2022 Mid-Atlantic Severe Wx Thread (General Discussion Etc)

[aldie 22]

I'm willing to take the hit for you eastern guys

[southmdwatcher]

3 to 5 inch plus jackpots along Sligo Creek and the Little Patuxent River would be problematic

[Eskimo Joe]

8 minutes ago, southmdwatcher said:

3 to 5 inch plus jackpots along Sligo Creek and the Little Patuxent River would be problematic

Sligo Creek flashes quickly, but it also goes down fast. The USGS gauge in Takoma Park shows we're down to baseline.

[yoda]

 

 

[osfan24]

It's the NAM, but it is an absolute beatdown along 95.

[Eskimo Joe]

12 minutes ago, osfan24 said:

It's the NAM, but it is an absolute beatdown along 95.

NAM NEST is....problematic. Has several 6 - 8 jackpots in the NW suburbs of Baltimore and DC.

[Kmlwx]

That would be ugly for Ellicott City....

[mappy]

3 minutes ago, Kmlwx said:

That would be ugly for Ellicott City....

No kidding, 6-9" in that area per 06z NAM 

[Kmlwx]

4 minutes ago, mappy said:

No kidding, 6-9" in that area per 06z NAM 

Wonder how their new drainage system would hold up

[Eskimo Joe]

7 minutes ago, Kmlwx said:

Wonder how their new drainage system would hold up

With all the new development NW of Historic EC, I don't think it's going to do much.

[mappy]

WxUSAF gets back from Hawaii to deal with flooding 

[WxUSAF]

Just now, mappy said:

WxUSAF gets back from Hawaii to deal with flooding 

Drought delayed but not denied??

[mappy]

8 minutes ago, WxUSAF said:

Drought delayed but not denied??

Unless you are @mattie g

[osfan24]

Latest NAM looks much better for CMD but still pretty bad for DC area. Seems to come through a bit earlier and quicker.

[Eskimo Joe]

22 minutes ago, osfan24 said:

Latest NAM looks much better for CMD but still pretty bad for DC area. Seems to come through a bit earlier and quicker.

@WxUSAFreturns and the rain runs away.

[yoda]

12z NAM NEST still drops 3 to 5 in DC metro into S MD 

[yoda]

7 minutes ago, Eskimo Joe said:

@WxUSAFreturns and the rain runs away.

 

[yoda]

12z FV3 Hi-Res is for DC metro

[yoda]

3 minutes ago, yoda said:

12z FV3 Hi-Res is for DC metro

 

[yoda]

Closer view 

[yoda]

Morning AFD update from LWX as of 1035am

NEAR TERM /THROUGH SATURDAY/...
Latest surface analysis show a quasi-stationary front stalled
near the VA/NC border with a cold front draped across the Great
Lakes. The stationary front will gradually lift north through
the day and into tonight and eventually interact/collide with
the approaching cold front.

Through the early afternoon, the local region is going to be
positioned between two shortwaves with subsidence. Guidance
continues to suggest showers and thunderstorms develop on the
lee-side pressure trough late this afternoon as a weak shortwave
moves through. These showers/thunderstorms then slowly advance
to the northeast, posing an isolated flood/flash flood threat
for any storms that train over the same area. Uncertainty in
coverage and placement of the lee-pressure trough and therefore
the thunderstorm placement is somewhat uncertain. Current
thinking is anywhere from the Shenandoah Valley to east of the
Blue Ridge. Any thunderstorm is capable of producing gusty
winds.

As the aforementioned frontal boundaries begin to merge nearby,
a line of convergence will develop overnight. A stronger
shortwave with low-level to surface based broad low pressure
will move over the frontal boundary this evening into the
overnight. This low will continue advancing along the front
through Saturday. PWs will be near record levels for the day,
with widespread 2-2.5" values (2-3 SA above climo). The WCL will
be high (above 4 km), with a high FZL indicating warm rain
processes will be dominant. Given the forecast low-level
forcing, the PWs in guidance seem realistic. There are two
variables leading to some uncertainty: 1) The amount of
instability (generally 100-750 J/kg) and 2) The spread in models
with where exacting the positioning of the front will be and
the amount of low-level and fgen forcing present with the low as
it moves nearby. Should the higher magnitudes of forcing be
realized, a higher-impact heavy rain event would be plausible,
however should the lower magnitudes of forcing come to fruition,
this may be more of a beneficial light to moderate soaking
rain.

The area of greatest concern remains over the largely
hydrophobic Baltimore/Washington Metro areas. FFG is lowest in
this area. Will continue to assess latest 12Z guidance before
making any headline considerations.

[Eskimo Joe]

11 minutes ago, yoda said:

12z FV3 Hi-Res is for DC metro

Yea that's a big yikes.

[Eskimo Joe]

Seems the meso guidance pushing PWATS close to 3", while the globals only around 2". Wonder if that's a resolution issue, or if the short term guidance is keying in on something the globals might be missing out on.

[AmericanWxFreak]

Seems like we’re just seeing this precip max just waffle around. Someone’s going to get some trouble tonight it’s just a matter of where. 

[MN Transplant]

HRRR is not enthused yet, but give it time.

[Eskimo Joe]

8 minutes ago, AmericanWxFreak said:

Seems like we’re just seeing this precip max just waffle around. Someone’s going to get some trouble tonight it’s just a matter of where. 

That's typical. QPF forecasting for systems that have several mesoscale features will waffle around. Only thing I've noticed over the years is that we see the axis of heavy rain wind up a bit further north and east from where the short term guidance shows up.

[SnowenOutThere]

33 minutes ago, Eskimo Joe said:

Seems the meso guidance pushing PWATS close to 3", while the globals only around 2". Wonder if that's a resolution issue, or if the short term guidance is keying in on something the globals might be missing out on.

It has felt supper humid so I guess it makes since that the PWATS are so high. What is the record for them around this time of year 

[SomeguyfromTakomaPark]

GFS likes moco

[Eskimo Joe]

Wonder if LWX is waiting for the Euro to come out before they make a decision on any watches.

[Eskimo Joe]

40 minutes ago, SnowenOutThere said:

It has felt supper humid so I guess it makes since that the PWATS are so high. What is the record for them around this time of year 

You can use the sounding climo page on SPC website:  https://www.spc.noaa.gov/exper/soundingclimo/