Severe storms 2015 general chatter

[Kmlwx]

Yoda, gotta remember that there is such a thing as shear that is TOO strong for not enough instability. Not saying that is or is not the case here but updrafts can get torn apart in low CAPE high shear environments. 

We'll probably fail because of a plethora of other reasons anyway. 

[yoda]

Yoda, gotta remember that there is such a thing as shear that is TOO strong for not enough instability. Not saying that is or is not the case here but updrafts can get torn apart in low CAPE high shear environments. 

We'll probably fail because of a plethora of other reasons anyway. 

 

True, but last time didn't we have like 70 kts bulk shear?

 

50 kts sounds like a good number

[high risk]

      absolutely true that diurnal heating in December has little influence.    I figured that someone would make the "wrong time of day" argument and tried to dismiss it but didn't really do a very good job of explaining myself.

 

Does time of day really matter on Dec 24th when we really aren't counting on the sun to destabilize? 

[Eskimo Joe]

Would be funny to see this MOD Risk and PDS watch bust hard out west.  Seems like a lot of shear and crapvection.

[MN Transplant]

Hey, we got Marginal from SPC.  Woo.

[yoda]

Would be funny to see this MOD Risk and PDS watch bust hard out west.  Seems like a lot of shear and crapvection.

 

Whoops

[yoda]

Yes, that is a 30 by EZF

 

[yoda]

00z NAM sounding at KIAD for 15z THUR:

 

 

[yoda]

[yoda]

[Sparky]

So what time does the big squall line hit?  After sunrise, before noon?

[yoda]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
950 PM EST WED DEC 23 2015

.SYNOPSIS...
A WARM FRONT IS PUSHING NORTH THROUGH THE REGION. A COLD FRONT
WILL MOVE INTO THE AREA EARLY FRIDAY AND REMAIN NEARBY THROUGH THE
WEEKEND.

&&

.NEAR TERM /THROUGH THURSDAY/...
AS OF 9PM...FIRST ROUND OF RAIN IS THROUGH. LINES OF HEAVY
SHOWERS AND ISOLATED THUNDERSTORMS MOVED THROUGH THE DC/BALT METRO
THEN DISCRETE SUPERCELLS (ELEVATED MESOCYCLONES) CROSSED SRN MD.
LOW PRESSURE IS OVER WI WITH THE MID-ATLANTIC FIRMLY IN THE WARM
SECTOR THROUGH THURSDAY.

NEXT LINE OF ACTIVITY IS AHEAD OF THE COLD FRONT AND MOVING EAST
THROUGH OHIO. HRRR HAS THIS ACTIVITY WANING BEFORE IT REACHES THE
ALLEGHENY HIGHLANDS (CURRENTLY ON TRACK FOR AROUND MIDNIGHT). WILL
NEED TO KEEP EYES ON THIS ACTIVITY THAT IS STILL GOING STRONG FOR
NOW.

MILD WITH LOW CLOUDS/FOG REFORMING OVER THE AREA IS THE STORY FOR
TONIGHT. MIN TEMPS MAY WELL HAVE BEEN REACHED IN THE MOST RECENT
RAIN. TEMPERATURES SHOULD EITHER HOLD STEADY OR SLOWLY INCREASE
REST OF THE NIGHT IN SLY FLOW 5-10MPH.

TEMPS THURSDAY HAVE BEEN THE TOPIC OF MUCH DISCUSSION GIVEN THEIR
EXPECTED EXCEEDENCE OF DAILY AND POSSIBLE MONTHLY MAX AND HI MIN
RECORDS. IN FACT...TEMPERATURES THIS EVENING ARE APPROACHING THE
MAX TEMPS FOR THURSDAY (SEE CLIMATE SECTION BELOW). GIVEN CLOUD
COVER/ADVECTION FOG...LOW CONFIDENCE IN VALUES...WENT WITH A BLEND
OF GMOS/MAV/MET/ SUPERBLEND WHICH GIVES LOW TO MID 70S. IT WOULD
BE EVEN HIGHER IF IT WERE SUNNY.

MARGINAL RISK FOR SEVERE WEATHER STILL ACROSS THE CWA WITH THE
PREFRONTAL ACTIVITY CURRENTLY OVER OHIO EXPECTED TO REDEVELOP
THROUGH THE MORNING ACROSS THE WRN PORTION OF THE CWA...THEN
PROGRESS EAST. HOWEVER...AS WITH MOST MESOSCALE DRIVEN
ACTIVITY...THERE IS LOW CONFIDENCE/COULD BE A SLOW BIAS TO
PROGRESS. IT MAY END UP BEING A RAINY DAY FOR PARTS OF THE AREA.
HIGH SHEAR/HELICITY VALUES AGAIN TOMORROW...SO A DAMAGING
WIND/ISOLATED TORNADO THREAT EXISTS.

[yoda]

[yoda]

LWX's local model ARW4N suggests (the 03z one) we get rocked all afternoon with its simulated reflectivity

[yoda]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
423 AM EST THU DEC 24 2015

.SYNOPSIS...
A COLD FRONT MOVES INTO THE REGION TODAY...REMAINING IN THE
VICINITY THROUGH THE WEEKEND AND INTO NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
A COLD FRONT APPROACHES FROM THE WEST TODAY...RESULTING IN
MULTIPLE CONCERNS FOR THE CWA. THE FIRST CONCERN IS THE INCREASED
RISK FOR SVR WX TODAY...MAINLY WINDS AND PSBL ISO TORNADO. COLD
FRONT NOTED AS OF 08Z BACK OVER WESTERN OH...WITH SCT SHOWERS OUT
AHEAD OF THE BOUNDARY. A COUPLE FACTORS WILL AID IN THIS ACTIVITY
STRENGTHENING AGAIN AS IT NEARS THE MID- ATLANTIC. MID LVL
SHORTWAVE WILL PROVIDE SOME FORCING AS IT SWINGS THRU THE AREA AND
TO THE NE TODAY. LATEST VAD PROFILES INDICATING 50KTS AT 2KFT...SO
LLJ IS IN PLACE...ALIGNED WITH THE APPALACHIANS AND IS EXPECTED AS
SUCH THRU AT LEAST THIS MORNING. A VERY MOIST AIRMASS IN PLACE
AFTR THE PASSAGE OF THE WARM FRONT YESTERDAY...WITH RECORD
BREAKING PWATS BEING OBSERVED ON THE 00Z SOUNDING. DEW PTS STILL
SHOWING IN THE 60S...AND WITH SLY FLOW KEEPING THE WAA IN
PLAY...EXPECTING TO SEE A FEW HUNDRED J/KG OF CAPE TODAY. THE
COMBINATION OF THE AFOREMENTIONED FACTORS WILL PLAY INTO A
MARGINAL RISK FOR SVR WX AS THE LINE OF STORMS TREK INTO THE CWA
AFTR DAYBREAK. WITH SOUNDINGS SHOWING THE LONG...SKINNY CAPE
SIGNATURE...NOT ANTICIPATING LONG LIVED SVR TSTMS AND AGAIN
DAMAGING WINDS BEING THE MAIN THREAT. WITH HIGH HELICITY VALUES
WITH INCRSD SLY WINDS AT THE SFC AND WSW WINDS ALOFT...CANNOT RULE
OUT THE POTENTIAL FOR A SHORT LIVED TORNADO EITHER. THE SVR THREAT
WILL DIMINISH TONIGHT.