7/29 Enhanced Risk Observations

[Rainshadow]

Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1226 AM CDT Thu Jul 29 2021

   Valid 291200Z - 301200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER A PORTION
   OF THE MIDDLE ATLANTIC REGION...

   ...SUMMARY...
   Thunderstorms associated with wind damage and a risk for a tornado,
   will be possible from the Ohio Valley, central Appalachians and
   Mid-Atlantic states on Thursday.

   ...Northeast through Middle Atlantic area...

   Upper pattern in this region will be characterized by a broad trough
   today. MCV/shortwave trough embedded within the synoptic trough will
   move from the lower Great Lakes to the Middle Atlantic. At the
   surface a warm front will move northward through the Middle
   Atlantic, while a cold front advances southeast, reaching PA and the
   central Appalachians by evening. Thunderstorms should be in progress
   at the start of the period in association with the MCV over the
   southern portion of the Great Lakes. Other storms may be ongoing in
   the warm-advection regime north of the warm front over a portion of
   the Middle Atlantic. Widespread multi-layer clouds may precede the
   warm front. However, the warm sector should become moderately
   unstable during the afternoon with 1000-2000 J/kg MLCAPE supported
   by the advection of richer low-level moisture and pockets of
   diabatic heating. Thunderstorms are expected to develop ahead of the
   cold front in association with ascent attending the southeast-moving
   MCV as well as along the southeast-advancing cold front. This area
   will reside within belt of stronger mid-upper flow associated with
   the synoptic trough supporting 40-45 kt effective bulk shear.
   Therefore, some supercells may evolve along with line segments with
   bowing structures as activity develops southeast during the
   afternoon into the evening. Primary threat appears to be damaging
   wind and possibly some hail, though low-level hodographs will be
   sufficient for a few tornadoes, especially if sufficient instability
   can develop in vicinity of the warm front.  

[tombo82685]

The latest HRRR depiction makes the most sense to me right now. But I like to use noon to 1pm as my go to point to figure if things are going to pan out. Cloud cover looks like biggest issue to me. Can already see cloud debris racing In through susq valley towards our region while low clouds continue to develop over the area in response to low level moist flow advecting up from south. Just seems awfully cloudy 

[ACwx]

I like using the 1-minute imagery for a lot of situations but especially for days like today. Seems like the best clearing will be from latitudes around Dover, DE on southward. North of there will be more iffy thanks to clouds.

https://rammb.cira.colostate.edu/ramsdis/online/loop.asp?data_folder=goes-16/mesoscale_01_band_02_sector_05&width=1000&height=1000&number_of_images_to_display=40&loop_speed_ms=80

[tombo82685]

SPC has pushed enhanced risk bit further north with morning update. Now it goes to just north of allentown

[tombo82685]

off latest 12z 3k nam, but this looks a bit more potent for wind damage. Look at the punch of dry air aloft towards the mid levels 

[Allsnow]

1 hour ago, tombo82685 said:

The latest HRRR depiction makes the most sense to me right now. But I like to use noon to 1pm as my go to point to figure if things are going to pan out. Cloud cover looks like biggest issue to me. Can already see cloud debris racing In through susq valley towards our region while low clouds continue to develop over the area in response to low level moist flow advecting up from south. Just seems awfully cloudy 

Feeling the east wind and clouds here currently. Imo this threat is cooked 

[tombo82685]

Gotta see if this area clears out. This is what could bring the instability if it does 

[tombo82685]

Just now, Allsnow said:

Feeling the east wind and clouds here currently. Imo this threat is cooked 

Up your way agreed, more stratiform rain for you instead of svr 

[greg ralls]

Mt. Holly Facebook page says to keep an eye on the weather today for a possible severe thunderstorm watch, but if I were a betting person, I’d bet on tornado watch based on the 5% SPC probability which is high for around these parts.

[Colin]

Still pretty cloudy here

[chescowx]

Both down the shore in Sea Isle and up in East Nantmeal plenty of clouds - even without those still expect we see some firing as we move through the day - hopefully Phillies squeeze in their twin bill!

 

[eastonwx]

Skies trying to brighten but still mainly cloudy, 75F

[Seanvolz98]

I’d call it a bright cloudy here in Manayunk at the moment... not too thrilled about our clearing prospects based off satellite. Pretty stark temperature contrasts of low mid 70s in our area and mid 80s in Baltimore where there’s more sun 

[mshaffer526]

Up to 79 here....sun is starting to feel stronger, although still filtered.

[cbelke]

Cloudy with a slight breeze. Only 76 right now.  

[mshaffer526]

Kinda feels like the Delmarva is situated in the best spot.  Much more sun/heat down there.

[tombo82685]

3 minutes ago, mshaffer526 said:

Kinda feels like the Delmarva is situated in the best spot.  Much more sun/heat down there.

But they are also further displaced from dynamics and backing of winds in relation to warm front

[cbelke]

3 minutes ago, tombo82685 said:

But they are also further displaced from dynamics and backing of winds in relation to warm front

But if we don't get some sun soon, there isn't going to be much happening.

[frankdp23]

Light rain shower here.

[eastonwx]

Is it a bit telling that there isn’t a watch issued by Mt. Holly yet?

[Qtown Snow]

[Colin]

Looks like some showers.  Grass will like it

[Colin]

13 minutes ago, eastonwx said:

Is it a bit telling that there isn’t a watch issued by Mt. Holly yet?

SPC issues watches 

[tombo82685]

It should bulk up a bit once past Harrisburg but I’ll sell on enhanced risk. Think slight risk was best call

[Chubbs]

80 - if anything the high clouds have thickened a bit recently