Severe storms 2015 general chatter

[Disc]

What does that show?  I have never seen that before -- as in I know its a sounding... but what is SHARPpy?

Sounding Hodograph Analysis and Research Program for Python. You can plot real-time soundings as well as forecast soundings for various models. Everything is written in Python and ran through the Anaconda command prompt.

[yoda]

SPC Day 1 disco is out

 

 

 

DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1150 PM CDT SUN APR 19 2015
                                                                                                                                                                                                                                           ...PORTIONS OF THE MID-ATLANTIC TO THE FL PENINSULA...
   THE OVERALL SYNOPTIC-SCALE PATTERN IS NOT FORECAST TO BE CONDUCIVE
   FOR DEFINITIVE SPATIOTEMPORAL OVERLAP OF DEEP ASCENT WITH STRONG
   MOISTURE RETURN/BUOYANCY...IN RESPONSE TO /1/ THE GROWING GAP
   BETWEEN THE NWD-TRACKING OCCLUDED CYCLONE CENTER AND RICHER
   TROPOSPHERIC MOISTURE RELEGATED TO THE SERN CONUS...AS WELL AS
   /2/ THE PARENT MID-LEVEL CYCLONIC PERTURBATION BECOMING CLOSED.

   REGARDLESS...STRENGTHENING MID-LEVEL WLYS ACROSS THE SERN STATES
   WILL ENCOURAGE EWD ADVECTION OF AN EML PLUME SAMPLED BY SUNDAY
   EVENING RAOBS OVER THE SRN GREAT PLAINS...INTO PARTS OF THE SE
   CONUS/CAROLINAS. RELATED STEEP MID-LEVEL LAPSE RATES WILL OVERLIE
   UPPER 50S TO LOWER 60S SFC DEWPOINTS AHEAD OF THE FRONT. THIS SHOULD
   SUPPORT MLCAPE AROUND 1000-2000 J/KG BY PEAK HEATING WITH LITTLE
   MLCINH ACROSS THE SLIGHT-RISK AREA. THIS IS WHERE A DIURNAL INCREASE
   IN CONVECTIVE COVERAGE AND INTENSITY IS EXPECTED AMIDST MODEST
   FRONTAL CONVERGENCE AND TERRAIN-ENHANCED CIRCULATIONS.
   LONG...STRAIGHT LINE HODOGRAPHS MAY SUPPORT SPLITTING SUPERCELL
   STRUCTURES INITIALLY...THOUGH AREAS OF LOCALIZED UPSCALE CONVECTIVE
   GROWTH INTO SEMI-ORGANIZED CONVECTIVE CLUSTERS ARE ANTICIPATED IN
   THE LOW-MLCINH ENVIRONMENT. ISOLATED TO SCATTERED SVR WIND/HAIL WILL
   BE LIKELY.

   MID-LEVEL HEIGHT FALLS WILL BE SOMEWHAT MORE PRONOUNCED ACROSS PARTS
   OF THE MID-ATLANTIC...AND SOMEWHAT GREATER SVR COVERAGE MAY OCCUR IN
   THIS REGION. THIS COULD WARRANT UPGRADE TO ENHANCED DESIGNATION IN
   SUBSEQUENT OUTLOOKS...AND A FEW ISOLATED INSTANCES OF SIGNIFICANT
   SVR HAIL ALSO CANNOT BE RULED OUT. HOWEVER...SUBSTANTIAL MID-LEVEL
   DRYING IN THE WAKE OF A LEAD DISTURBANCE PRESENTLY MOVING OVERHEAD
   PER WATER VAPOR IMAGERY...AND THE PRESENCE OF ONLY MODEST DEEP
   ASCENT OVER THE WARM SECTOR DURING PEAK HEATING...CAST TOO MUCH
   DOUBT ON THE IDENTIFICATION OF CORRIDORS OF ENHANCED AND/OR
   SIGNIFICANT SVR POTENTIAL. ALSO...ONE OR TWO SHORT-LIVED TORNADOES
   CANNOT BE RULED OUT ACROSS THE SLIGHT-RISK AREA GIVEN ENHANCED
   LOW-LEVEL SHEAR BENEATH A LLJ. HOWEVER...THE OVERALL TENDENCY FOR
   SFC WINDS TO VEER THUS LIMITING 0-1-KM SRH ACROSS THE WARM SECTOR
   RENDERS MARGINAL TORNADO PROBABILITIES FOR THIS OUTLOOK. RELATIVELY
   MORE BACKED SFC WINDS MAY BE FOUND FROM PARTS OF MD/DC INTO
   CNTRL/ERN PA AT THE NRN EDGE OF THE WARM SECTOR/WARM FRONT...WHERE
   SOMEWHAT GREATER TORNADO POTENTIAL MAY EXIST. HOWEVER...DIURNAL
   GAINS IN BUOYANCY COULD BE STUNTED BY RESIDUAL CLOUDS RELATED TO THE
   LEAD DISTURBANCE...ONCE AGAIN RENDERING ONLY MARGINAL PROBABILITIES
   FOR TORNADO POTENTIAL. CONVECTION WILL BEGIN WEAKENING BY EVENING AS
   IT NEARS/MOVES OFF THE ATLANTIC COAST.

[southmdwatcher]

That sounds like a pretty decent severe day for our area. and that is without the upgrade to enhanced that is pretty likely. HRRR is showing scattered areas of 2000 CAPE in the DC area on the 4z run at 3pm tomorrow. the SFC low is down to 978 mb over Lake Superior

[yoda]

03z SREFs a lil more robust and intriguing:

 

 

[yoda]

06z NAM gets around 2000 SBCAPE into IAD/DCA by 18z

[yoda]

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC

400 AM EDT MON APR 20 2015

.SYNOPSIS...

A WARM FRONT EXTENDING FROM LOW PRESSURE IN THE GREAT LAKES WILL

LIFT NORTH THIS MORNING. A COLD FRONT WILL PUSH EAST ACROSS THE

REGION LATE MONDAY. AN UPPER LOW WILL THEN PERSIST ACROSS THE

GREAT LAKES TO NEW ENGLAND THROUGHOUT THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...

EARLY THIS MORNING...PRIMARY SFC LOW IS CENTERED OVER MI...WITH

ANOTHER WAVE OF LOW PRESSURE OVER CENTRAL VA. LLJ/UPPER JET STREAK

INDUCED MDT/HVY RAINFALL IS PIVOTING NE...WITH DRYING NOTED IN WV

IMAGERY. MOST OF THE HEAVIER RAINFALL WILL LIKELY EXIT TO THE NE BY

AROUND 8 AM IF NOT SOONER. HAVE CANCELLED THE FLOOD WATCH WHERE

HEAVY RAIN ENDED...AND WILL FOLLOW SUIT AS SOON AS THE REST EXITS.

A FEW LIGHTER SHOWERS MAY LINGER.

A WARM FRONT LOCATED OVER CENTRAL VA EARLY THIS MORNING WILL QUICKLY

LIFT TO THE NORTH...LEADING TO A RELATIVE DRY BREAK INTO THE MIDDAY

HOURS. HOW THE ATMOSPHERE IS ABLE TO RECOVER WILL DETERMINE SVR WX

CHANCES LATER TODAY. MAY TAKE LLVL CLOUDS A BIT TO SCOUR OUT...THEN

QUESTION BECOMES HOW MUCH MID/HIGH LEVEL DEBRIS CLOUD PERSISTS.

MODEL CONSENSUS IS FOR HIGHS IN THE 70S...ALTHOUGH READINGS WILL

SOAR IF PROLONGED SUN DEVELOPS.

SHOWERS/STORMS WILL LIKELY INITIATE ALONG A PRE-FRONTAL

TROUGH...AIDED BY TERRAIN...DURING THE EARLY AFTERNOON HOURS. THESE

STORMS WILL PROPAGATE EASTWARD THROUGH LATE AFTERNOON/EARLY

EVENING. COVERAGE IS SOMEWHAT IN QUESTION...BUT SCATTERED-NUMEROUS

SEEMS PLAUSIBLE. CONSISTENT INDICATIONS OF AROUND 1000 J/KG INSTBY

AND 30 KT BULK SHEAR WILL LEAD TO THE POTENTIAL FOR ORGANIZED

STORMS. THERE MAY BE SOME DISCRETE CELLS INITIALLY...EVENTUALLY

MORPHING INTO LINE SEGMENTS. PRIMARY THREAT WILL BE DMGG

WINDS...ALTHOUGH STEEP MID LVL LAPSE RATES WILL BRING THE

POTENTIAL OF LARGE HAIL TOO. WHILE HODOGRAPHS NOT OVERLY

IMPRESSIVE...THERE IS SOME LLVL VEERING AND A VERY SMALL CHANCE OF

A TORNADO FROM ANY STRONG DISCRETE CELLS. AT THIS TIME...NO AREA

OF THE CWA IS PARTICULARLY FAVORED...ALTHOUGH PARAMETERS MAY BE

SLIGHTLY BETTER EAST OF THE MOUNTAINS.

[AvantHiatus]

Pretty sick rain rates with the warm front and a huge chunk of the warm sector is cloud-free. This will be a nice event.

[yoda]

"Some thunderstorms may be severe" is in all of the ZFP's...

[StudentOfClimatology]

http://www.ssec.wisc.edu/data/us_comp/us_comp.html

[snowfan]

12Z NAM fire wx nest will be run over the area, fwiw. 

[weatherCCB]

Sun should be out soon. This has some real potential

D.P on the rise also. Could be an exciting afternoon & evening.

[Kmlwx]

Very cloudy here still. Let's see how much sun we can get. 

[yoda]

[yoda]

..UPPER OH VALLEY AND PA  
CENTRAL APPALACHIANS EWD TO COASTAL  
CAROLINAS/MID ATLC...  
WIDELY SCATTERED TO SCATTERED TSTMS SHOULD DEVELOP THIS AFTN INVOF  
PREFRONTAL AND NEARLY FRONT-PARALLEL SFC TROUGH...WITH MORE ISOLATED  
DEVELOPMENT ELSEWHERE OVER WARM SECTOR.  SOME OF THIS ACTIVITY WILL  
BECOME SVR WITH LARGE HAIL...DAMAGING GUSTS AND A TORNADO OR TWO  
POSSIBLE.  
 
MIDLEVEL HEIGHT FALLS WILL OCCUR OVER THIS REGION AS PRIMARY VORTEX  
ALOFT SHIFTS IN THIS DIRECTION...WHILE SMALL PERTURBATIONS TRAVERSE  
ASSOCIATED SWLY FLOW ALOFT.  SOME CONCERNS LINGER ABOUT SPEED AT  
WHICH AIR MASS ACROSS PA/MID ATLC CAN DESTABILIZE AND RECOVER DUE TO  
LOW-LEVEL THETAE ADVECTION FOLLOWING EARLY-MORNING RAINFALL.   
HOWEVER...IR/VIS IMAGERY SHOWS POTENTIAL FOR SOME LOW-CLOUD BREAKUP  
AND SFC DIABATIC HEATING OVER THIS REGION AHEAD OF POTENTIAL AFTN  
CONVECTIVE ARC...IN ADDITION TO ADVECTION OF MIDLEVEL AIR CONTAINING  
STEEPER LAPSE RATES ACROSS THIS REGION.  SFC DEW POINTS SHOULD RISE  
BACK INTO 50S ACROSS MOST OF PRECONVECTIVE PA AND 60S FARTHER S.   
NET RESULT SHOULD BE GENERATION OF PLUME OF 1000-2000 J/KG  
MLCAPE...WITH FURTHER SUPPORT FROM MINIMAL MLCINH.  MIXED CONVECTIVE  
MODES ARE LIKELY...WITH 35-40 KT EFFECTIVE-SHEAR MAGNITUDES AND  
CURVED LOW-LEVEL HODOGRAPHS INDICATING POTENTIAL FOR A FEW  
SUPERCELLS AND BOWS AMIDST MULTICELL CLUSTERS AND BANDS.  AS  
SUCH...SVR THREAT IS MULTI-MODAL AS WELL.  
 
CONDITIONAL TORNADO RISK IS GREATER NEAR WARM FRONT WHERE SFC WINDS  
WILL BE MOST BACKED AND LOW-LEVEL VORTICITY IS RICHEST.  INSTABILITY  
TRENDS MAY LEAD TO UPGRADE IN UNCONDITIONAL PROBABILITIES LATER  
TODAY.  ATTM...THERE REMAINS TOO MUCH UNCERTAINTY REGARDING  
DESTABILIZATION IN WAKE OF MORNING RAIN...AND ALSO REGARDING  
STRENGTH OF LOWEST-1-KM FLOW TO ENLARGE ALREADY CURVED HODOGRAPHS  
AND BOOST SRH. 

[yoda]

Wow.... 30 hail and 30 wind too.... SPC going all in

[Kmlwx]

30% for hail too! That's pretty unusual around here. 

[Kmlwx]

Wow.... 30 hail and 30 wind too.... SPC going all in

 

Hatched hail at 1630z or GO HOME. 

[yoda]

Hatched hail at 1630z or GO HOME. 

 

I dunno about a mod risk... I don't think we will reach that criteria

[Ian]

Hail wedges

[Eskimo Joe]

Listening to the OEM brief and LWX downplays everything while SPC just upgraded us, lol.

[Ian]

Problem with enh is it used to be slight. Now everyone gets excited.

[yoda]

Problem with enh is it used to be slight. Now everyone gets excited.

 

ENH is like SLGT+

[Kmlwx]

Problem with enh is it used to be slight. Now everyone gets excited.

 

To be fair - Yoda and I probably would have been excited by any 30% even before the outlook change. Weenies fo' life. 

[Scuddz]

Disasterous forecast weekend for me.  Blew the nice morning/mid-day yesterday turned out to be and downplayed the severe threat for today only to have everything start trending better with a nice clearing heading our way.

[yoda]

[Bob Chill]

I'm hoping to get a foot of wind with blowing hail.

[Disc]

I get a bit bullish when these setups happen, but then I have to remind myself that we live in the Mid-Atlantic.

[snowfan]

Can't remember the last time I saw bigger than dime sized hail in this area. I think my car would appreciate it staying that way, but.....

[snowfan]

Already hitting 70 in spots s/sw of DC. Low 80s where it clears first??

[Kmlwx]

Can't remember the last time I saw bigger than dime sized hail in this area. I think my car would appreciate it staying that way, but.....

I have seen pea sized hail probably 3 times and something a bit smaller than dime once. Hail is like a unicorn for me. As I mentioned in this thread yesterday though...probably bodes well for hail for me at least since they just finished putting on our new roof.