October Discobs 2019

[North Balti Zen]

10 minutes ago, nw baltimore wx said:

1.78”

That checks out.

[adelphi_sky]

1.78” for the event. Nice rebound. What drought?!?


.

[MN Transplant]

79 at DCA.  DP near 70.  Soupy

[Kmlwx]

2 hours ago, yoda said:

@high risk @Kmlwx

Looks like one more chance Froday force severe storm... SPC day 4-8 disco mentions the chance

We'll see how it looks when we get to the midweek timeframe. GFS has the timing pretty bad right now. 

[WxUSAF]

80 at BWI

[CAPE]

40 minutes ago, WxUSAF said:

80 at BWI

Pretty gross out. Was outside blowing leaves and sweating. This storm did have tropical origins so I guess it's not that unusual, but it's late October man!

[H2O]

1.30" from that frontal passage yesterday.  Ground is soft again

[mappy]

2.25" yesterday. 

[high risk]

21 hours ago, yoda said:

@high risk @Kmlwx

Looks like one more chance Froday force severe storm... SPC day 4-8 disco mentions the chance

       it's definitely on the table, as the wind fields ahead of the fropa will be fantastic.    As with all of our fall systems, though, it's a question of instability.    Should be plenty warm and moist ahead of the front (Thursday night ?), but we may again deal with showers being too widespread to allow for any decent low level lapse rates. 

[Kmlwx]

23 hours ago, high risk said:

       it's definitely on the table, as the wind fields ahead of the fropa will be fantastic.    As with all of our fall systems, though, it's a question of instability.    Should be plenty warm and moist ahead of the front (Thursday night ?), but we may again deal with showers being too widespread to allow for any decent low level lapse rates. 

The timing looks pretty poor for now. 3km NAM and GFS seem to bring any sort of line in here at bad times in the diurnal cycle. I know this time of year the cycle matters a little less than it would in summer. But that doesn't bode well for having a peak of instability. Would like to see it either speed up to arrive Thursday afternoon - or slow down and nudge into the day on Friday. Shear looks excellent as you said. Assume we'll just get a pencil thin squall with no thunder/lightning with some gusty winds. Sub-severe would be my guess. 

[George BM]

7 minutes ago, Kmlwx said:

The timing looks pretty poor for now. 3km NAM and GFS seem to bring any sort of line in here at bad times in the diurnal cycle. I know this time of year the cycle matters a little less than it would in summer. But that doesn't bode well for having a peak of instability. Would like to see it either speed up to arrive Thursday afternoon - or slow down and nudge into the day on Friday. Shear looks excellent as you said. Assume we'll just get a pencil thin squall with no thunder/lightning with some gusty winds. Sub-severe would be my guess. 

Would be interesting to get the line through the region between 6 and 9pm. 

[Kmlwx]

7 minutes ago, George BM said:

Would be interesting to get the line through the region between 6 and 9pm. 

I think even with it coming in during peak heating it'll probably have very limited instability to work with. Ultimately it'll probably turn out very similar to the other day...tough for us to get anything of significance this late. 

November 16, 2006 had a 10% hatched tornado locally. It was exciting but not a whole lot happened. I remember rushing home from school. I think there was some isolated flooding. The reports from that day are very anemic on the SPC archive. 

ETA link for reference: https://www.spc.noaa.gov/exper/archive/event.php?date=20061116

 

[George BM]

4 minutes ago, Kmlwx said:

I think even with it coming in during peak heating it'll probably have very limited instability to work with. Ultimately it'll probably turn out very similar to the other day...tough for us to get anything of significance this late. 

November 16, 2006 had a 10% hatched tornado locally. It was exciting but not a whole lot happened. I remember rushing home from school. I think there was some isolated flooding. The reports from that day are very anemic on the SPC archive. 

ETA link for reference: https://www.spc.noaa.gov/exper/archive/event.php?date=20061116

 

I too remember that day. I just remember it raining heavily at times (with some lightning early in the afternoon) through about 3pm followed by skies rapidly clearing for late afternoon sunshine.

That day was certainly nothing compared to your favorite event two springs later on a June 4th afternoon. I wouldn't make it out of school to see that one though.

[high risk]

27 minutes ago, Kmlwx said:

The timing looks pretty poor for now. 3km NAM and GFS seem to bring any sort of line in here at bad times in the diurnal cycle. I know this time of year the cycle matters a little less than it would in summer. But that doesn't bode well for having a peak of instability. Would like to see it either speed up to arrive Thursday afternoon - or slow down and nudge into the day on Friday. Shear looks excellent as you said. Assume we'll just get a pencil thin squall with no thunder/lightning with some gusty winds. Sub-severe would be my guess. 

              I'm coming around a little on this event.     Timing looks to be very late evening, but even if it's a few hours later, with the clouds and strong warm advection, temps won't fall much at all after sunset.  (I'm seeing the NAM keep temps in the 70s until fropa.)     And a lot of the guidance (for now) shows a break in the rain for several hours ahead of the front, which would be awesome for trick or treaters and allow low-level lapse rates to steepen a bit, and some of the forecast soundings do suggest that any frontal band will be surface-based.     I think that a gusty line of intense showers is quite likely, with thunder and severe winds still a low threat but well above a zero threat.

[George BM]

Widespread severe winds from cold front forced "storms" are so rare at this time of the year unless we can get an October 2010-like bomb to bomb out further east through the Ohio Valley, Great Lakes, interior Northeast region. That worked out well from the Midwest into the Ohio Valley then. 

But of course you all probably know that. Just rambling. 

[Kmlwx]

21 minutes ago, George BM said:

I too remember that day. I just remember it raining heavily at times (with some lightning early in the afternoon) through about 3pm followed by skies rapidly clearing for late afternoon sunshine.

That day was certainly nothing compared to your favorite event two springs later on a June 4th afternoon. I wouldn't make it out of school to see that one though.

For as much crap as we all love to talk about DC failing at severe - we've had some pretty memorable days to track around the area - even if everyone didn't get hit. 9/24/2001, 4/28/2002, 6/4/2008, 6/29/2012 have all been truly special severe days around the DC area. There are some others as well. 

[yoda]

I assume you all saw SPC outlooked most of us on MRGL for Day 3

Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0220 AM CDT Tue Oct 29 2019

   Valid 311200Z - 011200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE UPPER
   OH VALLEY ACROSS THE CENTRAL APPALACHIANS AND VIRGINIA/CAROLINA
   PIEDMONT....

   ...SUMMARY...
   Isolated severe thunderstorms capable of strong wind gusts are
   possible from the Upper Ohio Valley across the central Appalachians
   and Virginia/Carolina Piedmont.

   ...Synopsis...
   A strong shortwave trough will extend from the Upper Midwest into
   northeast Mexico early Thursday. This shortwave is expected to
   quickly move northeastward into the Upper Great Lakes while
   maturing/deepening into a vertically stacked mid-latitude cyclone.
   By early Friday morning this mature system is expected to be
   centered over eastern Ontario/southern Quebec. Very strong
   southwesterly flow aloft will persist throughout the eastern
   periphery of the system spreading from the mid MS Valley through the
   TN and OH Valleys and into the Northeast during the period. 

   At the surface, a low initially over the middle OH Valley will
   quickly move northeastward while occluding. An attendant cold front
   will sweep eastward across the eastern CONUS, moving off the East
   Coast of the CONUS late Thursday night. Isolated to widely scattered
   thunderstorms are anticipated along and ahead of this front. 

   Given the very strong flow aloft and strong forcing for ascent, a
   narrow convective line capable of strong wind gusts is anticipated
   along the front from the Upper OH Valley across the central
   Appalachians and Virginia/Carolina Piedmont. Limited instability
   will preclude higher than 5%/Marginal probabilities for this
   outlook.

   ..Mosier.. 10/29/2019

[yoda]

LWX AFD also discusses the threat... saying that even with limited instability, chance for severe storms still there

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
The aforementioned high will move eastward into the Atlantic on
Wednesday, turning winds southerly as a cold front nears the Ohio
Valley. A digging upper trough will be kicking out of the Four
Corners Region at the same time, aiding in the genesis of surface
low pressure over the Lower Mississippi Valley. As these features
congeal and press eastward Wednesday and Wednesday night, we`ll see
moisture increase significantly across the Mid-Atlantic.
Precipitable water values Wednesday morning will start out less than
an inch, then surging throughout the day and ranging between 1.50-
1.75" by Wednesday evening. As a result, we`ll see showers increase
mid-morning Wednesday over the lower Shenandoah Valley and central
Virginia, increasing in coverage as they progress northeastward
through Wednesday night.

On Thursday, the frontal boundary will remain to our west over the
Ohio Valley, with continued shower activity. As low pressure rides
along this boundary and lifts northward through the TN/OH Valleys,
we`ll see a tightening of the pressure gradient, and an increase
in southerly breezes. The primary upper trough swings eastward
Thursday night as the surface low tracks into the Great Lakes
and the cold front pushes into our area. As a result, winds at
the surface and aloft will increase markedly, as well as rain
coverage and intensity as the cold front pushes through the area
into early Friday morning. Higher elevations will near Wind
Advisory criteria as a result, with windy conditions expected
elsewhere.

With a favorable position (right entrance) of the upper jet overhead
as the front progresses through the region Thursday evening and
Thursday night, coupled with the strong low to mid level winds, the
potential for strong to severe storms will exist as well.
Instability will be limited given the time of day, but with all
other main players in place, it won`t take much. Damaging wind gusts
would be the primary threat with a linear convective mode favored
with the forcing along the front. Latest timing with the front could
impact the early Friday morning commute before activity pushes off
to the east.

[mattie g]

1 hour ago, George BM said:

Would be interesting to get the line through the region between 6 and 9pm. 

That would suck. I want to enjoy Halloween with the kids!

[high risk]

3 minutes ago, mattie g said:

That would suck. I want to enjoy Halloween with the kids!

          Right now, a lot of guidance does show a warm, windy, and dry period for trick-or-treating.

 

[high risk]

17 minutes ago, yoda said:

LWX AFD also discusses the threat... saying that even with limited instability, chance for severe storms still there

 

 

             as I wrote a few posts back, I think this one has more potential than other similar-ish setups (although I'm certainly not "in" yet).

[Sparky]

49 minutes ago, Kmlwx said:

For as much crap as we all love to talk about DC failing at severe - we've had some pretty memorable days to track around the area - even if everyone didn't get hit. 9/24/2001, 4/28/2002, 6/4/2008, 6/29/2012 have all been truly special severe days around the DC area. There are some others as well. 

6/1/12 - the day of the tornadoes.  It was a scary day for me with a relatively close call near my neighborhood with an EF1 tornado followed by a couple more menacing cells that day which threatened dropping one.

[Kmlwx]

28 minutes ago, Sparky said:

6/1/12 - the day of the tornadoes.  It was a scary day for me with a relatively close call near my neighborhood with an EF1 tornado followed by a couple more menacing cells that day which threatened dropping one.

I think there was also a day (was it that one?) that had tornado watches for all or part of the area for like 24 straight hours or something. And I think a day in June 2013 that had a long track EF-0 tornado in MoCo. 

[George BM]

2 minutes ago, Kmlwx said:

I think there was also a day (was it that one?) that had tornado watches for all or part of the area for like 24 straight hours or something. And I think a day in June 2013 that had a long track EF-0 tornado in MoCo. 

Probably April 27-28, 2011.

[high risk]

19 minutes ago, George BM said:

Probably April 27-28, 2011.

            Yes, while the deep south was getting destroyed, we did indeed have close to 24 consecutive hours of tornado watches here which is just remarkable.    There were a few low end tornadoes in the local area during the afternoon and evening, and there was a long-track EF2 in the Shenandoah Valley after midnight.

 

[yoda]

30 minutes ago, high risk said:

            Yes, while the deep south was getting destroyed, we did indeed have close to 24 consecutive hours of tornado watches here which is just remarkable.    There were a few low end tornadoes in the local area during the afternoon and evening, and there was a long-track EF2 in the Shenandoah Valley after midnight.

 

For reference -- https://www.weather.gov/lwx/events_2011042728

That tornado was during the 2-3AM time period and tracked 33 miles... probably one of the longest continuous tornado in the LWX CWA

[Kmlwx]

3k NAM gets MLCAPE to 500+ into the area. Not bad. 

[Rhino16]

Who else is excited for Daylight Saving time to end so we won’t have to wait forever for a new model run to finish? They will be mostly done by the time I crawl out of bed.

[poolz1]

Dews pushing 70 just ahead of the front Thursday. Hoping we get trick or treating in before the line of storms push in. Looks nasty...

[yoda]

3 hours ago, Rhino16 said:

Who else is excited for Daylight Saving time to end so we won’t have to wait forever for a new model run to finish? They will be mostly done by the time I crawl out of bed.

Me lol