2013 Mid-Atlantic Severe General Discussion

[mappy]

meh, back to clouds

[H2O]

 

One thing I noted is how fast the clouds are moving from south to north. Strong flow!

morning disco talked about how windy it was going to be with such a strong gradient.

[Ellinwood]

One thing I noted is how fast the clouds are moving from south to north. Strong flow!

50 kt. jet at 1km AGL... pretty swift.

[Ellinwood]

Hi-res models are in good agreement with timing of the main line. Mixed bag as to how much pre-frontal convection there is.

The 9z run of the HRRR for 8pm today:

Before 00z the line looks more ragged but still has its act together by the time it reaches Leesburg.

[thunderman]

NSSL-WRF has a nice line as well.

[Kmlwx]

Timing on these lines always seems to be a few hours earlier than the models prog - wouldn't be surprised to see earlier timing.

[yoda]

Timing on these lines always seems to be a few hours earlier than the models prog - wouldn't be surprised to see earlier timing.

 

21z to 01z seems like the best time period for anything svr for us today

[Ellinwood]

Timing on these lines always seems to be a few hours earlier than the models prog - wouldn't be surprised to see earlier timing.

When that happens the timing is usually from the day before runs. I like to analyze them on a case-by-case basis matching up the current radar to the simulated reflectivity. The HRRR I showed has a decent/good grasp on where the rain is now (EDIT: if not a little faster than reality), so I think the timing of it is fairly solid. I always give anything 6+ hours out a +/- 1 hour buffer zone, anyway.

[yoda]

12z NAM sim radar has what looks to be a squall line/QLCS moving through btwn 7 and 9 pm

[thunderman]

Timing on these lines always seems to be a few hours earlier than the models prog - wouldn't be surprised to see earlier timing.

 ehh current guidance isn't doing that bad.  Looks like it has a good handle on things.

[Eskimo Joe]

Would be nice to get a 2 - 4 hour window of sun.

[H2O]

 

Would be nice to get a 2 - 4 hour window of sun.

good luck with that. satellite is cloud heavy

[Eskimo Joe]

 

good luck with that. satellite is cloud heavy

Don't ruin my day please.  

[Kmlwx]

Don't ruin my day please.

He will rain on our parade

[yoda]

21z at DCA per 12z NAM sounding is decent... instability is meh though

Though 00z its around 1000 SBCAPE and MLCAPE

[Ian]

Spc been over warning all week why stop now

[yoda]

Spc been over warning all week why stop now

 

Tornado Watch by 3?

[thunderman]

PDS Tornado Watch by 3?

fixed

[Kmlwx]

09z SREF over at the SPC site is lol - 

Mean supercell composite of 12 comes close to DC, sigtor pockets of two on the mean popping up too - good tornado ingredients too - not that it means much

[yoda]

LWX mentions tor risk in latest AFD as of 11 am

IN TERMS OF SEVERE THUNDERSTORM THREAT...12Z KIAD INDICATED A CAP
AROUND 700MB. HOWEVER...MODEL SOUNDINGS INDICATE THIS LAYER WILL
COOL BY A FEW DEGREES THIS AFTERNOON...WHILE DIURNAL SURFACE
HEATING CONTINUES. BIG VARIABLE WILL CONTINUE TO BE CLOUD COVER
AND ITS INFLUENCE ON INSTABILITY. FORECAST SOUNDINGS INDICATE
POTENTIAL FOR SOME BREAKS IN CLOUD COVER...AND THESE ARE BEING
OBSERVED IN PARTS OF WV AT THIS HOUR. THIS WOULD ENABLE CAPE TO
APPROACH 1000 J/KG OVER SOME LOCATIONS AT LEAST BRIEFLY. OTHERWISE
FORECAST IN ON TRACK FOR INCREASING MOISTURE DUE TO SOUTHERLY
FLOW AND A VERY STRONG JET OVER THE AREA WITH 50+KT WINDS ABOVE
850MB AHEAD OF THE FRONT. SPC HAS INCREASED SLIGHT RISK AREA TO
INCLUDE ALL OF THE FORECAST AREA FROM THE SHENANDOAH VALLEY
EWD...AND HI-RES MODELS LIKE THE HRRR INDICATE THE POTENTIAL FOR
AN ORGANIZED LINE OF SHOWERS/TSTMS TO DEVELOP AS THE FRONT
APPROACHES THIS AFTERNOON. ANY THUNDERSTORMS WILL HAVE POTENTIAL
TO TAP INTO THE STRONG WINDS ALOFT AND PRODUCE DAMAGING WINDS.
HODOGRAPHS ALSO INDICATE SOME POTENTIAL TORNADO RISK...ESPECIALLY
IF EMBEDDED SUPERCELLS DEVELOP WITH THE LINE OF THUNDERSTORMS.

[WinterWxLuvr]

You guys expecting a good line of storms?  Radar seems to be petering out.  What's the thinking on storms and rainfall this afternoon?

[Ian]

spinny showers.

[mappy]

spinny showers.

 

better or worse than globby flakes?

[MN Transplant]

About 45 seconds of sunshine.

[Kmlwx]

About 45 seconds of sunshine.

That was probably enough to buy you 2-3 extra units of CAPE

[Eskimo Joe]

This wet pattern is doing wonders for my garden.  Will be turning the soil over one time more this weekend, then in go the spring crops!

[Subtropics]

Anyone worried about long track violents tonight?

[Kmlwx]

Anyone worried about long track violents tonight?

 

Can't tell if serious lol

[snowfan]

Anyone worried about long track violents tonight?

lolz wut? long track violent farts, maybe??? Taco Friday will do that.

[thunderman]

Anyone worried about long track violents tonight?

 

yes ... could be several long track showers