July Discobs 2025

[weatherCCB]

Picked up a quick 0.50” in about 20 minutes 

[nw baltimore wx]

Here’s a shot of the storm in the Laurel area. Saw some broad lightning from my vantage point. Here’s the kicker. This picture is from Broadkill Beach on the Delaware Bay. It was the only thunderstorm on radar in that direction from where I was.

[pazzo83]

just stepped outside.  this is a brutal, brutal stretch.

[pazzo83]

looks like the drier air is moving in - enjoy it while we have it folks.

[Jebman]

I am so happy for you all, getting decent storm action. Hope you get more and stay safe!

[yoda]

Uh oh

.NEAR TERM /THROUGH TONIGHT/...
Early morning RAP and observations analysis shows a stalled frontal
boundary draped along the PA/MD border, stretching westward across
the OH Valley. This region and the Mid-Atlantic are sandwiched
between the Bermuda High (which is well west of its normal climo
position in the western Atlantic) and a weaker surface high over the
Upper Great Lakes. Abundant high level clouds this morning are
expected to persist all day, with building low level clouds once
mixing starts shortly after sunrise. This is going to keep highs
lower today, mainly in the low to mid 80s. Peak heat indices reach
the mid to upper 90s in Central VA.

Southerly flow into the stalled boundary continues to advect deep
tropical moisture into the region, so expect PWATs to jump well over
2" once again this afternoon. Aloft, a well timed shortwave trough
looks to move across our area during peak heating and the main
convective time window this afternoon to early evening. Modest deep-
layer westerly shear around 30 knots will be enough to support
organized deep convection, especially over the Shenandoah Valley and
Central VA. More than enough instability is going to be present in
this hot and humid airmass, with SBCAPE values of 1000-2000 J/kg.
This is where SPC has a Slight Risk (level 2 of 5) for severe storms
today, with damaging wind gusts as the main threat. The threat for
thunderstorms really drops off quickly north/east of the Potomac
River, with the Baltimore Metro to NE MD likely to stay clear for
the most part today.

The main threat is going to be flash flooding, which could be very
significant in parts of the Shenandoah Valley. The tropical airmass
will easily support rainfall rates of 1-2+" in 30 minutes, with
hourly rainfall rates of 3-4" possible in the heaviest
thunderstorms. Any area that sees either multiple rounds or training
thunderstorms is likely to experience some flooding.

Particularly worrying is the RRFS ensembles showing up to 40pct
chance of seeing 100yr RI rainfall amounts (which equates to roughly
5" or more of rain) in the central Shenandoah Valley. The HREF max
QPF also indicates the high-end potential of 4-7" of rain. Now these
extreme amounts won`t be widespread and might not occur, but the
potential is definitely there for worst-case scenario flash
flooding. As a result, a Moderate Risk of flash flooding has been
coordinated with WPC for the Central Shenandoah Valley, Blue Ridge
Mountains, and portions of the Central VA Piedmont. Elsewhere, a
Slight Risk of flash flooding extends north/east to around the
Potomac River. A (Flash) Flood Watch has been issued.

Scattered showers and thunderstorms could linger late into the
evening. Some CAMs indicate outflow boundaries generating additional
convection into the DC Metro and Southern MD late into the evening.
Muggy conditions continue tonight as temps settle in the upper 60s
to mid 70s. Low clouds and patchy fog are possible late tonight.

[MillvilleWx]

7 minutes ago, yoda said:

Uh oh

.NEAR TERM /THROUGH TONIGHT/...
Early morning RAP and observations analysis shows a stalled frontal
boundary draped along the PA/MD border, stretching westward across
the OH Valley. This region and the Mid-Atlantic are sandwiched
between the Bermuda High (which is well west of its normal climo
position in the western Atlantic) and a weaker surface high over the
Upper Great Lakes. Abundant high level clouds this morning are
expected to persist all day, with building low level clouds once
mixing starts shortly after sunrise. This is going to keep highs
lower today, mainly in the low to mid 80s. Peak heat indices reach
the mid to upper 90s in Central VA.

Southerly flow into the stalled boundary continues to advect deep
tropical moisture into the region, so expect PWATs to jump well over
2" once again this afternoon. Aloft, a well timed shortwave trough
looks to move across our area during peak heating and the main
convective time window this afternoon to early evening. Modest deep-
layer westerly shear around 30 knots will be enough to support
organized deep convection, especially over the Shenandoah Valley and
Central VA. More than enough instability is going to be present in
this hot and humid airmass, with SBCAPE values of 1000-2000 J/kg.
This is where SPC has a Slight Risk (level 2 of 5) for severe storms
today, with damaging wind gusts as the main threat. The threat for
thunderstorms really drops off quickly north/east of the Potomac
River, with the Baltimore Metro to NE MD likely to stay clear for
the most part today.

The main threat is going to be flash flooding, which could be very
significant in parts of the Shenandoah Valley. The tropical airmass
will easily support rainfall rates of 1-2+" in 30 minutes, with
hourly rainfall rates of 3-4" possible in the heaviest
thunderstorms. Any area that sees either multiple rounds or training
thunderstorms is likely to experience some flooding.

Particularly worrying is the RRFS ensembles showing up to 40pct
chance of seeing 100yr RI rainfall amounts (which equates to roughly
5" or more of rain) in the central Shenandoah Valley. The HREF max
QPF also indicates the high-end potential of 4-7" of rain. Now these
extreme amounts won`t be widespread and might not occur, but the
potential is definitely there for worst-case scenario flash
flooding. As a result, a Moderate Risk of flash flooding has been
coordinated with WPC for the Central Shenandoah Valley, Blue Ridge
Mountains, and portions of the Central VA Piedmont. Elsewhere, a
Slight Risk of flash flooding extends north/east to around the
Potomac River. A (Flash) Flood Watch has been issued.

Scattered showers and thunderstorms could linger late into the
evening. Some CAMs indicate outflow boundaries generating additional
convection into the DC Metro and Southern MD late into the evening.
Muggy conditions continue tonight as temps settle in the upper 60s
to mid 70s. Low clouds and patchy fog are possible late tonight.

Area of greatest concern will be between Winchester down to Staunton, preferably I-66 to I-64. Strong consensus in the CAMs on that area being the focal point. I wouldn't rule out areas into WV being targeted as well with the ML depicting a relatively solid signal for a QPF maxima along I-79 and the interior. This is a very rich moisture environment with the KIAD sounding topping 2.37", putting it at the all-time daily max to date and in the 99th percentile for the week encompassing 7/14-21. Someone is going to get nailed pretty good today with heavy rains and flash flood prospects. 

[yoda]

 

https://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=qpferd

 

[nj2va]

17 hours ago, mdhokie said:

Can't even escape the humidity in the mountains.. @nj2va I don't remember summers this humid, you've been out here longer, do you?

It’s gotten noticeably more humid the last few summers. We have our AC running most times we’re there now in the summer. We used to rarely use it. Next year is our 10th year having our house there, which seems crazy! Feels like it was just yesterday. 

[stormy]

Another day and another Flood Watch.  Maybe this time more than sprinkles?   Yes, I broadcast at 6:45.  Expected rainfall next 24 hrs., 1 to possibly 6 inches!

The WPC and Sterling FD bullseyes my area for flooding rainfall.  

RRFS ensembles indicate a 40% chance of 100 yr. amounts

HREF Max Qp indicates 4 - 7 inches.

The ICON is the only normally sampled model that has any interest. The GFS, ECM, GEM, NAM and HRRR are not impressed with potential.

If today is another bust for Augusta County, my explanation for my newsletter will be tough!   Hopefully, it occasionally pours from 3 - 9 pm.

[katabatic]

2 hours ago, nj2va said:

It’s gotten noticeably more humid the last few summers. We have our AC running most times we’re there now in the summer. We used to rarely use it. Next year is our 10th year having our house there, which seems crazy! Feels like it was just yesterday. 

This is only my third summer living here but there have been multiple days it's felt like Florida. In the little hut I live in, I don't have central air but the window units are on constant overdrive. My neighbor, Anastasia Beaverhausen, only has fans, so this has been a tough summer.

[yoda]

12z sounding PWATs at RNK was 1.60... WAL 2.12... IAD 1.99