Thursday washout: much needed rain

[MN Transplant]

22 minutes ago, SnowenOutThere said:

Genuinely curious as it always seems like the NAM 3k has the most orthographic precip out of all models always (including the other high res ones). Is it actually more accurate or is it overdoing it?

It is overly sensitive to terrain.

[SnowenOutThere]

27 minutes ago, MN Transplant said:

It is overly sensitive to terrain.

So would the HRRR be preferable over it or is it still worth blending. 

[Eskimo Joe]

12 minutes ago, SnowenOutThere said:

So would the HRRR be preferable over it or is it still worth blending. 

HRRR is preferred

[nw baltimore wx]

Well, I did it.

No, I didn’t start the snow blower, but I did clean the gutters.  

[weatherCCB]

3 minutes ago, nw baltimore wx said:

Well, I did it.

No, I didn’t start the snow blower, but I did clean the gutters.  

Same here. Hope we didn’t jinx the rain.

[yoda]

18 minutes ago, nw baltimore wx said:

Well, I did it.

No, I didn’t start the snow blower, but I did clean the gutters.  

 

[stormy]

3 hours ago, BlizzardNole said:

Too bad you can't hunt in my neighborhood.  We must have about one tree demon squirrel for every 100 square feet.

I have been squirrel hunting for decades.  Introduced by my dad.  They are a gourmets delight prepared properly.

Population varies from year to year based largely on last years hard mast crop. More mast last year, more squirrels this year.

[SnowenOutThere]

1 hour ago, Eskimo Joe said:

HRRR is preferred

What mechanism causes the NAM to mess it up? I’m learning more about actual meteorology in college rn so Im interested to what physics part is messes up

[high risk]

4 hours ago, SnowenOutThere said:

What mechanism causes the NAM to mess it up? I’m learning more about actual meteorology in college rn so Im interested to what physics part is messes up

      Personally, I look at both the HRRR and NAM Nest as my go-to CAMs.   The 3 Hi-Res Windows are lower on my list.

     The HRRR and NAM Nest both have their strengths and weaknesses.    The HRRR has a big advantage in running hourly, and there are things it does to create a more accurate starting point (a sophisticated assimilation of radar data, heavy usage of surface obs....)    The NAM Nest hasn't been updated in 8 years.  The HRRR hasn't had a recent update but was last updated 4 years ago.

     In terms of biases with rainfall, NAM Nest tends to run wet, but the HRRR sometimes runs dry - might be microphysics, but tough to confirm.   And the HRRR is very sensitive to the hourly updates, so its solutions bounce around a lot.    The NAM Nest tends to be too cool with sfc temps, but it handles low-level inversions way better than the HRRR due to a better PBL scheme.  And as noted earlier, the NAM Nest tends to overdo orographic precip due to a very sharp topography field that was put in to enhance winds over terrain.    That's just a few things off of the top of my head.    

[IronTy]

Heavy rain, cool and windy out right now.  Feels like a proper fall storm for once.  

[wxdude64]

5 hours ago, stormy said:

I have been squirrel hunting for decades.  Introduced by my dad.  They are a gourmets delight prepared properly.

Population varies from year to year based largely on last years hard mast crop. More mast last year, more squirrels this year.

We had a guy at work that made awesome squirrel gravy and biscuits.

[wxdude64]

Looks like somewhere between 0.33-0.40 in the gauge eyeballing it with a flashlight from living room window. A steady rain falling since 5 pm or so. Currently 46.2/45.4 degrees at 10:35 pm. 

[North Balti Zen]

Rain. Nice to see a system actually hit our area flush again. Looks like particularly heavy rain after 3 am up toward Fallston. 

[North Balti Zen]

RAIN 

sheets of heavy rain now 

[Jrlg1181]

Right at 1 inch down here now...

Cold rainy night...

[HokieEnginerd]

Huh.  Just got a clap of thunder near Gainesville.

[North Balti Zen]

Hoo boy - so weird to actually get a notable system. So much rain, Regionals for boys and girls hs cross country is this afternoon at pikesville HS and that route is gonna be an absolute mess 

[JenkinsJinkies]

1 hour ago, North Balti Zen said:

Hoo boy - so weird to actually get a notable system. So much rain, Regionals for boys and girls hs cross country is this afternoon at pikesville HS and that route is gonna be an absolute mess 

It’s normally quite easy to get decent rain around here. Now if this were happening in winter this wouldn’t be a slam dunk for a big snow because there’s more to go wrong when it comes to that.

[WxUSAF]

Thought I’d wake up to finally seeing a complete precip shield but nope! 0.8-0.9” so far. 

[snowfan]

Looks like many of us stand a good chance to dry out this afternoon. And someone in the 95 corridor is going to get above 70. 

[mappy]

1.09” since midnight 

[H2O]

It’s rained. That’s all I know. Not having a functioning wx station is a bummer 

[yoda]

Morning LWX and SPC discussion mentioned a few supercells possible with brief tornado threat

The southern low will serve as the triple point, eventually
merging with the western low and tracking toward southern
Pennsylvania this afternoon. It will draw a warmer and more
moist airmass northward with it, representing the area with the
highest risk of severe weather. So far, nothing on region radar
suggests the development of deeper/more organized convection.
But this threat will be worth watching through the morning hours
as the airmass rapidly changes. Most HREF parameters have
increased compared to 24 hours ago in suggesting
thunderstorm/severe weather potential. Damaging winds will be
the main threat given strong wind fields/shear aloft, but there
could also be a brief tornado risk near the triple point. The
main time window seems to be between 5 AM and 1 PM. Some
guidance indicates a trailing line of convection that crosses
during the afternoon hours with the first front/wind shift, but
it`s not clear how much this can organize as the better low
level wind fields may have already passed. In terms of rainfall,
some localized amounts over 1 inch have been observed. Overall
heavier elements are localized and very fast moving, so the
short term flooding risk seems low. Will have to continue to
monitor this threat though, as locations that end up in the 2-3
inch bin could see some minor high water issues. Most locations
should end up in the 60s today as there should be breaks of sun
this afternoon, with some places along the I-95 corridor
potentially near 70.

[yoda]

 Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1220 AM CDT Thu Oct 30 2025

   Valid 301200Z - 311200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF THE MIDDLE ATLANTIC...

   ...SUMMARY...
   Thunderstorms with an isolated damaging wind/tornado threat may
   occur from coastal North Carolina into parts of the Mid Atlantic.

   ...Middle Atlantic...

   Seasonally strong upper low over eastern TN is beginning to eject
   northeast, partly in response to an upstream speed max digging
   southeast across the northern High Plains. This lead low will
   advance into WV by 18z before moving into upstate NY by the end of
   the period. Favorable high-level diffluence/large-scale ascent will
   encourage a surface low to be drawn north-northwest across the
   Middle Atlantic to a position near the MD/PA border by mid day. This
   track will permit higher theta-e air mass to overspread eastern
   VA/Delmarva into southeast PA such that buoyancy will become
   supportive of deep convection.

   Early-day shear will prove strongest across the Middle Atlantic as
   LLJ will be focused across eastern MD into central PA. LLJ will
   shift quickly north into NY by 18z along with more focused low-level
   warm advection. Prior to this, forecast soundings exhibit strongly
   sheared environment with adequate instability for thunderstorms.
   While the maximum SBCAPE should peak near 500-600 J/kg, a few robust
   updrafts are possible given the strength of the wind fields.
   Isolated strong/severe thunderstorms, possibly supercells, may
   generate damaging winds and perhaps a tornado or two. Greatest risk
   is between sunrise and 21z.

   ..Darrow/Wendt.. 10/30/2025

[SnowtoRain]

0.91"

[WVclimo]

Getting some thunder here.  0.50” so far.

[yoda]

Pretty decent line forming west of EZF 

[EastCoast NPZ]

Im out in Indiana, but it looks like a good drought-denter in-progress at home.  Nearby wx station at 1.25" so far.  Great to finally see a meaningful system.

[CAPE]

0.72" so far. Most of that has fallen in the last few hours.

[MN Transplant]

1.09” for the morning report.  Highest single day report since July 15th.