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Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 353 PM EDT Sat Jul 08 2023 Day 2 Valid 12Z Sun Jul 09 2023 - 12Z Mon Jul 10 2023 ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE MID-ATLANTIC INTO WESTERN NEW ENGLAND... ...20Z Update... ...Mid-Atlantic through New England... In coordination with all the forecast offices from DC/Baltimore north through New England, a Moderate Risk area was introduced with this afternoon's update for portions of the Mid-Atlantic into western New England. All guidance continues to hone in on a corridor of heavy rainfall caused by numerous training showers and thunderstorms developing across the Moderate Risk area Sunday afternoon for southern and western areas, then progressing through New England Sunday Night. Expect a widespread 2-4 inch event especially from eastern PA north through VT. However local amounts are likely to exceed 6 inches of rain, with the most likely areas for the higher rainfall totals through the Catskills/Poconos of NY/PA and also through the Green Mountains of VT. Much of this area has been very hard hit in recent days with heavy rainfall, with a large area over 300% of climatological normal rains per 2-week AHPS data. Adding a stalling front into the mix which will allow for training of abnormally high moisture air on the order of PWATs to 1.75 inches makes for a likely scenario for flash flooding, especially when adding terrain influences into the mix. With the full day's worth of HREF data first available at 12Z, it's notable that portions of east central VT have a 30% chance of exceeding 100-year annual return intervals for the amount of rain expected, with the Catskills/Poconos and Green Mountains all over 70% chance of exceeding 3 and 6 hour FFGs Sunday afternoon and evening. The steady signal of widespread rain and good model agreement on both timing and areal amounts added enough confidence to the forecast to upgrade to the Moderate Risk for this update.

Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 353 PM EDT Sat Jul 08 2023 Day 2 Valid 12Z Sun Jul 09 2023 - 12Z Mon Jul 10 2023 ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE MID-ATLANTIC INTO WESTERN NEW ENGLAND... ...20Z Update... ...Mid-Atlantic through New England... In coordination with all the forecast offices from DC/Baltimore north through New England, a Moderate Risk area was introduced with this afternoon's update for portions of the Mid-Atlantic into western New England. All guidance continues to hone in on a corridor of heavy rainfall caused by numerous training showers and thunderstorms developing across the Moderate Risk area Sunday afternoon for southern and western areas, then progressing through New England Sunday Night. Expect a widespread 2-4 inch event especially from eastern PA north through VT. However local amounts are likely to exceed 6 inches of rain, with the most likely areas for the higher rainfall totals through the Catskills/Poconos of NY/PA and also through the Green Mountains of VT. Much of this area has been very hard hit in recent days with heavy rainfall, with a large area over 300% of climatological normal rains per 2-week AHPS data. Adding a stalling front into the mix which will allow for training of abnormally high moisture air on the order of PWATs to 1.75 inches makes for a likely scenario for flash flooding, especially when adding terrain influences into the mix. With the full day's worth of HREF data first available at 12Z, it's notable that portions of east central VT have a 30% chance of exceeding 100-year annual return intervals for the amount of rain expected, with the Catskills/Poconos and Green Mountains all over 70% chance of exceeding 3 and 6 hour FFGs Sunday afternoon and evening. The steady signal of widespread rain and good model agreement on both timing and areal amounts added enough confidence to the forecast to upgrade to the Moderate Risk for this update.

Flood Watch National Weather Service Baltimore MD/Washington DC 323 PM EDT Sat Jul 8 2023 DCZ001-MDZ004>006-008-011-013-014-016>018-503>508-VAZ053>055-501-502- 505-506-526-527-090330- /O.NEW.KLWX.FA.A.0002.230709T1600Z-230710T0200Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ District of Columbia-Frederick MD-Carroll-Northern Baltimore-Cecil- Southern Baltimore-Prince Georges-Anne Arundel-Charles-St. Marys- Calvert-Northwest Montgomery-Central and Southeast Montgomery- Northwest Howard-Central and Southeast Howard-Northwest Harford- Southeast Harford-Fairfax-Arlington/Falls Church/Alexandria-Stafford- Northern Fauquier-Southern Fauquier-Western Loudoun-Eastern Loudoun- Northwest Prince William-Central and Southeast Prince William/Manassas/Manassas Park- Including the cities of Reisterstown, Silver Spring, Haymarket, Greenbelt, Washington, Lexington Park, Falls Church, Ellicott City, Frederick, Franconia, California, Leesburg, Montclair, Suitland-Silver Hill, Warrenton, North Beach, Dale City, Ballenger Creek, Lisbon, Woodbridge, Germantown, Centreville, Chesapeake Beach, Manassas, Severna Park, Ashburn, Jarrettsville, Purcellville, Columbia, Camp Springs, Reston, Bethesda, Eldersburg, Dunkirk, Herndon, Cockeysville, Arlington, McLean, Elkton, College Park, St. Charles, Gaithersburg, Rockville, Falmouth, South Gate, Odenton, Bowie, Chantilly, Glen Burnie, Prince Frederick, Aberdeen, Annandale, Clinton, Damascus, Alexandria, Turnbull, Laurel, Westminster, Lake Ridge, Severn, Huntingtown, Annapolis, Arnold, Waldorf, Baltimore, Sterling, and Lusby 323 PM EDT Sat Jul 8 2023 ...FLOOD WATCH IN EFFECT FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING... * WHAT...Flash flooding caused by excessive rainfall is possible. * WHERE...Portions of DC, Maryland and northern Virginia, including the following areas: in DC, District of Columbia. In Maryland, Anne Arundel, Calvert, Carroll, Cecil, Central and Southeast Howard, Central and Southeast Montgomery, Charles, Frederick MD, Northern Baltimore, Northwest Harford, Northwest Howard, Northwest Montgomery, Prince Georges, Southeast Harford, Southern Baltimore and St. Marys. In northern Virginia, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park, Eastern Loudoun, Fairfax, Northern Fauquier, Northwest Prince William, Southern Fauquier, Stafford and Western Loudoun. * WHEN...From Sunday afternoon through Sunday evening. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. * ADDITIONAL DETAILS... - Slow moving thunderstorms capable of producing very heavy rainfall are expected across the watch area Sunday afternoon into Sunday evening. A widespread 1 to 2 inches of rainfall is expected across the watch area, with isolated totals in excess of 4 inches possible. This heavy rainfall may lead to rapid rises of water on creeks, streams, urban and poor drainage areas, and in other flood-prone locations. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.

@CAPE should be getting some good rain

Impossible since that jackpots @BlizzardNole

I am guessing some what look like mamamtus clouds by Nats Park? I'm at the game tonight and this is what I see over the LF foul pole

Baseball to softball sized hail at night

Outflow boundary pushing through you and me right now on Radarscope

Hope you had a great birthday @WxWatcher007! Hope you are having a great chase day as well

FWIW, no changes on the 20z SPC OTLK

Warned now for gusts to 60mph BULLETIN - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Warning National Weather Service Baltimore MD/Washington DC 302 PM EDT Mon Jul 3 2023 The National Weather Service in Sterling Virginia has issued a * Severe Thunderstorm Warning for... Central Fauquier County in northern Virginia... Northern Culpeper County in northern Virginia... * Until 345 PM EDT. * At 302 PM EDT, a severe thunderstorm was located near Warrenton, moving east at 20 mph. HAZARD...60 mph wind gusts. SOURCE...Radar indicated. IMPACT...Damaging winds will cause some trees and large branches to fall. This could injure those outdoors, as well as damage homes and vehicles. Roadways may become blocked by downed trees. Localized power outages are possible. Unsecured light objects may become projectiles. * Locations impacted include... Warrenton, New Baltimore, Opal, Catlett, Calverton, Turnbull, Airlie, Broken Hill, Auburn and Casanova. PRECAUTIONARY/PREPAREDNESS ACTIONS... For your protection move to an interior room on the lowest floor of a building. && LAT...LON 3861 7757 3865 7793 3874 7794 3881 7770 TIME...MOT...LOC 1902Z 268DEG 17KT 3870 7789 HAIL THREAT...RADAR INDICATED MAX HAIL SIZE...<.75 IN WIND THREAT...RADAR INDICATED MAX WIND GUST...60 MPH

70/30 wind probs are decent

Comes out on kamala usually 5-10 minutes before SPC puts it up https://kamala.cod.edu/SPC/

Watch up till 10pm

I'd watch the cell entering Culpepper county... looks like its increasing VIL and could have a small hail core soon

Watch coming soon... 95% per SPC MCD https://www.spc.noaa.gov/products/md/md1401.html Mesoscale Discussion 1401 NWS Storm Prediction Center Norman OK 1242 PM CDT Mon Jul 03 2023 Areas affected...Portions of the Mid-Atlantic Concerning...Severe potential...Severe Thunderstorm Watch likely Valid 031742Z - 031945Z Probability of Watch Issuance...95 percent SUMMARY...Scattered storms will develop in a hot, moist environment. Scattered damaging winds and isolated large hail will be possible. One or more severe thunderstorm watches are likely for much of the Mid-Atlantic in the next 1-2 hours. DISCUSSION...Early-afternoon satellite imagery shows developing cumulus along the Appalachians. Some stable billow clouds remain in central/northern Virginia, but they have shown a dissipating trend over the last hour. Farther south, a weak MCV is slowly moving east in central North Carolina. Some convection has recently developed along the northeastern flank of this feature where temperatures are in the low 90s F. Due to modest rising mid-level heights, it seems that convection may still take some time to mature, with the MCV-related storms potentially being an exception. Modest mid-level winds remaining across the region (diminishing with southward extent) will lead to 30-35 kts of effective shear. Strong surface heating and dewpoints in the upper 60s to low 70s F will support 1000-2000 J/kg MLCAPE (greater with southward extent). Scattered thunderstorms are expected over the next few hours with the potential for strong/severe wind gusts. Large hail is possible with supercell structures, but will be more isolated in nature. A severe thunderstorm watch is likely for much of the Mid-Atlantic region in the next 1-2 hours. ..Wendt/Grams.. 07/03/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...AKQ...LWX...RAH...RNK...

Oh I see SPC... 30 wind and 15 hail (which was made much smaller)

Impressive... most Impressive lol Some clearing here... can see some blue sky off to my west

Updated morning portion of the LWX AFD... rest of it after this is the same as the early morning disco NEAR TERM /THROUGH TONIGHT/... In response to the remnant mesoscale convective vortex (MCV), light radar returns are noted across the region. Based on their appearance, these should not amount to much in terms of precipitation amounts. Like yesterday, cloud cover is fairly extensive, although there are some breaks seen on the visible satellite imagery. Considering the thermodynamic environment as shown on the 12Z IAD sounding, mid-level lapse rates are somewhat marginal, averaging around 6 C/km. Low-level lapse rates should quickly steepen given daytime heating which would yield higher downdraft CAPE (DCAPE). Capping also appears to be less of an issue, accompanied by plenty of 0-6 km shear which runs around 35 knots. But overall, much will depend on scouring some of this early/mid morning cloud cover.

Lol at the impressive UD Helicity swath just north of the DC metro this afternoon on the 06z NAM NEST

We try again today lol... 2/15/15 from SPC with talk of a few supercells possible Morning AFD from LWX below: For the rest of today through tonight, an upper-level trough will slide through the Ohio Valley into New England while high pressure remains offshore. A south to southwest flow will continue to usher in very warm and humid conditions to the area. There should be enough breaks of sunshine this morning, and also behind the aforementioned MCV this afternoon for the atmosphere to destabilize. Latest guidance shows around 1.5-3 KJ/KG of MLCAPE developing ahead of a weak cold front/surface trough that will most likely move into the area later this afternoon into this evening from the west (associated with upper-level trough axis to our north). The moderate CAPE will combine with stronger shear profiles, increasing the threat for some severe storms with damaging wind gusts and large hail being the primary threats. However, the low-level flow may be backed somewhat, increasing low-level shear, so an isolated tornado cannot be ruled out. The best chance for severe storms and an isolated tornado will be around mid afternoon through this evening near and east of the Blue Ridge/Catoctin Mountains (where instability will be highest east of the weak cold front/surface trough). When comparing the atmosphere to yesterday thermodynamically, it is similar. There was a small stable layer along with mid- level clouds at times that caused convection to be more sporadic. There is a similar setup today, but it does appear that the low-level forcing will be a bit stronger with the weak boundary moving in. Therefore, we went areal with the pops with scattered to numerous showers and thunderstorms (highest pops near/east of Blue Ridge and Catoctins). Convection should wane later tonight with the loss of daytime heating. Warm and humid conditions will persist with patchy fog possible, especially in areas that do receive rainfall

Severe Thunderstorm Watch issued till 11pm for the NE third of the region including the DC and BWI metros

00z NAM NEST also has two rounds between 18z and 02z