THIS WILL HAVE TO BE MONITORED CLOSELY ON THURSDAY AFTERNOON.TEMPS WILL BE ABOVE NORMAL AGAIN.

[buckeyefan1]

CAE.....

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
A BROAD BUT AMPLIFIED UPPER TROUGH IN THE MIDWEST WILL BE MOVING
EAST AS DEEP LOW PRESSURE MOVES INTO SOUTHERN CANADA. A STRONG
SURFACE COLD FRONT WILL BE IN THE APPALACHIAN MOUNTAINS AND GULF
COAST AREA EARLY THURSDAY. A WARM FRONT WILL SET UP ACROSS THE
NORTH MIDLANDS SO MOST OF THE AREA SHOULD BE IN WARM SECTOR.
INCREASING MOISTURE/ISENTROPIC LIFT EARLY THURSDAY ALTHOUGH DEEPER
MOISTURE/STRONGER LIFT LIKELY IN THE UPSTATE REGION CLOSER TO
UPPER LEVEL JET DYNAMICS AND AREA OF WEAK LOW PRESSURE TRACKING
NORTHEAST. BASED ON LATEST HIGH RESOLUTION MODELS BACKED OFF ON
POPS EARLY IN THE DAY WITH FOCUS MAINLY WEST. AS FRONT APPROACHES
FROM THE WEST IN THE LATE AFTERNOON...LIFT EXPECTED TO INCREASE
AND INSTABILITY POSSIBLY MODERATE. STRONGEST INSTABILITY LIKELY IN
THE EAST. PRECIPITABLE WATER STILL EXPECTED TO BE ABOVE
NORMAL...NEAR 1.75 INCHES. MODEL QPF IS A LITTLE LOWER THAN
PREVIOUS RUNS...ALTHOUGH SREF STILL NEAR 1 INCH. FORECAST
CATEGORICAL POPS LATE AFTERNOON THROUGH EARLY EVENING. WITH 50KT
LOW LEVEL JET THERE IS POTENTIAL FOR A FEW SEVERE THUNDERSTORMS.
MILD CONDITIONS AHEAD OF FRONT MOS CONSENSUS ACCEPTED. FRONT
MOVING THROUGH AREA BETWEEN 05Z AND 09Z. SHOWERS MOVING EAST OF
AREA BY MORNING SO CUT POPS BACK LATE. COLD ADVECTION
FRIDAY...EXPECT BREEZY CONDITIONS. SECONDARY FRONT/UPPER TROUGH
MOVING THROUGH IN THE AFTERNOON ENHANCING COLD ADVECTION BUT
DOWNSLOPE SHOULD OFFSET IT SOMEWHAT. SO TEMPERATURE FORECAST
UPPER 50S TO MID 60S FRIDAY. DIMINISHING WIND FRIDAY NIGHT AND AIR
MASS COLD. 850MB TEMPERATURES -2C TO -5C. GUIDANCE TEMPERATURE
ACCEPTED NEAR OR BELOW FREEZING.

 

[Brick Tamland]

How do things look this morning? Still just wait and see?

[downeastnc]

How do things look this morning? Still just wait and see?

 

Yep, some decent breaks in the clouds here if the sun can get up and do some work then that might bump cape up some in the east, I would definitely say best chance of severe will stay east of I95.....

[Solak]

I wish they'd narrow down the timeframe. Have to drive from here up to near the PNC Arena for a 1:30 dr. appointment. Not looking forward to I-40 in the rain.

NCZ008>011-025>028-040>043-073>078-083>086-088-089-181200-GRANVILLE-VANCE-WARREN-HALIFAX-DURHAM-FRANKLIN-NASH-EDGECOMBE-CHATHAM-WAKE-JOHNSTON-WILSON-STANLY-MONTGOMERY-MOORE-LEE-HARNETT-WAYNE-ANSON-RICHMOND-SCOTLAND-HOKE-CUMBERLAND-SAMPSON-655 AM EST THU DEC 17 2015THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL NORTH CAROLINA..DAY ONE...TODAY AND TONIGHT.A FEW STRONG TO SEVERE STORMS ARE POSSIBLE THIS AFTERNOON AS ACOLD FRONT CROSSES THE REGION. THE MAIN THREAT FROM STORMS WILL BE HEAVY RAIN AND DAMAGING WIND GUSTS. SOME OF THE STRONGERSTORMS COULD EXHIBIT PERSISTENT ROTATION THAT COULD RESULT IN ABRIEF TORNADO TOUCHDOWN.

[Brick Tamland]

Yep, some decent breaks in the clouds here if the sun can get up and do some work then that might bump cape up some in the east, I would definitely say best chance of severe will stay east of I95.....

 

I figured the rain and clouds here this morning would keep down the instability, which has been the case 99% of the time this year whenever there was talk of severe weather.

[Isopycnic]

How do things look this morning? Still just wait and see?

wet. Wait and see

[Solak]

Looks like the update has shifted the severe threat to the Southeast coastal areas.

 

0 retweets 0 likes

 

[Brick Tamland]

Pouring rain now. I doubt we even have any storms at all this afternoon here.

[18zAnalog]

Saw some thunder and heavy rain last night, but no sign of severe. Looks like some possibilities next week

[Shawn]

Looking at soundings, the threat is showing up again for Christmas eve all the way over here in Columbia, SC.  Nothing off the charts, but the risk is possible for us in GA/SC/NC.

 

A good many questions to answer still though.  Looks like it won't be as bad as to our West, but who knows.

[Snowless in Carrollton]

I can't help but laugh at the difference in tone between FFC and James Spann regarding tomorrow's severe weather event. 

 

FFC:  THERE ALSO

APPEARS TO BE A BIT MORE INSTABILITY WITH THE SECOND WAVE SO
ISOLATED THUNDERSTORMS WILL BE POSSIBLE TONIGHT AND WEDNESDAY AS
THIS WAVE MOVES ACROSS THE STATE.

 

SPANN:  HIGH IMPACT SEVERE WEATHER EVENT POSSIBLE TOMORROW AFTERNOON AND TOMORROW NIGHT

 

I can't imagine the impact of this event being that much different between my area and 15 miles to my west.

[Solak]

For Wednesday...

 

[Solak]

US National Weather Service Birmingham Alabama added 2 new photos.

7 mins ·

*Severe Weather Outbreak Expected on Wednesday and Wednesday Night*

Graphic 1 (Wednesday 3 PM - Midnight)
Confidence has increased enough for us to upgrade the Northwest part of the area to a Significant Risk. This is due to the potential for strong and long-lived tornadoes tomorrow afternoon into tomorrow night.

Graphic 2 (Thursday Morning 12 AM - 6 AM)
The severe weather threat, including the threat for tornadoes, is now expected to continue after midnight tomorrow night.

[kayman]

I can't help but laugh at the difference in tone between FFC and James Spann regarding tomorrow's severe weather event. 

 

FFC:  THERE ALSO

APPEARS TO BE A BIT MORE INSTABILITY WITH THE SECOND WAVE SO

ISOLATED THUNDERSTORMS WILL BE POSSIBLE TONIGHT AND WEDNESDAY AS

THIS WAVE MOVES ACROSS THE STATE.

 

SPANN:  HIGH IMPACT SEVERE WEATHER EVENT POSSIBLE TOMORROW AFTERNOON AND TOMORROW NIGHT

 

I can't imagine the impact of this event being that much different between my area and 15 miles to my west.

 

I've come to the conclusion that the Peachtree City office (FFC) is clueless when it comes to severe weather forecasting.  Just a few weeks ago we had multiple tornado debris and vortex signatures with the same cell going through the heart of the Atlanta urbanized area but only a tornado warning after the Coweta and Fulton counties law enforcement reported damage and sightings.  

 

This is indicative of the lackadaisical habit of ignoring SPC mesoscale discussions on severe weather in nearby east Alabama and northwest Georgia as reported around 1PM EST on that most recent episode.  Just because this region has gotten lucky on missing major severe weather outbreaks, all it takes is one.  They are drawing unnecessary criticism and attention to this one NWS office, and I just don't pay them any attention anymore.  I read what BMX says because that one office seems to be very attentive to severe weather and adhere to that accordingly.

[Brick Tamland]

Wish we had more posters from Alabama here. I am glad someone posted about this because I haven't heard anything about it until now. 

[Shawn]

Wish we had more posters from Alabama here. I am glad someone posted about this because I haven't heard anything about it until now. 

 

I did here, lol.

 

Looking at soundings, the threat is showing up again for Christmas eve all the way over here in Columbia, SC.  Nothing off the charts, but the risk is possible for us in GA/SC/NC.

 

A good many questions to answer still though.  Looks like it won't be as bad as to our West, but who knows.

 

 

Anyway, any cells that get going could go severe over this way.  We have a much much lower chance at getting much going.  Northern Georgia areas might be in a better spot of course...

 

Aside from that, I think the NAM 4KM is way overdone even out that way.  With no forcing, I am not sure how much we can expect.. simulated radar signatures anemic the further East you go.

[PelicanGuy]

And from Jackson, Miss.:

 

[max100]

Wish we had more posters from Alabama here. I am glad someone posted about this because I haven't heard anything about it until now. 

Because this thread is definitely Carolina sided.  In fact Georgia should move out of it.

[Brick Tamland]

Because this thread is definitely Carolina sided.  In fact Georgia should move out of it.

 

What has anyone said about the Carolinas? Or maybe more people from these states could just post more.

[max100]

What has anyone said about the Carolinas? Or maybe more people from these states could just post more.

If you post anything about GA, AL and god forbid MS, it is generally ignored here.

[Snowless in Carrollton]

Wish we had more posters from Alabama here. I am glad someone posted about this because I haven't heard anything about it until now.

I'm 15 miles away. Isn't that close enough ?

[Brick Tamland]

If you post anything about GA, AL and god forbid MS, it is generally ignored here.

 

There just aren't as many posters form there, especially AL and MS. That's not anyone's fault. If you want more people talking about those states, then you need more posters from there.

[max100]

I'm 15 miles away. Isn't that close enough ?

Yes, but you and I both live in the conservative land of FFC...

[Hvward]

I did here, lol.

Anyway, any cells that get going could go severe over this way. We have a much much lower chance at getting much going. Northern Georgia areas might be in a better spot of course...

Aside from that, I think the NAM 4KM is way overdone even out that way. With no forcing, I am not sure how much we can expect.. simulated radar signatures anemic the further East you go.

0-1km speed shear will be what sets this one off so while forcing will be lacking, the air in the low levels will be circulating in horizontal tube fashion, so any convective updraft could turn one of these tubes vertical and produce a spin-up. I believe that is why the SPC has put out the enhanced risk. There will be significant speed shear over MS/AL/TN late tomorrow evening and that could produce a few violent twisters. I hate to see this type system so close to Christmas. Hopefully the chances die down over the next couple of model runs.

[max100]

This is from Dixie Alley Tornadoes on Facebook.

 

https://www.facebook.com/DixieAlleyTornadoes/photos/a.187127608290168.1073741828.187108644958731/208221622847433/?type=3&theater

 

[calculus1]

If you post anything about GA, AL and god forbid MS, it is generally ignored here.

 

Well, then try to spice it up a little bit.  Make it more interesting.  Interesting things aren't ignored.  Things that don't affect me are often ignored.  But not interesting things.  For instance, I doubt I would comment on the fact that traffic is rather horrible in Charlotte today.  That is rather boring, and it doesn't affect me.  However, if I were told that the traffic was horrible due to an army of elves that had commandeered all Charlotte Uber vehicles in an effort to meet Santa's deadline, that might elicit a response.  That is interesting.  And unusual.

[max100]

Well, then try to spice it up a little bit.  Make it more interesting.  Interesting things aren't ignored.  Things that don't affect me are often ignored.  But not interesting things.  For instance, I doubt I would comment on the fact that traffic is rather horrible in Charlotte today.  That is rather boring, and it doesn't affect me.  However, if I were told that the traffic was horrible due to an army of elves that had commandeered all Charlotte Uber vehicles in an effort to meet Santa's deadline, that might elicit a response.  That is interesting.  And unusual.

Well considering that most of your weather comes from these areas you should take note and be interested.   Case and point, the map I just posted has not elicited any interest so far??

[Brick Tamland]

Well considering that most of your weather comes from these areas you should take note and be interested.   Case and point, the map I just posted has not elicited any interest so far??

 

I'm from NC and I am interested in following this. We can't help that there are not many people here from AL and MS. Most people are not interested unless it's in their backyard. You want more people talking about, then more people from those states need to post here. That simple. Whining about it because a lot of posters in the SE are from the Carolinas isn't going to do anything.